Methods and systems for providing respiratory support

Abstract

A method for providing respiratory support to a patient during a medical procedure includes: providing a gas flow to the patient via a patient interface system having at least one outflow vent; controlling the gas flow at a first supply flow rate and generating a first interface pressure and an exhaust flow through the at least one outflow vent at a first exhaust flow rate; and controlling the gas flow at a second supply flow rate and generating a second interface pressure and an exhaust flow through the at least one outflow vent at a second exhaust flow rate. A first predetermined flow resistance of the at least one outflow vent at the first exhaust flow rate is different from a second predetermined flow resistance of the at least one outflow vent at the second exhaust flow rate.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Application No. 63 / 601,152, filed November 20, 2023, the contents of which are deemed to be incorporated herein by reference. Technical Field

[0003] This invention relates to methods, systems, and apparatus for providing respiratory support to patients. The invention particularly, but not exclusively, relates to providing respiratory support involving high-flow-rate gases. Background Technology

[0004] Patients with impaired respiratory function or at risk of impaired respiratory function may benefit from high-flow respiratory support (which may include high-flow therapy). Nasal high-flow (NHF) is a form of high-flow respiratory support and can be beneficial for patients undergoing anesthetic procedures, including sedation and general anesthesia, by improving dead space clearance in the airway and reducing the risk of hypoxemia, for example. High-flow respiratory support can also be used in the ICU, wards, emergency rooms, or any other situation requiring respiratory support.

[0005] However, in certain situations, such as during anesthesia, some patients remain at risk of residual hypoxemia during apnea or spontaneous breathing, even if they are receiving NHF respiratory support. This may be due to physiological reasons such as upper and / or lower airway obstruction, mouth breathing, and pulmonary shunting. This can lead to complications due to insufficient intrapulmonary oxygen reserves, low levels of O2 delivered to the lungs, and rapid desaturation of blood oxygen levels to low levels. The aim is to reduce the risk of patient impairment associated with these complications.

[0006] Any discussion or reference in this document to any literature, action, material, device, article of manufacture, or any other matter considered prior art, including any discussion in the background of the invention, is intended to interpret the context of this application. It should not be construed as an admission or implication that any material is part of public, known, or common general knowledge. Summary of the Invention

[0007] Embodiments of the present invention relate to systems, methods, and apparatus for providing respiratory support to patients suffering from or at risk of respiratory impairment.

[0008] In one aspect, the present invention provides a method for providing respiratory support to a patient during a medical procedure, the method comprising: providing a gas flow to a patient via a patient interface system having at least one outflow vent; controlling the gas flow at a first supply flow rate and generating a first interface pressure and an exhaust flow through the at least one outflow vent at a first exhaust flow rate; and controlling the gas flow at a second supply flow rate and generating a second interface pressure and an exhaust flow through the at least one outflow vent at a second exhaust flow rate; wherein a first predetermined flow resistance of the at least one outflow vent at the first exhaust flow rate is different from a second predetermined flow resistance of the at least one outflow vent at the second exhaust flow rate.

[0009] In another aspect, the present invention provides a method for providing respiratory support to a patient during a medical procedure, the method comprising: providing a gas flow to a patient via a patient interface system having at least one outflow ventilator; controlling the gas flow at a first supply flow rate and generating a first interface pressure and an exhaust flow at a first exhaust flow rate through at least one outflow ventilator; controlling the gas flow at a second supply flow rate and generating a second interface pressure and an exhaust flow at a second exhaust flow rate through at least one outflow ventilator; wherein a second rate of change of the second interface pressure associated with the second exhaust flow rate is greater than a first rate of change of the first interface pressure associated with the first exhaust flow rate.

[0010] In some embodiments, the method includes controlling the gas flow at a first supply flow rate before the second supply flow rate. In some embodiments, the method includes controlling the gas flow at a second supply flow rate before the first supply flow rate. In some embodiments, the second supply flow rate may be higher than the first supply flow rate, or vice versa.

[0011] In some embodiments, the first supply flow rate is greater than about 0 LPM, about 10 LPM, about 20 LPM, about 30 LPM, about 40 LPM, or about 50 LPM. In some embodiments, the second supply flow rate is greater than about 40 LPM, about 50 LPM, about 60 LPM, about 70 LPM, about 80 LPM, about 90 LPM, or about 100 LPM. However, these ranges are merely examples and do not limit the flow rates that can be provided according to embodiments of the invention.

[0012] In some embodiments, the method includes providing a second supply flow rate in response to an indication of a patient's condition. The patient's condition may include, for example, patient status or patient parameter values. An indication of a patient's condition may be determined by one or more of the following: observation of the patient and / or patient parameters; user confirmation of administration of a therapy (such as an anesthetic) to the patient; measurement of one or more patient parameters; a control device determining an indication of a patient's condition using data received from a user or one or more devices monitoring patient parameters; and the patient's self-report of their condition.

[0013] In some embodiments, one or more patient parameters include: depth of sedation; heart rate; EEG signal value; EKG / ECG signal value; EMG signal value; blood oxygen concentration; blood oxygen saturation (SpO2); exhaled oxygen concentration; blood CO2 concentration; transcutaneous CO2 concentration (TcCO2); transcutaneous O2 concentration (TcO2); exhaled CO2 concentration; and blood glucose level.

[0014] In some embodiments, patient condition includes conditions selected from the group consisting of: lower or upper airway obstruction; soft palate obstruction; absence of spontaneous breathing; unmet inspiratory needs; patient at risk of apnea; adequate sedation depth; and expiratory airway pressure at or nearing a suboptimal threshold.

[0015] In some embodiments, the method includes controlling a first and / or second supply flow rate by one or more of the following:

[0016] - In response to the user's confirmation of the patient's condition, the user manually selects the second supply flow rate;

[0017] - When the control device receives user input confirming the patient's condition, the control device determines the second supply flow rate; and

[0018] - When the control device determines the presence of a patient condition using data received from one or more devices that monitor patient condition parameters, the control device determines a second supply flow rate.

[0019] In some embodiments, the method includes providing a first supply flow rate before delivering the anesthetic to the patient and a second supply flow rate after delivering the anesthetic to the patient. In some embodiments, the method includes providing the second supply flow rate in response to an instruction that the anesthetic is being or has been delivered to the patient.

[0020] In some embodiments, an indication that an anesthetic is being or has been administered to the patient can be determined by one or more of the following:

[0021] - Clinicians observe patients and / or patient parameters and manually input instructions into the control device; and

[0022] - The control device uses data received from the user or one or more devices that monitor patient parameters, which provide an indication that an anesthetic is being or has been administered to the patient.

[0023] In some embodiments, the method includes providing respiratory support before anesthetic delivery and / or before the patient begins anesthesia or sedation.

[0024] In some embodiments, the method includes controlling the gas flow at a third supply flow rate and generating a third interface pressure and an exhaust flow through at least one outlet vent at a third exhaust flow rate, wherein the rate of change of the third interface pressure associated with a change in the third exhaust flow rate is less than the rate of change of the second interface pressure associated with a change in the second exhaust flow rate.

[0025] In some embodiments, the method includes controlling the gas flow at a third supply flow rate and generating a third interface pressure and an exhaust flow rate through at least one outflow vent at a third exhaust flow rate, wherein the third predetermined flow resistance of the at least one outflow vent at the third exhaust flow rate is different from the second predetermined flow resistance of the at least one outflow vent at a second exhaust flow rate.

[0026] In some embodiments, the third supply flow rate is lower than the second supply flow rate.

[0027] In some embodiments, the method includes providing a third supply flow rate in response to indications of different patient conditions. These different patient conditions may include conditions selected from the group consisting of: a patent lower or upper airway; a clear soft palate; spontaneous breathing; the patient's inspiratory needs being met; a predetermined alertness level being met; and expiratory interface pressure being met or exceeding an optimal threshold.

[0028] In some embodiments, for a first exhaust flow rate value in the range of about 0 LPM to about 40 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, the first rate of change of the first interface pressure may be in the range of about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

[0029] In some embodiments, for a second exhaust flow rate value in the range of greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM, the second rate of change of the second interface pressure may be in the range of greater than about 0.1 cmH2O / Lmin-1 to less than about 0.6 cmH2O / Lmin-1, or about 0.15 cmH2O / Lmin-1 to about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

[0030] In some embodiments, the corresponding interface pressure and exhaust flow rate of the first and second rates of change are related such that, when presented graphically, their relationship includes one or more of the following:

[0031] - The first rate of change and the second rate of change show a stepwise variation;

[0032] - The first rate of change and the second rate of change change gradually change;

[0033] - The first rate of change and the second rate of change exhibit a curved relationship;

[0034] - The first rate of change and / or a portion of the second rate of change have a non-constant gradient;

[0035] - The transition between the first and second exhaust velocities is non-stepwise;

[0036] - The transition between the second and third exhaust velocities is non-stepwise.

[0037] In some embodiments, one or both of the first rate of change and the second rate of change are non-constant.

[0038] In some embodiments, the method includes controlling the gas flow and producing one or more of the following:

[0039] - A first exhaust flow rate of approximately 40 LPM and a first interface pressure of approximately 3-5 cmH2O, such as approximately 4 cmH2O;

[0040] - A first exhaust flow rate of approximately 30 LPM and a first interface pressure of approximately 2-4 cmH2O, such as approximately 3 cmH2O;

[0041] - A second exhaust flow rate of approximately 50 LPM and a second interface pressure of approximately 5-8 cmH2O, such as approximately 6 cmH2O;

[0042] - A second exhaust flow rate of approximately 55 LPM and a second interface pressure of approximately 6-8 cmH2O;

[0043] - A second exhaust flow rate of approximately 60 LPM and a second interface pressure of approximately 7-9 cmH2O; and

[0044] - A second exhaust flow rate of approximately 70 LPM and a second interface pressure of approximately 7-15 cmH2O, such as approximately 9-12 cmH2O, such as approximately 9-10 cmH2O, or approximately 10-12 cmH2O.

[0045] In some embodiments, the method includes operating a flow source to provide a gas flow, wherein the flow source is controlled by a control device configured to receive control inputs provided by a user and / or control inputs generated by a processor.

[0046] In some embodiments, the patient interface system includes a patient interface configured to provide a gas flow to one or both nostrils of a patient, and includes at least one outflow vent configured to generate a predetermined interface pressure and a predetermined target exhaust flow rate from the at least one outflow vent in response to a predetermined supply flow rate to the patient interface.

[0047] In some embodiments, the patient interface includes at least one sealing element, such as a nasal pillow, nasal fork, nasal pad, nasal sleeve, or nasal prosthesis, configured to form a substantially sealed seal with the patient’s nostrils to substantially limit gas escape except through the at least one outflow vent.

[0048] In some embodiments, the method includes the step of placing a patient interface on a patient.

[0049] In some embodiments, the patient is undergoing a medical procedure, such as a scheduled medical procedure, while receiving respiratory support.

[0050] In some embodiments, the method includes providing the patient with an anesthetic.

[0051] In some embodiments, the gas flow provided at one or both of a first supply flow rate and a second supply flow rate includes a 100% O2 concentration.

[0052] In some embodiments, the rate of change is the average rate of change.

[0053] In some embodiments, the first predetermined flow resistance of at least one outlet vent at the first exhaust flow rate is in the range of greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

[0054] In some embodiments, the first exhaust flow rate is between about 0 LPM and about 40 LPM, or between about 30 LPM and about 40 LPM, or between about 35 LPM and about 45 LPM.

[0055] In some embodiments, the second predetermined flow resistance of at least one outlet vent at the second exhaust flow rate is in the range of greater than about 0.15 cmH2O / Lmin-1 to less than about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

[0056] In some embodiments, the second exhaust flow rate is between greater than about 40 LPM and about 100 LPM, or between about 40 LPM and about 70 LPM, or between about 40 LPM and about 60 LPM, or between about 50 LPM and about 70 LPM, or between about 50 LPM and about 60 LPM, or between about 60 LPM and about 70 LPM.

[0057] In some embodiments, the first flow resistance and the second flow resistance at the corresponding exhaust flow rate, and / or the first rate of change and the second rate of change, can be measured in a simulation test.

[0058] In some embodiments, the patient does not experience apnea during the provision of respiratory support.

[0059] In some embodiments, for a given exhaust flow rate, the flow resistance is attributed to the size and / or shape of at least one outflow vent.

[0060] In some embodiments, the total cross-sectional area of ​​at least one outflow vent is from about 20 to about 100 mm. 2 or about 35mm 2 approximately 80 mm 2 or about 35 mm 2 Approximately 60 mm 2 or about 35 mm 2 Approximately 50 mm 2 or about 35 mm2 Approximately 40 mm 2 or about 35 mm 2 Approximately 45 mm 2 Within the range.

[0061] In another aspect, the present invention provides a method for providing respiratory support to a patient, the method comprising: - providing a gas flow to a patient via a patient interface system, the patient interface system including at least one outflow vent and a sealing element that substantially restricts gas from escaping from the patient except via the at least one outflow vent; controlling the supply flow rate of gas to the patient interface system and generating an interface pressure and an exhaust flow at an exhaust flow rate through the at least one outflow vent; wherein the interface pressure and the exhaust flow rate constitute a non-linear relationship.

[0062] In some embodiments, the nonlinear relationship includes polynomial components, preferably quadratic polynomial components.

[0063] In some embodiments, the patient interface system includes a patient interface configured to provide a gas flow to one or both nostrils of a patient. The patient interface includes a body portion including at least one outflow vent, the at least one outflow vent being configured to generate a predetermined interface pressure and an associated predetermined exhaust flow rate from the at least one outflow vent in response to a predetermined supply flow rate into one or both nostrils.

[0064] In some embodiments, the patient interface system includes a patient interface configured to provide a gas flow to one or both nostrils of a patient. The patient interface includes a body portion including at least one outflow vent, the at least one outflow vent being configured to generate a first flow resistance at a first supply flow rate, the first flow resistance being different from a second flow resistance at a second supply flow rate.

[0065] In some embodiments, the sealing element includes at least one nasal pillow, nasal fork, nasal pad, nasal sleeve, or nasal prosthesis configured to form a substantially sealed seal with the patient’s nostrils to substantially restrict gas escape except through the at least one outflow vent.

[0066] In some embodiments, the patient interface system includes a patient interface comprising at least one gas delivery element configured to provide a gas flow into a patient's nostrils, and at least one outflow vent includes at least one opening located in the nostril and surrounding an insert in the nasal fork.

[0067] In some embodiments, the total cross-sectional area of ​​at least one outflow vent is from about 20 to about 100 mm. 2 or about 35mm 2 approximately 80 mm2 or about 35 mm 2 Approximately 60 mm 2 or about 35 mm 2 Approximately 50 mm 2 or about 35 mm 2 Approximately 40 mm 2 or about 35 mm 2 Approximately 45 mm 2 Within the range.

[0068] In some embodiments, at least one outflow vent includes a plurality of openings, which are not all of the same size and / or shape.

[0069] In some embodiments, at least one outflow vent may include at least one small opening and at least one large opening.

[0070] In some embodiments, the cross-sectional dimension of at least one small opening is less than about 1 mm, preferably less than about 0.75 mm, or about 0.5 mm, or about 0.3 to 0.7 mm.

[0071] In some embodiments, the cross-sectional dimension of at least one large opening is greater than about 1 mm or greater than about 2 mm, such as about 1 mm to about 2 mm or about 2 mm to about 3 mm.

[0072] In some embodiments, the total cross-sectional area of ​​at least one small opening is similar to the total cross-sectional area of ​​at least one large opening.

[0073] In some embodiments, when in use, the direction of flow from at least one large opening is different from the direction of flow from at least one small opening.

[0074] In some embodiments, during use, the flow from at least one small opening is directed toward the patient's mouth.

[0075] In some embodiments, during use, the flow from at least one large opening is directed away from the patient's mouth.

[0076] In some embodiments, the patient interface is configured to generate interface pressure during the provision of respiratory support.

[0077] In some embodiments, for a given exhaust flow rate, the flow resistance is attributed to the size and / or shape of at least one outflow vent.

[0078] In some embodiments, the total cross-sectional area of ​​at least one outflow vent is from about 20 to about 100 mm. 2 or about 35mm 2 approximately 80 mm 2 or about 35 mm2 Approximately 60 mm 2 or about 35 mm 2 Approximately 50 mm 2 or about 35 mm 2 Approximately 40 mm 2 or about 35 mm 2 Approximately 45 mm 2 Within the range.

[0079] In some embodiments, the patient interface includes at least one sampling port. This at least one sampling port may be coupled to or provided with a gas sampling line to provide fluid communication between the gas in the patient interface and at least one sensor. The at least one sensor may include, for example, a pressure, temperature, gas composition, CO2, or humidity sensor.

[0080] In some embodiments, the patient interface includes at least one gas sampling catheter that is adjustable to position a sampling tip in the patient's oral cavity region during use. The gas sampling catheter may be attached to the patient interface, such as removably attached to the patient interface.

[0081] In some embodiments, the patient interface includes at least one access port that is normally closed and openable to allow an instrument to enter the nasal cavity via the patient interface. The access port may include a valve, such as a duckbill valve, that can be opened by inserting the instrument. The access port may include a removable cap. The removable cap may include at least one or more outflow vents.

[0082] In some embodiments, the supply flow rate is greater than about 0 LPM, about 10 LPM, about 20 LPM, about 30 LPM, about 40 LPM, or about 50 LPM, or about 60 LPM, or about 70 LPM, or about 80 LPM, or about 90 LPM, or about 100 LPM, or about 110 LPM, or about 120 LPM, or about 130 LPM, or about 140 LPM, or about 150 LPM. However, these ranges are merely examples and do not limit the flow rates that can be provided according to embodiments of the invention.

[0083] In some embodiments, the method includes controlling a first supply flow rate by one or more of the following:

[0084] - In response to the user's confirmation of the patient's condition, the user manually selects the supply flow rate;

[0085] - When the control device receives user input confirming the patient's condition, the control device determines the supply flow rate; and

[0086] When the control device determines the presence of a patient condition using data received from one or more devices that monitor patient condition parameters, the control device determines the supply flow rate.

[0087] Patient condition may include conditions selected from the following groups: lower or upper airway obstruction; soft palate obstruction; absence of spontaneous breathing; unmet inspiratory needs; patient at risk of apnea; adequate sedation; and expiratory airway pressure at or nearing an optimal threshold.

[0088] In some embodiments, the method includes controlling the gas flow and producing one or more of the following:

[0089] - Exhaust flow rate of approximately 40 LPM and interface pressure of approximately 3-5 cmH2O, such as approximately 4 cmH2O;

[0090] - Exhaust flow rate of approximately 30 LPM and interface pressure of approximately 2-4 cmH2O, such as approximately 3 cmH2O;

[0091] - Exhaust flow rate of approximately 50 LPM and interface pressure of approximately 5-8 cmH2O, such as approximately 6 cmH2O;

[0092] - Exhaust flow rate of approximately 55 LPM and interface pressure of approximately 6-8 cmH2O;

[0093] - An exhaust flow rate of approximately 60 LPM and an interface pressure of approximately 7-9 cmH2O; and

[0094] - Exhaust flow rate of approximately 70 LPM and interface pressure of approximately 7-15 cmH2O, such as approximately 9-12 cmH2O, such as approximately 9-10 cmH2O, or approximately 10-12 cmH2O.

[0095] In another aspect, the present invention provides a patient interface for providing respiratory support, the interface comprising: a gas flow path (e.g., via a nasal element of the patient interface) for providing a gas flow to a patient; at least one outflow vent configured to allow exhaust flow of gas; and a sealing element that, in use, substantially prevents gas from escaping from the patient except via the at least one outflow vent; wherein the patient interface is configured to generate an interface pressure during the provision of respiratory support; and wherein the interface pressure and the exhaust flow rate through the at least one outflow vent form a non-linear relationship, the non-linear relationship including a rate of change of interface pressure in the range of greater than 0.15 cmH2O / Lmin⁻¹ to less than 0.5 cmH2O / Lmin⁻¹ for exhaust flow rate values ​​in the range of greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM.

[0096] In some embodiments, the nonlinear relationship includes, for exhaust flow rate values ​​greater than about 0 LPM to about 40 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, the rate of change of the interface pressure is greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

[0097] In some embodiments, the nonlinear relationship includes polynomial components, preferably quadratic polynomial components.

[0098] In some embodiments, at least one outflow vent is configured to generate a predetermined exhaust flow rate for a predetermined supply flow rate during use.

[0099] In some embodiments, at least one outflow vent is configured to generate a predetermined interface pressure and an associated exhaust flow rate for a predetermined supply flow rate during use.

[0100] In some embodiments, the total cross-sectional area of ​​at least one outflow vent is from about 20 to about 100 mm. 2 or about 35mm 2 approximately 80 mm 2 or about 35 mm 2 Approximately 60 mm 2 or about 35 mm 2 Approximately 50 mm2 or about 35 mm 2 Approximately 40 mm 2 or about 35 mm 2 Approximately 45 mm 2 Within the range.

[0101] In some embodiments, the patient interface includes at least one gas delivery element configured to provide a gas flow into the patient's nostrils, and at least one outflow vent includes at least one opening in at least one insert located in the nostril and surrounding the nasal fork. The at least one insert may be provided separately from the patient interface. In some embodiments, the at least one insert is provided separately from the patient interface. In some embodiments, a sealing element may be provided by the at least one insert.

[0102] In some embodiments, the patient interface includes at least one gas delivery element configured to provide a gas flow into one or both nostrils of the patient.

[0103] In some embodiments, the sealing element includes at least one nasal pillow, nasal fork, nasal pad, nasal cover, or nasal support, configured to form a substantial seal with the patient's nostrils.

[0104] In some embodiments, the sealing element is integrated with or incorporated into the gas delivery element. In some embodiments, the sealing element may include at least one outflow vent.

[0105] In some embodiments, the patient interface includes a body portion including at least one outflow vent. The body portion may include a chamber between a gas inlet of the patient interface and the patient, the chamber including restrictors that cause asymmetric flow to the patient's nostrils.

[0106] In some embodiments, the patient interface includes a gas delivery side member that includes a collapsible portion that closes or partially closes to reduce or stop the flow through the first patient interface.

[0107] In some embodiments, the collapsible portion is configured to collapse when force is applied by placing the breathing mask over the patient interface.

[0108] In some embodiments, the size of at least one outflow vent is configured to allow gas flow from the breathing mask to the patient.

[0109] In some embodiments, the breathing mask includes a balloon valve mask.

[0110] In some embodiments, the patient interface is configured to generate an asymmetric flow distribution into the patient's nostrils.

[0111] In some embodiments, the patient interface is configured to receive lateral gas inlet, preferably unilateral gas inlet.

[0112] In some embodiments, the patient interface includes at least one sampling port. This at least one sampling port may be coupled to or provided with a gas sampling line to provide fluid communication between the gas in the patient interface and at least one sensor. The at least one sensor may include, for example, a pressure, temperature, gas composition, CO2, or humidity sensor.

[0113] In some embodiments, the patient interface includes at least one gas sampling catheter that is adjustable to position a sampling tip in the patient's oral cavity region during use. The gas sampling catheter may be attached to the patient interface, such as removably attached to the patient interface.

[0114] In some embodiments, the patient interface includes at least one access port that is normally closed and openable to allow an instrument to enter the nasal cavity via the patient interface. The access port may include a valve, such as a duckbill valve, that can be opened by inserting the instrument. The access port may include a removable cap. The removable cap may include at least one or more outflow vents.

[0115] In some embodiments, the patient interface includes a headband connector to stabilize the patient interface on the patient during use.

[0116] In some embodiments, the patient interface includes a holding mechanism configured to improve the sealing of the sealing element.

[0117] In some embodiments, at least one outflow vent is configured to generate a pressure differential of about 7 cmH2O to about 15 cmH2O between the patient and the atmosphere at a supply flow rate of about 70 L / min during use.

[0118] In some embodiments, at least one outflow vent is configured to produce an exhaust rate substantially corresponding to the supplied gas flow rate from the patient interface when the patient's mouth is closed and during breath-holding or when the patient's breathing is paused.

[0119] In some embodiments, at least one outflow vent is immutable. For example, its size and / or shape may be immutable.

[0120] In some embodiments, at least one outflow vent includes a cross-sectional shape, which includes a circle, an ellipse, an egg, an oblong, a quadrilateral, or a square-round shape.

[0121] In some embodiments, at least one outflow vent includes 1 or 2 or 3 or 4 or 5 or 6 discrete openings, or more such as 10, 15, 20, 25, 30, 35, 40, 45, 50 discrete openings, or significantly more such as 100, 150, 200 discrete openings or more, or any number thereof.

[0122] In some embodiments, at least one outflow vent includes six discrete openings, each with a cross-sectional dimension of about 3 mm.

[0123] In some embodiments, at least one outflow vent includes a plurality of openings, which are not all of the same size and / or shape.

[0124] In some embodiments, at least one outflow vent may include at least one small opening and at least one large opening.

[0125] In some embodiments, the cross-sectional dimension of at least one small opening is less than about 1 mm, preferably less than about 0.75 mm, or about 0.5 mm, or about 0.3 to 0.7 mm.

[0126] In some embodiments, the cross-sectional dimension of at least one large opening is greater than about 1 mm or greater than about 2 mm, such as about 1 mm to about 2 mm or about 2 mm to about 3 mm.

[0127] In some embodiments, the total cross-sectional area of ​​at least one small opening is similar to the total cross-sectional area of ​​at least one large opening.

[0128] In some embodiments, when in use, the direction of flow from at least one large opening is different from the direction of flow from at least one small opening.

[0129] In some embodiments, during use, the flow from at least one small opening is directed toward the patient's mouth.

[0130] In some embodiments, during use, the flow from at least one large opening is directed away from the patient's mouth.

[0131] In some embodiments, the patient interface is configured to generate interface pressure during the provision of respiratory support. In some embodiments, at least one outflow ventilator is shaped to produce transitional or turbulent characteristics, preferably at a flow rate above about 50 LPM.

[0132] In some embodiments, interface pressure includes average interface pressure.

[0133] In some embodiments, the rate of change is an average rate of change. In other embodiments, the rate of change is an instantaneous rate of change.

[0134] In some embodiments, the rate of change is determined in the absence of patient respiratory effects.

[0135] In some embodiments, the patient interface includes a ventilation component that includes at least one outflow ventilation port. In some embodiments, the ventilation component may be removable to allow the instrument to enter the nasal cavity via the patient.

[0136] In another aspect, the present invention provides a method for providing respiratory support to a patient, the method comprising: providing first respiratory support to a patient using a first patient interface; placing a second patient interface above the first patient interface to reduce or stop the flow of the first respiratory support to the first patient interface; and providing second respiratory support using the second patient interface; wherein the first patient interface includes at least one airway, the size of which is configured such that the second respiratory support from the second patient interface can be provided to the patient via the first patient interface.

[0137] In some embodiments, the patient interface includes at least one nasal fork configured to provide first respiratory support to at least one nostril of the patient.

[0138] In some embodiments, the first patient interface includes at least one sealing element, which includes a nasal pillow, nasal fork, nasal pad, nasal sleeve, or nasal prosthesis, configured to form a substantially sealed seal with the patient’s nostrils to substantially limit gas escape except through the at least one vent.

[0139] In some embodiments, the first patient interface includes a body portion that includes at least one air vent.

[0140] In some embodiments, the first patient interface includes a gas delivery side member that includes a collapsible portion that closes or partially closes to reduce or stop the flow through the first patient interface.

[0141] In some embodiments, the collapsible portion is configured to collapse when a force is applied by placing the second patient interface over the first patient interface.

[0142] In some embodiments, the first breathing support includes: controlling the gas flow at a first supply flow rate and generating a first interface pressure and an exhaust flow through at least one vent at a first exhaust flow rate; and controlling the gas flow at a second supply flow rate and generating a second interface pressure and an exhaust flow through at least one outlet vent at a second exhaust flow rate; wherein a second rate of change of the second interface pressure associated with the second exhaust flow rate is greater than a first rate of change of the first interface pressure associated with the first exhaust flow rate.

[0143] In some embodiments, at least one vent is configured to provide, for example:

[0144] - For a first exhaust flow rate value greater than about 0 LPM to about 40 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, or when the supply flow rate is less than 15 LPM, providing a first predetermined flow resistance in use within the range of greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1; and

[0145] - For a second exhaust flow rate value in the range of greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM, a second predetermined flow resistance is provided in use in the range of greater than about 0.15 cmH2O / Lmin-1 to less than about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

[0146] In some embodiments, the first respiratory support includes providing a gas flow to a patient interface at a supply flow rate and generating an interface pressure and an exhaust flow through at least one ventilator at an exhaust flow rate, wherein the values ​​of the interface pressure and the exhaust flow rate constitute a non-linear relationship comprising a polynomial.

