Patient gas delivery system and method

Abstract

1. A device arranged in fluid communication with a patient interface arranged to communicate with a patient's airway during respiratory therapy, the device comprising: an inlet for receiving breathable gas from a respiratory apparatus; an outlet for conveying breathable gas to the patient interface; a body portion extending between the inlet and the outlet, the body portion including a trigger port; and one or more sensors, the output of which is used to determine a status of the trigger port.

Description

[Technical field]

[0001] The present disclosure relates generally to patient gas delivery systems and methods. [Background technology]

[0002] Positive End Expiratory Pressure (PEEP) and / or Peak Inspiratory Pressure (PIP) can be controllably provided to the patient during respiration, resuscitation or assisted breathing (ventilation).

[0003] PEEP is the pressure delivered to a patient throughout the expiratory phase of positive pressure ventilation, resuscitation, or assisted breathing. PIP is the maximum desired pressure provided to a patient during the inspiratory phase of positive pressure ventilation, resuscitation, or assisted breathing. The patient may be a neonate or infant requiring respiratory assistance or resuscitation. When applying PEEP or PIP, the patient's upper airway and lungs are held open by the applied pressure.

[0004] Some respiratory therapy systems, such as those that can be used for infant resuscitation, rely on a T-piece device to manually adjust the pressure of the breathable gas delivered to the patient. Existing infant resuscitation breathing systems incorporating a T-piece device are often pneumatic and operate from a fixed gas flow source, usually a wall source, with a preset or manually adjustable flow rate. In use, the gas flow source supplies a flow of breathable gas to a breathing apparatus (e.g., a resuscitation device), which then supplies breathable gas to the patient via interconnected gas delivery tubing, a T-piece device, and a suitable patient interface. Typically, a flow meter is used to control or monitor the flow rate of the gas flow from the fixed gas flow source. In addition, the breathing apparatus includes a user control device that allows the operator to set and monitor the pressure of the breathable gas delivered to the patient. Some existing breathing apparatus may be constant flow devices, i.e., the breathing apparatus does not adjust the flow rate of breathable gas delivered to the patient. Instead, a fixed gas flow source operates at a constant flow rate, and the breathing apparatus includes a pressure relief valve and a calibrated flow resistance that can be adjusted to achieve the desired PEEP and PIP. In these systems, a T-piece device typically has an orifice that can be blocked or unblocked by the breathing system operator. When the orifice is blocked, the pressure delivered is determined by a pressure regulator in the breathing apparatus. This is the "PIP" pressure setting. When the orifice is open, the pressure delivered is determined by a pressure regulator inside the T-piece device. This is the "PEEP" pressure setting. As the orifice is repeatedly blocked and unblocked, PIP and PEEP are supplied to the patient to deliver a breath to the patient. Summary of the Invention [Means for solving the problem]

[0005] References herein to external sources, including patents and other literature, are generally for the purpose of providing a context for discussing the features of the present invention, and unless otherwise specified, references to such sources should not be construed as an admission that such sources are prior art or form part of the common general knowledge in the art in any jurisdiction.

[0006] In a first aspect, the present disclosure provides a device arranged in fluid communication with a patient interface arranged in communication with an airway of a patient during respiratory therapy, the device comprising: an inlet for receiving breathable gas from the breathing apparatus; an outlet for delivering breathable gas to a patient interface; a body portion extending between the inlet and the outlet, the body portion including a trigger port; one or more sensors, an output of the one or more sensors being used to determine a status of the trigger port; Equipped with.

[0007] In some configurations, the body portion includes one or more sensing ports.

[0008] In a second aspect, the present disclosure provides a device arranged in fluid communication with a patient interface arranged in communication with an airway of a patient during respiratory therapy, the device comprising: an inlet for receiving breathable gas from the breathing apparatus; an outlet for delivering breathable gas to a patient interface; a body portion extending between an inlet and an outlet, the body portion including a trigger port and one or more sensing ports arranged to be fluidly connected to one or more sensors, an output of the one or more sensors being used to determine a status of the trigger port; Equipped with.

[0009] In some configurations, the body portion includes a first member and the trigger port is formed in a wall or end of the first member.

[0010] In some configurations, the body portion includes a second member, the second member being a substantially hollow configuration that defines a passageway through which breathable gas can flow.