[0147] In some embodiments, the nonlinear relationship includes polynomial components, preferably quadratic polynomial components.

[0148] In some embodiments, for a given exhaust flow rate, the flow resistance may be attributed to the size and / or shape of at least one vent.

[0149] In some embodiments, the total cross-sectional area of ​​at least one vent can be from about 20 to about 100 mm. 2 or about 35mm 2 approximately 80 mm 2 or about 35 mm 2 Approximately 60 mm 2 or about 35 mm 2 Approximately 50 mm 2 or about 35 mm 2 Approximately 40 mm 2or about 35 mm 2 Approximately 45 mm 2 Within the range.

[0150] In some embodiments, the method includes the step of positioning a first patient interface, including at least one nasal sealing element, on a patient.

[0151] In some embodiments, the method includes the step of removing the second patient interface to resume providing first respiratory support.

[0152] In some embodiments, the second patient interface includes a ventilation port or expiratory pathway for venting gas.

[0153] In some embodiments, the method includes the step of alternating between first respiratory support and second respiratory support by removing or applying a second patient interface.

[0154] In some embodiments, a second respiratory support is provided to achieve one or more of the following, such as: increasing patient oxygenation; delivering one or more substances to the patient's airway; changing the interface pressure; changing the gas flow rate; different controls over the interface pressure; and different controls over the gas flow rate.

[0155] In some embodiments, at least one vent is immutable. For example, its size and / or shape may be immutable.

[0156] In some embodiments, at least one vent includes a cross-sectional shape, which includes a circle, an ellipse, an egg, an oblong, a quadrilateral, or a square-round shape.

[0157] In some embodiments, at least one vent includes 1 or 2 or 3 or 4 or 5 or 6 discrete openings, or more such as 10, 15, 20, 25, 30, 35, 40, 45, 50 discrete openings, or significantly more such as 100, 150, 200 discrete openings or more, or any number in between.

[0158] In some embodiments, at least one vent includes six discrete openings, each with a cross-sectional dimension of about 3 mm.

[0159] In some embodiments, at least one vent is configured to produce transitional or turbulent characteristics, preferably at flow rates above about 50 LPM.

[0160] In some embodiments, at least one outflow vent includes a plurality of openings, which are not all of the same size and / or shape. In some embodiments, at least one outflow vent may include at least one small opening and at least one large opening.

[0161] In some embodiments, the cross-sectional dimension of at least one small opening is less than about 1 mm, preferably less than about 0.75 mm, or about 0.5 mm, or about 0.3 to 0.7 mm. In some embodiments, the cross-sectional dimension of at least one large opening is greater than about 1 mm or greater than about 2 mm, such as about 1 mm to about 2 mm or about 2 mm to about 3 mm.

[0162] In some embodiments, the total cross-sectional area of ​​at least one small opening is similar to the total cross-sectional area of ​​at least one large opening.

[0163] In some embodiments, during use, the flow from at least one large opening is directed in a different direction than the flow from at least one small opening. In some embodiments, during use, the flow from at least one small opening is directed toward the patient's mouth. In some embodiments, during use, the flow from at least one large opening is directed away from the patient's mouth.

[0164] In some embodiments, the second patient interface includes a mask, such as a balloon valve mask.

[0165] In some embodiments, interface pressure includes average interface pressure.

[0166] In another aspect, the present invention provides a system for providing respiratory support to a patient, the system comprising: a patient interface system for providing a gas flow to the patient, the patient interface system having at least one outflow vent; and a gas source controllable to: provide a gas flow at a first supply flow rate and generate a first interface pressure and an exhaust flow through the at least one outflow vent at a first exhaust flow rate; and provide a gas flow at a second supply flow rate and generate a second interface pressure and an exhaust flow through the at least one outflow vent at a second exhaust flow rate; wherein a first predetermined flow resistance of the at least one outflow vent at the first exhaust flow rate is different from a second predetermined flow resistance of the at least one outflow vent at the second exhaust flow rate.

[0167] In another aspect, the present invention provides a system for providing respiratory support to a patient, the system comprising: a patient interface system for providing a gas flow to the patient, the patient interface system having at least one outflow ventilator; and a gas source controllable to: provide a gas flow at a first supply flow rate and generate a first interface pressure and an exhaust flow at a first exhaust flow rate through the at least one outflow ventilator; and provide a gas flow at a second supply flow rate and generate a second interface pressure and an exhaust flow at a second exhaust flow rate through the at least one outflow ventilator; wherein a second rate of change of the second interface pressure associated with a change in the second exhaust flow rate is greater than a first rate of change of the first interface pressure associated with a change in the first exhaust flow rate.

[0168] In some embodiments, the system may include a controller for controlling a gas source, the controller comprising one or more of the following:

[0169] - A control device, comprising a processor for calculating one or both of a first supply flow rate and a second supply flow rate based on one or more user inputs and / or other signals received by the processor; and

[0170] - A control selector for users to directly select one or both of the first and second supply flow rates.

[0171] In some embodiments, the system may include a humidifier.

[0172] In some embodiments, the controller controls the gas flow at the first supply flow rate before the second supply flow rate.

[0173] In some embodiments, the controller controls the gas at a second supply flow rate before the first supply flow rate.

[0174] In some embodiments, the second supply flow rate is higher than the first supply flow rate.

[0175] In some embodiments, the first supply flow rate is greater than about 0 LPM, about 10 LPM, about 20 LPM, about 30 LPM, about 40 LPM, or about 50 LPM.

[0176] In some embodiments, the second supply flow rate is greater than about 40 LPM, about 50 LPM, about 60 LPM, about 70 LPM, about 80 LPM, about 90 LPM, or about 100 LPM.

[0177] In some embodiments, a second supply flow rate is provided in response to indications of the patient's condition.

[0178] In some embodiments, an indication of a patient's condition may be determined by one or more of the following:

[0179] - Observation of patients and / or patient parameters;

[0180] - User confirmation of treatment administration to patients;

[0181] - Instrumental measurement of one or more patient parameters;

[0182] - The control device uses data received from the user or one or more devices monitoring patient parameters to determine indications of the patient's condition; and

[0183] - The patient's self-report of their condition.

[0184] In some embodiments, one or more patient parameters may include, for example, depth of sedation; heart rate; EEG signal value; EKG / ECG signal value; EMG signal value; blood oxygen concentration; blood oxygen saturation (SpO2); exhaled oxygen concentration; blood CO2 concentration; transcutaneous CO2 concentration (TcCO2); transcutaneous O2 concentration (TcO2); exhaled CO2 concentration; and blood glucose level.

[0185] In some embodiments, patient condition includes conditions selected from the group consisting of: lower or upper airway obstruction; soft palate obstruction; absence of spontaneous breathing; unmet inspiratory needs; patient at risk of apnea; adequate sedation depth; and expiratory airway pressure at or nearing a suboptimal threshold.

[0186] In some embodiments, the controller is operable to control a first supply flow rate and / or a second supply flow rate by one or more of the following: the user manually selecting a second supply flow rate in response to confirmation of an indication of a patient's condition; the controller determining a second supply flow rate when it receives user input confirming an indication of a patient's condition; and the controller determining a second supply flow rate when it determines the presence of a patient's condition using data received from one or more devices that monitor patient condition parameters.

[0187] In some embodiments, the system may be operable to provide a first supply flow rate before delivering the anesthetic to the patient and a second supply flow rate after delivering the anesthetic to the patient.

[0188] In some embodiments, the system may be operable to provide a second supply flow rate in response to an indication that an anesthetic is being or has been delivered to the patient.

[0189] In some embodiments, the indication that an anesthetic is being or has been administered to the patient is determined by one or more of the following: a clinician observes the patient and / or patient parameters and manually inputs the indication into a control device; and the control device uses data received from the user or one or more devices that monitor patient parameters, which provide an indication that an anesthetic is being or has been administered to the patient.

[0190] In some embodiments, the system may be operable to provide respiratory support prior to anesthetic delivery and / or before the patient begins anesthesia or sedation.

[0191] In some embodiments, the system may be operable to control the gas flow at a third supply flow rate and generate a third interface pressure and an exhaust flow through at least one outlet vent at a third exhaust flow rate, wherein the rate of change of the third interface pressure associated with a change in the third exhaust flow rate is less than the rate of change of the second interface pressure associated with a change in the second exhaust flow rate.

[0192] In some embodiments, the system may be operable to control the gas flow at a third supply flow rate and generate a third interface pressure and an exhaust flow rate through at least one outflow vent at a third exhaust flow rate, wherein the third predetermined flow resistance of the at least one outflow vent at the third exhaust flow rate is different from the second predetermined flow resistance of the at least one outflow vent at a second exhaust flow rate.

[0193] In some embodiments, the third supply flow rate is lower than the second supply flow rate.

[0194] In some embodiments, the system may be operable to provide a third supply flow rate in response to indications of different patient conditions.

[0195] In some embodiments, different patient conditions include conditions selected from, for example, the group consisting of: the lower or upper airway is open; the soft palate is no longer obstructed; spontaneous breathing is present; the patient's inspiratory needs are met; a predetermined level of alertness is met; and the expiratory interface pressure is met or exceeds an optimal threshold.

[0196] In some embodiments, for a first exhaust flow rate value in the range of about 0 LPM to about 40 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, the first rate of change may be in the range of about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

[0197] In some embodiments, for a second exhaust flow rate value in the range of greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM, the second rate of change may be in the range of greater than about 0.1 cmH2O / Lmin-1 to less than about 0.6 cmH2O / Lmin-1, or about 0.15 cmH2O / Lmin-1 to about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

[0198] In some embodiments, the corresponding interface pressures and exhaust flow rates of the first and second rates of change are related such that, when presented graphically, their relationship includes one or more of the following: a stepwise change between the first and second rates of change; a gradual change between the first and second rates of change; a curvilinear change between the first and second rates of change; a portion of the first and / or second rates of change having a non-constant gradient; a non-stepwise change at the transition between the first and second exhaust flow rates; and a non-stepwise change at the transition between the second and third exhaust flow rates.

[0199] In some embodiments, one or both of the first rate of change and the second rate of change are non-constant.

[0200] In some embodiments, the system may be operable to control the gas flow and produce one or more of the following:

[0201] - A first exhaust flow rate of approximately 40 LPM and a first interface pressure of approximately 3-5 cmH2O, such as approximately 4 cmH2O;

[0202] - A first exhaust flow rate of approximately 30 LPM and a first interface pressure of approximately 2-4 cmH2O, such as approximately 3 cmH2O;

[0203] - A second exhaust flow rate of approximately 50 LPM and a second interface pressure of approximately 5-8 cmH2O, such as approximately 6 cmH2O;

[0204] - A second exhaust flow rate of approximately 55 LPM and a second interface pressure of approximately 6-8 cmH2O;

[0205] - A second exhaust flow rate of approximately 60 LPM and a second interface pressure of approximately 7-9 cmH2O; and

[0206] - A second exhaust flow rate of approximately 70 LPM and a second interface pressure of approximately 7-15 cmH2O, such as approximately 9-12 cmH2O, such as approximately 9-10 cmH2O, or approximately 10-12 cmH2O.

[0207] In some embodiments, the gas source is controlled by a control device configured to receive control inputs provided by a user and / or control inputs generated by a processor.

[0208] In some embodiments, the patient interface system includes a patient interface configured to provide a gas flow to one or both nostrils of a patient, and includes at least one outflow vent configured to generate a predetermined interface pressure and a predetermined target exhaust flow rate from the at least one outflow vent in response to a predetermined supply flow rate to the patient interface.

[0209] In some embodiments, the patient interface includes at least one sealing element, such as a nasal pillow, nasal fork, nasal pad, nasal sleeve, or nasal prosthesis, configured to form a substantially sealed seal with the patient’s nostrils to substantially limit gas escape except through the at least one outflow vent.

[0210] In some embodiments, the system may be operable to provide respiratory support to a patient undergoing a medical procedure, such as a scheduled medical procedure.

[0211] In some embodiments, the gas flow provided at one or both of a first supply flow rate and a second supply flow rate includes a 100% O2 concentration.

[0212] In some embodiments, the rate of change is the average rate of change.

[0213] In some embodiments, the first predetermined flow resistance of at least one outlet vent at the first exhaust flow rate is in the range of greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

[0214] In some embodiments, the first exhaust flow rate is between about 0 LPM and about 40 LPM, or between about 30 LPM and about 40 LPM, or between about 35 LPM and about 45 LPM.

[0215] In some embodiments, the second predetermined flow resistance of at least one outlet vent at the second exhaust flow rate is in the range of greater than about 0.15 cmH2O / Lmin-1 to less than about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

[0216] In some embodiments, the second exhaust flow rate is between greater than about 40 LPM and about 100 LPM, or between about 40 LPM and about 70 LPM, or between about 40 LPM and about 60 LPM, or between about 50 LPM and about 70 LPM, or between about 50 LPM and about 60 LPM, or between about 60 LPM and about 70 LPM.

[0217] In another aspect, the present invention provides a system for providing respiratory support to a patient, the system comprising: a patient interface system for providing a gas flow to the patient, the patient interface system including at least one outflow vent and a seal that substantially restricts gas from escaping from the patient except via the at least one outflow vent; and a gas source controllable to: provide a gas flow rate to the patient interface system during use, and generate an interface pressure at the patient and an exhaust flow at an exhaust flow rate through the at least one outflow vent; wherein the interface pressure and the exhaust flow rate constitute a non-linear relationship.

[0218] In some embodiments, the nonlinear relationship includes polynomial components, preferably quadratic polynomial components.

[0219] In another aspect, the present invention provides a system for providing respiratory support to a patient, the system comprising: a first patient interface for providing first respiratory support to a patient, the first patient interface including at least one airway, the size of the at least one airway being configured to allow the provision of second respiratory support to the patient when the flow of first respiratory support to the first patient interface has been reduced or stopped; one or more flow sources providing a gas flow for one or both of the first and second respiratory support; and a controller for controlling the one or more flow sources.

[0220] In some embodiments, the system includes or can operate with a second patient interface configured to reduce or stop the flow of first respiratory support to the first patient interface and provide second respiratory support when placed over the first patient interface.

[0221] In some embodiments, the first patient interface includes at least one nasal delivery element configured to provide first respiratory support to at least one nostril of the patient. In some embodiments, the at least one nasal delivery element includes a nasal fork or nasal pillow.

[0222] In some embodiments, the first patient interface includes at least one sealing element. In some embodiments, the at least one sealing element includes a nasal pillow, nasal fork, nasal pad, nasal sleeve, or nasal prosthesis, configured to form a substantially sealed seal with the patient's nostrils to substantially limit gas escape except through the at least one airway.

[0223] In some embodiments, the first patient interface includes a body portion that includes at least one air vent.

[0224] In some embodiments, the first patient interface includes a gas delivery side member that includes a collapsible portion that closes or partially closes to reduce or stop flow through the first patient interface. The collapsible portion may be configured to collapse when a force is applied by placing a second patient interface over the first patient interface.

[0225] In some embodiments, the first breathing support includes: controlling the gas flow at a first supply flow rate and generating a first interface pressure and an exhaust flow through at least one vent at a first exhaust flow rate; and controlling the gas flow at a second supply flow rate and generating a second interface pressure and an exhaust flow through at least one outlet vent at a second exhaust flow rate; wherein a second rate of change of the second interface pressure associated with the second exhaust flow rate is greater than a first rate of change of the first interface pressure associated with the first exhaust flow rate.

[0226] In some embodiments, at least one vent is configured to provide:

[0227] - For a first exhaust flow rate value greater than about 0 LPM to about 40 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, or when the supply flow rate is less than 15 LPM, providing a first predetermined flow resistance in use within the range of greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1; and

[0228] - For a second exhaust flow rate value in the range of greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM, a second predetermined flow resistance is provided in use in the range of greater than about 0.15 cmH2O / Lmin-1 to less than about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

[0229] In some embodiments, the total cross-sectional area of ​​at least one outflow vent is from about 20 to about 100 mm. 2 or about 35mm 2 approximately 80 mm 2 or about 35 mm 2Approximately 60 mm 2 or about 35 mm 2 Approximately 50 mm 2 or about 35 mm 2 Approximately 40 mm 2 or about 35 mm 2 Approximately 45 mm 2 Within the range.

[0230] In some embodiments, at least one outflow vent includes a plurality of openings, which are not all of the same size and / or shape. In some embodiments, at least one outflow vent may include at least one small opening and at least one large opening. In some embodiments, the cross-sectional dimension of at least one small opening is less than about 1 mm, preferably less than about 0.75 mm, or about 0.5 mm, or about 0.3 to 0.7 mm. In some embodiments, the cross-sectional dimension of at least one large opening is greater than about 1 mm or greater than about 2 mm, such as about 1 mm to about 2 mm or about 2 mm to about 3 mm.

[0231] In some embodiments, the total cross-sectional area of ​​at least one small opening is similar to the total cross-sectional area of ​​at least one large opening.

[0232] In some embodiments, during use, the flow from at least one large opening is directed in a different direction than the flow from at least one small opening. In some embodiments, during use, the flow from at least one small opening is directed toward the patient's mouth. In some embodiments, during use, the flow from at least one large opening is directed away from the patient's mouth.

[0233] In some embodiments, the patient interface includes at least one sampling port. This at least one sampling port may be coupled to or provided with a gas sampling line to provide fluid communication between the gas in the patient interface and at least one sensor. The at least one sensor may include, for example, a pressure, temperature, gas composition, CO2, or humidity sensor.

[0234] In some embodiments, the patient interface includes at least one gas sampling catheter that is adjustable to position a sampling tip in the patient's oral cavity region during use. The gas sampling catheter may be attached to the patient interface, such as removably attached to the patient interface.

[0235] In some embodiments, the patient interface includes at least one access port that is normally closed and openable to allow an instrument to enter the nasal cavity via the patient interface. The access port may include a valve, such as a duckbill valve, that can be opened by inserting the instrument. The access port may include a removable cap. The removable cap may include at least one or more outflow vents.

[0236] In some embodiments, the first respiratory support includes providing a gas flow to a patient interface at a supply flow rate and generating an interface pressure and an exhaust flow through at least one ventilator at an exhaust flow rate, wherein the values ​​of the interface pressure and the exhaust flow rate form a non-linear relationship.

[0237] In some embodiments, the nonlinear relationship includes polynomial components, preferably quadratic polynomial components.

[0238] In some embodiments, operation of the system requires positioning a first patient interface, including at least one nasal sealing element, on a patient.

[0239] In some embodiments, operation of the system requires the removal of the second patient interface to restore the provision of primary respiratory support.

[0240] In some embodiments, the second patient interface includes a ventilation port or expiratory pathway for venting gas.

[0241] In some embodiments, the system is operable to alternate between first and second respiratory support by removing or applying a second patient interface.

[0242] In some embodiments, a second respiratory support is provided to achieve one or more of the following: increasing patient oxygenation; delivering one or more substances to the patient's airway; changing the interface pressure; changing the gas flow rate; different controls over the interface pressure; and different controls over the gas flow rate.

[0243] In some embodiments, at least one vent is immutable. For example, its size and / or shape may be immutable.

[0244] In some embodiments, at least one vent includes a cross-sectional shape, which includes a circle, an ellipse, an egg, an oblong, a quadrilateral, or a square-round shape.

[0245] In some embodiments, at least one vent includes 1 or 2 or 3 or 4 or 5 or 6 discrete openings, or more such as 10, 15, 20, 25, 30, 35, 40, 45, 50 discrete openings, or significantly more such as 100, 150, 200 discrete openings or more, or any number in between.

[0246] In some embodiments, at least one vent includes six discrete openings, each with a cross-sectional dimension of about 3 mm.

[0247] In some embodiments, at least one vent is configured to produce transitional or turbulent characteristics, preferably at flow rates above about 50 LPM.

[0248] In some embodiments, the second patient interface includes a mask, such as a balloon valve mask.

[0249] In some embodiments, interface pressure includes average interface pressure.

[0250] In another aspect, the present invention provides a patient interface for providing respiratory support, the interface comprising:

[0251] - A gas flow path used to deliver gas to the patient;

[0252] - At least one outflow vent, the at least one outflow vent being configured to allow exhaust flow of gas; and

[0253] - A sealing element that substantially prevents gas from escaping from the patient during use, except via the at least one outflow ventilator;

[0254] At least one of the outflow vents includes multiple openings, which are not all of the same size and / or shape.

[0255] It should be understood that when the patient interface is used with the patient's mouth closed or covered, the sealing element essentially prevents gas from escaping from the patient except through at least one outflow vent.

[0256] In some embodiments, at least one outflow vent includes a plurality of openings, which are not all of the same size and / or shape. In some embodiments, at least one outflow vent may include at least one small opening and at least one large opening. In some embodiments, the cross-sectional dimension of at least one small opening is less than about 1 mm, preferably less than about 0.75 mm, or about 0.5 mm, or about 0.3 to 0.7 mm. In some embodiments, the cross-sectional dimension of at least one large opening is greater than about 1 mm or greater than about 2 mm, such as about 1 mm to about 2 mm or about 2 mm to about 3 mm.

[0257] In some embodiments, the total cross-sectional area of ​​at least one small opening is similar to the total cross-sectional area of ​​at least one large opening.

[0258] In some embodiments, during use, the flow from at least one large opening is directed in a different direction than the flow from at least one small opening. In some embodiments, during use, the flow from at least one small opening is directed toward the patient's mouth. In some embodiments, during use, the flow from at least one large opening is directed away from the patient's mouth.

[0259] In some embodiments, the patient interface is configured to generate interface pressure during the provision of respiratory support.

[0260] In another aspect, the present invention provides a patient interface for providing respiratory support, the patient interface comprising: a gas flow path for providing a gas flow to a patient; at least one outflow vent configured to allow a gas exhaust flow at an exhaust flow rate; and a sealing element that substantially prevents gas from escaping from the patient during use, except via the at least one outflow vent; wherein the at least one outflow vent has a predetermined flow resistance during use.

[0261] In some embodiments, when the exhaust flow rate is greater than about 0 LPM to about 40 LPM, or between about 30 LPM and about 40 LPM, or between about 35 LPM and about 45 LPM, the predetermined flow resistance of at least one outlet vent is in the range of greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

[0262] In some embodiments, when the exhaust flow rate is between greater than about 40 LPM and about 100 LPM, or between about 40 LPM and about 70 LPM, or between about 40 LPM and about 60 LPM, or between about 50 LPM and about 70 LPM, or between about 50 LPM and about 60 LPM, or between about 60 LPM and about 70 LPM, the predetermined flow resistance of at least one outlet vent is in the range of greater than about 0.15 cmH2O / Lmin-1 to less than about 0.5 cmH2O / Lmin-1, or between about 0.2 cmH2O / Lmin-1 and about 0.4 cmH2O / Lmin-1, or between about 0.2 cmH2O / Lmin-1 and about 0.3 cmH2O / Lmin-1.

[0263] In some embodiments, the predetermined flow resistance can be measured in a simulation test.

[0264] In some embodiments, during use, a supply flow rate is provided to the patient interface to generate interface pressure and an exhaust flow at an exhaust flow rate through at least one outflow ventilator.

[0265] In some embodiments, the total cross-sectional area of ​​at least one outflow vent is from about 20 to about 100 mm. 2 or about 35mm 2 approximately 80 mm 2 or about 35 mm 2 Approximately 60 mm 2 or about 35 mm 2 Approximately 50 mm2 or about 35 mm 2 Approximately 40 mm 2 or about 35 mm 2 Approximately 45 mm 2 Within the range.

[0266] In some embodiments, the patient interface includes at least one gas delivery element configured to provide a gas flow into the patient's nostrils, and at least one outflow vent includes at least one opening located in the nostril and surrounding at least one insert of the at least one gas delivery element.

[0267] In some embodiments, the sealing element is provided by at least one insert.

[0268] In some embodiments, at least one insert is provided separately from the patient interface.

[0269] In some embodiments, the patient interface includes at least one gas delivery element configured to provide a gas flow into one or both nostrils of the patient.

[0270] In some embodiments, the sealing element includes at least one nasal pillow, nasal fork, nasal pad, nasal cover, or nasal support, configured to form a substantial seal with the patient's nostrils.

[0271] In some embodiments, the sealing element is integrated with or incorporated into the gas delivery element. In some embodiments, the sealing element includes at least one outflow vent.

[0272] In some embodiments, the patient interface includes a body portion that includes at least one outflow ventilator.

[0273] In some embodiments, the main body includes a chamber between the gas inlet of the patient interface and the patient, the chamber including a constraint that causes the flow to the patient's nostrils to be asymmetrical.

[0274] In some embodiments, the patient interface includes a gas delivery side member that includes a collapsible portion that closes or partially closes to reduce or stop the flow through the first patient interface.

[0275] In some embodiments, the collapsible portion is configured to collapse when force is applied by placing the breathing mask over the patient interface.

[0276] In some embodiments, the size of at least one outflow vent is configured to allow gas flow from the breathing mask to the patient.

[0277] In some embodiments, the breathing mask includes a balloon valve mask.

[0278] In some embodiments, the patient interface is configured to generate an asymmetric flow distribution into the patient's nostrils.

[0279] In some embodiments, the patient interface is configured to receive lateral gas inlet, preferably unilateral gas inlet.

[0280] In some embodiments, the patient interface includes at least one sampling port.

[0281] In some embodiments, at least one sampling port may be coupled to or provided with a gas sampling line to provide fluid communication between the gas in the patient interface and at least one sensor. In some embodiments, at least one sensor includes a pressure, temperature, gas composition, CO2, or humidity sensor.

[0282] In some embodiments, the patient interface includes at least one gas sampling catheter that is adjustable to position a sampling tip in the patient's oral cavity region during use. In some embodiments, the gas sampling catheter may be attached to the patient interface, such as removably attached to the patient interface.

[0283] In some embodiments, the patient interface includes at least one access port that is normally closed and openable to allow an instrument to enter the nasal cavity via the patient interface. In some embodiments, the access port includes a removable cap. The removable cap may include at least one or more outflow vents.

[0284] In some embodiments, the patient interface includes a headband connector to stabilize the patient interface on the patient during use.

[0285] In some embodiments, the patient interface includes a holding mechanism configured to improve the sealing of the sealing element.

[0286] In some embodiments, at least one outflow vent is configured to generate a pressure differential of about 7 cmH2O to about 15 cmH2O between the patient and the atmosphere at a supply flow rate of about 70 L / min during use.

[0287] In some embodiments, at least one outflow vent is configured to produce an exhaust rate substantially corresponding to the supplied gas flow rate from the patient interface when the patient's mouth is closed and during breath-holding or when the patient's breathing is paused.

[0288] In some embodiments, at least one outflow vent has an invariable size and / or shape.

[0289] In some embodiments, at least one outflow vent includes a cross-sectional shape, which includes a circle, an ellipse, an egg, an oblong, a quadrilateral, or a square-round shape.

[0290] In some embodiments, at least one outflow vent includes 1, 2, 3, 4, 5, or 6 discrete openings.

[0291] In some embodiments, at least one outflow vent includes six discrete openings, each with a cross-sectional dimension of about 3 mm.

[0292] In some embodiments, at least one outflow vent includes a plurality of openings, which are not all of the same size and / or shape. In some embodiments, at least one outflow vent includes at least one small opening and at least one large opening. In some embodiments, the cross-sectional dimension of at least one small opening is less than about 1 mm, preferably less than about 0.75 mm, or about 0.5 mm, or about 0.3 to 0.7 mm. In some embodiments, the cross-sectional dimension of at least one large opening is greater than about 1 mm or greater than about 2 mm, such as about 1 mm to about 2 mm or about 2 mm to about 3 mm.

[0293] In some embodiments, the total cross-sectional area of ​​at least one small opening is similar to the total cross-sectional area of ​​at least one large opening.

[0294] In some embodiments, during use, the flow from at least one large opening is directed in a different direction than the flow from at least one small opening. In some embodiments, during use, the flow from at least one small opening is directed toward the patient's mouth. In some embodiments, during use, the flow from at least one large opening is directed away from the patient's mouth.

[0295] In some embodiments, at least one outflow vent is configured to produce transitional or turbulent characteristics, preferably at flow rates above about 50 LPM.

[0296] In some embodiments, the patient interface includes a ventilation component that includes at least one outflow ventilation port. In some embodiments, the ventilation component is removable to allow the instrument to enter the nasal cavity via the patient interface.

[0297] In another aspect, the present invention provides a system for providing respiratory support to a patient, the system comprising: a patient interface for providing a gas flow to the patient, the patient interface having at least one outflow vent to allow a gas exhaust flow at an exhaust flow rate; a sealing element that, in use, substantially prevents gas from escaping from the patient except via the at least one outflow vent; a gas source operable to provide a gas flow; and a controller operable to control the flow rate of the gas flow provided to the patient interface at a predetermined supply flow rate; wherein the at least one outflow vent has a predetermined flow resistance in use.

[0298] In some embodiments, the system includes a flow source that can be controlled by a controller to provide a gas flow at a predetermined supply flow rate.

[0299] In some embodiments, the patient interface includes the patient interface according to any one of the foregoing aspects.

[0300] In some embodiments, the system includes a humidifier.

[0301] In some embodiments, the predetermined supply flow rate is in the range of about 0 LPM, about 10 LPM, about 20 LPM, about 30 LPM, about 40 LPM, about 50 LPM, about 60 LPM, about 70 LPM, about 80 LPM, about 90 LPM, or about 100 LPM.

[0302] In some embodiments, the controller is operable to control a predetermined supply flow rate at a first supply flow rate greater than about 0 LPM, about 10 LPM, about 20 LPM, about 30 LPM, about 40 LPM, or about 50 LPM.

[0303] In some embodiments, the controller is operable to control a predetermined supply flow rate at a second supply flow rate that is higher than the first supply flow rate, and optionally, greater than about 40 LPM, about 50 LPM, about 60 LPM, about 70 LPM, about 80 LPM, about 90 LPM, or about 100 LPM.

[0304] In some embodiments, a second supply flow rate is provided in response to indications of the patient's condition.

[0305] In some embodiments, an indication of a patient's condition is determined by one or more of the following: observation of the patient and / or patient parameters; user confirmation of administration of a therapy to the patient; instrument measurement of one or more patient parameters; a control device using data received from a user or one or more devices that monitor patient parameters to determine an indication of a patient's condition; and the patient's self-report of their condition.

[0306] In some embodiments, one or more patient parameters include: depth of sedation; heart rate; EEG signal value; EKG / ECG signal value; blood oxygen concentration; blood oxygen saturation (SpO2); exhaled oxygen concentration; blood CO2 concentration; transcutaneous CO2 concentration (TcCO2); transcutaneous O2 concentration (TcO2); exhaled CO2 concentration; and blood glucose level.

[0307] In some embodiments, patient condition includes conditions selected from the group consisting of: lower or upper airway obstruction; soft palate obstruction; absence of spontaneous breathing; unmet inspiratory needs; patient at risk of apnea; adequate sedation depth; and expiratory airway pressure at or nearing a suboptimal threshold.

[0308] In some embodiments, the controller is operable to control a first supply flow rate and / or a second supply flow rate by one or more of the following: the user manually selecting a second supply flow rate in response to confirmation of an indication of a patient's condition; the controller determining a second supply flow rate when it receives user input confirming an indication of a patient's condition; and the controller determining a second supply flow rate when it determines the presence of a patient's condition using data received from one or more devices that monitor patient condition parameters.

[0309] In some embodiments, the system is operable to provide a first supply flow rate before delivering the anesthetic to the patient and a second supply flow rate after delivering the anesthetic to the patient.

[0310] In some embodiments, the system is operable to provide a second supply flow rate in response to an indication that an anesthetic is being or has been delivered to the patient.

[0311] In some embodiments, the indication that an anesthetic is being or has been administered to the patient is determined by one or more of the following: a clinician observes the patient and / or patient parameters and manually inputs the indication into a control device; and the control device uses data received from the user or one or more devices that monitor patient parameters, which provide an indication that an anesthetic is being or has been administered to the patient.

[0312] In some embodiments, the system is operable to provide respiratory support prior to anesthetic delivery and / or before the patient begins anesthesia or sedation.

[0313] In some embodiments, the system is operable to control the gas flow at a third supply flow rate. In some embodiments, the third supply flow rate is less than the second supply flow rate.

[0314] In some embodiments, the system is operable to provide a third supply flow rate in response to indications of different patient conditions.

[0315] In some embodiments, different patient conditions include conditions selected from the group consisting of: the lower or upper airway is open; the soft palate is no longer obstructed; spontaneous breathing is present; the patient's inspiratory needs are met; a predetermined level of alertness is met; and the expiratory interface pressure is met or exceeds an optimal threshold.

[0316] In some embodiments, the controller is configured to receive control input provided by the user and / or control input generated by the processor.

[0317] In some embodiments, the patient interface is configured to provide a flow of gas into one or both of the patient's nostrils.

[0318] In some embodiments, the system is operable to provide respiratory support to a patient undergoing a medical procedure, such as a scheduled medical procedure.

[0319] In some embodiments, the gas stream supplied at a predetermined supply flow rate includes a 100% O2 concentration.

[0320] In some embodiments, the first predetermined flow resistance of at least one outflow vent at a first exhaust flow rate through the at least one outflow vent is in the range of greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

[0321] In some embodiments, the first exhaust flow rate is between about 0 LPM and about 40 LPM, or between about 30 LPM and about 40 LPM, or between about 35 LPM and about 45 LPM.

[0322] In some embodiments, the second predetermined flow resistance of at least one outlet vent at the second exhaust flow rate is in the range of greater than about 0.15 cmH2O / Lmin-1 to less than about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

[0323] In some embodiments, the second exhaust flow rate is between greater than about 40 LPM and about 100 LPM, or between about 40 LPM and about 70 LPM, or between about 40 LPM and about 60 LPM, or between about 50 LPM and about 70 LPM, or between about 50 LPM and about 60 LPM, or between about 60 LPM and about 70 LPM.

[0324] In some embodiments, for a given exhaust flow rate, the flow resistance is attributed to the size and / or shape of at least one outflow vent.

[0325] In some embodiments, the total cross-sectional area of ​​at least one outflow vent is from about 20 to about 100 mm. 2 or about 35mm 2 approximately 80 mm 2or about 35 mm 2 Approximately 60 mm 2 or about 35 mm 2 Approximately 50 mm 2 or about 35 mm 2 Approximately 40 mm 2 or about 35 mm 2 Approximately 45 mm 2 Within the range.

[0326] In some embodiments, the system is operable to control the gas flow and generate one or more of the following: an exhaust flow rate of about 40 LPM and an interface pressure of about 3-5 cmH2O, such as about 4 cmH2O; an exhaust flow rate of about 30 LPM and an interface pressure of about 2-4 cmH2O, such as about 3 cmH2O; an exhaust flow rate of about 50 LPM and an interface pressure of about 5-8 cmH2O, such as about 6 cmH2O; an exhaust flow rate of about 55 LPM and an interface pressure of about 6-8 cmH2O; an exhaust flow rate of about 60 LPM and an interface pressure of about 7-9 cmH2O; and an exhaust flow rate of about 70 LPM and an interface pressure of about 7-15 cmH2O, such as about 9-12 cmH2O, or about 9-10 cmH2O or about 10-12 cmH2O.

[0327] It should be understood that, based on the various aspects, embodiments, and examples disclosed herein, when using the patient interface, the sealing element substantially prevents gas from escaping from the patient except through at least one outflow vent. This sealing method achieves optimal effect when the patient's mouth is closed or covered. Therefore, exhalation enters the patient interface through the nostrils, not through the mouth.

[0328] It should be understood that each of the aspects described herein may include one or more features, modifications, and alternatives described in the context of one or more other aspects, and may suitably include one or more features, modifications, and alternatives of any embodiment described below. For the sake of brevity, such features, modifications, and alternatives are not disclosed repeatedly in each aspect, although those skilled in the art will understand that combinations of such features, modifications, and alternatives disclosed for some aspects and embodiments are equally applicable to other aspects and form part of the subject matter of the invention.

[0329] To make the invention easier to understand and practice, one or more embodiments thereof will now be described by way of example only with reference to the accompanying drawings. Attached Figure Description

[0330] The invention will now be described in more detail with reference to the accompanying drawings. It should be understood that the embodiments shown are merely examples and should not be considered as limiting the scope of the invention as defined in the appended claims.

[0331] Figure 1 This is a schematic diagram of a system for providing respiratory support according to an embodiment of the present invention.

[0332] Figure 2 It is a flowchart schematically illustrating a method of providing respiratory support, wherein at least one outflow ventilator has a first predetermined flow resistance (RTF) at a first exhaust flow rate that is different from the at least one outflow ventilator at a second predetermined flow resistance (RTF) at a second exhaust flow rate.

[0333] Figure 3 This is a flowchart schematically illustrating a method for providing respiratory support, wherein a second rate of change of a second interface pressure associated with a second exhaust flow rate is greater than a first rate of change of a first interface pressure associated with a first exhaust flow rate.

[0334] Figure 4 A PQ curve according to an embodiment of the present invention is shown, which represents the relationship between exhaust flow rate and interface pressure.

[0335] Figure 5 This is a flowchart illustrating a method for providing respiratory support to a patient, where the interface pressure and exhaust flow rate have a non-linear relationship.

[0336] Figure 6 This is a graphical representation of the interface pressure and exhaust flow rate that can be generated according to embodiments of the present invention.

[0337] Figure 7 It is a graphical representation of interface pressure relative to the supply flow rate.

[0338] Figure 8 This is a schematic diagram of the patient interface according to an embodiment of the present invention.

[0339] Figure 9 It shows Figure 8 The patient interface is rotated for better observation of the headband connector and outflow ventilator.

[0340] Figure 10 A patient wearing a patient interface embodiment and a face mask according to the present invention is shown.

[0341] Figure 11 The images show the first (essentially open) configuration and the second (essentially closed) configuration, respectively. Figure 10 A cross-section of a portion of the patient interface.

[0342] Figure 12A patient interface with a channel through which a headband can pass is shown.

[0343] Figure 13 A patient interface is shown, which has a headband connector located on the main body and a corresponding headband connector located on the gas delivery conduit.

[0344] Figure 14 A patient interface is shown, which has a headband connector located at a distance from the main body of the patient interface.

[0345] Figure 15 This is a schematic cross-sectional view of the patient interface, showing the chambers within the main body.

[0346] Figure 16 This is a schematic cross-sectional view of the patient interface, showing a chamber within the main body and a constraint within the chamber that generates asymmetrical interface pressure for asymmetrical flow toward the nostrils.

[0347] Figure 17 This is a flowchart schematically illustrating the steps of this method 700 for providing respiratory support involving bag-mask ventilation.

[0348] Figure 18 A patient interface with at least one sampling port is shown.

[0349] Figure 19 A patient interface is shown, which has a sealing insert for use with the patient interface.

[0350] Figure 20 A patient interface is shown, wherein at least one outflow ventilator includes a small opening and a large opening.

[0351] Figure 21 This is a schematic diagram showing that the flow from at least one outflow vent is directed toward the patient's mouth.

[0352] Figure 22 This is a schematic diagram showing that the flow from at least one outflow vent is directed away from the patient's mouth.

[0353] Figure 23 This is a schematic diagram of a portion of a patient interface, which has an access port with a valve in a normally closed arrangement.

[0354] Figure 24 It shows Figure 23 It is part of the patient interface, in which a tube is inserted into the access port and the valve is in the open position.

[0355] Figure 25A patient interface is shown having an access port that is formed when the ventilation component is removed from the patient interface. Detailed Implementation

[0356] There are several situations in which a patient may have impaired respiratory function or be at risk of impaired respiratory function. One situation involves medical procedures in which the patient is given anesthesia to enable them to tolerate the procedures. Anesthesia may include situations where the patient is awake or unconscious (as opposed to entering natural sleep). Due to the combined administration of anesthetics to the patient to achieve sedation, the patient may become unable to maintain adequate airway protection and / or spontaneous ventilation. Therefore, the patient is at risk of impaired respiratory function. This may also occur due to physiological reasons, regardless of whether anesthesia is used. In these situations, providing respiratory support according to embodiments of the invention may be desirable.

[0357] NHF can provide a solution for meeting a patient's oxygenation and therapeutic needs during anesthesia procedures. However, some patients may have underlying physiological reasons that inhibit the success of NHF or reduce its benefits. Some examples include: upper airway obstruction (including the nasal passages and nasopharynx), such as soft palate closure; lower airway obstruction (including the larynx, trachea, bronchial tree, and lungs); mouth breathing (which carries room air and can dilute the O2 concentration of the delivered gas); and pulmonary shunting (i.e., deoxygenated blood moving from the right side of the heart to the left side and not participating in gas exchange in the pulmonary vessels, such as due to atelectasis).

[0358] In this specification, HF or “high flow rate” means, but is not limited to, a flow rate higher than any conventional / normal gas flow rate, such as a flow rate higher than the normal inspiratory flow rate of a healthy patient. Alternatively or additionally, this flow rate may be higher than some other threshold flow rate relevant to the context; for example, a flow rate that provides a gas flow to a patient at a flow rate that meets or exceeds inspiratory needs may be considered “high flow rate” because it is higher than the nominal flow rate that would otherwise be provided. Therefore, “high flow rate” is context-dependent, and what constitutes a “high flow rate” depends on many factors, such as the patient’s health status, the type of procedure / therapy / support provided, the patient’s nature (large, small, adult, child), etc. Those skilled in the art will understand from the context what constitutes a “high flow rate.” A flow rate exceeding or higher than the flow rate that would otherwise be provided.

[0359] However, without limitation, some indicators of high flow can be as follows.

[0360] In some configurations, gas is delivered to the patient at a flow rate greater than or equal to about 5 or 10 liters per minute (5 or 10 LPM).

[0361] In some configurations, gas is delivered to the patient at a flow rate of about 5 LPM or about 10 LPM to about 150 LPM, or about 15 LPM to about 95 LPM, or about 20 LPM to about 90 LPM, or about 25 LPM to about 85 LPM, or about 30 LPM to about 80 LPM, or about 35 LPM to about 75 LPM, or about 40 LPM to about 70 LPM, or about 45 LPM to about 65 LPM, or about 50 LPM to about 60 LPM. For example, the gas flow rate supplied or provided to the patient interface via the system or from a flow source or flow regulator may include, but is not limited to, flow rates of at least about 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150 LPM or greater, and a useful range may be selected between any of these values ​​(e.g., about 20 LPM to about 90 LPM, about 40 LPM to about 70 LPM, about 40 LPM to about 80 LPM, about 50 LPM to about 80 LPM, about 60 LPM to about 80 LPM, about 70 LPM to about 100 LPM, about 70 LPM to about 80 LPM).

[0362] In the “high flow” configuration, the delivered gas will be selected based on the intended use, such as for therapy and / or respiratory support. The delivered gas may include a percentage of oxygen (also referred to herein as oxygen fraction or oxygen concentration). In some configurations, the percentage of oxygen in the delivered gas may be about 15% to about 100%, 20% to about 100%, or about 30% to about 100%, or about 40% to about 100%, or about 50% to about 100%, or about 60% to about 100%, or about 70% to about 100%, or about 80% to about 100%, or about 90% to about 100%, or about 100%, or 100%.

[0363] The flow rate for "high flow" therapy can vary for premature infants / children (weighing approximately 1 to approximately 30 kg). The flow rate can be set from 0.4 to 8 LPM / kg, with a minimum of approximately 0.5 LPM and a maximum of approximately 70 LPM. For patients weighing less than 2 kg, the maximum flow rate can be set to 8 LPM.

[0364] High flow rates have been found to effectively meet or exceed a patient’s normal inspiratory flow rate in order to increase oxygenation and / or reduce the work of breathing.

[0365] High flow rates can be used to facilitate gas exchange and / or provide respiratory support by delivering high volumes of oxygen and / or other gases and by removing CO2 from the patient's airway. High flow rates may be particularly useful before, during, or after medical and / or anesthesia procedures.

[0366] When used before medical procedures, high gas flow can pre-oxygenate patients, resulting in higher blood oxygen saturation levels and lung oxygenation, thus providing an oxygen buffer during the apnea phase of medical and / or anesthesia procedures.

[0367] During medical procedures where respiratory function may be impaired (e.g., weakened or stopped), such as anesthesia, a continuous supply of oxygen can be used to maintain healthy respiratory function. When this supply is impaired, hypoxemia and / or hypercapnia may occur. During anesthesia procedures, such as general anesthesia, which may render the patient unconscious, the patient can be monitored to detect when this occurs. If the oxygen supply is impaired, the clinician can stop the medical procedure and promote oxygen supply and / or CO2 removal. This can be achieved, for example, by providing artificial ventilation to the patient via an anesthesia bag and mask, or by delivering a high flow of gas to the patient's airway using a high-flow-rate breathing system.

[0368] Other benefits of high gas flow rates include increased pressure in the patient's airway, providing pressure support to open the airway, trachea, lungs / alveoli, and bronchioles. This opening of the structures enhances oxygenation and, to some extent, helps remove CO2.

[0369] During intubation, the increased pressure can also prevent structures such as laryngeal lamps from obstructing the vocal cords' field of vision. When humidified, the high gas flow rate can also prevent the airway from drying out, reduce damage to the mucociliary mucosa, and lower the risk of laryngospasm and risks associated with airway dryness, such as nasal bleeding, aspiration (due to nasal bleeding), and airway obstruction, swelling, and bleeding.

[0370] However, when NHF is delivered via a non-sealed patient interface including a nose fork inserted into the patient's nostril (“conventional NHF”), there is significant, uncontrolled, and difficult-to-measure leakage between the nose fork and the environment. Therefore, for a given supply flow rate, there is variability in the pressure within the patient's airway (e.g., nasal cavity and / or lower airway) between patients, and also in the proportion of flow supplied to the patient's upper and lower airways. Additionally, entrainment of room air can reduce the effective fraction of inhaled O2 (FiO2) in spontaneously breathing patients, the fraction of O2 delivered to the patient's lungs in patients with apnea, and / or the fraction with the mouth open or closed. Air entrainment is generally higher at low supply flow rates, especially when the supply flow rate is below the patient's inspiratory demand. However, when the patient is breathing through their mouth, air entrainment can occur even at higher supply flow rates above inspiratory demand. This effect varies over time and between different patients and is difficult to measure.

[0371] Because clinicians using conventional NHF techniques have little or no control over these factors, the therapy may become suboptimal due to, for example, insufficient pressure in the nasal cavity (based on the patient's inlet size and the choice of predetermined flow rate), or due to other reasons, such as underlying pathology and / or physiology, like nasal obstruction that hinders nasal oxygenation. Therefore, providing guidance and training on appropriate supply flow rate selection is an important aspect of NHF patient safety in current practice; however, because this type of guidance is generalized, clinicians do not always easily identify when or why NHF might be unsuccessful for a particular patient, or how to address this.

[0372] Respiratory support systems utilizing sealed patient interfaces have been used in anesthesia procedures. However, such respiratory support systems are pressure-controlled rather than flow-controlled, meaning the gas supply flow rate is controlled to provide a target pressure rather than a target flow rate. Flow control systems may involve controlling the supply flow rate as described herein. For example, the gas supply flow rate can be set to a predetermined flow rate. The predetermined flow rate can be adjustable, for example, by controlling a proportional valve and / or blower motor speed, manually controlling a flow meter, or by or using a control device. The supply flow rate can remain substantially constant throughout the patient's respiratory cycle. The supply flow rate can be substantially equal to the predetermined flow rate throughout the patient's respiratory cycle. That is, the supply flow rate can be delivered independently of the patient's influence. The supply flow rate can vary over time, and / or the delivered oxygen concentration of the gas supply flow can vary over time. This time-varying characteristic can be independent of the patient's respiratory cycle.

[0373] The sealed patient interfaces used in pressure control systems are specifically designed with restrictive deflection vents, which provide higher resistance to the flow of exhaust gas to provide pressure-controlled respiratory support. In use, the supply flow of respiratory gas is restricted to a low rate to limit the pressure generated by the flow resistance of the deflection vents. Therefore, pressure-controlled respiratory support may not offer the aforementioned benefits of high-flow-rate respiratory support. Furthermore, if used in flow control systems, these sealed interfaces would generate high patient pressure, particularly during exhalation. Therefore, they are not suitable for use with the higher gas supply flow rates that may be provided in flow control systems, where the supply flow rate can be set to meet inspiratory needs, such as in HF respiratory support. Providing such high flow rates through a system with restrictive vents may pose increasing risks to the patient, such as barotrauma and / or gastric distension.

[0374] Embodiments of the present invention provide methods and systems for controlling the supply flow rate of gas provided to a patient via a patient interface, and for generating patient interface pressure and exhaust flow rate from the patient interface. In some embodiments, the rate of increase of the interface pressure at higher exhaust flow rates is greater than the rate of increase of the interface pressure at lower exhaust flow rates. A patient interface system is also provided, comprising an outflow vent for allowing the exhaust flow of gas to escape, for use with the system and / or method. These outflow vents are sufficiently non-limiting to provide low flow resistance (RTF), which allows for the safe delivery of high-flow respiratory support according to the disclosed embodiments. Non-limiting outflow vents may generate more noise in use than more limiting outflow vents. However, it should be understood that in the clinical environments to which the methods, systems, and apparatus of the present invention are applicable, given the background noise levels in, for example, operating rooms and wards, this noise has a minimal impact on patient comfort.

[0375] Reference Figure 1 The respiratory system 100 includes a flow source 104 for providing a gas flow 106 at a predetermined flow rate. The gas flow 106 may include pure oxygen (e.g., an oxygen fraction of 1% or an oxygen concentration of 100%), or a mixture of oxygen with one or more other gases. In an alternative embodiment, the respiratory system 100 may have a connector for coupling to a flow source (not shown), which is external to and fluidly connected to the respiratory system 100. Therefore, the flow source 104 may be part of the respiratory system 100 or may be provided separately to the respiratory system 100. In some embodiments, the flow source may include multiple separate components, some of which are part of the respiratory system 100, and some of which are provided separately to the system 100.

[0376] exist Figure 1 In the illustrated embodiment, the respiratory system 100 may include a flow source 104, a humidifier 108 for heating and humidifying the gas flow 106, an inhalation tubing 110, a tubing 114 (e.g., a drying line or a heated breathing tube), a patient interface 112, one or more pressure reducing valves (not shown), and a filter (not shown).

[0377] The flow source 104 may include an oxygen supply component 120, such as an in-wall oxygen supply, an oxygen tank, other gas tanks and / or a flow device with a flow generator 122. Figure 1A flow source 104 is shown, comprising a flow generator 122, an optional air inlet 124, and an optional connection to an oxygen source (such as a canister or O2 generator) 120 via a shut-off valve and / or regulator and / or other gas flow controller 126, but this is only one option. The flow generator 122 may use one or more valves to control the flow delivered to the patient 102, or optionally, the flow generator 122 may include a blower (not shown) to facilitate the movement of the gas flow 106. The flow source 104 may be one or a combination of the flow generator 122, the oxygen source 120, and the air source 124. The flow source 122 is shown as part of the respiratory system 100, although in the case of an external oxygen canister or an in-wall source, it may be considered a separate component, in which case the respiratory system 100 has a connection port to such a flow source. The flow source provides a gas flow that can be delivered to the patient via an inspiratory tube 110 and a patient interface 112.

[0378] Patient interface 112, disclosed in further detail elsewhere herein, may form part of a patient interface system that is substantially sealed to the patient's nose to substantially prevent gas outflow except via at least one outflow vent provided in the patient interface system. This at least one outflow vent may be located in the body of patient interface 112 or in a conduit in fluid communication with patient interface 112 through which gas leaving patient interface 112 may travel to exit via the at least one outflow vent. In some embodiments, patient interface 112 may include a nasal cannula with a body including a manifold and a nasal fork; and / or a nasal pillow mask; and / or a nasal mask; or any other suitable type of nasal patient interface. Flow source 104 may provide a gas flow rate, for example, from 0.5 liters per minute (LPM) to 375 liters per minute (LPM), or any range within that range, or even a range with higher or lower limits, as previously described.

[0379] The flow source 104 is operable to provide a gas flow 106 at any suitable flow rate according to the patient's needs and / or the relevant respiratory support required. The flow rate of the gas flow 106 can be a continuous flow rate. In particular, the flow rate of the gas flow 106 can be a continuous flow rate independent of the patient's breathing. The continuous flow rate can be variable or generally constant.

[0380] A humidifier 108 may optionally be positioned between the flow source 104 and the patient 102 to provide humidification of the gas flow 106. In some embodiments, the humidifier 108 may be part of the flow source 104. For example, the flow generator 122 may include a built-in humidifier. Humidification of the gas flow 106 can allow for comfortable delivery of the gas flow at low and / or high flow rates. Humidity in the delivered gas flow also prevents the patient's airway from drying out, thereby reducing mucociliary damage and lowering the risk of laryngospasm. Humidity in the gas flow can also reduce the risks associated with airway dryness, such as nasal bleeding, aspiration (due to nasal bleeding), and airway obstruction, swelling, and bleeding. It can also reduce the risk of the laryngoscope sticking to the patient's skin in a dry airway, which can be traumatic for the patient. In some configurations, the gas flow may be humidified to contain more than 10 mg / L of water, or more than 20 mg / L, or more than 30 mg / L, or up to 44 mg / L. In some embodiments, the gas stream can be heated to 21°C to 42°C, or 25°C to 40°C, or 31°C to 37°C, or about 31°C, or about 37°C by a heater (not shown). The heater can be incorporated into or a humidifier 108 can be provided such that the gas stream is substantially humidified and heated simultaneously.

[0381] One or more sensors 128, 130, 132, 134, or any other suitable sensors, such as flow rate, pressure, gas type, humidity, temperature, can be placed throughout the system 100 and / or at, on, or near the patient 102. Alternatively or additionally, sensors from which such parameters can be derived can be used. Additionally or alternatively, sensors 128 to 134 can be one or more physiological sensors for sensing physiological parameters of the patient, such as, but not limited to, blood pressure, heart rate, oxygen saturation, partial pressure of oxygen in the blood (blood oxygen concentration), respiratory rate, end-tidal carbon dioxide, partial pressure of carbon dioxide in the blood (blood CO2 concentration), transcutaneous CO2 concentration (TcCO2), transcutaneous O2 concentration (TcO2), exhaled CO2 concentration, blood oxygen saturation (SpO2), exhaled O2 concentration, blood glucose level, and anesthetic levels in the patient 102. Alternatively or additionally, sensors from which such parameters can be derived can be used. Other patient sensors may include EEG sensors, EKG / ECG sensors, EMG sensors, a trunk band for detecting respiration, and any other suitable sensors. One or more of the sensors may be part of or external to the respiratory system 100, wherein the respiratory system 100 receives input from any external sensors. The sensors may be configured to communicate with the control unit 138.

[0382] exist Figure 1In the illustrated embodiment, sensor 136 may be configured to measure one or more patient parameters at patient 102. This may be placed on patient interface 112, for example, to measure or otherwise allow parameters such as pressure, flow rate, O2 concentration, and CO2 concentration to be determined at the patient's airway (e.g., inside or outside / near the mouth and / or nose and / or patient interface). Sensor 136 may continuously / periodically measure / sample parameters near the patient's airway to continuously monitor parameters at the patient's airway during operation of system 100, thereby providing respiratory support to patient 102. In some examples, the parameters of interest may be determined indirectly. For example, when the flow resistance of the patient interface is known, an indication of flow rate may be indirectly determined from a measurement of the interface pressure, as may be determined during testing or calibration. Monitoring one or more parameters such as pressure, flow rate, O2 concentration, and CO2 concentration at the patient's airway during operation of system 100 enables the system to determine the patient's condition. This document refers, for example, to... Figure 18 Other examples that allow parameter sensing are described.

[0383] System 100 also includes a control device 138 configured to operatively communicate with sensors 130-136 to receive input from the sensors, thereby allowing determination of the presence of one or more “patient conditions” of patient 102, which can trigger operation of system 100 to alter the respiratory support provided. One such alteration may involve changing the gas supply flow rate in gas flow 106.

[0384] Upon receiving an input or instruction from processing sensor data to determine the patient's condition, the control device 138 may control the supply flow rate to change (increase or decrease) the flow rate of gas flow 106, or may instruct the user of system 100 to do so, or may otherwise perform the methods disclosed herein without involving a change (increase or decrease) in the supply gas flow rate. The patient condition indication may indicate that the patient is receiving or has received anesthesia, or is at risk of apnea or respiratory arrest. In some examples, the patient condition indication may correspond to a patient state, or may correspond to a patient parameter value that meets a predefined threshold indicating the patient state. Patient parameters may include, but are not limited to, one or more of the following: the patient's depth of sedation (which may be determined, for example, by a bispectral index (BIS) monitor); heart rate; EEG signal value; EKG / ECG signal value; EMG signal value; blood oxygen concentration; blood oxygen saturation (SpO2); exhaled oxygen concentration; blood CO2 concentration; transcutaneous CO2 concentration (TcCO2); exhaled CO2 concentration; and blood glucose level. Patient conditions may include, but are not limited to, conditions selected from the group consisting of: lower or upper airway obstruction; soft palate obstruction; absence of spontaneous breathing; unmet inspiratory needs; patient at risk of apnea; satisfactory depth of sedation; and expiratory airway pressure at or nearing a suboptimal threshold. Therefore, in response to the indicated patient condition, the supply flow rate can be controlled to a second supply flow rate, which may be a higher flow rate than the first supply flow rate. In another embodiment, in response to the indicated patient condition, the supply flow rate can be controlled to a second supply flow rate, which may be a lower flow rate than the first supply flow rate. In some cases, clinicians or other users may control the gas flow to change the supply flow rate even without indication of a patient condition, such as based on clinical judgment or for other reasons.