[0011] In some configurations, the second member is configured to allow attachment to an inlet of a patient interface.

[0012] In some configurations, the first member and the second member are permanently joined.

[0013] In some configurations, the first and second members are joined together using ultrasonic welding, adhesives, or overmolding.

[0014] In some configurations, the first member and the second member are removably joined to one another.

[0015] In some configurations, the one or more sensors include one or more pressure sensors and / or flow sensors.

[0016] In some configurations, the one or more sensors include at least one differential pressure sensor.

[0017] In some configurations, the at least one differential pressure sensor includes a flow restriction in the gas flow path positioned to create a pressure differential across the flow restriction.

[0018] In some configurations, the flow restriction can include one or more deflectable flaps, variable orifice membranes / diaphragms, and the like.

[0019] In some configurations, a deflectable flap is positioned between the first member and the second member.

[0020] In some configurations, the one or more sensors extend at least partially into the interior cavity of the body portion.

[0021] In some configurations, the one or more sensors extend at least partially into the one or more sensing ports.

[0022] In some configurations, the sensor or sensors are housed within a body portion of the device.

[0023] In some configurations, at least one of the one or more sensors is located outside the body portion and positioned to receive the flow of breathable gas from the one or more sensing ports.

[0024] In some configurations, the one or more sensing ports include two pressure sensing ports extending outwardly from a wall of the body portion.

[0025] In some configurations, at least one of the one or more sensors is used to measure the flow rate of breathable gas delivered to the patient.

[0026] In some configurations, at least one of the one or more sensors is used to measure the pressure of breathable gas within the device or within the patient interface.

[0027] In some configurations, the status of the trigger port includes an open state and a closed state.

[0028] In some configurations, when the trigger port is blocked by an operator's finger, the trigger port is in a closed state.

[0029] In some configurations, the trigger port, when not blocked by an operator's finger, is in an open state, allowing airflow within the device to exit to the ambient air.

[0030] In some configurations, the trigger port is an orifice formed in a wall of the body portion.

[0031] In some configurations, the trigger port is a circular orifice formed in a wall of the body portion.

[0032] In some configurations, the output of the one or more sensors is received or obtained by a controller, which determines the status of the trigger port and / or a change in the status of the trigger port based on the output.

[0033] In some configurations, the controller controls the operation of the breathing apparatus so that breathable gas is delivered to the patient at a suitable pressure.

[0034] In some configurations, the controller controls the operation of the breathing apparatus by setting the motor speed of the flow generator.

[0035] In some configurations, the controller sends a control signal to the respiratory device when there is a change in the status of the trigger port.

[0036] In some configurations, the device includes a coupling mechanism that allows it to be removably connected to a patient interface.

[0037] In some configurations, the device receives breathable gas from a breathing apparatus via a conduit.

[0038] In some configurations, the conduit is inserted into an inlet of the device.

[0039] In some configurations, the device is a T-piece device.

[0040] In a further aspect, the present disclosure provides a method for producing a method for treating a cancer cell comprising: A device according to the first or second aspect of the present disclosure; a conduit coupled at a first end to the inlet of the device and arranged at a second end to connect to a gas outlet of the breathing apparatus so as to receive a flow of breathable gas therefrom; A device circuit comprising:

[0041] In some configurations, the conduit includes a connector at the second end for connecting to a breathing apparatus.

[0042] In some configurations, the connector comprises a tapered connecting portion arranged for insertion into the outlet of the respiratory apparatus.

[0043] In some configurations, the conduit has a length of between 1 and 2 meters, between about 1.5 and 2 meters, or 1.6 meters.

[0044] In some configurations, the conduit is permanently connected to the inlet of the device.

[0045] In a third aspect, the present disclosure provides an interface assembly for use in respiratory therapy, the interface assembly comprising: A device according to any one or more of the first or second aspects of the present disclosure; a patient interface disposed in communication with an airway of the patient during respiratory therapy; Includes.

[0046] In a fourth aspect, the present disclosure provides a gas delivery system for delivering breathable gas to a patient, comprising: a respiratory apparatus including a flow generator, a controller arranged to control the flow generator, and one or more sensors configured to determine a source flow rate (Fs) from the flow generator and an interface gas flow rate (Fm); a conduit assembly for delivering breathable gas from the flow generator to the patient; an interface assembly arranged to receive breathable gas from the conduit assembly and deliver breathable gas to a patient, the interface assembly including a trigger port; Equipped with A gas delivery system is provided, wherein the controller is arranged to calculate a difference between a source flow rate and an interface gas flow rate, determine a status of a trigger port based on the difference, and operate the flow generator to provide breathable gas to the patient at a pressure based on the determined status of the trigger port.

[0047] In some configurations, the interface assembly includes: a patient interface in communication with the patient's airway; a device fluidly coupled to the patient interface and to the conduit assembly for delivering breathable gas from the conduit assembly to the patient interface; Includes.

[0048] In some configurations, the one or more sensors include one or more of a flow sensor, a pressure sensor, a differential pressure sensor, a mass flow sensor, an ultrasonic flow sensor, and / or a thermistor.

[0049] In some configurations, the differential pressure sensor includes a flow restriction in the gas flow path, the flow restriction positioned to create a pressure differential across the flow restriction.

[0050] In some configurations, the flow restriction can include one or more deflectable flaps, variable orifice membranes / diaphragms, and the like.

[0051] In some configurations, the differential pressure sensor includes two pressure sensing elements positioned to measure first and second pressures of breathable gas within the device.

[0052] In some configurations, the pressure sensing element includes a pressure sensing tube.

[0053] In some configurations, the device includes two pressure sensing ports and the pressure sensing element is positioned to make pressure measurements via the pressure sensing ports.

[0054] In some configurations, the pressure sensing element is positioned to measure a pressure differential across the deflectable flap.

[0055] In some configurations, the trigger port is located within the wall of the device.

[0056] In some configurations, the device is a T-piece device.

[0057] In some configurations, the status of the trigger port includes at least a closed state and an open state.

[0058] In some configurations, if the trigger port is blocked by an object restricting or preventing gas flow through the trigger port, the status of the trigger port is closed, and if the trigger port is not blocked, the status of the trigger port is open.

[0059] In some configurations, the controller Comparing the difference with a first threshold flow rate (Fa) and / or a second threshold flow rate (Fb); A status of the trigger port is determined based on the comparison, the trigger port being either open or closed. They are arranged as follows.

[0060] In some configurations, the controller Retrieves the previous status of the trigger port from memory, If the previous status of the trigger port was an open state, the difference is compared to a first threshold flow rate Fa, and if the previous status of the trigger port was a closed state, the difference is compared to a second threshold flow rate Fb; determining a current status of the trigger port based on the comparison; Determines whether the trigger port's status has changed by comparing the previous status with the current status They are arranged as follows.

[0061] In some configurations, the trigger port is in a closed state when the difference between the supply source flow rate and the interface gas flow rate is less than the first threshold flow rate (ΔF < Fa).

[0062] In some configurations, when the difference is greater than the second threshold flow rate (ΔF > Fb), the trigger port is in an open state.

[0063] In some configurations, the second threshold flow rate is calculated based on the interface pressure.

[0064] In some configurations, the second threshold flow rate is calculated from K * sqrt(Pm), where Pm is the interface pressure and K is a coefficient determined experimentally or during a calibration step.

[0065] In some configurations, the second threshold flow rate is in the range of 0.5 to 10 liters per minute (L / min).

[0066] In some configurations, the second threshold flow rate is set to a constant level.

[0067] In some configurations, the second threshold flow rate is 1 L / min.

[0068] In some configurations, the first threshold flow rate is determined based on the interface pressure.

[0069] In some configurations, the first threshold flow rate is calculated from Fa = J * sqrt(Pm), where Pm is the interface pressure and J is a coefficient determined experimentally or during a calibration step.

[0070] In some configurations, the first threshold flow rate is in the range of 0.5 to 10 L / min.

[0071] In some configurations, the first threshold flow rate is set to a constant level.

[0072] In some configurations, the first threshold flow rate is set to 1 L / min.

[0073] In some configurations, the controller is configured to operate the flow generator to deliver breathable gas to the patient at a first pressure when the trigger port is determined to be in a closed state and at a second pressure when the trigger port is determined to be in an open state.

[0074] In some configurations, the first pressure is greater than the second pressure.

[0075] In some configurations, the first pressure is a high pressure and the second pressure is a low pressure.