[0385] Control device 138 can operatively communicate with user interface 140, which may include a display device and input / output (I / O) elements for receiving user input, such as buttons, dial pads, and / or touchscreens. User interface 140 may present one or more indicators to provide indications of the patient's condition, and / or present one or more parameters determined by control device 138 based on sensor data to indicate the patient's condition. The one or more indicators may include any one or more of sound indicators (e.g., buzzers, alarms), light indicators (e.g., LEDs), graphics, and numerical values. Alternatively or additionally, control device 138 may generate alphanumeric messages, animations, video, or other outputs for display on the display device of user interface 140 and / or may broadcast audio.

[0386] User interface 140 may receive information from a user (e.g., a clinician or patient) that can be used to control or determine oxygen concentration, anesthetic gas reagents, temperature or humidity requirements of gas flow 106, and / or flow rate requirements of gas flow 106. As a non-limiting example, user interface 140 may be used to receive manual user input controlling the gas flow rate to be provided to the patient (i.e., the supply flow rate). Alternatively or additionally, respiratory system 100 may be configured such that control device 138 can determine the gas flow rate to be provided to the patient based on input received from the user and / or via sensors providing input related to patient condition identification. Such patient conditions may include the patient being in a pre-anesthesia state, for which a first supply flow rate may be provided during the pre-oxygenation phase, and / or the patient being under anesthesia or anesthetized (which may include the patient experiencing apnea or respiration), for which a second supply flow rate may be provided, which may correspond to a flow rate higher than the first supply flow rate.

[0387] In some embodiments, the respiratory system 100 may be configured to deliver high-flow-rate gas to a patient and to regulate parameters of the high-flow-rate gas delivered to the patient, such as supply flow rate, exhaust flow rate, patient interface pressure, gas volume, and gas composition.

[0388] Although Figure 1 A single control device 138 is shown, but it should be understood that the respiratory system may include one or more control devices and / or be configured to interact with one or more control devices external to the respiratory system (e.g., via a network connection). In practice, the control device 138 may also include one or more processors to control the operation of the respiratory system 100, including, for example, determining patient parameters based on sensor signals, determining the presence of a patient condition, and determining respiratory support appropriate for the indicated patient condition.

[0389] The respiratory system 100 can be an integrated or separate component-based arrangement, typically as follows: Figure 1 The dashed box indicates this. In some configurations, the respiratory system may include a modular arrangement of components. Furthermore, the respiratory system may include some of the components shown, not all of which are necessarily required. Additionally, catheters and patient interfaces / patient interface systems are not necessarily part of system 100 and may be supplied separately and used with the system to provide the required respiratory support. Hereinafter, it will be referred to as respiratory system 100, but this should not be considered limiting.

[0390] The respiratory system 100 can be used in a variety of situations, including but not limited to pre-oxygenation during anesthesia procedures, during or after administration of anesthetic or sedative agents to the patient during anesthesia procedures. Some applications include, for example, high-flow respiratory support, high-flow therapy, ventilation, and providing a high-flow gas stream in operating rooms, ICUs, or emergency rooms. The respiratory system 100 can be used during patient monitoring, treatment, respiratory support, or supplemental oxygen delivery.

[0391] Figure 2 This is a flowchart schematically illustrating a method 200 for providing respiratory support to a patient during a medical procedure. This method may be used, for example, as shown in reference... Figure 1 The described system is used to perform the method. Method 200 includes, in step 202, providing a gas flow to a patient via a patient interface system having at least one outflow vent. In step 204, the method includes controlling the gas flow at a first supply flow rate and generating a first interface pressure and an exhaust flow through the at least one outflow vent at a first exhaust flow rate. In step 206, the method includes controlling the gas flow at a second supply flow rate and generating a second interface pressure and an exhaust flow through the at least one outflow vent at a second exhaust flow rate. Through the operation of method 200, a first predetermined flow resistance (RTF) of the at least one outflow vent at the first exhaust flow rate is different from a second predetermined flow resistance (RTF) of the at least one outflow vent at the second exhaust flow rate. In some examples, the first predetermined RTF of the at least one outflow vent at the first exhaust flow rate is less than the second predetermined RTF of the at least one outflow vent at the second exhaust flow rate. It should be understood that, in examples involving more than one outflow vent, the term "exhaust velocity" refers to the total exhaust velocity through all outflow vents, and the term "flow resistance" refers to the total flow resistance caused by all outflow vents. In some examples, the first supply velocity and the second supply velocity may be approximately the same as the corresponding exhaust velocity.

[0392] In some examples, the first predetermined RTF of at least one outflow vent at the first exhaust flow rate can be greater than about 0 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹, or about 0.05 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹, or about 0.1 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹. The second predetermined RTF of at least one outflow vent at the second exhaust flow rate can be greater than about 0.15 cmH2O / Lmin⁻¹ to less than about 0.5 cmH2O / Lmin⁻¹, or about 0.2 cmH2O / Lmin⁻¹ to about 0.4 cmH2O / Lmin⁻¹, or about 0.2 cmH2O / Lmin⁻¹ to about 0.3 cmH2O / Lmin⁻¹. For a given exhaust flow rate, the RTF of at least one outlet vent can be attributed to the size and / or shape of that at least one vent, for example, to the total cross-sectional area of ​​one or more vents, as described in further detail below. The flow resistance of at least one outlet vent can be determined as the difference between the interface pressure and the ambient pressure divided by the exhaust flow rate. Relatedly, as discussed below, there exists a nonlinear pressure-flow relationship for the gas, which is attributed to the size and / or shape of at least one outlet vent. Therefore, since the exhaust flow rate is a function of the supply flow rate of the gas provided to the patient, the RTF of at least one outlet vent with a given size and / or shape can be varied by controlling the flow rate of the gas supplied to the patient interface system during use. This does not require adjusting the size and / or shape of the at least one vent itself.

[0393] In some examples involving restrictors for generating non-uniform flow in the chamber of a patient interface, as discussed below, it should be understood that at least two outflow vents should be provided, one on each side of the restrictor, to allow flow to exit the chamber. In such an arrangement, the interface pressure on each side of the chamber (i.e., on each side of the restrictor) approximates the pressure in the corresponding nostril of the patient, and the average of these pressures represents the pressure within the patient's nasal cavity (in the absence of net flow to or from the patient).

[0394] As described elsewhere herein, a patient interface may include a sealing element. The sealing element substantially prevents gas from escaping from the patient except via at least one outflow vent provided in the patient interface system. The patient interface system may include a patient interface 112 and an inspiratory conduit 110 that provides a gas flow path for supplying gas to the patient. At least one outflow vent may be provided in the patient interface 112, and / or the at least one outflow vent may be part of the inspiratory conduit through which exhaled gas from the patient may exit the patient interface system. The method may include the step of applying the patient interface to the patient in step 201.

[0395] Figure 3 This is a flowchart schematically illustrating a method 300 for providing respiratory support to a patient during a medical procedure. The method may be described using, for example, reference... Figure 1 The method is performed using the described system. In step 302, the method includes providing a gas flow to a patient via a patient interface system having at least one outflow vent. In step 304, the method includes controlling the gas flow at a first supply flow rate and generating a first interface pressure (P). 接口 The method includes controlling the gas flow at a second supply flow rate and generating a second interface pressure (P) at a first exhaust flow rate (EFR) through at least one outlet vent. In step 306, the method further includes controlling the gas flow at a second supply flow rate and generating a second interface pressure (P). 接口 ) and the exhaust flow rate (EFR) through at least one outlet vent at a second exhaust flow rate. Due to the non-linear relationship between interface pressure and exhaust flow rate, the second interface pressure (P) associated with the second exhaust flow rate (EFR) is... 接口 The second rate of change (RoC) is greater than the first interface pressure (P) associated with the first exhaust flow rate (EFR). 接口 The first rate of change (RoC) of the flow rate. In use, this can be observed as a higher RTF. The RoC of the patient interface can be determined using simulation or testing protocols, as discussed below. The RoC can be an instantaneous RoC value, or an average value measured over, for example, a range of first exhaust flow rate values ​​including a first exhaust flow rate and a range of second exhaust flow rate values ​​including, for example, a second exhaust flow rate. The method may include the step of applying the patient interface to the patient in step 301.

[0396] Figure 2 and Figure 3 Steps 204 / 304 and 206 / 306 are shown in the order of controlling the gas flow at the first supply flow rate before the second supply flow rate. However, this is not mandatory, and the method can be modified such that step 206 / 306, which includes controlling the gas flow at the second supply flow rate, occurs before step 204 / 304, which includes controlling the first supply flow rate, as indicated by the dashed arrows.

[0397] In some examples, the second supply flow rate is higher than the first supply flow rate. In some examples, the second inlet pressure and the second exhaust flow rate are both higher than the first inlet pressure and the first exhaust flow rate. When applying methods 200 and 300 to provide respiratory support to a patient during the induction of anesthesia, it may be as follows: a first supply flow rate is provided to pre-oxygenate the patient, and once the patient has been administered anesthetic, a higher second supply flow rate is provided to support the patient's oxygenation needs. The first supply flow rate may be greater than about 0 LPM, about 10 LPM, about 20 LPM, about 30 LPM, about 40 LPM, or about 50 LPM, or higher, such as about 60 LPM, about 70 LPM, about 80 LPM, about 90 LPM, about 100 LPM, about 110 LPM, about 120 LPM, about 130 LPM, about 140 LPM, or about 150 LPM, or values ​​between these values. The second supply flow rate can be greater than about 40 LPM, about 50 LPM, about 60 LPM, about 70 LPM, about 80 LPM, about 90 LPM, or about 100 LPM, or higher, such as about 110 LPM, about 120 LPM, about 130 LPM, about 140 LPM, or about 150 LPM, or values ​​in between. In some examples, the second supply flow rate can be less than 40 LPM, such as about 20 LPM or about 30 LPM, or values ​​in between.

[0398] In some examples, the first exhaust flow rate may be the same as the first supply flow rate. In some examples, the second exhaust flow rate may be the same as the second supply flow rate. In some examples, the first exhaust flow rate may be between greater than about 0 LPM and about 40 LPM, or between greater than about 0 LPM and about 30 LPM, or between about 30 LPM and about 40 LPM, or between about 35 LPM and about 45 LPM. In some examples, the second exhaust flow rate may be between greater than about 40 LPM and about 100 LPM, or between about 40 LPM and about 70 LPM, or between about 40 LPM and about 60 LPM, or between about 50 LPM and about 70 LPM, or between about 50 LPM and about 60 LPM, or between about 60 LPM and about 70 LPM. In some examples, the first and second (and third) supply flow rates may be substantially the same as the corresponding exhaust flow rates.

[0399] In some examples, the method includes providing a second supply flow rate in response to an indication of the patient's condition. The indication of the patient's condition may be determined in step 205 / 305 by one or more of the following: observation of the patient and / or patient parameters, such as by a clinician; user confirmation of the administration of therapy to the patient, such as by providing input to user interface 140; measurement of one or more patient parameters, such as by sensors forming part of system 100 or external sensors, the values ​​from which may be provided manually via user interface 140; control devices using data received from the user or one or more devices (e.g., sensors monitoring patient parameters) to determine the indication of the patient's condition; and the patient's self-report of their condition, and input provided or a request made by the user or caregiver via user interface 140.

[0400] In the system providing method 200 / 300, an indication of the patient's condition can be provided to the control device 138 by a user interacting with user interface 140. Alternatively or additionally, the patient's condition can be determined by a processor of the control device 138, which is programmed with predefined thresholds for one or more patient parameters, for example, in a lookup table or function stored in memory associated with the control device 138. These predefined thresholds can be used to indicate the presence of a patient condition when compared with data received from sensor signals provided as input to the control device. Thus, a patient condition can correspond to a patient state, or it can correspond to a patient parameter value that satisfies a predefined threshold, which indicates a patient state. Patient parameters may include, but are not limited to, one or more of the following: the patient's depth of sedation (which can be determined, for example, by a BIS monitor); heart rate; EEG signal value; EKG / ECG signal value; EMG signal value; blood oxygen concentration; blood oxygen saturation (SpO2); exhaled oxygen concentration; blood CO2 concentration; transcutaneous CO2 concentration (TcCO2); transcutaneous O2 concentration (TcO2); exhaled CO2 concentration; and blood glucose level. Patient conditions may include, but are not limited to, conditions selected from the following groups: lower or upper airway obstruction; soft palate obstruction; absence of spontaneous breathing; unmet inspiratory needs; patient at risk of apnea; adequate sedation; and expiratory airway pressure at or nearing a suboptimal threshold. Therefore, a second supply flow rate, which may be higher than the first supply flow rate, may be supplied in response to the indicated patient condition.

[0401] Control of the first and / or second supply flow rates can be achieved by one or more of the following: in response to confirmation of an indication of the patient's condition by a user (or a system that may include suitable sensors as described above), the user manually selects the second supply flow rate, for example, in a system where the control device includes a control knob on the flow source. In some embodiments, when the control device receives user input confirming the patient's condition, it uses methods such as... Figure 1 The controller of the control device 138 implements control, which controls a second supply flow rate selected or predetermined by the user, or determines the second supply flow rate, for example, by a processor associated with the control device. In some embodiments, when the control device determines the presence of a patient condition, for example by a processor associated with the control device, using data received from one or more devices (e.g., sensors) that monitor patient condition parameters, it may use methods such as... Figure 1 The controller of the control device 138 determines the second supply flow rate, thereby achieving control.

[0402] In some embodiments, a first supply flow rate may be provided before the anesthetic is administered to the patient, and a second supply flow rate may be provided after the anesthetic is administered to the patient. Thus, a second supply flow rate may be provided in response to an indication that the anesthetic is being or has been administered to the patient. The indication that the anesthetic is being or has been administered to the patient can be determined by a clinician observing the patient and / or patient parameters and manually inputting the indication into the control device 138 using the user interface 140. In some embodiments, the control device 138 may use data received from a user or one or more devices (e.g., sensors or BIS) that provide the indication that the anesthetic is being or has been administered to the patient.

[0403] In some embodiments, respiratory support is provided to the patient according to method 200 or 300 before anesthetic delivery and / or before the patient begins anesthesia or sedation. For example, a first supply flow rate and a second supply flow rate may be provided to the patient during a pre-oxygenation phase prior to the introduction of anesthesia. For example, if the patient is determined to have an obstructed soft palate. An advantage of the present invention, compared to a conventional NHF, is that it generates higher interface pressure (which in turn generates higher nasal cavity pressure) at the second exhaust flow rate range, which can help relieve soft palate obstruction that a conventional NHF cannot overcome. Alternative parameters for nasal cavity pressure can be determined by measuring the patient interface pressure in the substantially sealed nasal interface.

[0404] In some embodiments, method 200 includes, in step 210, controlling the gas flow at a third supply flow rate and generating a third interface pressure (P). 接口 And an exhaust flow through at least one outflow vent at a third exhaust flow rate (EFR), wherein the third predetermined flow resistance (RTF) of the at least one outflow vent at the third exhaust flow rate (EFR) is different from the second predetermined flow resistance of the at least one outflow vent at the second exhaust flow rate.

[0405] In some embodiments, method 300 includes, in step 310, controlling the gas flow at a third supply flow rate and generating a third interface pressure (P). 接口) and exhaust flow through at least one outlet vent at a third exhaust flow rate (EFR), wherein the third interface pressure (P) associated with the change in the third exhaust flow rate (EFR) 接口 The rate of change (RoC) of the second exhaust flow rate (EFR) is less than that of the second interface pressure (P) associated with the change in the second exhaust flow rate (EFR). 接口 The rate of change (RoC) of ).

[0406] For example, when the patient's condition has changed, the third supply flow rate may be lower than the second supply flow rate. Therefore, the RoC of the third interface pressure, third EFR, third predetermined RTF, and the third interface pressure associated with changes in the third EFR may all be lower than those at the second supply flow rate. The third supply flow rate, third interface pressure, third EFR, and third predetermined RTF may all be the same as the corresponding first supply flow rate, first interface pressure, first EFR, and first predetermined RTF. For example, if the patient's condition remains unchanged, the third supply flow rate may be higher than the second supply flow rate. Therefore, the RoC of the third interface pressure, third EFR, third predetermined RTF, and the third interface pressure associated with changes in the third EFR may all be higher than those at the second supply flow rate.

[0407] Therefore, in some embodiments, the method includes providing a third supply flow rate that may be provided in response to an indication of a (second) patient condition different from a previously identified (first) patient condition. The indication of the second patient condition may be determined in step 209 / 309 by one or more of the following: observation of the patient and / or patient parameters; measurement of one or more patient parameters, for example, by sensors forming part of system 100 or external sensors, the values ​​from which may be provided manually via user interface 140; control devices using data received from the user or one or more devices monitoring patient parameters (e.g., sensors) to determine the indication of the different patient condition; and the patient's self-report of their condition, and input provided or a request made by the user or caregiver via user interface 140. The method does not require the third supply flow rate to be provided indefinitely. The method may include changing control from the third supply flow rate to a first or second supply flow rate.

[0408] In the system providing method 200 / 300, an indication of the second condition can be provided to the control device 138 by a user interacting with the user interface 140. Alternatively or additionally, the second patient condition can be determined by a processor of the control device 138, which is programmed with predefined thresholds for one or more patient parameters, for example, in a lookup table or function stored in memory associated with the control device 138. These predefined thresholds can be used to indicate the presence of the second patient condition when compared with data received from sensor signals provided as input to the control device. Thus, the second patient condition can correspond to a patient state, or it can correspond to a patient parameter value that meets a predefined threshold, which indicates the patient state. The second patient condition can be selected from, for example, the group consisting of: the lower or upper airway becoming open; the soft palate no longer obstructing; spontaneous breathing being present; the patient's inspiratory needs being met; a predetermined level of alertness being met; and expiratory interface pressure being met or exceeding an optimal threshold. These conditions can indicate awakening or recovery from anesthesia or apnea.

[0409] In some embodiments, the exhaust flow rate and the inlet pressure are correlated such that the rate of change of the inlet pressure increases with increasing exhaust flow rate, particularly at higher exhaust flow rates. In use, for a given gas supply flow rate, this can result in a higher inlet pressure than that produced by a conventional NHF (using a non-sealed inlet), especially at higher exhaust flow rates. This can provide certain advantages, which will be discussed below. In some embodiments, the exhaust flow rate (Q) and the inlet pressure (P) can be correlated such that they exhibit a non-linear relationship when presented graphically. In some embodiments, the non-linear relationship is a relationship that may be referred to as a PQ curve. The PQ curve may contain polynomial components. In some embodiments, the polynomial components may be quadratic polynomial components. Figure 4 An example of a PQ curve according to an embodiment of the present invention is shown at position 402.

[0410] Exhaust flow rate is a function of the supply flow rate of gas provided to the patient. In some examples, the first and second (and third) supply flow rates can be approximately the same as the corresponding exhaust flow rates. Therefore, increasing the supply flow rate can increase the exhaust flow rate. Exhaust flow rate can also be affected by patient-dependent flow, such as the patient's inspiratory and expiratory flow rates, and whether the patient's mouth is open or closed. Figure 4 The PQ curve in the diagram represents the relationship between the inlet pressure and the exhaust flow rate in the absence of net flow to or from the patient, such as during breath-holding, during the transition between inhalation and exhalation, or during apnea. Figure 4The curved PQ curve in the figure can be time-averaged, and / or the interface pressure can represent the average interface pressure over several patient respiratory cycles. There may be some variation in the PQ curve 402, which is attributed to component variability or sensor measurement variability. As shown, the curved PQ curve 402 is represented as a single line rather than a band, and can represent instantaneous or mean, median, or average pressure values.

[0411] PQ curves (such as curve 402) or values ​​representing the relationship between interface pressure and exhaust flow rate can be obtained by performing a simulation or test protocol using a patient interface of the type required for respiratory support. In such a test, the nasal element of the patient interface is sealed to simulate a patient in the absence of net flow to or from the patient. Interface pressure is measured within a range of supply flow rates. Depending on the method of providing respiratory support, the range of supply flow rates may include at least a first supply flow rate and / or a second supply flow rate and / or a third supply flow rate. Since there is no patient, the exhaust flow rate (e.g., the first exhaust flow rate and the second exhaust flow rate or the third exhaust flow rate) will be the same as the supply flow rate (e.g., the first supply flow rate, the second supply flow rate, and the third supply flow rate, respectively). Furthermore, the measured interface pressure values ​​(including the first interface pressure and the second interface pressure measured for the first exhaust flow rate and the second exhaust flow rate, respectively, and the third interface pressure measured optionally for the third exhaust flow rate) can be used to generate PQ distribution curves, tables, or functions. The flow resistance at at least one outlet can be determined as the difference between the interface pressure and the ambient pressure divided by the exhaust flow rate. Using values ​​from simulations, the total RTF of at least one outflow ventilator in the patient interface can be determined for a range of exhaust flow rates.

[0412] Furthermore, simulations or tests can be used to determine whether the patient interface exhibits a rate of change in interface pressure (dP) with respect to changes in exhaust flow rate (dQ) over a range of supply flow rates. Using values ​​obtained from simulations or tests, dP / dQ can be calculated as a continuous function and then used to determine instantaneous values ​​at one or more specific flow rates. For example, the instantaneous rate of change can be determined, for instance, by calculating the slope of the tangent to the PQ curve function at a given exhaust flow rate (e.g., a first exhaust flow rate and a second exhaust flow rate). Alternatively, the rate of change can also be determined as the average rate of change over a range of exhaust flow rate values, including, for example, a first exhaust flow rate or a second exhaust flow rate. Using such simulations or tests, it can be determined whether respiratory support provided using the patient interface has at least one outflow vent configured to achieve RTF and a rate of change in interface pressure that meets the criteria of this invention.

[0413] In some examples, the second rate of change of the second interface pressure associated with the second exhaust velocity is greater than the first rate of change of the first interface pressure associated with the first exhaust velocity. This is represented in PQ curve 402, which has a first rate of change of interface pressure in the first exhaust velocity range A' and a second rate of change of interface pressure in the second exhaust velocity range B'. The rate of change can be within an exhaust velocity range that includes either the first exhaust velocity value or the second exhaust velocity value (e.g., ...). Figure 4 The rate of change is the average value determined within the flow velocity ranges A' and B' in the given flow velocity range. Figure 4 The instantaneous value determined by the flow velocity A or B in the medium. For example... Figure 4 As shown, the second rate of change at B' is greater than the first rate of change at A'. Similarly, the second rate of change at B is greater than the first rate of change at A. From Figure 4 It can be understood that the rate of change of the interface pressure is determined relative to the flow rate (rather than time). In some embodiments, for a first exhaust flow rate value in the range of greater than about 0 LPM to about 40 LPM, or greater than about 0 LPM to about 30 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, the first rate of change may be in the range of greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1. In some embodiments, for a second exhaust flow rate value in the range of greater than about 30 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM, the second rate of change may be in the range of greater than about 0.1 cmH2O / Lmin⁻¹ to less than about 0.6 cmH2O / Lmin⁻¹, or about 0.15 cmH2O / Lmin⁻¹ to about 0.5 cmH2O / Lmin⁻¹, or about 0.2 cmH2O / Lmin⁻¹ to about 0.4 cmH2O / Lmin⁻¹, or about 0.2 cmH2O / Lmin⁻¹ to about 0.3 cmH2O / Lmin⁻¹. In some examples, the first and second (and third) supply flow rates may be substantially the same as the corresponding exhaust flow rates.

[0414] This invention can provide a supply flow rate that achieves a high exhaust flow rate under safe patient pressure. This will combine Figure 6Further discussion. Utilizing various aspects of the present invention, clinicians can achieve an interface pressure of approximately 3-5 cmH2O at an exhaust flow rate of approximately 40 LPM, and can achieve a higher interface pressure of approximately 10-12 cmH2O at an exhaust flow rate of approximately 70 LPM, which is higher than the average patient airway pressure achievable with a conventional NHF at the same flow rate with the patient's mouth closed.

[0415] In some embodiments, this is achieved using a patient interface having at least one outflow vent and a sealing element. The sealing element can substantially restrict gas escape from the patient except via at least one outflow vent. The exhaust flow rate and interface pressure disclosed herein can be achieved by providing a predetermined low flow resistance (RTF) between the patient interface and the surrounding environment (referred to herein as the “environment”), which can be achieved by providing at least one outflow vent.

[0416] The predetermined RTF of at least one outflow vent described herein can be advantageous when the supply flow rate is less than the patient's inspiratory demand, making it easier to entrain ambient air to compensate for any shortfall in inspiratory demand. That is, ambient air entering the patient interface through the outflow vent during inspiration can supplement the supply flow. Due to the low RTF, pressure loss is reduced, and the work of inhalation can be reduced. With this in mind, although the terms "exhaust flow rate" and "outflow vent" are mentioned throughout the disclosure, these do not limit the flow direction of gas that can pass through at least one outflow vent to a direction from the patient to the environment. This is because a low RTF that allows for high exhaust flow rates can also allow inward flow from the environment to the patient, with a flow rate that is the same as or similar to the exhaust flow rates described above. Simply put, the flow through at least one outflow vent can be in either direction.

[0417] In some examples, the method and / or system may include the use of a patient interface having a very low RTF through at least one outflow ventilator, such that the at least one outflow ventilator typically allows bidirectional flow into and out of the interface. In such examples, the total RTF flowing out of at least one vent can be greater than about 0 cmH2O / Lmin⁻¹ to about 0.5 cmH2O / Lmin⁻¹, or about 0.1 cmH2O / Lmin⁻¹ to about 0.4 cmH2O / Lmin⁻¹, or about 0.1 cmH2O / Lmin⁻¹ to about 0.3 cmH2O / Lmin⁻¹, or about 0.2 cmH2O / Lmin⁻¹ to about 0.3 cmH2O / Lmin⁻¹, or greater than about 0 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹, or about 0.05 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹, or about 0.1 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹, or greater than about 0.15 cmH2O / Lmin⁻¹ to less than about 0.5 cmH2O / Lmin⁻¹. The supply flow rate may be between approximately 0.2 cmH2O / Lmin⁻¹ and approximately 0.4 cmH2O / Lmin⁻¹, or approximately 0.2 cmH2O / Lmin⁻¹ and approximately 0.3 cmH2O / Lmin⁻¹. The supply flow rate may be greater than approximately 0 LPM, approximately 10 LPM, approximately 20 LPM, approximately 30 LPM, approximately 40 LPM, or approximately 50 LPM, or higher, such as approximately 60 LPM, approximately 70 LPM, approximately 80 LPM, approximately 90 LPM, approximately 100 LPM, approximately 110 LPM, approximately 120 LPM, approximately 130 LPM, approximately 140 LPM, or approximately 150 LPM, or values ​​between these values. The supply flow rate may be approximately the same as or higher than the exhaust flow rate.

[0418] By substantially eliminating the aforementioned uncontrolled leakage paths between the patient interface and the environment in conventional NHF, the present invention provides a method that can provide more consistent performance over time and across different patients. This is achieved by substantially eliminating uncontrolled leakage between the nostril and the patient interface, such that gas leaves the patient primarily via at least one outflow vent, wherein the at least one outflow vent is calibrated to have higher flow resistance at higher exhaust flow rates.

[0419] According to the methods, systems, and apparatus of the present invention, respiratory support can be provided to patients undergoing medical procedures (such as scheduled medical procedures) where the patient has weakened respiratory function, is at risk of weakened respiratory function, or is experiencing respiratory arrest. However, it should be understood that the invention can also be applied to other settings, such as hospitals or healthcare settings, or other situations where respiratory support can be provided. The method may involve utilizing… Figure 4 The PQ curve provides respiratory support, controlling the supply flow rate to produce the desired exhaust flow rate and interface pressure. Similar to conventional NHF, these methods and systems are flow-controlled and can be safely used with existing gas sources in a manner familiar to clinicians. However, unlike conventional NHF, the methods and systems of this invention can produce higher mean interface pressures at higher flow rates and potentially have smaller inter-patient pressure variations.

[0420] It should be understood that, according to embodiments of the present invention, the rate of change of interface pressure with respect to exhaust flow rate does not need to remain constant within the range of P or Q values. The rate of change may include a PQ curve, and in some embodiments, the PQ curve may include a polynomial component, such as a quadratic polynomial component. Figure 4 An example of a PQ curve according to an embodiment of the present invention is shown at 402. The rate of change may include an average rate of change over an operating flow rate range or pressure range, or within a subrange of an operating range. The operating flow rate range or subrange of an operating range includes the flow rate value that provides respiratory / clinical support during use. Rates of change achieved through the various examples disclosed herein can be determined using simulations or tests as described above. For example, the first and / or second rates of change may include an average rate of change. Furthermore, the relationship between P and Q of the first and second rates of change may be such that, when presented graphically, their relationship includes one or more of the following: a stepwise change between the first and second rates of change; a gradual change between the first and second rates of change; a curvilinear change between the first and second rates of change; a portion of the first and / or second rates of change having a non-constant gradient; a non-stepwise change at the transition between the first and second exhaust flow rates; and a non-stepwise change at the transition between the second and third exhaust flow rates.

[0421] In some embodiments, the method includes controlling the gas flow and generating one or more of the following: a first exhaust flow rate of about 40 LPM and a first interface pressure of about 3-5 cmH2O, such as about 4 cmH2O; a first exhaust flow rate of about 30 LPM and a first interface pressure of about 2-4 cmH2O, such as about 3 cmH2O; a second exhaust flow rate of about 50 LPM and a second interface pressure of about 5-8 cmH2O, such as about 6 cmH2O; a second exhaust flow rate of about 55 LPM and a second interface pressure of about 6-8 cmH2O; a second exhaust flow rate of about 60 LPM and a second interface pressure of about 7-9 cmH2O; and a second exhaust flow rate of about 70 LPM and a second interface pressure of about 7-15 cmH2O, such as about 9-12 cmH2O, such as about 9-10 cmH2O, or about 10-12 cmH2O. In some examples, the first and second (and third) supply flow rates may be substantially the same as the corresponding exhaust flow rates.

[0422] The method may include operating a flow source 104 to provide a gas flow, wherein the flow source is controlled by a control device 138 configured to receive control inputs provided by a user via a user interface 140 and / or control inputs generated by a processor including a portion of the control device 138 or operatively communicating with the control device 138.

[0423] It should be understood that the measured interface pressure may be affected if the patient's mouth is open. For example, at a given supply flow rate, the measurable interface pressure is greater when the mouth is closed than when the mouth is open. Unlike conventional NHF, the interface pressure generated according to the present invention can be more consistent across different patients and can produce higher pressure in the nasal cavity at higher exhaust flow rates. This can help overcome soft palate closure, even if the central airway pressure remains low due to subsequent mouth opening. Figure 18 A patient interface with at least one sampling port is shown, which can be used to measure interface pressure. Alternatively or additionally, the interface pressure can be derived or estimated from the system pressure discussed below.

[0424] In some embodiments, the patient may be undergoing a medical procedure, such as a predetermined medical procedure, while respiratory support is being provided. The method may include administering an anesthetic to the patient. The patient may breathe spontaneously for at least a portion of the medical procedure, but may lose consciousness or be sedated (as opposed to entering a natural sleep or drowsy state) after the administration of the anesthetic. The patient may breathe involuntarily for at least a portion of the medical procedure after the administration of the anesthetic. The patient does not require apnea during the medical procedure. The gas flow provided at one or both of a first and a second supply flow rate may include a 100% O2 concentration, although this is not mandatory, and the gas flow may include a mixture of gases such as air and O2 or other respiratory gases.

[0425] Figure 5 This is a flowchart schematically illustrating a method 500 for providing respiratory support to a patient. This method may be used, for example, as shown in [reference needed]. Figure 1 The system described is used to perform this. Method 500 includes, in step 502, providing a gas flow to a patient via a patient interface system including at least one outflow vent and a sealing element. The sealing element can substantially restrict gas escape from the patient except via at least one outflow vent. In step 504, the method includes controlling the gas supply flow rate to the patient interface system and generating an interface pressure (P). 接口 ) and exhaust flow at an exhaust flow rate (EFR) through at least one outlet vent. Through the operation of method 500, the interface pressure (P 接口 The relationship between exhaust flow rate (EFR) and exhaust gas velocity (FFR) is nonlinear. This nonlinear relationship may contain polynomial components, such as quadratic polynomial components, etc. Figure 4 The PQ curve is 402.

[0426] It should be understood that the nonlinear relationship does not need to be entirely curvilinear. The nonlinear relationship between interface pressure and exhaust velocity can be correlated such that, when presented graphically, the rate of change between interface pressure and exhaust velocity includes one or more of the following: a stepwise change between the first and second rates of change; a gradual change between the first and second rates of change; a curvilinear change between the first and second rates of change; a portion of the first and / or second rates of change having a non-constant gradient; a non-stepwise change at the transition between the first and second exhaust velocities; or a non-stepwise change at the transition between the second and third exhaust velocities. The rate of change expressed as a nonlinear relationship does not need to be constant.

[0427] For a first exhaust flow rate value greater than about 0 LPM to about 40 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, the first rate of change between the interface pressure and the exhaust flow rate may be greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1. For a second exhaust flow rate value greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM, the second rate of change of the interface pressure with the exhaust flow rate may be greater than about 0.1 cmH2O / Lmin-1 to less than about 0.6 cmH2O / Lmin-1, or about 0.15 cmH2O / Lmin-1 to about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

[0428] At step 504, controlling the supply flow rate may include controlling the gas flow and generating an interface pressure based on an exhaust flow rate-interface pressure relationship, which includes one or more values ​​selected from, but not limited to, the group consisting of: a first exhaust flow rate of about 40 LPM and a first interface pressure of about 3-5 cmH2O, such as about 4 cmH2O; a first exhaust flow rate of about 30 LPM and a first interface pressure of about 2-4 cmH2O, such as about 3 cmH2O; a second exhaust flow rate of about 50 LPM and a second interface pressure of about 5-8 cmH2O, such as about 6 cmH2O; a second exhaust flow rate of about 55 LPM and a second interface pressure of about 6-8 cmH2O; a second exhaust flow rate of about 60 LPM and a second interface pressure of about 7-9 cmH2O; and a second exhaust flow rate of about 70 LPM and a second interface pressure of about 7-15 cmH2O, such as about 9-12 cmH2O, such as about 9-10 cmH2O, or about 10-12 cmH2O. In some examples, the first supply flow rate and the second supply flow rate can be approximately the same as the corresponding exhaust flow rate.

[0429] In some examples, the first exhaust flow rate can be between about 0 LPM and about 40 LPM, or between about 30 LPM and about 40 LPM, or between about 35 LPM and about 45 LPM. In some examples, the second exhaust flow rate can be between about 40 LPM and about 100 LPM, or between about 40 LPM and about 70 LPM, or between about 40 LPM and about 60 LPM, or between about 50 LPM and about 70 LPM, or between about 50 LPM and about 60 LPM, or between about 60 LPM and about 70 LPM. In some examples, the first supply flow rate and the second supply flow rate can be substantially the same as the corresponding exhaust flow rate.

[0430] As disclosed herein in conjunction with other aspects, the exhaust flow rate is a function of the supply flow rate of gas provided to the patient. A first supply flow rate may be provided, which produces a first exhaust flow rate and a first interface pressure, and a second (or subsequent) supply flow rate may be provided, which produces a second (or subsequent) exhaust flow rate and a second (or subsequent) interface pressure, wherein the graphical representation of the interface pressure versus the exhaust flow rate value is non-linear. In some examples, this non-linear graphical representation includes polynomial components. This non-linear graphical representation may be determined based on simulations or tests as described herein. The first and second supply flow rates may include ranges as disclosed elsewhere herein and may be selected, for example, in response to indications of the patient's condition as disclosed elsewhere herein, to provide respiratory support.

[0431] The patient interface system may include a patient interface as described elsewhere herein. In some embodiments, the method includes, in step 501, applying the patient interface to a patient. The patient interface may be configured to provide a flow of gas into the patient's nostrils and may include a body portion including at least one outflow vent configured to generate a predetermined interface pressure due to an exhaust flow rate from the at least one outflow vent, the exhaust flow rate being a function of a supply flow rate. In some embodiments, the patient interface may include a body portion including at least one outflow vent configured to generate a first flow resistance at a first supply flow rate, the first flow resistance being different from the second flow resistance at a second supply flow rate as described above. In some embodiments, the patient interface may include a pair of nose forks configured to provide a flow of gas into the patient's nostrils, and at least one outflow vent includes at least one opening located in each nostril in an insert surrounding the nose fork. In such examples, the insert includes a sealing element as described elsewhere herein, and at least one outflow vent. In some embodiments, the patient interface may include a pair of nose forks configured to provide a flow of gas into the patient's nostrils, and at least one outflow vent includes at least one opening in a sealed body formed around each nose fork.

[0432] Figure 6 This is a graphical representation of the interface pressure and exhaust velocity that can be generated by the method according to the invention, wherein at least one outflow vent has a low total RTF and can be considered "permissive" (dark curve, 602) compared to the interface pressure and exhaust velocity in a restrictive system with a restrictive deflector vent having a higher total RTF. As disclosed elsewhere, the exhaust velocity (Q) generated according to the invention... 排气 Q is a function of the gas supply flow rate provided to the patient. Therefore, Q 排气 It is the supply flow rate (Q) 设定 The patient interface system includes at least one outflow vent and a sealing element that substantially restricts gas from escaping from the patient except via the at least one outflow vent in Q. 设定 There is an expected interface pressure (P) at that location. 预期 In cases of respiratory arrest, during breath-holding or between inspiration and expiration, and when the patient's mouth is closed (i.e., in the absence of flow into or out of the patient), Q 排气 equals Q 设定 ,like Figure 6 As shown. The same applies in simulations or tests as disclosed in this document. Actual interface stress in use (P) 实际During the respiratory cycle of a patient breathing spontaneously (or otherwise), the minimum patient pressure (P) can be maintained. 最小 ) and maximum patient stress (P 最大 The variation between ) and Q 排气 Change along the dark arrow. For example, P 最大 It can be the pressure reached at the patient's peak expiratory flow rate. Therefore, in spontaneously breathing patients, P... 实际 Around P 预期 Change. For example... Figure 6 As shown, the permissive system represented by curve 602 can advantageously allow higher flow velocities than the restrictive system represented by curve 604, without exceeding P. UL .

[0433] As those skilled in the art will understand, the flow control method disclosed herein may involve the use of system 100, which can be configured to operate within a predefined pressure range. In some examples, this can be achieved, for example, by programming control device 138 to operate at a desired lower pressure limit P. LL With pressure upper limit P UL This is achieved by providing breathing support between them. In one example, P LL It can be 0 cmH2O. In another example, the control device 138 can be programmed to P LL Set to approximately 1 cmH2O, and set P UL The value is set at approximately 12 cmH2O. P UL and P LL It can be applied in a supply flow rate range of approximately 0 to 100 LPM. One or more pressure reducing valves may be installed in system 100 to detect when the sensor determines that the interface pressure has exceeded P. UL In cases where pressure is released from the flow path, the control device 138 can be programmed to control the operation of the flow source 104 to reduce the flow to the patient. This allows the method and system to release pressure beyond the patient's peak inspiratory demand. 设定 Below is a safe P 预期 Operation (due to Q) 排气 and P 实际 It is Q 设定 Q is a function of (the function of the lungs). In patients with sleep apnea, there is no or almost no inspiratory demand (e.g., flow generated by gas exchange in the lungs), therefore Q is a function of (the function of the lungs). 设定 It can be higher than 0 L / min or higher than the peak inspiratory demand of a typical patient (e.g., 20-30 L / min), for example, for a Q of 40 L / min. 设定 P 预期 It could be about 4 cmH2O, or for a Q of 70 L / min 设定 P 预期 It can be between approximately 9-12 cmH2O.

[0434] Advantageously, this system also allows for typical patient flow rates (Qi) in spontaneously breathing patients. 患者 ) for a series of suitable and / or safe P 实际 Provide respiratory support because Q 排气 and P 实际 It is Q 设定 And the variable Q resulting from patient flow (e.g., respiration). 患者 The function of both. For example, in patients with closed mouths, for a Q of 40 L / min 设定 And 30 L / min peak expiratory flow Q 患者 The combination of Q 排气 It is approximately 70 L / min, and P 最大 It could be approximately 8 cmH2O. In another example, in a patient with a closed mouth, for a Q of 70 L / min... 设定 And 30 L / min peak expiratory flow Q 患者 The combination of Q 排气 It is approximately 100 L / min, and P 最大 It can be approximately 15 cmH2O.

[0435] Configure system 100 to operate at the lower pressure limit (P). LL ) and upper pressure limit (P UL Operating between these parameters can provide constraints on permissible patient pressure ranges to avoid situations that could endanger patient safety. These pressure limits can be programmed into control device 138 such that when the control device receives a sensor signal indicating excessive supply or patient flow rate, a pressure relief valve or other mechanism is actuated to remove pressure from the patient interface until the monitored pressure is within a pre-programmed range. For example, if Q... 设定 and / or Q 患者 Too high, P 实际 It may exceed or fail to reach a certain safe or desired level. Therefore, P UL Maximum safe or comfort pressure limits can be defined, which are typically within the P range. 最大 The above levels are used, for example, to prevent harm to the patient and / or avoid bloating. If it exceeds P... UL Safety procedures can be initiated within the system to prevent harm to the patient. This may involve actuating the pressure reducing valve and / or the pressure-sensing flow controller and / or shutting off the flow source 104, and / or reducing the control value used to supply the flow rate.

[0436] In some examples, system 100 can be configured such that control device 138 allows P 实际 Deviation from P within a respiratory cycle LL and P ULTolerable amount. Therefore, in some examples, system 100 may utilize a system pressure sensor to detect P. 实际 When does it fall on P? LL and P UL Outside the range, the control device 138 is programmed to change Q instantaneously. 设定 To respond so that P 实际 Return to P UL and P LL Within this range. This may be advantageous in situations such as, for example... Figure 7 The graph shows the occurrence of rapid inspiration. Rapid inspiration may lead to P... 实际 Decrease to P LL In this case, the control device 138 can adjust Q instantaneously. 设定 , so as to P 实际 Upgrade to at least P LL As shown in the figure.

[0437] Embodiments of the present invention include, or may use, a patient interface that can be applied to a patient to provide a gas flow for providing respiratory support as disclosed herein. The patient interface includes a nasal delivery element (such as a pair of nasal forks or nasal pillows) for providing a gas flow into the nasal cavity and at least one outflow vent that allows gas to escape from inside the patient interface to the outside of the patient interface. One or more sealing elements are provided. These one or more sealing elements substantially prevent the escape of the gas flow from the patient (or from the patient interface) except via at least one outflow vent. In some examples, the one or more sealing elements may be additional (e.g., applied to) the nasal delivery element. In some examples, the one or more sealing elements may be integrated with or form part of the nasal delivery element. The patient interface includes a gas flow path coupled to or in fluid communication with, for example, an inspiratory conduit 110, through which a gas flow is received. The gas flow is provided at a supply flow rate. As described elsewhere herein, the exhaust flow rate is a function of the supply flow rate. At least one outflow vent is configured, for example, in size and / or shape, such that when gas is supplied to the patient interface at a predetermined supply flow rate (e.g., in the absence of patient breathing), an exhaust flow of gas is generated at a predetermined interface pressure. In this case, the exhaust flow rate may substantially correspond to the supply flow rate. It should be understood that the relationship between the exhaust flow rate generated by the configuration of at least one outflow vent and the interface pressure can be described in this invention as "in the absence of patient breathing." It should be understood that this is not limited to situations where the patient is in a state of apnea and should be considered to also include situations, such as when the patient's mouth is closed during breath-holding or the interval between inspiration and expiration, or situations where relevant measurements can be obtained without being affected by breathing or flow into or out of the patient's airway. For the testing / simulation described herein, this means sealing the nasal element of the patient interface to simulate a patient in the absence of net flow into or out of the patient.

[0438] The patient interface is configured to generate interface pressure during the provision of respiratory support when a gas flow rate controlled according to the methods disclosed herein is supplied. In some embodiments, the configuration of at least one outflow vent is fixed. This reduces the variability of respiratory support provided to the patient over time and reduces variability between different patients. It should be understood that “exhaust flow rate” may include a series of flow rate values ​​and, when more than one outflow vent is provided, corresponds to the total exhaust flow rate through all outflow vents. In some embodiments, at least one outflow vent is configured such that the interface pressure and exhaust flow rate generated by the patient interface during use have a non-linear relationship. This relationship can be determined by plotting the values ​​of interface pressure and exhaust flow rate generated within a supply flow rate range in the absence of patient breathing. This relationship can be obtained by performing a simulation or testing scheme as described elsewhere herein. This scheme can be applied in reverse to determine the configuration of at least one outflow vent. For example, the required flow resistance can be determined by determining the required interface pressure values ​​for a series of exhaust flow rate values ​​(which are the same as the supply flow rate values ​​in a simulation environment). This can be used to inform the total cross-sectional area of ​​the vent, which in turn can be used to inform the size and / or shape of the vent.

[0439] In some examples, the nonlinear relationship includes (partially or entirely) a curvilinear relationship, which may be referred to as a PQ curve. The PQ curve may contain polynomial components. In some embodiments, the polynomial components may be quadratic polynomial components. Figure 4 An example of a PQ curve according to an embodiment of the invention is shown at 402. Other PQ curves are also contemplated within the scope of the invention. For example, a PQ curve may include a rate of change (of pressure P within the range of exhaust flow rate Q), which may be constant or may not be constant within the value range; the rate of change may include an average rate of change within the operating flow rate range or pressure range, or within a subrange of the operating range. For example, a PQ curve or a portion thereof may include an average rate of change. In some examples, a PQ curve may include one or more of the following: a gradual change between the first rate of change and the second rate of change; a step-like change between the first rate of change and the second rate of change; a gradual change between the first rate of change and the second rate of change; a curvilinear change between the first rate of change and the second rate of change; a portion of the first rate of change and / or the second rate of change having a non-constant gradient; a non-step-like change at the transition between the first exhaust flow rate and the second exhaust flow rate; and a non-step-like change at the transition between the second exhaust flow rate and the third exhaust flow rate. The interface pressure P may include an average or mean interface pressure measured within the flow rate range.

[0440] In some examples, the patient interface is configured such that, during use, the interface pressure and the exhaust flow rate through at least one outlet vent form a non-linear relationship, which includes the rate of change of the interface pressure in the range of greater than 0.15 cmH2O / Lmin⁻¹ to less than 0.5 cmH2O / Lmin⁻¹. In some examples, for a first exhaust flow rate value in the range of greater than about 0 LPM to about 40 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, the first rate of change in the PQ curve may be in the range of greater than about 0 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹, or about 0.05 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹, or about 0.1 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹. In some examples, for a second exhaust flow rate value in the range of greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM, the second rate of change in the PQ curve may be in the range of greater than about 0.1 cmH2O / Lmin⁻¹ to less than about 0.6 cmH2O / Lmin⁻¹, or about 0.15 cmH2O / Lmin⁻¹ to about 0.5 cmH2O / Lmin⁻¹, or about 0.2 cmH2O / Lmin⁻¹ to about 0.4 cmH2O / Lmin⁻¹, or about 0.2 cmH2O / Lmin⁻¹ to about 0.3 cmH2O / Lmin⁻¹. The rate of change may include an average or mean rate of change. In some examples, the supply flow rate may be approximately the same as the corresponding exhaust flow rate.

[0441] In some examples, the patient interface may include a non-sealed patient interface with nasal delivery elements (such as a pair of nasal forks) and an insert placed within each of the patient's nasal passages. The insert may be configured to normalize a portion of the patient's nasal passage, such that the insert, together with the nasal delivery elements, can substantially occupy the entire patient's nasal passage, and at least one outflow vent is provided in the insert.

[0442] For example, the patient interface may include at least one nasal element configured to provide a flow of air into a patient's nostrils, and at least one outflow vent may include a gap defined between a nasal fork and an insert located in the nostril. In other examples, the patient interface includes at least one nasal fork configured to provide a flow of air into a patient's nostrils, and at least one outflow vent includes one or more openings located in the nostril and surrounding the insert of the nasal fork. In such an arrangement, the insert includes a sealing element and at least one outflow vent.

[0443] Advantages of patient interfaces including inserts may include the ability to adapt the inserts to existing unsealed patient nasal interfaces that are otherwise unsuitable for providing the respiratory support disclosed herein. Therefore, the inserts can be supplied together with the unsealed patient nasal interfaces. Alternatively, the inserts can be supplied, for example, in pairs as separate products, which can be supplied as accessories for use with unsealed patient nasal interfaces. The inserts can be applied above each fork to standardize the operation of the unsealed patient nasal interface, eliminating inter-patient variability in the exhaust flow around the nasal fork, and substantially replaced by at least one outflow vent disposed in at least one insert, or formed between the fork and the insert, wherein at least one outflow vent has a known configuration. This configuration results in the interface producing a desired exhaust flow rate and interface pressure for a predetermined supply flow rate. The desired exhaust flow rate (Q) and interface pressure (P) can be correlated according to a PQ curve.

[0444] In other examples, the patient interface includes a pair of nose forks configured to provide airflow into one or both nostrils of a patient, and sealing elements include at least one nose pillow, nose fork, nose pad, nose cover, or nose support configured to form a substantial seal with or around the patient's nostrils. Thus, the sealing elements can be integrated with or incorporated therein with a gas delivery element that is inserted into or onto the patient's nostrils during use. In some examples, the sealing elements may also include at least one outflow vent in a manner similar to the insert described above. Alternatively or additionally, the patient interface may also include a body portion that includes at least one outflow vent.

[0445] exist Figure 8 and Figure 18An example of a patient interface 520 according to an embodiment of the present invention is provided. The patient interface includes a body portion 521 and a nasal pillow 522, the body portion having an outflow vent 530. In use, the nasal pillow 522 is inserted into the patient's nostril to form a substantially sealed seal, such that gas from within the body portion 521 is delivered to a nasal airway, and gas from the nasal airway (which may include gas supplied to the patient and gas exhaled from the patient) can exit the nostril and the patient interface into the environment via the outflow vent 530. Therefore, sealing the nasal pillow 522 minimizes unknown leakage between the patient interface 520 and the patient's nostril. For a given exhaust flow rate or range of exhaust flow rates, minimizing unknown leakage minimizes the variability of interface pressure over time and between different patients. Although in Figure 8 The example uses a nose pillow 522, but it should be understood that other sealing elements can be used as alternatives, such as sealing forks, nose pads, nose supports, etc. Figure 19 An example of a sealing insert 720 applied above the nose fork 113 of the patient interface 112 is shown. Here, the insert 720 is provided with a plurality of outflow vents 730 through which gas (indicated by dashed lines) can exit the patient's nostrils. The outflow vents 730 may be arranged around the entire circumference of the insert 710 or a portion thereof. The outflow vents may be arranged in a single row, multiple rows, or some other pattern. Alternatively, the outflow vents 730 may be arranged in a substantially random pattern. Arrow 106 indicates the flow of gas entering the nostril from the nose fork 113 during use. It should be understood that in some examples, the sealing insert 720 may be integrally formed with the patient interface. For example, the functions of the sealing insert 720 and the nose fork 113 may be integrated to form a sealing fork (not shown).

[0446] Figure 8 The example is set with 6 outflow vents (best shown in Figure 9These outflow vents are configured to generate an interface pressure (P) for a predetermined supply flow rate and an exhaust flow at an exhaust flow rate (Q) through at least one outflow vent during use; wherein the interface pressure and exhaust flow rate have a non-linear relationship. However, it should be understood that in some examples, fewer than or more than six outflow vents may be provided. At least one outflow vent is configured, for example, to have a size and / or shape set to achieve a low RTF, for example, through the total cross-sectional area of ​​the vent. It should be understood that a low RTF may include values ​​of a first flow resistance and / or a second flow resistance as disclosed herein. Thus, a high exhaust flow rate can be generated at a patient interface pressure that is safe at supply flow rates commonly used in providing conventional HF respiratory support. At least one outflow vent 530 may also be designed to achieve a specific pressure differential or range between the patient interface 520 and ambient air during use at high supply flow rates (i.e., supply flow rates commonly used in conventional HF respiratory support). For example, the outflow vent 530 can be designed to achieve a pressure differential of approximately 7 cmH2O to approximately 15 cmH2O for an exhaust flow rate of 70 LPM during use (in the absence of net flow to and from the patient). The permissible properties of at least one outflow vent (resulting from low RTF) have another advantage: they can be used to supply gas to and exhaust gas from the patient interface body, for example, during bag-mask ventilation, as described in further detail below.

[0447] exist Figure 8 , Figure 9 and Figure 14 In the example, when the patient interface 520 is applied to a patient, an outflow vent 530 is disposed in a ventilation member 531 facing outwards from the patient. The ventilation member 531 may comprise a substantially rigid material, such as a plastic or polymer material, configured to form a friction fit or clamping engagement with the body portion 521 of the patient interface. The ventilation member 531 and the body portion 521 may together define a chamber 532 as discussed below. In some embodiments, the ventilation member may also include one or more retaining mechanisms 540 for connecting a headband connector, such as a headband, as... Figure 8 and Figure 9 As shown. In other examples, there is no venting component, and the outlet vent is formed or overmolded onto the interface, or formed in the interface body, such that the interface body including the vent is formed as a single, integral piece.

[0448] At least one outflow vent 530 can also be configured to exhibit transitional or turbulent characteristics (e.g., Re > about 2000 to 3500) at high supply flow rates to achieve exhaust flow rates and interface pressures aligned with preferred PQ curves. At high supply flow rates, such as above 50 LPM, the exhaust gas flow exiting at least one outflow vent 530 may have transitional and / or turbulent characteristics that enable a greater pressure differential between the patient interface and the environment, which translates to higher interface pressures relative to conventional NHFs (using non-sealed nasal interfaces), thereby contributing to exhaust flow rates and patient pressures that provide rate-of-change performance, including the nonlinear curves disclosed herein, during use.

[0449] At least one outflow vent 530 may also be configured to minimize condensation blockage, which may occur due to the humidity level of the gas supplied to and / or exhaled by the patient being higher than that of ambient air. In some examples, the size and / or shape of at least one outflow vent 530 may be configured such that, for a given pressure within the patient interface, the capillary pressure of the condensate droplets is less than the interface pressure.

[0450] In some examples, at least one outflow vent 530 may include a width dimension of approximately 3 mm. For example, if the cross-sectional shape of at least one outflow vent 530 is circular, oval, or elliptical, this dimension includes the diameter and the major or minor axis, respectively. Other cross-sectional shapes that may be suitable for at least one outflow vent 530 include, for example, oblong, quadrilateral, or squarish-oval. There may be 1, 2, 3, 4, or 5 outflow vents, or more such as 10, 15, 20, 25, 30, 35, 40, 45, 50, or significantly more such as 100, 150, 200, or more, or any number therein. Outflow vents provided in the patient interface need not have the same size, shape, or cross-sectional area. As mentioned, for a given exhaust flow rate, the RTF of at least one outflow vent may be attributed to the size and / or shape of that at least one vent, for example, to the total cross-sectional area of ​​the vents provided in the interface system. When more than one vent is provided, RTF refers to the total RTF of all individual vents combined. The total cross-sectional area of ​​the vents can range from approximately, for example, about 20 to approximately 100 mm². 2 Such as approximately 35 mm 2 approximately 80 mm 2 or about 35mm 2 Approximately 60 mm 2 Within a certain range. In some examples, the total cross-sectional area of ​​the vent can be, for example, about 35 mm. 2 approximately 50mm 2 Such as approximately 35 mm 2 Approximately 40 mm 2or about 35 mm 2 Approximately 45 mm 2 Within the range. In some non-limiting examples, the total cross-sectional area of ​​at least one outflow vent may include approximately 42 mm. 2 It spans approximately six openings, each approximately 3 mm in diameter; or approximately 44 mm. 2 It spans approximately 14 openings, each approximately 2 mm in diameter; approximately 30 mm 2 It spans approximately 17 openings, each approximately 1.5 mm in diameter; approximately 35 mm 2 It spans approximately five openings, each approximately 3 mm in diameter. In some examples, the average cross-sectional area of ​​each opening, including at least one outflow vent, ranges from approximately 1.5 to 8 mm. 2 For example, each opening is about 7 mm 2 It can be the average value, or approximately 5 mm. 2 With 8 mm 2 The low RTF of at least one outflow ventilator 530 also facilitates bag-mask ventilation as discussed below. Preferably, at least one outflow ventilator 530 is immutable (i.e., has a fixed configuration) to limit performance variability over time and between different patients.