[0076] In some configurations, the high pressure gas flow corresponds to a peak inspiratory pressure (PIP) and the low pressure gas flow corresponds to a positive end expiratory pressure (PEEP).

[0077] In some configurations, for infant or neonatal patients, PEEP can be set to 1, 2, 3, 4, 5, 6, 7, or 8 cmH. 2 O, PIP is 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 cmH 2 Equivalent to O.

[0078] In some configurations, the controller operates the flow generator by setting the motor speed of the flow generator.

[0079] In some configurations, the flow generator motor speed is adjusted over a predetermined time interval.

[0080] In some configurations, the predetermined time interval is between 100 and 400 ms, or between 100 and 300 ms, or between 100 and 200 ms, or about 150 ms.

[0081] In some configurations, the flow generator is fluidly connected to a breathable gas source, which may be a wall-mounted gas source.

[0082] In some configurations, the system includes a humidifier that adds moisture to the breathable gas before it is delivered to the patient.

[0083] In some configurations, the system is used to deliver breathable gas to resuscitate a patient or to deliver positive pressure ventilation (PPV) therapy to a patient.

[0084] In a fifth aspect, the present disclosure provides a gas delivery system comprising: determining a source gas flow rate; Determining a delivery gas flow rate; calculating a difference between the source gas flow rate and the delivered gas flow rate; causing the gas delivery system to deliver breathable gas to the patient at a pressure based on the calculated difference between the source gas flow rate and the delivered gas flow rate; A method for controlling the

[0085] In some configurations, determining the source gas flow rate comprises: Receiving or acquiring measurements from one or more first sensors; determining a first flow rate, the flow rate (Fs) of the source gas stream based on the measurements; Includes.

[0086] In some configurations, determining the delivery gas flow rate comprises: receiving or acquiring measurements from one or more second sensors; determining a second flow rate, the flow rate of breathable gas delivered to the patient interface (Fm) based on the measurements; Includes.

[0087] In some configurations, the step of calculating the difference between the source gas flow rate and the delivered gas flow rate comprises: Calculating the difference between the first flow rate and the second flow rate (ΔF = Fs - Fm). including.

[0088] In some configurations, the method compares the difference between the first flow rate and the second flow rate with a first threshold flow rate (Fa) and / or a second threshold flow rate (Fb), determines the status of the trigger port based on the comparison, and further includes.

[0089] In some configurations, the status of the trigger port includes an open state or a closed state.

[0090] In some configurations, the method obtains the previous status of the trigger port, where the previous status of the trigger port includes an open state or a closed state, when the previous status of the trigger port is in the open state, compares the difference between the first flow rate and the second flow rate with the first threshold flow rate Fa, or when the previous status of the trigger port is in the closed state, compares the difference between the first flow rate and the second flow rate with the second threshold flow rate Fb, determines the current status of the trigger port based on the comparison, judges whether the status of the trigger port has changed by comparing the previous status with the current status, and includes.

[0091] In some configurations, the trigger port is in the closed state when the difference is less than the first threshold flow rate (ΔF < Fa).

[0092] In some configurations, the trigger port is in the open state when the difference is greater than the second threshold flow rate (ΔF > Fb).

[0093] In some configurations, the second threshold flow rate is calculated based on the interface pressure.

[0094] In some configurations, the second threshold flow rate is calculated from K*sqrt(Pm), where Pm is the interface pressure and K is a coefficient determined experimentally or during a calibration stage.

[0095] In some configurations, the second threshold flow rate is in the range of 0.5 to 10 L / min.

[0096] In some configurations, the second threshold flow rate is set at a constant level.

[0097] In some configurations, the second threshold flow rate is set at a constant level of 1 L / min.

[0098] In some configurations, the first threshold flow rate is determined based on the interface pressure.

[0099] In some configurations, the first threshold flow rate is calculated from Fa=J*sqrt(Pm), where Pm is the interface pressure and J is a coefficient determined experimentally or during a calibration stage.

[0100] In some configurations, the first threshold flow rate is in the range of 0.5 to 10 L / min.

[0101] In some configurations, the first threshold flow rate is set at a constant level.

[0102] In some configurations, the first threshold flow rate is set at a constant level of 1 L / min.