[0451] When more than one outflow vent is provided, each of the two or more outflow vents does not need to have the same size and / or shape. For example, a patient interface for providing respiratory support may include a gas flow path for providing gas flow to the patient, at least one outflow vent configured to allow exhaust flow of gas, and a sealing element that, in use and when the patient's mouth is closed, substantially prevents gas from escaping from the patient except via the at least one outflow vent, wherein the at least one outflow vent includes multiple openings, not all of which have the same size and / or shape. In some examples, the at least one outflow vent may include openings having at least two different sizes and / or shapes. In one example, the at least one outflow vent includes at least one small opening and at least one large opening. The patient interface may be configured to generate interface pressure during the provision of respiratory support.

[0452] In some examples, the cross-sectional diameter of the small opening may be less than about 1 mm or less than about 0.7 mm. In some examples, the cross-sectional diameter of the small opening may range from about 0.5 mm to about 0.7 mm or from about 0.5 mm to about 1 mm. There may be multiple small openings. In some examples, there may be 5, 10, or 20 small openings, or there may be more or fewer small openings. These small openings may all have the same size and / or shape. On the other hand, the small openings do not need to have the same size and / or shape.

[0453] In some examples, the cross-sectional diameter of the large opening is greater than about 1 mm or greater than about 2 mm. In some examples, the cross-sectional diameter of the large opening can range from about 1 mm to about 3 mm or from about 2 mm to about 3 mm. There can be multiple large openings. There can be 1, 2, 3, 4, or 5 large openings. When there is more than one large opening, they can all have the same size and / or shape. On the other hand, the large openings do not need to have the same size and / or shape.

[0454] In some examples, the total cross-sectional area (CSA) of the smaller opening may be similar to that of the larger opening. In some examples, approximately 50% of the total CSA of at least one outflow vent is attributable to the total CSA of the smaller opening, and approximately 50% of the total CSA of at least one outflow vent is attributable to the total CSA of the larger opening. In some examples, the total CSA of the smaller opening is within approximately 5%, or approximately 2%, of the total CSA of the larger opening, or vice versa. In another example, approximately 75% of the total CSA of at least one outflow vent is attributable to the total CSA of the smaller opening, and approximately 25% of the total CSA of at least one outflow vent is attributable to the total CSA of the larger opening. For example, Figure 20 It shows two large openings and 54 small openings, each large opening with a diameter of 2 mm and each small opening with a diameter of 0.7 mm, resulting in 27 mm. 2 Of the total CSA, approximately 78% can be attributed to small openings.

[0455] Including small openings allows some flow from at least one outflow vent to be at a lower Reynolds number, making the flow through the small opening closer to laminar flow compared to the more turbulent flow through a large opening. In some examples, the size and / or shape of the large opening can be configured to achieve a desired nonlinear relationship (i.e., a PQ curve) between the interface pressure and the exhaust velocity, as described elsewhere in this document. Simultaneously, small openings can be configured to achieve therapeutic effects. In some examples, therapeutic effects may include gas cloud effects resulting from the lower Reynolds number and laminar flow through the small opening.

[0456] like Figure 20 As shown, in some examples, the smaller opening 530A can be an order of magnitude larger than the larger opening 530B. This allows a sufficient portion of the exhaust flow to exit through the smaller opening, thus contributing to the gas cloud effect. Figure 20In the process, there is a single row of small openings 530A, which essentially extends around the front of the patient interface 520 or the ventilation member 531. A second row of small openings 530A may be provided on a portion of the exhaust member 531, which guides the gas leaving the second row downwards as shown, i.e., towards the mouth during use. The presence of the orifices also reduces the noise generated by the exhaust flow leaving the patient interface due to the higher degree of laminar flow and / or a reduction in the amount of turbulence that would otherwise exit through the larger opening 530B. Figure 20 In one specific example shown, there are two large openings and 54 small openings, each large opening having a diameter of 2 mm and each small opening having a diameter of 0.7 mm. Other arrangements are also envisioned, in which at least one outflow vent includes, for example, about 2 to about 5 large openings and about 30 to about 70 small openings. The small and / or large openings can be arranged on the patient interface 520 in a manner suitable for clinical needs.

[0457] In some examples, the diameter of the small opening can range from about 0.5 mm to about 1 mm, or from about 0.5 mm to about 0.75 mm. As the diameter decreases, the interface pressure required to overcome the capillary pressure becomes higher if condensation forms in the opening. Therefore, further reduction in orifice size may be disadvantageous.

[0458] In examples where both large and small openings are provided, it may be advantageous for the flow from the large opening to be directed in a different direction than the flow from the small opening. This can be particularly advantageous when it is desirable to generate a region of low-speed exhaust flow through the small opening, i.e., the gas cloud effect described above. Otherwise, the region of low-speed exhaust flow through the small opening may be disturbed by a high-speed flow from the large opening if their directions are the same or similar.

[0459] In such Figure 20 In the example shown, a large number of small openings concentrated towards a specific area of ​​the patient interface (or towards the patient's anatomical site during use) can create a diffusion cloud of exhaust gas exiting the interface through these openings. In a specific but non-limiting example, there may be about 50, for example, substantially circular, small openings, each with a diameter of about 0.7 mm. In another example, where the patient interface includes only small openings designed to achieve the cloud effect (excluding large openings), there may be about 150 small openings, and these small openings may be substantially circular and have a diameter of about 0.7 mm.

[0460] The size and / or number of small and large openings can be selected or adjusted to achieve a specific desired relationship between interface pressure and exhaust flow rate. The size and / or number of small and large openings can be selected or adjusted so that a specific portion of the exhaust flow can exit through each "type" of opening. Since the flow resistance of each opening depends on the exhaust flow rate, for a given flow rate, the number of openings of each size can be adjusted to allow a specific portion of the exhaust flow to exit, for example, for a desired portion at 50 L / min or another specific given flow rate or flow rate range.

[0461] In some examples, the direction of the flow from at least one large opening may differ from the direction of the flow from at least one small opening. In some examples, the flow from at least one small opening may be directed toward the patient's mouth. Directing the flow from multiple (or all) small openings in a common direction (such as toward the mouth) can help create an air cloud effect at the desired location.

[0462] The small opening can be directed towards the mouth, and the flow exiting the small opening has a lower velocity than the flow exiting the large opening. Due to the lower velocity, the flow from the small opening can create a therapeutic gas cloud around the mouth. This gas cloud effect can be beneficial when the patient breathes through their mouth and inhales air through their oral cavity. The presence of a therapeutic gas cloud in this area can provide the patient with increased FiO2 compared to the absence of a therapeutic gas cloud.

[0463] In the example above, it might be desirable to direct flow from openings of different types (or sizes) in different directions. In other examples, it might be desirable for all flow from at least one outflow vent to be directed in a specific direction during use. This can differ from... Figure 8 , Figure 9 , Figures 14 to 16 as well as Figure 18 The examples shown depict the direction of the exhaust flow, which, when in use, exits at least one outflow vent in a direction away from and substantially orthogonal to the patient's face.

[0464] In one example, it may be desirable to direct substantially all exhaust flow from at least one outflow vent toward the patient's mouth during use, such that all therapeutic gas flow leaving at least one outflow vent is directed toward the mouth. This allows some therapeutic gas from at least one outflow vent to be entrained by the patient as they inhale through their mouth. In some examples, at least one outflow vent 530 may be located on a surface or edge of the patient interface 520, or on a surface or edge of the ventilation member 531, such that at least one outflow vent is directed toward the patient's mouth during use, as... Figure 21 As shown.

[0465] In another example, the flow from at least one large opening can be directed away from the patient's mouth. Therefore, at least one outflow vent 530 may be located on the surface or edge of the patient interface 520, or on the surface or edge of the ventilation member 531, such that at least one outflow vent is directed away from the patient's mouth during use, as... Figure 22 As shown. There may be clinical situations where it may be beneficial to direct the flow away from at least one outflow vent away from the patient's mouth, such as towards the patient's forehead. This situation may arise if a clinician is working on the patient's mouth / nose area and wishes that the flow from at least one outflow vent is not directed towards itself or its clinical operating area. In some cases, directing the flow towards the patient's forehead may also reduce oxygen flow around the patient's head and neck area.

[0466] In some examples, the patient interface may include an access port. This access port may be normally closed to allow interface pressure to be generated during the provision of respiratory support using the patient interface. However, the access port may be utilized if a clinician needs to access the nasal cavity during treatment. For example, if a clinician wishes to insert a nasogastric (NG) tube or other instruments via the nasal cavity, or to insert a gas sampling catheter via the access port.

[0467] Access ports may include normally closed but openable duckbill valves or check valves to allow insertion of, for example, smaller tubes or tools into the nasal cavity. Figure 23 and Figure 24 An example is provided, which shows the corresponding Figure 15 and Figure 16 As part of the patient interface 520, the patient interface has been improved to include an access port 539 and a valve component 537. Figure 23 In this configuration, valve component 537 is in a closed arrangement, ensuring that gas does not leave chamber 532 via access port 539 during respiratory support provided using the patient interface. Figure 24 In this configuration, the NG tube 720 is inserted via access port 537, pushing against valve member 539 to move it into an open arrangement. For access to the nasal cavity, the NG tube 720 is inserted through chamber 532 and nasal occiput 522. When the NG tube 720 is removed from access port 537, the valve member returns to a normally closed arrangement. In some examples, valve member 537 may have a degree of flexibility to form a basic seal around the inserted tube, allowing for continuous respiratory support when using access port 537.

[0468] In another example, the access port may include an opening formed when a ventilation member 531 containing at least one outflow ventilator 530 is removed from the patient interface 520. Such an access opening may be larger than... Figure 23 and Figure 24Access opening. Figure 25 An example is shown, illustrating an access opening 537 with an NG tube 720 inserted. The ventilation member 531 may include a frictional or clamping engagement with the body portion 521 of the patient interface 520. In some embodiments, it may be preferred that no tools are required to remove the ventilation member 531 from the body portion 521 of the patient interface. Therefore, in some examples, one or both of the body portion 521 and the removable ventilation member 531 may include features such as tabs (not shown) to facilitate removal of the ventilation member, thereby exposing the access port 537, so that no tools are required. Seals or gaskets may be provided on one or both of the ventilation member 531 and the body portion 521 to ensure that gas does not escape from between the patient interface when used to provide respiratory support.

[0469] In another example, sampling port 538 or the outflow vent can be used as an access port if it has a sufficiently sized receiving tube or tool. For example, an NG tube or gas sampling conduit can be inserted through sampling port 538, such as... Figure 18 As shown, without removing the ventilation component 531.

[0470] Figure 8 and Figure 9 The outflow vent 530 shown is disposed in the main body 521; however, as discussed above, this is not necessary, and at least one outflow vent may alternatively or additionally be disposed in a gas delivery conduit (e.g., a gas delivery side arm) 524 forming part of the patient interface system. The gas delivery side arm 524 may be integrally formed or assembled with the main body 521 of the patient interface 520 and may be configured to provide connection at the coupling 526 with the inspiratory conduit 110 ( Figure 1 The gas delivery side arm 524 may include a substantially rigid conduit configured to remain patency and minimize squeezing and / or kinking during the delivery of respiratory support; however, it should be understood that such a gas delivery side arm may not be suitable for providing respiratory support involving bag-mask ventilation.

[0471] In some examples, the gas delivery side arm 524 includes a portion that may be less rigid compared to the rest of the conduit, such that forces acting on the collapsible portion can alter parameters of the flow path through that portion. For example, forces acting on the collapsible portion can significantly reduce or stop flow through the conduit, and in some cases, by triggering a reduction in flow from a flow source. Such a portion can be considered as... Figure 10The collapsible portion 525 is shown. The collapsible portion 525 can be a closed or partially closed portion to reduce or stop flow through the sealed patient interface 520, for example, when pressure is applied to that portion. This can be useful or desirable to facilitate bag-mask ventilation of the patient using a bag-mask ventilation device applied above the patient interface 520. In some examples, if it is necessary to maintain patient safety, excess flow can be drained from the system 100 via a pressure relief valve (not shown). In some examples, the force applied to the collapsible portion 525 can cause an increase in pressure in the system 100, which can be detected by a sensor that provides input to a control device 138, which in turn reduces the flow supplied by the flow source 104.

[0472] In some configurations, the structure of the gas delivery conduit 524 can facilitate balloon mask ventilation to a patient, the gas delivery conduit having a collapsible portion 525 configured to transition from a first configuration to a second configuration, in the first configuration a first level of gas can pass through the collapsible portion 525, and in the second configuration a second level of gas can pass through the collapsible portion 525.

[0473] In some configurations, the collapsible portion 525 is configured to be more collapsible than other portions of the gas delivery conduit 524, or otherwise better adapted to alter the gas flow through the collapsible portion 525 (thus stopping or reducing the gas flow through the conduit and to the patient), and / or to allow a mask seal to be applied above the top of the conduit. In other configurations, the entire gas delivery conduit 524 may be configured to be collapsible.

[0474] In some embodiments, the first configuration is a substantially open configuration, and the second configuration is a substantially closed configuration. That is, the gas delivery conduit 524 is configured to be more collapsible, deformable, or otherwise adapted to completely or partially block the flow at the collapsible portion 525 than other portions of the gas delivery conduit 524. In the second configuration, the flow of gas to the nasal delivery element can be reduced or stopped.

[0475] Figure 11 An example of this configuration is shown, in which the supply Figure 10The collapsible portion 525 of the gas delivery conduit 524 of the patient interface 520 is substantially closed by the seal 624 of the mask 620. In such an embodiment, the length of the collapsible portion 525 of the gas delivery conduit 524 (i.e., the more collapsible or deformable portion) should be greater than or equal to the width of the portion of the seal 624 of the mask 620 that presses over the collapsible section of the gas delivery conduit. This ensures that the seal 624 of the mask 620 does not press over the non-collapsible portion of the gas delivery conduit 524. For example, the collapsible portion 525 may extend from a distance of 35 mm or less from a portion of the body portion 521 or the center of the user's nose to at least 50 mm from a portion of the body portion 521 or the center of the user's nose. The length of the collapsible portion 525 may be at least about 5 mm, about 1 mm to about 30 mm, about 5 mm to about 15 mm, or about 10 mm. In some embodiments, the length of the first portion may be at least 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm or greater.

[0476] The collapsible portion 525 can gradually transition between a first configuration and a second configuration based on the relative level of the forces applied to the walls of the collapsible portion 525. For example, as Figure 10 As shown, force can be applied through the seal 624 of the mask 620. In this example, the collapsible portion 525 is configured to be positioned below the seal 624 of the mask 620. Alternatively, force can be applied to the collapsible portion 525 in other ways, such as with a clamp (not shown), or alternatively, a physician can compress the catheter by pressing on the catheter wall with their fingers or thumb.

[0477] In some embodiments, the seal 624 of the mask 620 acts on the collapsible portion 525 of the gas delivery conduit 524, such that the collapsible portion 525 forms a seal or at least a blockage between the first patient interface 520 and the flow generator 122. Additionally, the seal of the mask forms a seal or at least a partial seal over the collapsible portion 525 of the gas delivery conduit 524.

[0478] Therefore, balloon-mask ventilation can be achieved simply by applying a second patient interface, including a mask 620 (such as a balloon mask), to the patient's face, such that the mask's seal causes the collapseable portion 525 of the gas delivery conduit 524 of the first patient interface 520 to collapse (partially or completely). In some examples, this stops or "shuts down" or reduces the respiratory support supplied by the patient interface 520 and also provides a basic seal between the mask 620 and the patient's face and the outer surface of the collapseable portion 525 of the gas delivery conduit 524, enabling respiratory support to be provided through the second patient interface including the mask 620 while the respiratory support provided by the first patient interface 520 is stopped or reduced.

[0479] The patient interface 520 with a collapsible portion 525 allows users such as anesthesiologists, nurses, or clinicians to provide alternative respiratory support to a patient using a second patient interface such as a balloon valve mask (i.e., a balloon mask) 620, while preventing or restricting the delivery of gas to the patient from the first patient interface 520. The first patient interface 520 is constructed and functions such that when the collapsible portion 525 of the patient interface 520 is moved to a collapsed configuration, it reduces or shuts off the delivery of high-flow-rate gas to the patient and allows the delivery of alternative respiratory support and / or respiratory therapy or anesthetic gas via the mask. Accordingly, the size of at least one outflow vent 530 of the patient interface 520 can be configured to allow gas flow to the patient from the mask 620, and vice versa. Figure 19When the insert 710 is applied to a patient nasal interface with a collapsible portion, it also allows the mask 620 to be used above the nasal interface, because the size of at least one outflow vent 730 can be configured to allow airflow from the mask 620 to the patient, and vice versa. It should be understood that the insert 710 need not be a separate component. In some examples, the insert 710 may be integrated into the patient interface 520, for example, incorporated into the nasal fork or nasal pad 522. Thus, although the sealing element (i.e., the nasal pillow 522 or the insert 710) provides a substantial seal around the nasal fork within the patient's nasal passage, the patient can still receive balloon mask ventilation when the first patient interface is held on the patient's face in a collapsed configuration. In some embodiments, removing the mask 620 from the patient's face allows the respiratory support provided by the first patient interface 520 to be restored as the catheter returns from a collapsed configuration to an open configuration. Therefore, the collapsible portion 524 can be resilient, allowing it to reopen when the collapse force is removed. Advantageously, the low-RTF ventilation port 530 in the first patient interface 520 (and the ventilation port 730 in the insert 710) reduces the impact of flow leaving the sealed first patient interface on the balloon-mask ventilation process, and / or on monitoring patient parameters (e.g., CO2) using sensors on the balloon-mask. This also reduces any difference in the "balloon feel" feedback experienced by clinicians during balloon actuation compared to the balloon feel when the balloon-mask 620 is applied over the first patient interface 520, compared to when it is applied directly to the patient's face. The advantage of this method is that the first patient interface 520 (or the nasal insert 710) can remain in place if balloon-mask ventilation is required, which can save crucial time, such as in emergency situations.

[0480] In some examples, the patient interface 520 includes a holding mechanism 540, such as Figure 9 The headband connector is best shown in the rotated view. This headband connector may include fasteners, clips, or connectors disposed on one or both sides of the body portion 521 for connecting a headband, such as headband 542 ( Figure 12 and Figure 13 The headband is designed to be secured in place after the patient interface 520 is applied to the patient's face. The headband can be removed from the connector 540 or permanently attached to the main body 521 via the connector.

[0481] In some examples, the patient interface 520 may include a channel 550 through which a headband 542 may pass, such as Figure 8 , Figure 9 and Figure 12As shown. The headband 542 can freely pass through the channel 550, which can be located on the same side of the patient interface and the gas delivery catheter 524, and is positioned such that when the headband passes through the channel and is applied to the patient, the gas delivery catheter is substantially aligned with the headband. This reduces or avoids bending or kinking of the gas delivery catheter 524. The reduced movement of the gas delivery catheter 524 caused by the headband 542 passing through the channel 550 also reduces mechanical stress on the nasal pillow 522 that forms a seal within the patient's nasal passage.

[0482] exist Figure 13 In another example shown, a retaining mechanism 540a may be located on the non-gas delivery side of the main body 521, and a second retaining mechanism 540b may be located on the gas delivery conduit 524 on the opposite side of the main body, but spaced apart from the main body. When the headband 542 is connected to the retaining mechanisms 540a, b and applied to the patient, the retaining mechanism 540b, located on the gas delivery conduit 524, can apply tension to the gas delivery conduit, which can reduce or prevent bending or kinking of the gas delivery conduit 524.

[0483] exist Figure 14 In another example shown, the patient interface 520 may include a non-gas delivery side arm 528, which includes a holding mechanism 540 for attaching a headband, such as a headband 542, to secure it in place after the patient interface 520 is applied to the patient's face. In such an arrangement, a holding mechanism 540a may be disposed on the non-gas delivery side arm 528, spaced apart from the body portion 521 on one side, and a second holding mechanism 540b may be disposed on the gas delivery side arm 524, spaced apart from the body portion on the other side. The patient interface 520 may or may not include a collapsible portion 525.

[0484] The main body 521 includes a chamber 532 defined between the gas inlet 534 of the patient interface 520 and the patient. The chamber 532 may include all cavities within the main body 521, including cavities through which gas can pass within the nasal bolster 522. The chamber 532 is... Figure 15 and Figure 16 The cross-sectional view is shown. In some examples, the chamber can be modified to create asymmetric pressure within chamber 532, which in turn can create asymmetric flow at the nostrils. This can have beneficial effects even if the overall flow passes through the nasal cavity and across the nasopharynx, at least at the end of expiration or during a respiratory pause (if the patient is breathing spontaneously), or during apnea. This can have a purge effect in the upper airway and can improve the clearance of dead space in the airway.

[0485] exist Figure 15In one example shown, an asymmetric flow is created because a single gas delivery conduit 524 supplies gas to the inlet 534. The incoming gas stagnates asymmetrically in chamber 532, creating a static pressure difference between the two nasal occiputs 522, resulting in higher pressure at the portion of the chamber furthest from the inlet, near the point of flow change indicated by the arrow. Increasing the velocity of the incoming gas flow can increase the static pressure at the nasal occiput 522 located distal to the inlet 534.

[0486] In some examples, chamber 532 includes a restraint that disrupts the flow from gas inlet 534 within chamber 532. In some examples, the restraint may include a narrowing of chamber 532, for example by shortening... Figure 15 The distance between the opposing wall portions is indicated by the middle arrows N. In another example, the restraint 536 may include a perforated wall 536, such as... Figure 16 As shown, as gas from inlet 534 travels further within the chamber, restrictor 536 restricts the flow, causing the pressure on the proximal side of the chamber to rise relative to the distal side, resulting in asymmetrical flow. In other examples, the restrictor may include, for example, protrusions, porous mesh, or other features within chamber 532 to create asymmetrical flow toward the patient's nostrils. One such feature may include the surface and / or shape of a portion of the inner wall of chamber 532. For example, a portion of the wall may be angled, curved, or include surface textures that guide the flow, such that they enter the nostrils asymmetrically. In some examples involving restrictors for creating uneven flow within the chamber of the patient interface, at least one outflow vent should be provided on each side of the restrictor to allow flow to exit the chamber. In such an arrangement, the interface pressure, i.e., the pressure on each side of the chamber (i.e., the pressure on each side of the restrictor), is close to the corresponding nostril of the patient, and the average of these pressures may represent the pressure within the patient's nasal cavity.

[0487] The restrictor provides the physical feature that divides chamber 532 into two sides. The restrictor can be used to achieve asymmetry between the two sides of chamber 532. As a result, during use, the patient's nasal passage will also experience pressure asymmetry. This can be used to achieve overall CO2 flow purging during nasal exhalation. The nature and / or size and / or extent of the restrictor between the two sides of the chamber can determine the degree of flow asymmetry. Therefore, lateral gas entry can be a contributing factor to asymmetry and improved CO2 purging. During use, patient anatomy may also affect pressure asymmetry, as may the patient flow and the flow rate provided to the patient interface (and then to the patient). In some examples, with increasing provided flow rate, a greater degree of purging can be observed for the same patient flow rate.

[0488] Alternatively or additionally, the patient interface 520 can be configured to allow for a jetting action of gas into the chamber 532. In some examples, the jetting action involves directing the incoming gas toward a side of the chamber 532 away from the gas inlet 534. This can be achieved when a high flow rate of gas (such as in NHF) is provided at the inlet 534, as the flow velocity allows for further penetration of the gas into the chamber 532 compared to the case of a lower flow rate gas. This jetting action can generate a purge flow that can be achieved at the end of expiration during use and is independent of any restraints within the chamber 532. It should be understood that the asymmetry achieved by the jetting action of gas entering the chamber 532 can be provided as an alternative or additional solution to restraints within the chamber 532 that also provide asymmetry.

[0489] In some examples, it may be desirable to determine one or more properties of the gas within chamber 532, and therefore at least one sampling port may be provided. Figure 18 An example of a patient interface 520, including a sampling port 538, is provided. Although Figure 18 Two sampling ports are shown, but in some examples, more sampling ports may be available. In other examples, only one sampling port may be provided. At least one sampling port may be coupled to or provide a sampling line that provides fluid communication between the sampling port and the sensor or measuring device. The sensor or measuring device may be located in the system's control unit 138, or may include a separate component operatively communicating with the control unit. operative communication may involve wired and / or wireless communication of sensor signals from the sensor or measuring device to the control unit 138. Thus, at least one sampling port provides a pathway for fluid communication between the gas within chamber 532 and sensors, such as pressure sensors, gas type or gas composition sensors (e.g., carbon dioxide analyzers or gas analyzers), temperature or humidity sensors. For example, the gas types of interest may include CO2, O2, and N2. Figure 18 In one example shown, sampling port 538 can be configured to measure patient interface pressure, and sampling port can also be configured to measure gas composition (e.g., CO2). In another example (not shown), a single sampling port 538 is configured to measure patient interface pressure.

[0490] In some cases, such as when a patient exhales through their mouth rather than their nose, it may be desirable to sample gas from the oral cavity to determine, for example, the gas composition. Therefore, in some examples, the patient interface may include an adjustable gas sampling catheter with a sampling tip positioned or locatable near the oral cavity to sample exhaled gas from the mouth. The gas sampling catheter can be adjusted using a manipulable core, such as a flexible wire, which allows adjustment of the sampling tip's position before or during use of the patient interface. In some examples, the gas sampling catheter may be removably attached to the patient interface 520. This attachment may be achieved via clips, magnets, friction fits, etc., in a location with sufficient rigidity to support the gas sampling catheter. Suitable locations for attaching the gas sampling catheter may include, for example, a coupling 526 and a ventilation member 531. The gas sampling catheter may be coupled to or provided with a sampling line that provides fluid communication between the sampling tip and a sensor or measuring device. The combined use of the gas sampling catheter and sampling port 538 allows for simultaneous nasal and oral sampling. Sampling via at least one sampling port 538 and / or the gas sampling catheter enables measurements of gas properties, including pressure, gas composition, temperature, humidity, etc., to be periodic or substantially continuous. In another example, the patient interface may not have any sampling port 538, and the gas sampling catheter may be steerable and selectively positioned such that it can be moved to sample from the oral cavity region or from an area near or adjacent to at least one outflow vent of the patient interface. That is, the gas sampling port can be moved to a position near (e.g., anteriorly) at least one outflow vent, where it can sample exhaled gas leaving the patient interface chamber via that at least one outflow vent. In examples where the patient interface has sampling port 538, the gas sampling catheter may also be positioned to sample from outside at least one outflow vent in such a manner.

[0491] Determining the pressure within the patient interface 520 may be desirable for several reasons. For example, the interface pressure can be used as a proxy parameter for the patient's nasal pressure. Furthermore, the patient interface pressure can be used to provide an indication of a good seal between the interface and the patient's face, and the presence of significant leakage. The interface pressure can be measured directly using a pressure sensor connected to the sampling port 538 as described above. Alternatively or additionally, the interface pressure can be determined or estimated indirectly from other pressure measurements within the system 100. The interface pressure values ​​obtained directly or indirectly can be used by the control device 138 to control elements of the system 100 and / or to be presented on the user interface 140.

[0492] The interface pressure can be indirectly determined using pressure measurements upstream of the sealed patient interface and by applying knowledge of pressure drops in other components within system 100. The pressure measured when the high-flow system 100 (i.e., flow source 104) is started is the sum of pressure drops in each component of the system (humidifier 108, catheters 110, 114, etc.). Each component of the system can be characterized such that, when assembled into a system, the pressure drop through each component for a specific supply flow rate is known. This characterization can be predetermined during bench testing. Characterization of the pressure drop through each component allows for estimation of the interface pressure, since the interface pressure is the measured system pressure minus the sum of pressure drops on components in system 100 between the system pressure measurement location and interface 520. Specifically, the interface pressure can be the pressure within chamber 532, and therefore, one of the components characterizing the pressure drop can be any interface catheter upstream of chamber 532 (even if they are integrally formed with the chamber). Using this technique, pressure can be estimated anywhere in the system 100 upstream of chamber 532, and the pressure within patient interface 520 (specifically chamber 532) can be estimated without directly measuring the pressure within the patient interface / chamber. This can be advantageous because it eliminates the need for sensors or connections to sensors on the interface itself, thus avoiding potentially obtrusive components near the patient's face. However, indirect measurements may be less accurate if, for example, there is an unintended bend or kink in the supply tubing, as this could affect flow resistance through various components in the system. For this reason, when the accuracy of the patient interface pressure value is critical, direct pressure measurement via sampling port 538 is preferable.