[0103] In some configurations, the method further comprises: operating the gas delivery system to deliver breathable gas to the patient at a first pressure if the trigger port is determined to be in a closed state; operating the gas delivery system to deliver breathable gas to the patient at a second pressure if the trigger port is determined to be in an open condition; Further includes:

[0104] In some configurations, the method further comprises: operating the gas delivery system to continue delivering breathable gas to the patient at either the first pressure or the second pressure until a change in status of the trigger port occurs. Further includes:

[0105] In some configurations, the first pressure is greater than the second pressure.

[0106] In some configurations, the first pressure corresponds to a peak inspiratory pressure (PIP) and the second pressure corresponds to a positive end expiratory pressure (PEEP).

[0107] In some configurations, for infant or neonatal patients, PEEP can be set to 1, 2, 3, 4, 5, 6, 7, or 8 cmH. 2 O, PIP is 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 cmH 2 Equivalent to O.

[0108] In some configurations, the step of operating the gas delivery system to deliver breathable gas to the patient at the first pressure or the second pressure comprises: Transmitting a control signal to a flow generator in the system Includes.

[0109] In some configurations, the flow generator is operated by controlling the speed of the flow generator motor.

[0110] In some configurations, the flow generator is operated by controlling the speed of a blower fan.

[0111] In some configurations, the motor speed is varied for a predetermined interval of time until the delivered breathable gas reaches the first pressure or the second pressure.

[0112] In some configurations, the predetermined time interval is between 100 and 400 ms, or between 100 and 300 ms, or between 100 and 200 ms, or about 150 ms.

[0113] In some configurations, the method further comprises: causing the trigger port to be in a closed state by substantially reducing or preventing air flow through the trigger port; allowing air flow through the trigger port, thereby causing the trigger port to remain open; Further includes:

[0114] In some configurations, causing the trigger port to be in a closed state includes blocking the trigger port with an object, and causing the trigger port to be in an open state includes removing the object from the trigger port.

[0115] In some configurations, the object is an operator's finger.

[0116] In some configurations, determining the second flow rate comprises: Measuring a first pressure of the breathable gas at a first location; Measuring a second pressure of the breathable gas at a second location; calculating a pressure difference between the first pressure and the second pressure; calculating a flow rate (Fm) of breathable gas delivered to the patient interface based on the pressure differential; Includes.

[0117] In some configurations, the first location is at or near the inlet of the device, where the device receives breathable gas from a conduit assembly that is in fluid communication with the flow generator.

[0118] In some configurations, the second location is at or near the outlet of the device, where the device delivers breathable gas to the patient interface.

[0119] In some configurations, the second pressure is an interface pressure.

[0120] In a seventh aspect, the present disclosure provides a method of delivering breathable gas to a patient via an interface assembly, the interface assembly including a trigger port; determining a status of the trigger port by determining a source gas flow rate produced by the gas delivery system and a delivered gas flow rate delivered to the interface assembly; causing the gas delivery system to deliver breathable gas to the patient at a pressure based on the determined status of the trigger port; The present invention provides a method comprising:

[0121] In some configurations, determining the source gas flow rate comprises: Receiving or acquiring measurements from one or more first sensors; determining a first flow rate, the flow rate (Fs) of the source gas stream based on the measurements; Includes.

[0122] In some configurations, determining the delivery gas flow rate comprises: receiving or acquiring measurements from one or more second sensors; determining a second flow rate, the flow rate of breathable gas delivered to the patient interface (Fm) based on the measurements; Includes.

[0123] In some configurations, the method further includes calculating a difference between the first flow rate and the second flow rate (ΔF=Fs−Fm).

[0124] In some configurations, the method further comprises: comparing a difference between the first flow rate and the second flow rate to a first threshold flow rate (Fa) and / or a second threshold flow rate (Fb); determining a status of the trigger port based on the comparison; and Further includes:

[0125] In some configurations, the status of the trigger port includes an open state or a closed state.

[0126] In some configurations, the method includes obtaining a previous status of the trigger port, where the previous status of the trigger port includes an open state or a closed state; when the previous status of the trigger port is in the open state, comparing the difference between the first flow rate and the second flow rate with a first threshold flow rate Fa, or when the previous status of the trigger port is in the closed state, comparing the difference between the first flow rate and the second flow rate with a second threshold flow rate Fb; determining a current status of the trigger port based on the comparison; determining whether the status of the trigger port has changed by comparing the previous status with the current status. and

[0127] In some configurations, the trigger port is in the closed state when the difference is less than the first threshold flow rate (ΔF < Fa).