[0493] As discussed above, various aspects of the present invention facilitate balloon mask ventilation of patients over a substantially sealed nasal interface as disclosed herein. Figure 17This is a flowchart schematically illustrating the steps of a method 700 involving providing respiratory support via bag-mask ventilation. In step 702, first respiratory support is provided to the patient using a first patient interface. The first respiratory support may be provided during the pre-oxygenation phase of a medical procedure, prior to the administration of anesthesia to the patient. The method may include applying the first patient interface 520 to the patient in an earlier step 701. In some examples, the method of providing respiratory support may include administering anesthesia in step 703. In step 704, a second patient interface (such as a bag-mask) is applied over the first patient interface to reduce or stop the flow of the first respiratory support to the first patient interface. The second patient interface may include an airway or expiratory pathway for expelling gas. In step 706, second respiratory support is provided to the patient using the second patient interface. This second respiratory support may include “bag-mask ventilation”; a technique for providing flow to the patient by manually actuating a bag, typically used in emergency situations or prior to intubation. As disclosed above, the first patient interface includes at least one airway (also referred to herein as an outflow airway) sized such that second respiratory support from a second patient interface can be provided to the patient via the first patient interface, including when the patient's mouth is closed.

[0494] The first patient interface may include features as disclosed elsewhere herein. A collapsible portion in the gas delivery conduit (as shown in reference...) Figure 10 and Figure 11 The described method essentially closes when force is applied by applying a mask seal to the first patient interface, thereby significantly reducing or stopping the flow to the first patient interface. At least one airway provides low RTF, thus providing a flow path from the second patient interface to the chamber of the first patient interface, in which gas travels via the nasal pillow, nasal fork, or insert of the first patient interface into the nostril. Unlike conventional unsealed nasal HF patient interfaces with balloon mask ventilation, the first patient interface according to the invention includes at least one sealing element that forms a substantial seal with the patient's nostril. Unlike conventional HF systems where gas flows from the balloon mask around the nasal fork into the nasal airway, in the method of the invention, gas flows from the balloon mask through the first patient interface and through the sealed nasal pillow into the nasal airway. The method may include, in step 708, removing the second patient interface to restore the provision of first respiratory support. The method may also include, according to the steps of method 700, alternating between first and second respiratory support by removing or applying the second patient interface.

[0495] In some examples, the first respiratory support provided in step 702, as described elsewhere herein, includes controlling the gas flow at a first supply flow rate and generating a first interface pressure and an exhaust flow at a first exhaust flow rate through at least one ventilator; and controlling the gas flow at a second supply flow rate and generating a second interface pressure and an exhaust flow at a second exhaust flow rate through at least one outlet ventilator; wherein a second rate of change of the second interface pressure associated with the second exhaust flow rate is greater than a first rate of change of the first interface pressure associated with the first exhaust flow rate. Such methods have been combined with Figure 2 and Figure 3 It has been described.

[0496] At least one vent can be configured to provide a first exhaust flow rate value in the range of about 0 LPM to about 40 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, or when the supply flow rate is less than 15 LPM, to provide a first predetermined flow resistance in the range of about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1. At least one vent can be configured to provide a second predetermined flow resistance in use within the range of a second exhaust flow rate greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM.

[0497] In some examples, the patient interface may include at least one outflow ventilator with a very low RTF, such that the height of the at least one outflow ventilator allows flow to enter and exit the interface in both directions. In such examples, the total RTF flowing out of at least one vent can be greater than about 0 cmH2O / Lmin⁻¹ to about 0.5 cmH2O / Lmin⁻¹, or about 0.1 cmH2O / Lmin⁻¹ to about 0.4 cmH2O / Lmin⁻¹, or about 0.2 cmH2O / Lmin⁻¹ to about 0.3 cmH2O / Lmin⁻¹, or greater than about 0 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹, or about 0.05 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹, or about 0.1 cmH2O / Lmin⁻¹ to about 0.15 cmH2O / Lmin⁻¹, or greater than about 0.15 cmH2O / Lmin⁻¹ to less than about 0.5 cmH2O / Lmin⁻¹, or about 0.2 cmH2O / Lmin⁻¹. The supply flow rate can be between approximately 0.4 cmH2O / Lmin⁻¹ and approximately 0.2 cmH2O / Lmin⁻¹ and approximately 0.3 cmH2O / Lmin⁻¹. The supply flow rate can be greater than approximately 0 LPM, approximately 10 LPM, approximately 20 LPM, approximately 30 LPM, approximately 40 LPM, or approximately 50 LPM, or higher, such as approximately 60 LPM, approximately 70 LPM, approximately 80 LPM, approximately 90 LPM, approximately 100 LPM, approximately 110 LPM, approximately 120 LPM, approximately 130 LPM, approximately 140 LPM, or approximately 150 LPM, or values ​​between these values. The supply flow rate can be approximately the same as or higher than the exhaust flow rate.

[0498] As described elsewhere in this document, the first respiratory support may include providing a gas flow to the patient interface at a supply flow rate and generating an interface pressure and an exhaust flow through at least one ventilator at an exhaust flow rate, wherein the values ​​of the interface pressure and the exhaust flow rate constitute a non-linear relationship. This non-linear relationship may include polynomial components, preferably quadratic polynomial components.

[0499] Secondary respiratory support may be provided to achieve one or more effects in the patient, such as, but not limited to: increasing the patient's oxygenation; delivering one or more substances to the patient's airway; changing the interface pressure, such as increasing the pressure in the patient's upper and / or lower airway to clear obstructions such as soft palate closure or to check airway patency; changing the gas flow rate; controlling the interface pressure differently than that achievable with primary respiratory support; and different controls on the gas flow rate.

[0500] Various aspects of the present invention provide methods, systems, and apparatus for providing respiratory support that allow for the generation of patient pressure and exhaust flow rates at high supply flow rates, providing advantages over conventional unsealed HF respiratory support. One advantage is the generation of higher interface pressures (e.g., up to about 15 cmH2O) at higher exhaust flow rates. When used in flow control systems as disclosed herein, the methods and systems using the sealed patient interface of the present invention can generate high interface pressures, particularly during patient exhalation, and this can translate into higher patient airway pressures, particularly in the nasal airway. Sealed patient interfaces have been used in anesthesia procedures; however, because pressure-based respiratory support requires restrictive deflection vents, these interfaces are unsuitable for high-flow systems as their use may pose risks to the patient, such as barotrauma and / or gastric distension.

[0501] Unlike CPAP, currently disclosed methods, systems, and devices are flow-controlled and allow for high supply and exhaust flow rates, providing good airway clearance that reduces rebreathing of high-CO2, O2-depleted gases, thereby improving oxygenation. Airway clearance is improved by rapidly purging the dead space of the patient interface with freshly supplied gas because the flow flux (i.e., the amount of fresh gas supplied to the patient interface in a given time equal to the amount of gas expelled from the patient interface in a given time (ignoring patient respiration)) can be higher than with a CPAP interface. Alternatively or additionally, asymmetrical nostril gas pressure can generate nasal purge flow, for example, during and near respiratory pauses.

[0502] Various aspects of the present invention provide methods, systems, and apparatus for providing high-flow respiratory support that control the flow rate of gas supplied to a patient and generate at least one outflow vent from a patient interface, an exhaust flow with an exhaust velocity, and an interface pressure. The exhaust velocity (Q) and interface pressure (P) can be correlated, configured by at least one outflow vent to provide a predefined RTF for a given supply flow rate range (e.g., in a simulated or test environment), and its PQ curves such that the rate of change of patient pressure increases with increasing exhaust velocity. This provides clinicians with a useful option to achieve substantially higher patient pressure at higher flow rates compared to conventional unsealed NHFs. This can be used by clinicians to achieve more desirable pressure-based clinical outcomes in flow-controlled high-flow systems. During anesthesia procedures, this can be particularly beneficial for high-risk populations (e.g., those with high BMI) by improving upper airway patency, reducing atelectasis, and improving overall oxygenation.

[0503] As mentioned above, allowing high-flow exhaust rates through the patient interface also provides good bag-mask compatibility during anesthesia procedures. The ability to perform bag-mask ventilation over the nasal patient interface becomes easier because the flow generated by bag actuation can easily flow from the mask to the patient through at least one low-RTF outflow vent in the nasal patient interface, and vice versa. Advantageously, this also reduces the difference between the “bag feel” (i.e., the feedback received by the clinician during bag actuation) and the actual patient pressure, especially with the mouth closed. Conversely, delivering bag-mask ventilation over a nasal interface with a higher RTF deflection vent may require the clinician to actuate the bag more extensively to achieve a certain patient pressure or tidal volume compared to one or more low-RTF vents. Greater bag actuation results in a poor bag feel compared to bag actuation at a lower patient interface without a higher RTF. This can make it more difficult for the clinician to deliver air from the bag and may affect patient treatment.

[0504] Aspects of the present invention can reduce the variability of the gas exhaust flow path from the patient by providing a patient interface having at least one outflow vent and a sealing element, wherein the sealing element can substantially restrict gas escape from the patient except via the at least one outflow vent. This, in turn, reduces the variability of the interface pressure (which can be a proxy parameter for the pressure generated in the nasal cavity) at a given supply / exhaust flow rate. This contrasts with conventional NHFs with unsealed nasal cannulas, where uncontrolled leakage occurs due to patient-to-patient variability in the exhaust flow path between the nasal fork and the patient's nostril, resulting in greater patient-to-patient variability of the interface pressure, particularly at higher exhaust flow rates.

[0505] At a given exhaust flow rate (e.g., in the absence of respiration or as determined in a simulation), PQ curves with minimal or no variability in patient pressure provide clinicians with improved performance consistency and patient pressure prediction when controlling various flow rates.

[0506] In this specification, references to numerical ranges disclosed herein (e.g., 1 to 10) are intended to include references to all rational numbers within that range (e.g., 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9, and 10) as well as any range of rational numbers within that range (e.g., 2 to 8, 1.5 to 5.5, and 3.1 to 4.7), and thus all subranges of all ranges explicitly disclosed herein are explicitly disclosed. These are merely examples of specific intentions, and all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are to be considered as expressly stated in a similar manner in this application.

[0507] When the terms “comprising,” “including,” “containing,” or “containing” are used in this specification (including the claims), they should be interpreted as indicating the presence of the stated feature, integer, step, or component, but do not exclude the presence of one or more other features, integers, steps, or components, or combinations thereof.

[0508] It should be understood that various modifications, additions and / or alterations may be made to the foregoing description without departing from the scope of the invention as defined in the appended claims.

[0509] Future patent applications may be filed based on or claim priority to this application. It should be understood that the following claims are provided by way of example only and are not intended to limit the scope of rights that may be claimed in any such future application. Features may be added to or omitted from the claims later to further define or redefine the invention.

[0510] The alternatives are listed in the first and second sets of clauses below:

[0511] Article 1

[0512] 1. A patient interface for providing respiratory support, the interface comprising:

[0513] - A gas flow path used to deliver gas to the patient;

[0514] - At least one outflow vent, the at least one outflow vent being configured to allow exhaust flow of gas; and

[0515] - A sealing element that substantially prevents gas from escaping from the patient during use, except via the at least one outflow ventilator;

[0516] At least one of the outflow vents includes multiple openings, which are not all of the same size and / or shape.

[0517] 2. The patient interface according to Clause 1, wherein at least one outflow ventilator comprises at least one small opening and at least one large opening.

[0518] 3. The patient interface according to Clause 2, wherein the cross-sectional dimension of at least one small opening is less than about 1 mm, preferably less than about 0.75 mm, or about 0.5 mm, or about 0.3 to 0.7 mm.

[0519] 4. The patient interface according to Clause 2 or Clause 3, wherein at least one large opening has a cross-sectional dimension greater than about 1 mm or greater than about 2 mm, such as about 1 mm to about 2 mm or about 2 mm to about 3 mm.

[0520] 5. A patient interface according to any one of clauses 2 to 4, wherein the total cross-sectional area of ​​at least one small opening is similar to the total cross-sectional area of ​​at least one large opening.

[0521] 6. A patient interface according to any one of clauses 2 to 5, wherein, in use, the direction of flow from at least one large opening is different from the direction of flow from at least one small opening.

[0522] 7. A patient interface according to any one of clauses 2 to 6, wherein, in use, a flow from at least one small opening is directed toward the patient's mouth.

[0523] 8. A patient interface according to any one of clauses 2 to 7, wherein, in use, flow from at least one large opening is directed away from the patient's mouth.

[0524] 9. A patient interface according to any one of Clauses 1 to 8, wherein the patient interface is configured to generate interface pressure during the provision of respiratory support.

[0525] Article 2

[0526] 1. A patient interface for providing respiratory support, the patient interface comprising:

[0527] - A gas flow path used to deliver gas to the patient;

[0528] - At least one outflow vent, the at least one outflow vent being configured to allow gas exhaust flow at an exhaust flow rate; and

[0529] - A sealing element that substantially prevents gas from escaping from the patient during use, except via the at least one outflow ventilator;

[0530] At least one of the outflow vents has a predetermined flow resistance during use.

[0531] 2. The patient interface according to Clause 1, wherein when the exhaust flow rate is greater than about 0 LPM to about 40 LPM, or between about 30 LPM and about 40 LPM, or between about 35 LPM and about 45 LPM, the predetermined flow resistance of at least one outlet ventilator is in the range of greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

[0532] 3. The patient interface according to Clause 1 or 2, wherein when the exhaust flow rate is greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM, the predetermined flow resistance of at least one outlet ventilator is in the range of greater than about 0.15 cmH2O / Lmin-1 to less than about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

[0533] 4. A patient interface according to any one of Clauses 1 to 3, wherein the predetermined flow resistance can be measured in a simulation test.

[0534] 5. A patient interface according to any one of Clauses 1 to 4, wherein, in use, a supply flow rate is provided to the patient interface to generate interface pressure and an exhaust flow at an exhaust flow rate through at least one outflow vent.

[0535] 6. The patient interface according to any one of Clauses 1 to 5, wherein the total cross-sectional area of ​​at least one outflow ventilator is in the range of about 20 to about 100 mm2, or about 35 mm2 to about 80 mm2, or about 35 mm2 to about 60 mm2, or about 35 mm2 to about 50 mm2, or about 35 mm2 to about 40 mm2, or about 35 mm2 to about 45 mm2.

[0536] 7. A patient interface according to any one of clauses 1 to 6, wherein the patient interface includes at least one gas delivery element configured to provide a gas flow into the patient's nostrils, and at least one outflow vent includes:

[0537] - At least one opening located in the nostril, surrounding at least one insert of at least one gas delivery element.

[0538] 8. The patient interface as described in Clause 7, wherein the sealing element is provided by at least one insert.

[0539] 9. The patient interface as described in Clause 7 or Clause 8, wherein at least one insert is provided separately from the patient interface.

[0540] 10. A patient interface according to any one of clauses 1 to 6, wherein the patient interface includes at least one gas delivery element configured to provide a gas flow to one or both nostrils of a patient.

[0541] 11. A patient interface according to any one of clauses 1 to 6 and 10, wherein the sealing element comprises at least one nasal pillow, nasal fork, nasal pad, nasal sleeve or nasal support, configured to form a substantially seal with the patient's nostrils.

[0542] 12. The patient interface according to any one of Clauses 10 to 11, wherein the sealing element is integrated with or into the gas delivery element, and optionally, wherein the sealing element includes at least one outflow vent.

[0543] 13. The patient interface according to any one of Clauses 1 to 12, wherein the patient interface includes a body portion including at least one outflow vent.

[0544] 14. The patient interface according to Clause 13, wherein the main body includes a chamber between the gas inlet of the patient interface and the patient, the chamber including a constraint that causes asymmetry in the flow to the patient's nostrils.

[0545] 15. A patient interface according to any one of Clauses 1 to 14, wherein the patient interface includes a gas delivery side member, the gas delivery side member including a collapsible portion that closes or partially closes to reduce or stop flow through the first patient interface.

[0546] 16. The patient interface as described in Clause 15, wherein the collapsible portion is configured to collapse when force is applied by placing a breathing mask over the patient interface.

[0547] 17. A patient interface according to any one of Clauses 1 to 16, wherein the size of at least one outflow vent is configured to allow gas flow from a breathing mask to the patient.

[0548] 18. The patient interface as described in Clause 16 or Clause 17, wherein the breathing mask includes a balloon valve mask.

[0549] 19. A patient interface according to any one of Clauses 1 to 18, wherein the patient interface is configured to generate an asymmetric flow distribution into the patient's nostrils.

[0550] 20. A patient interface according to any one of clauses 1 to 19, wherein the patient interface is configured to receive lateral gas inlet, preferably unilateral gas inlet.

[0551] 21. The patient interface according to any one of clauses 1 to 20, comprising at least one sampling port.

[0552] 22. The patient interface according to Clause 21, wherein at least one sampling port is connectable to or provides a gas sampling line to provide fluid communication between the gas in the patient interface and at least one sensor, optionally wherein the at least one sensor includes a pressure, temperature, gas composition, CO2, or humidity sensor.

[0553] 23. A patient interface according to any one of clauses 1 to 22, comprising at least one gas sampling catheter adjustable to position a sampling tip in the oral cavity region of the patient during use.

[0554] 24. The patient interface as described in Clause 23, wherein a gas sampling catheter may be attached to the patient interface, such as being removably attached to the patient interface.

[0555] 25. A patient interface according to any one of clauses 1 to 24, comprising at least one access port that is normally closed and openable to allow an instrument to enter the nasal cavity via the patient interface.

[0556] 26. The patient interface according to Clause 25, wherein the access port includes a removable cover, and optionally, wherein the removable cover includes at least one or more outflow vents.

[0557] 27. The patient interface according to any one of Clauses 1 to 26, wherein the patient interface includes a headband connector for securing the patient interface to the patient during use.

[0558] 28. A patient interface according to any one of Clauses 1 to 27, wherein the patient interface includes a holding mechanism configured to improve the sealing of the sealing element.

[0559] 29. A patient interface according to any one of clauses 1 to 29, wherein at least one outflow vent is configured to, in use, generate a pressure differential of about 7 cmH2O to about 15 cmH2O between the patient and the atmosphere at a supply flow rate of about 70 L / min.

[0560] 30. A patient interface according to any one of clauses 1 to 30, wherein at least one outflow ventilator is configured to produce an exhaust rate substantially corresponding to the supplied gas flow rate from the patient interface when the patient's mouth is closed and during breath-holding or when the patient's breathing is paused.

[0561] 31. A patient interface according to any one of clauses 1 to 30, wherein at least one outflow ventilator comprises an invariable size and / or shape.

[0562] 32. The patient interface according to any one of Clauses 1 to 31, wherein at least one outflow vent includes a cross-sectional shape, the cross-sectional shape including circular, elliptical, oval, oblong, quadrilateral or square-round.

[0563] 33. A patient interface according to any one of clauses 1 to 32, wherein at least one outflow ventilator comprises 1, 2, 3, 4, 5, or 6 discrete openings.

[0564] 34. The patient interface according to any one of clauses 1 to 33, wherein at least one outflow ventilator comprises six discrete openings, each opening having a cross-sectional dimension of about 3 mm.

[0565] 35. A patient interface according to any one of clauses 1 to 34, wherein at least one outflow ventilator comprises a plurality of openings, not all of which have the same size and / or shape.

[0566] 36. A patient interface according to any one of clauses 1 to 34, wherein at least one outflow ventilator comprises at least one small opening and at least one large opening.

[0567] 37. The patient interface according to Clause 36, wherein at least one small opening has a cross-sectional dimension of less than about 1 mm, preferably less than about 0.75 mm, or about 0.5 mm, or about 0.3 to 0.7 mm.

[0568] 38. A patient interface according to Clause 36 or Clause 37, wherein at least one large opening has a cross-sectional dimension greater than about 1 mm or greater than about 2 mm, such as about 1 mm to about 2 mm or about 2 mm to about 3 mm.

[0569] 39. A patient interface according to any one of clauses 36 to 38, wherein the total cross-sectional area of ​​at least one small opening is similar to the total cross-sectional area of ​​at least one large opening.

[0570] 40. A patient interface according to any one of clauses 36 to 39, wherein, in use, the direction of flow from at least one large opening is different from the direction of flow from at least one small opening.

[0571] 41. A patient interface according to any one of clauses 36 to 40, wherein, in use, a flow from at least one small opening is directed toward the patient's mouth.

[0572] 42. A patient interface according to any one of clauses 36 to 41, wherein, in use, flow from at least one large opening is directed away from the patient's mouth.

[0573] 43. A patient interface according to any one of clauses 1 to 42, wherein at least one outflow vent is shaped to produce transitional or turbulent characteristics, preferably at a flow rate above about 50 LPM.

[0574] 44. A patient interface according to any one of clauses 1 to 43, comprising a ventilation component including at least one outflow ventilation port.

[0575] 45. The patient interface as described in Clause 44, wherein the ventilation component is removable to allow the instrument to enter the nasal cavity via the patient interface.

[0576] 46. ​​A system for providing respiratory support to a patient, the system comprising:

[0577] - A patient interface for providing a gas flow to a patient, the patient interface having at least one outflow vent to allow a gas exhaust flow at an exhaust flow rate, and a sealing element that substantially prevents gas from escaping from the patient during use, except via the at least one outflow vent.

[0578] - A gas source, operable to provide a gas flow; and

[0579] - A controller operable to control the flow rate of gas supplied to the patient interface at a predetermined supply flow rate;

[0580] At least one of the outflow vents has a predetermined flow resistance during use.

[0581] 47. The system according to Clause 46 includes a flow source that can be controlled by a controller to provide a gas flow at a predetermined supply flow rate.

[0582] 48. A system according to Clause 46 or Clause 47, comprising a patient interface according to any one of Clauses 1 to 45.

[0583] 49. The system according to any one of clauses 46 to 48, comprising a humidifier.

[0584] 50. A system according to any one of Clauses 46 to 49, wherein the predetermined supply flow rate is in the range of about 0 LPM, about 10 LPM, about 20 LPM, about 30 LPM, about 40 LPM, about 50 LPM, about 60 LPM, about 70 LPM, about 80 LPM, about 90 LPM or about 100 LPM.

[0585] 51. The system according to any one of Clauses 46 to 50, wherein the controller is operable to control a predetermined supply flow rate at a first supply flow rate greater than about 0 LPM, about 10 LPM, about 20 LPM, about 30 LPM, about 40 LPM, or about 50 LPM.

[0586] 52. The system according to Clause 51, wherein the controller is operable to control a predetermined supply flow rate at a second supply flow rate, the second supply flow rate being higher than the first supply flow rate, and optionally, greater than about 40 LPM, about 50 LPM, about 60 LPM, about 70 LPM, about 80 LPM, about 90 LPM, or about 100 LPM.

[0587] 53. The system described in Clause 52, wherein a second supply flow rate is provided in response to an indication of the patient's condition.

[0588] 54. In a system according to Clause 53, the indication of the patient's condition is determined by one or more of the following:

[0589] - Observation of patients and / or patient parameters;

[0590] - User confirmation of treatment administration to patients;

[0591] - Instrumental measurement of one or more patient parameters;

[0592] - The control device uses data received from the user or one or more devices monitoring patient parameters to determine indications of the patient's condition; and

[0593] - The patient's self-report of their condition.

[0594] 55. The system according to Clause 54, wherein one or more patient parameters include:

[0595] - Depth of sedation;

[0596] - Heart rate;

[0597] - EEG signal value;

[0598] - EKG / ECG signal value;

[0599] - Blood oxygen concentration;

[0600] - Blood oxygen saturation (SpO2);

[0601] - Exhaled oxygen concentration;

[0602] - Blood CO2 concentration;

[0603] - Transdermal CO2 concentration (TcCO2);

[0604] - Transdermal O2 concentration (TcO2);

[0605] - Exhaled CO2 concentration; and

[0606] - Blood sugar level.

[0607] 56. A system according to any one of clauses 53 to 55, wherein the patient condition includes conditions selected from the group consisting of:

[0608] - Lower or upper airway obstruction;

[0609] - Soft palate obstruction;

[0610] - No spontaneous breathing;

[0611] - The patient's inspiratory needs are not being met;

[0612] - The patient is at risk of apnea or sleep apnea.

[0613] - To meet the patient's sedation depth; and

[0614] - Expiratory airway pressure is at or near the suboptimal threshold.

[0615] 57. The system according to any one of Clauses 53 to 56, wherein the controller is operable to control a first supply flow rate and / or a second supply flow rate by one or more of the following: the second supply flow rate being manually selected by the user in response to confirmation of an instruction by the user regarding the patient's condition; the second supply flow rate being determined by the control device when the control device receives user input confirming the instruction regarding the patient's condition; and the second supply flow rate being determined by the control device when the control device determines the presence of a patient condition using data received from one or more devices monitoring patient condition parameters.

[0616] 58. A system according to any one of clauses 46 to 57, operable to provide a first supply flow rate before delivery of an anesthetic to a patient and a second supply flow rate after delivery of an anesthetic to a patient.

[0617] 59. A system according to any one of Clauses 53 to 58, operable to provide a second supply flow rate in response to an instruction that an anesthetic is being or has been delivered to a patient.

[0618] 60. A system according to Clause 59, wherein an indication that an anesthetic is being or has been administered to a patient is determined by one or more of the following: a clinician observes the patient and / or patient parameters and manually inputs the indication into a control device; and the control device uses data received from a user or one or more devices that monitor patient parameters, which provide an indication that an anesthetic is being or has been administered to the patient.

[0619] 61. A system according to any one of Clauses 46 to 60, operable to provide respiratory support prior to the delivery of anesthetic agents and / or before the patient begins anesthesia or sedation.

[0620] 62. The system according to any one of Clauses 53 to 60, which is operable to control the gas flow at a third supply flow rate.

[0621] 63. The system according to Clause 62, wherein the third supply flow rate is less than the second supply flow rate.

[0622] 64. A system as described in Clause 62 or Clause 63, operable to provide a third supply flow rate in response to instructions regarding different patient conditions.

[0623] 65. The system according to Clause 64, wherein different patient conditions include conditions selected from the group consisting of: the lower or upper airway is open; the soft palate is no longer obstructed; spontaneous breathing is present; the patient's inspiratory needs are met; a predetermined level of alertness is met; and the expiratory interface pressure is met or exceeds an optimal threshold.

[0624] 66. A system according to any one of Clauses 46 to 65, wherein the controller is configured to receive control input provided by the user and / or control input generated by the processor.

[0625] 67. A system according to any one of clauses 46 to 66, wherein the patient interface is configured to provide a flow of gas into one or both nostrils of the patient.

[0626] 68. A system according to any one of Clauses 46 to 67, operable to provide respiratory support to a patient undergoing a medical procedure, such as a scheduled medical procedure.

[0627] 69. The system according to any one of Clauses 46 to 68, wherein the gas stream supplied at a predetermined supply flow rate comprises a 100% O2 concentration.

[0628] 70. The system according to any one of Clauses 46 to 69, wherein a first predetermined flow resistance at at least one outflow vent at a first exhaust flow rate through the at least one outflow vent is in the range of greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

[0629] 71. The system according to any one of Clauses 70, wherein the first exhaust flow rate is between more than about 0 LPM and about 40 LPM, or between about 30 LPM and about 40 LPM, or between about 35 LPM and about 45 LPM.

[0630] 72. The system according to any one of Clauses 46 to 71, wherein the second predetermined flow resistance of at least one outlet vent at the second exhaust flow rate is in the range of greater than about 0.15 cmH2O / Lmin-1 to less than about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

[0631] 73. The system according to Clause 72, wherein the second exhaust flow rate is between greater than about 40 LPM and about 100 LPM, or between about 40 LPM and about 70 LPM, or between about 40 LPM and about 60 LPM, or between about 50 LPM and about 70 LPM, or between about 50 LPM and about 60 LPM, or between about 60 LPM and about 70 LPM.

[0632] 74. A system according to any one of clauses 46 to 73, wherein for a given exhaust flow rate, the flow resistance is attributed to the size and / or shape of at least one outflow vent.

[0633] 75. The system according to any one of Clauses 46 to 74, wherein the total cross-sectional area of ​​at least one outflow vent is in the range of about 20 to about 100 mm2, or about 35 mm2 to about 80 mm2, or about 35 mm2 to about 60 mm2, or about 35 mm2 to about 50 mm2, or about 35 mm2 to about 40 mm2, or about 35 mm2 to about 45 mm2.

[0634] 76. A system according to any one of clauses 46 to 77, operable to control a gas flow and produce one or more of the following:

[0635] - Exhaust flow rate of approximately 40 LPM and interface pressure of approximately 3-5 cmH2O, such as approximately 4 cmH2O;

[0636] - Exhaust flow rate of approximately 30 LPM and interface pressure of approximately 2-4 cmH2O, such as approximately 3 cmH2O;

[0637] - Exhaust flow rate of approximately 50 LPM and interface pressure of approximately 5-8 cmH2O, such as approximately 6 cmH2O;

[0638] - Exhaust flow rate of approximately 55 LPM and interface pressure of approximately 6-8 cmH2O;

[0639] - An exhaust flow rate of approximately 60 LPM and an interface pressure of approximately 7-9 cmH2O; and

[0640] - Exhaust flow rate of approximately 70 LPM and interface pressure of approximately 7-15 cmH2O, such as approximately 9-12 cmH2O, such as approximately 9-10 cmH2O, or approximately 10-12 cmH2O.

Claims

1. A method for providing respiratory support to a patient during a medical procedure, the method comprising: - A gas flow is provided to the patient via a patient interface system having at least one outflow ventilator; - The gas flow is controlled at a first supply flow rate, and a first interface pressure and an exhaust flow at a first exhaust flow rate through the at least one outlet vent are generated; as well as - The gas flow is controlled at a second supply flow rate, and a second interface pressure and an exhaust flow at a second exhaust flow rate through the at least one outlet vent are generated; The first predetermined flow resistance of the at least one outflow vent at the first exhaust flow rate is different from the second predetermined flow resistance of the at least one outflow vent at the second exhaust flow rate.

2. A method for providing respiratory support to a patient during a medical procedure, the method comprising: - A gas flow is provided to the patient via a patient interface system having at least one outflow ventilator; - The gas flow is controlled at a first supply flow rate, and a first interface pressure and an exhaust flow at a first exhaust flow rate through the at least one outlet vent are generated; - Control the gas flow at a second supply flow rate and generate a second interface pressure and an exhaust flow rate through the at least one outlet vent at a second exhaust flow rate; - Wherein the second rate of change of the second interface pressure associated with the second exhaust flow rate is greater than the first rate of change of the first interface pressure associated with the first exhaust flow rate.

3. The method according to claim 1 or claim 2, wherein the gas flow is controlled at the first supply flow rate before the second supply flow rate.

4. The method according to claim 1 or claim 2, wherein the gas flow is controlled at the second supply flow rate before the first supply flow rate.

5. The method according to any one of the preceding claims, wherein the second supply flow rate is higher than the first supply flow rate.

6. The method according to any one of the preceding claims, wherein the first supply flow rate is greater than about 0 LPM, about 10 LPM, about 20 LPM, about 30 LPM, about 40 LPM or about 50 LPM.

7. The method according to any one of the preceding claims, wherein the second supply flow rate is greater than about 40 LPM, about 50 LPM, about 60 LPM, about 70 LPM, about 80 LPM, about 90 LPM, or about 100 LPM.

8. The method according to any one of the preceding claims, comprising providing the second supply flow rate in response to an indication of the patient's condition.

9. The method of claim 8, wherein the indication of the patient's condition is determined by one or more of the following: - Observation of the patients and / or patient parameters; - User confirmation of administering the therapy to the patient; - Measurement of one or more patient parameters; - The control device uses data received from the user or one or more devices that monitor patient parameters to determine an indication of the patient's condition; as well as - The patient's self-report of their condition.

10. The method of claim 9, wherein the one or more patient parameters include: - Depth of sedation; - Heart rate; - EEG signal value; - EKG / ECG signal value; - EMG signal value; - Blood oxygen concentration; - Blood oxygen saturation (SpO2); - Exhaled oxygen concentration; - Blood CO2 concentration; - Transdermal CO2 concentration (TcCO2); - Transdermal O2 concentration (TcO2); - Exhaled CO2 concentration; and - Blood sugar level.

11. The method according to any one of claims 8 to 10, wherein the patient condition includes conditions selected from the group consisting of: - Lower or upper airway obstruction; - Soft palate obstruction; - No spontaneous breathing; - The patient's inspiratory needs are not being met; - The patient is at risk of respiratory arrest; - To meet the patient's required sedation depth; as well as - Expiratory airway pressure is at or near the suboptimal threshold.

12. The method according to any one of claims 8 to 11, comprising controlling the first supply flow rate and / or the second supply flow rate by one or more of the following: - In response to the user's confirmation of the patient's condition, the user manually selects the second supply flow rate; - When the control device receives user input confirming the patient's condition, the control device determines the second supply flow rate; and - When the control device determines the presence of the patient condition using data received from one or more devices that monitor patient condition parameters, the control device determines the second supply flow rate.

13. The method according to any one of the preceding claims, comprising providing the first supply flow rate before delivering the anesthetic to the patient, and providing the second supply flow rate after delivering the anesthetic to the patient.

14. The method according to any one of the preceding claims, comprising providing the second supply flow rate in response to an instruction that an anesthetic is being or has been delivered to the patient.

15. The method of claim 14, wherein the indication that the anesthetic is being or has been administered to the patient is determined by one or more of the following: - The clinician observes the patient and / or patient parameters and manually inputs the instructions into the control device; and - The control device uses data received from the user or one or more devices that monitor patient parameters, which provide an indication that an anesthetic is being or has been administered to the patient.

16. The method according to any one of the preceding claims, comprising providing the respiratory support prior to the administration of the anesthetic and / or prior to the initiation of anesthesia or sedation of the patient.

17. The method according to any one of the preceding claims, comprising controlling the gas flow at a third supply flow rate and generating a third interface pressure and an exhaust flow through the at least one outlet vent at a third exhaust flow rate, wherein the rate of change of the third interface pressure associated with a change in the third exhaust flow rate is less than the rate of change of the second interface pressure associated with a change in the second exhaust flow rate.

18. The method according to any one of the preceding claims, comprising controlling the gas flow at a third supply flow rate and generating a third interface pressure and an exhaust flow rate through the at least one outlet vent at a third exhaust flow rate, wherein the third predetermined flow resistance of the at least one outlet vent at the third exhaust flow rate is different from the second predetermined flow resistance of the at least one outlet vent at the second exhaust flow rate.

19. The method of claim 17 or claim 18, wherein the third supply flow rate is lower than the second supply flow rate.

20. The method according to any one of claims 17 to 19, further comprising providing the third supply flow rate in response to an indication of a different patient condition.

21. The method of claim 20, wherein the different patient conditions include conditions selected from the group consisting of: - The lower or upper airway becomes clear; - The soft palate is no longer blocked; - He / She is breathing spontaneously; - The patient's inspiratory needs are met; - Meet the predetermined alert level; and - The expiratory interface pressure meets or exceeds the optimal threshold.

22. The method according to any one of claims 2 to 21, wherein for a first exhaust flow rate value in the range of about 0 LPM to about 40 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, the first rate of change of the first interface pressure is in the range of about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

23. The method according to any one of claims 2 to 22, wherein for a second exhaust flow rate value in the range of greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM, the second rate of change of the second interface pressure is capable of being in the range of greater than about 0.1 cmH2O / Lmin-1 to less than about 0.6 cmH2O / Lmin-1, or about 0.15 cmH2O / Lmin-1 to about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

24. The method according to any one of claims 2 to 23, wherein the corresponding interface pressure and exhaust flow rate of the first rate of change and the second rate of change are related such that, when presented graphically, their relationship includes one or more of the following: - The first rate of change and the second rate of change exhibit a stepwise variation; - The first rate of change and the second rate of change change are progressively different; - The first rate of change and the second rate of change exhibit a curvilinear relationship; - The first rate of change and / or a portion of the second rate of change have a non-constant gradient; - The transition between the first exhaust velocity and the second exhaust velocity exhibits a non-stepwise change; and - The transition between the second exhaust velocity and the third exhaust velocity is non-stepwise.

25. The method according to any one of claims 2 to 24, wherein one or both of the first rate of change and the second rate of change are non-constant.

26. The method according to any one of the preceding claims, comprising controlling the gas flow and producing one or more of the following: - A first exhaust flow rate of approximately 40 LPM and a first interface pressure of approximately 3-5 cmH2O, such as approximately 4 cmH2O; - A first exhaust flow rate of approximately 30 LPM and a first interface pressure of approximately 2-4 cmH2O, such as approximately 3 cmH2O; - A second exhaust flow rate of approximately 50 LPM and a second interface pressure of approximately 5-8 cmH2O, such as approximately 6 cmH2O; - A second exhaust flow rate of approximately 55 LPM and a second interface pressure of approximately 6-8 cmH2O; - A second exhaust flow rate of approximately 60 LPM and a second interface pressure of approximately 7-9 cmH2O; and - A second exhaust flow rate of approximately 70 LPM and a second interface pressure of approximately 7-15 cmH2O, such as approximately 9-12 cmH2O, such as approximately 9-10 cmH2O, or approximately 10-12 cmH2O.

27. The method according to any one of the preceding claims, comprising operating a flow source to provide the gas flow, wherein the flow source is controlled by a control device configured to receive control input provided by a user and / or control input generated by a processor.

28. The method according to any one of the preceding claims, wherein the patient interface system includes a patient interface configured to provide the gas flow to one or both nostrils of the patient, and includes at least one outflow vent, the at least one outflow vent being configured to generate a predetermined interface pressure and a predetermined target exhaust flow rate from the at least one outflow vent in response to a predetermined supply flow rate to the patient interface.

29. The method according to any one of the preceding claims, wherein the patient interface includes at least one sealing element, such as a nasal pillow, nasal fork, nasal pad, nasal sleeve, or nasal prosthesis, configured to form a substantially sealed seal with the patient's nostrils to substantially restrict gas escape except via the at least one outflow vent.

30. The method of claim 28 or claim 29, further comprising the step of placing the patient interface on the patient.

31. The method according to any one of the preceding claims, wherein the patient is undergoing a medical procedure, such as a predetermined medical procedure, during the provision of the respiratory support.

32. The method according to any one of the preceding claims, comprising providing the patient with an anesthetic.

33. The method according to any one of the preceding claims, wherein the gas stream provided at one or both of the first supply flow rate and the second supply flow rate comprises a 100% O2 concentration.

34. The method according to any one of claims 2 to 34, wherein the rate of change is an average rate of change.

35. The method according to claim 1 or any one of claims 3 to 34 when dependent on claim 1, wherein the first predetermined flow resistance of the at least one outlet vent at the first exhaust flow rate is in the range of greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

36. The method according to any one of the preceding claims, wherein the first exhaust flow rate is between about 0 LPM and about 40 LPM, or between about 30 LPM and about 40 LPM, or between about 35 LPM and about 45 LPM.

37. The method according to claim 1 or any one of claims 3 to 36 when dependent on claim 1, wherein the second predetermined flow resistance of the at least one outlet vent at the second exhaust flow rate is in the range of greater than about 0.15 cmH2O / Lmin-1 to less than about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

38. The method according to any one of the preceding claims, wherein the second exhaust flow rate is between greater than about 40 LPM and about 100 LPM, or between about 40 LPM and about 70 LPM, or between about 40 LPM and about 60 LPM, or between about 50 LPM and about 70 LPM, or between about 50 LPM and about 60 LPM, or between about 60 LPM and about 70 LPM.

39. The method according to any one of the preceding claims, wherein the first flow resistance and the second flow resistance, and / or the first rate of change and the second rate of change at the corresponding exhaust flow rates, can be measured in a simulation test.

40. The method according to any one of the preceding claims, wherein the patient does not experience apnea during the provision of the respiratory support.

41. The method according to claim 1 and any one of claims 3 to 40 when dependent on claim 1, wherein for a given exhaust flow rate, the flow resistance is attributed to the size and / or shape of the at least one outflow vent.

42. The method according to any one of the preceding claims, wherein the total cross-sectional area of ​​the at least one outflow vent is from about 20 to about 100 mm. 2 or about 35 mm 2 approximately 80 mm 2 or about 35 mm 2 Approximately 60 mm 2 or about 35 mm 2 Approximately 50 mm 2 or about 35 mm 2 Approximately 40 mm 2 or about 35 mm 2 Approximately 45 mm 2 Within the range.

43. A patient interface for providing respiratory support, the interface comprising: - A gas flow path used to provide gas flow to the patient; - At least one outflow vent, said at least one outflow vent being configured to allow exhaust flow of gas; as well as - A sealing element that, in use, substantially prevents gas from escaping from the patient except via the at least one outflow vent. The patient interface is configured to generate interface pressure during the provision of the respiratory support; and The interface pressure and the exhaust flow rate through the at least one outlet vent form a nonlinear relationship, the nonlinear relationship including exhaust flow rate values ​​in the range of greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM, the rate of change of the interface pressure being in the range of greater than 0.15 cmH2O / Lmin-1 to less than 0.5 cmH2O / Lmin-1.

44. The patient interface of claim 43, wherein the nonlinear relationship comprises, for exhaust flow rates greater than about 0 LPM to about 40 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, the rate of change of the interface pressure is greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1.

45. The patient interface according to claim 43 or 44, wherein the nonlinear relationship comprises a polynomial component, preferably a quadratic polynomial component.

46. ​​The patient interface according to any one of claims 43 to 45, wherein the at least one outflow vent is configured to generate a predetermined exhaust flow rate in use for a predetermined supply flow rate.

47. The patient interface according to any one of claims 43 to 46, wherein the at least one outflow vent is configured to generate a predetermined interface pressure and an associated exhaust flow rate for a predetermined supply flow rate during use.

48. The patient interface according to any one of claims 43 to 47, wherein the total cross-sectional area of ​​the at least one outflow ventilator is from about 20 to about 100 mm. 2 or about 35 mm 2 approximately 80 mm 2 or about 35 mm 2 Approximately 60 mm 2 or about 35mm 2 Approximately 50 mm 2 or about 35 mm 2 Approximately 40 mm 2 or about 35 mm 2 Approximately 45 mm 2 Within the range.

49. The patient interface according to any one of claims 43 to 48, wherein the patient interface includes at least one gas delivery element configured to provide the gas flow into the nostrils of the patient, and the at least one outflow vent includes: - At least one opening in at least one insert located in the nostril and surrounding the nasal fork.

50. The patient interface of claim 49, wherein the at least one insert is provided separately from the patient interface.

51. The patient interface according to any one of claims 43 to 50, wherein the patient interface includes at least one gas delivery element configured to provide the gas flow to one or both nostrils of the patient.

52. The patient interface according to any one of claims 43 to 51, wherein the sealing element comprises at least one nasal pillow, nasal fork, nasal pad, nasal sleeve, or nasal support, configured to form a substantially seal with the patient's nostrils.

53. The patient interface according to any one of claims 49 to 52, wherein the sealing element is integrated with or incorporated into the gas delivery element, and optionally, wherein the sealing element includes the at least one outflow vent.

54. The patient interface according to any one of claims 43 to 53, wherein the patient interface comprises a body portion, the body portion including the at least one outflow vent.

55. The patient interface of claim 54, wherein the main body includes a chamber between the gas inlet of the patient interface and the patient, the chamber including a constraint that causes flow asymmetry to the patient's nostrils.

56. The patient interface according to any one of claims 43 to 55, wherein the patient interface includes a gas delivery side member, the gas delivery side member including a collapsible portion, the collapsible portion being closed or partially closed to reduce or stop flow through the first patient interface.

57. The patient interface of claim 56, wherein the collapsible portion is configured to collapse when a force is applied by placing a breathing mask over the patient interface.

58. The patient interface according to any one of claims 43 to 57, wherein the size of the at least one outflow vent is configured to allow gas flow from the breathing mask to the patient.

59. The patient interface according to claim 57 or claim 58, wherein the breathing mask comprises a balloon valve mask.

60. The patient interface according to any one of claims 43 to 59, wherein the patient interface is configured to generate an asymmetric flow distribution into the patient's nostrils.

61. The patient interface according to any one of claims 43 to 60, wherein the patient interface is configured to receive lateral gas inlet, preferably unilateral gas inlet.

62. The patient interface according to any one of claims 43 to 61, comprising at least one sampling port.

63. The patient interface of claim 62, wherein the at least one sampling port is connectable to or provides a gas sampling line to provide fluid communication between the gas in the patient interface and at least one sensor, optionally wherein the at least one sensor includes a pressure, temperature, gas composition, CO2, or humidity sensor.

64. The patient interface according to any one of claims 43 to 63, comprising at least one gas sampling catheter, said at least one gas sampling catheter being adjustable to position a sampling tip at the oral cavity region of the patient during use.

65. The patient interface of claim 64, wherein the gas sampling catheter is attachable to the patient interface, such as being removably attached to the patient interface.

66. The patient interface according to any one of claims 43 to 65, comprising at least one access port that is normally closed and capable of being opened to allow an instrument to enter the nasal cavity via the patient interface.

67. The patient interface of claim 66, wherein the access port includes a removable cover, and optionally, wherein the removable cover includes one or more of the at least one outflow ventilator.

68. The patient interface according to any one of claims 43 to 67, wherein the patient interface includes a headband connector for stabilizing the patient interface on the patient during use.

69. The patient interface according to any one of claims 43 to 68, wherein the patient interface includes a retaining mechanism configured to improve the sealing of the sealing element.

70. The patient interface according to any one of claims 43 to 69, wherein the at least one outflow vent is configured to, in use, generate a pressure differential of about 7 cmH2O to about 15 cmH2O between the patient and the atmosphere at a supply flow rate of about 70 L / min.

71. The patient interface according to any one of claims 43 to 70, wherein the at least one outflow vent is configured to generate an exhaust rate substantially corresponding to the supplied gas flow rate from the patient interface when the patient's mouth is closed and during breath-holding or when the patient's breathing is paused.

72. The patient interface according to any one of claims 43 to 71, wherein the at least one outflow vent is invariable.

73. The patient interface according to any one of claims 43 to 72, wherein the at least one outflow vent has a cross-sectional shape, the cross-sectional shape including a circle, an ellipse, an egg, an oblong, a quadrilateral, or a square-round shape.

74. The patient interface according to any one of claims 43 to 73, wherein the at least one outflow vent comprises 1, 2, 3, 4, 5, or 6 discrete openings.

75. The patient interface according to any one of claims 43 to 74, wherein the at least one outflow vent comprises six discrete openings, each opening having a cross-sectional dimension of about 3 mm.

76. The patient interface according to any one of claims 43 to 75, wherein the at least one outflow ventilator comprises a plurality of openings, not all of which have the same size and / or shape.

77. The patient interface according to any one of claims 43 to 76, wherein the at least one outflow vent includes at least one small opening and at least one large opening.

78. The patient interface according to claim 77, wherein the cross-sectional dimension of the at least one small opening is less than about 1 mm, preferably less than about 0.75 mm, or about 0.5 mm, or about 0.3 to 0.7 mm.

79. The patient interface according to claim 77 or claim 78, wherein the cross-sectional dimension of the at least one large opening is greater than about 1 mm or greater than about 2 mm, such as about 1 mm to about 2 mm or about 2 mm to about 3 mm.

80. The patient interface according to any one of claims 77 to 79, wherein the total cross-sectional area of ​​the at least one small opening is similar to the total cross-sectional area of ​​the at least one large opening.

81. The patient interface according to any one of claims 77 to 80, wherein, in use, the direction of flow from the at least one large opening is different from the direction of flow from the at least one small opening.

82. The patient interface according to any one of claims 77 to 81, wherein, in use, the flow from the at least one small opening is directed toward the patient's mouth.

83. The patient interface according to any one of claims 77 to 82, wherein, in use, flow from the at least one large opening is directed away from the patient's mouth.

84. The patient interface according to any one of claims 43 to 83, wherein the patient interface is configured to generate interface pressure during the provision of the respiratory support.

85. The patient interface according to any one of claims 43 to 84, wherein the at least one outflow vent is shaped to produce transitional or turbulent characteristics, preferably at a flow rate above about 50 LPM.

86. The patient interface according to any one of claims 43 to 85, wherein the interface pressure includes average interface pressure.

87. The patient interface according to any one of claims 43 to 86, wherein the rate of change is an average rate of change.

88. The patient interface according to any one of claims 43 to 87, wherein the rate of change is determined in the absence of patient respiratory effects.

89. The patient interface according to any one of claims 43 to 88, comprising a ventilation component, the ventilation component including the at least one outflow ventilator.

90. The patient interface of claim 89, wherein the ventilation component is removable to allow the instrument to enter the nasal cavity via the patient interface.

91. A method of providing respiratory support to a patient, the method comprising: - Provide initial respiratory support to the patient using the first patient interface; - Place the second patient interface above the first patient interface to reduce or stop the flow of the first respiratory support to the first patient interface; as well as - Provide second respiratory support using the second patient interface; The first patient interface includes at least one airway, the size of which is configured such that second respiratory support from the second patient interface can be provided to the patient via the first patient interface.

92. The method of claim 91, wherein the first patient interface includes at least one nasal fork configured to provide the first respiratory support to at least one nostril of the patient.

93. The method of claim 91 or claim 91, wherein the first patient interface includes at least one sealing element, the at least one sealing element including a nasal pillow, nasal fork, nasal pad, nasal sleeve or nasal support, configured to form a substantially sealed seal with the patient's nostrils to substantially restrict gas escape except via the at least one air vent.

94. The method according to any one of claims 91 to 93, wherein the first patient interface comprises a body portion, the body portion comprising the at least one air vent.

95. The method according to any one of claims 91 to 94, wherein the first patient interface includes a gas delivery side member, the gas delivery side member including a collapsible portion, the collapsible portion being closed or partially closed to reduce or stop flow through the first patient interface.

96. The method of claim 95, wherein the collapsible portion is configured to collapse when a force is applied due to placing the second patient interface over the first patient interface.

97. The method according to any one of claims 91 to 96, wherein the first respiratory support comprises: - The gas flow is controlled at a first supply flow rate, and a first interface pressure and an exhaust flow through the at least one vent at a first exhaust flow rate are generated; as well as - Control the gas flow at a second supply flow rate and generate a second interface pressure and an exhaust flow rate through the at least one outlet vent at a second exhaust flow rate; The second rate of change of the second interface pressure associated with the second exhaust flow rate is greater than the first rate of change of the first interface pressure associated with the first exhaust flow rate.

98. The method according to any one of claims 91 to 97, wherein the at least one vent is configured to provide: - For a first exhaust flow rate value greater than about 0 LPM to about 40 LPM, or about 30 LPM to about 40 LPM, or about 35 LPM to about 45 LPM, or when the supply flow rate is less than 15 LPM, to provide a first predetermined flow resistance in use within the range of greater than about 0 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.05 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1, or about 0.1 cmH2O / Lmin-1 to about 0.15 cmH2O / Lmin-1; and - For a second exhaust flow rate value in the range of greater than about 40 LPM to about 100 LPM, or about 40 LPM to about 70 LPM, or about 40 LPM to about 60 LPM, or about 50 LPM to about 70 LPM, or about 50 LPM to about 60 LPM, or about 60 LPM to about 70 LPM, a second predetermined flow resistance is provided in use in the range of greater than about 0.15 cmH2O / Lmin-1 to less than about 0.5 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.4 cmH2O / Lmin-1, or about 0.2 cmH2O / Lmin-1 to about 0.3 cmH2O / Lmin-1.

99. The method according to any one of claims 91 to 98, wherein the first respiratory support comprises providing a gas flow to the patient interface at a supply flow rate and generating an interface pressure and an exhaust flow through the at least one ventilation port at an exhaust flow rate, wherein the values ​​of the interface pressure and the exhaust flow rate constitute a nonlinear relationship, the nonlinear relationship comprising a polynomial.

100. The method of claim 99, wherein the nonlinear relationship comprises polynomial components, preferably quadratic polynomial components.

101. The method according to any one of claims 98 to 100, wherein for a given exhaust flow rate, the flow resistance is attributed to the size and / or shape of the at least one vent.

102. The method according to any one of claims 91 to 101, wherein the total cross-sectional area of ​​the at least one vent is from about 20 to about 100 mm. 2 or about 35 mm 2 approximately 80 mm 2 or about 35 mm 2 Approximately 60 mm 2 or about 35 mm 2 Approximately 50 mm 2 or about 35 mm 2 Approximately 40 mm 2 or about 35 mm 2 Approximately 45 mm 2 Within the range.

103. The method according to any one of claims 91 to 102, wherein the method includes the step of positioning the first patient interface, including at least one nasal sealing element, on the patient.

104. The method of any one of claims 91 to 103, wherein the method includes the step of removing the second patient interface to restore the provision of the first respiratory support.

105. The method according to any one of claims 91 to 104, wherein the second patient interface includes a ventilation port or expiratory pathway for discharging gas.

106. The method according to any one of claims 91 to 105, comprising the step of alternating between the first respiratory support and the second respiratory support by removing or applying the second patient interface.

107. The method according to any one of claims 91 to 106, wherein the second respiratory support is provided to achieve one or more of the following: - Increase patient oxygenation; - To deliver one or more substances into the patient's airway; - Change the interface pressure; - Change the gas flow rate; - Different controls over interface pressure; and - Different controls over gas flow rate.

108. The method according to any one of claims 91 to 107, wherein the at least one vent is invariable.

109. The method according to any one of claims 91 to 108, wherein the at least one vent has a cross-sectional shape, the cross-sectional shape including a circle, an ellipse, an egg, an oblong, a quadrilateral, or a square-round shape.

110. The method according to any one of claims 91 to 109, wherein the at least one vent comprises 1, 2, 3, 4, 5, or 6 discrete openings.

111. The method according to any one of claims 91 to 110, wherein the at least one vent comprises six discrete openings, each opening having a cross-sectional dimension of about 3 mm.

112. The method according to any one of claims 91 to 111, wherein the at least one vent is shaped to produce transition or turbulent characteristics, preferably at a flow rate above about 50 LPM.

113. The patient interface according to any one of claims 91 to 112, wherein the at least one outflow vent includes a plurality of openings, which are not all of the same size and / or shape.

114. The patient interface according to any one of claims 91 to 113, wherein the at least one outflow vent includes at least one small opening and at least one large opening.

115. The patient interface according to claim 114, wherein the cross-sectional dimension of the at least one small opening is less than about 1 mm, preferably less than about 0.75 mm, or about 0.5 mm, or about 0.3 to 0.7 mm.

116. The patient interface according to claim 114 or claim 115, wherein the cross-sectional dimension of the at least one large opening is greater than about 1 mm or greater than about 2 mm, such as about 1 mm to about 2 mm or about 2 mm to about 3 mm.

117. The patient interface according to any one of claims 114 to 116, wherein the total cross-sectional area of ​​the at least one small opening is similar to the total cross-sectional area of ​​the at least one large opening.

118. The patient interface according to any one of claims 114 to 117, wherein, in use, the direction of flow from the at least one large opening is different from the direction of flow from the at least one small opening.

119. The patient interface according to any one of claims 114 to 118, wherein, in use, the flow from the at least one small opening is directed toward the patient's mouth.

120. The patient interface according to any one of claims 114 to 19, wherein, in use, flow from the at least one large opening is directed away from the patient's mouth.

121. The method according to any one of claims 91 to 120, wherein the second patient interface comprises a face mask.

122. The method according to any one of claims 91 to 121, wherein the second patient interface comprises a balloon valve mask.

123. The method according to any one of claims 91 to 122, wherein the interface pressure includes average interface pressure.

124. A system for providing respiratory support to a patient, the system comprising: - A patient interface system for providing a gas flow to the patient, the patient interface system having at least one outflow vent. as well as - A gas source, said gas source being controllable to: A gas flow is provided at a first supply flow rate, generating a first interface pressure and an exhaust flow at a first exhaust flow rate through the at least one outlet vent; and A gas flow is provided at a second supply flow rate, and a second interface pressure and an exhaust flow rate are generated through the at least one outlet vent at a second exhaust flow rate. The first predetermined flow resistance of the at least one outflow vent at the first exhaust flow rate is different from the second predetermined flow resistance of the at least one outflow vent at the second exhaust flow rate.

125. A system for providing respiratory support to a patient, the system comprising: - A patient interface system for providing a gas flow to the patient, the patient interface system having at least one outflow vent. as well as - A gas source, said gas source being controllable to: A gas flow is provided at a first supply flow rate, generating a first interface pressure and an exhaust flow at a first exhaust flow rate through the at least one outlet vent; and A gas flow is provided at a second supply flow rate, and a second interface pressure and an exhaust flow rate are generated through the at least one outlet vent at a second exhaust flow rate. The second rate of change of the second interface pressure associated with the change of the second exhaust velocity is greater than the first rate of change of the first interface pressure associated with the change of the first exhaust velocity.

126. A system for providing respiratory support to a patient, the system comprising: - A first patient interface for providing first respiratory support to the patient, the first patient interface including at least one airway, the size of the at least one airway being configured to allow second respiratory support to be provided to the patient when the flow of first respiratory support to the first patient interface has been reduced or stopped; - One or more flow sources, the one or more flow sources providing gas flow to one or both of the first respiratory support and the second respiratory support; as well as - A controller for controlling the one or more stream sources.

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