[0128] In some configurations, the trigger port is in the open state when the difference is greater than the second threshold flow rate (ΔF > Fb).

[0129] In some configurations, the second threshold flow rate is calculated based on the interface pressure.

[0130] In some configurations, the second threshold flow rate is calculated from K * sqrt(Pm), where Pm is the interface pressure and K is a coefficient determined experimentally or during a calibration phase.

[0131] In some configurations, the second threshold flow rate is in the range of 0.5 to 10 L / min.

[0132] In some configurations, the second threshold flow rate is set to a constant level.

[0133] In some configurations, the second threshold flow rate is set at a constant level of 1 L / min.

[0134] In some configurations, the first threshold flow rate is determined based on the interface pressure.

[0135] In some configurations, the first threshold flow rate is calculated from Fa=J*sqrt(Pm), where Pm is the interface pressure and J is a coefficient determined experimentally or during a calibration stage.

[0136] In some configurations, the first threshold flow rate is in the range of 0.5 to 10 L / min.

[0137] In some configurations, the first threshold flow rate is set at a constant level.

[0138] In some configurations, the first threshold flow rate is set at a constant level of 1 L / min.

[0139] In some configurations, the method further comprises: operating the gas delivery system to deliver breathable gas to the patient at a first pressure if the trigger port is determined to be in a closed state; operating the gas delivery system to deliver breathable gas to the patient at a second pressure if the trigger port is determined to be in an open condition; Further includes:

[0140] In some configurations, the method further comprises: operating the gas delivery system to continue delivering breathable gas to the patient at either the first pressure or the second pressure until a change in status of the trigger port occurs. Further includes:

[0141] In some configurations, the first pressure is greater than the second pressure.

[0142] In some configurations, the first pressure corresponds to a peak inspiratory pressure (PIP) and the second pressure corresponds to a positive end expiratory pressure (PEEP).

[0143] In some configurations, for infant or neonatal patients, PEEP can be set to 1, 2, 3, 4, 5, 6, 7, or 8 cmH. 2 O, PIP is 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 cmH 2 Equivalent to O.

[0144] In some configurations, causing the gas delivery system to deliver breathable gas to the patient at the first pressure or the second pressure includes: Transmitting a control signal to a flow generator in the system Includes.

[0145] In some configurations, the flow generator is operated by controlling the speed of the flow generator motor.

[0146] In some configurations, the flow generator is operated by controlling the speed of a blower fan.

[0147] In some configurations, the motor speed is varied for a predetermined interval of time until the delivered breathable gas reaches the first pressure or the second pressure.

[0148] In some configurations, the predetermined time interval is between 100 and 400 ms, or between 100 and 300 ms, or between 100 and 200 ms, or about 150 ms.

[0149] In some configurations, the method further comprises: causing the trigger port to be in a closed state by substantially reducing or preventing air flow through the trigger port; allowing air flow through the trigger port, thereby causing the trigger port to remain open; Further includes:

[0150] In some configurations, causing the trigger port to be in a closed state includes blocking the trigger port with an object, and causing the trigger port to be in an open state includes removing the object from the trigger port.

[0151] In some configurations, the object is an operator's finger.

[0152] In some configurations, determining the second flow rate comprises: Measuring a first pressure of the breathable gas at a first location; Measuring a second pressure of the breathable gas at a second location; calculating a pressure difference between the first pressure and the second pressure; calculating a flow rate (Fm) of breathable gas delivered to the patient interface based on the pressure differential; Includes.

[0153] In some configurations, the first location is at or near the inlet of the device, where the device receives breathable gas from a conduit assembly that is in fluid communication with the flow generator.

[0154] In some configurations, the second location is at or near the outlet of the device, where the device delivers breathable gas to the patient interface.

[0155] In some configurations, the second pressure is the interface pressure Pm.

[0156] In an eighth aspect, the present disclosure provides a gas delivery system for delivering breathable gas to a patient, comprising: a respiratory apparatus including a flow generator, a controller arranged to control the flow generator, and at least one sensor proximate to the flow generator, the at least one sensor configured to determine at least a source flow rate (Fs) from the flow generator; a conduit assembly for delivering breathable gas from the flow generator to the patient; an interface assembly arranged to receive breathable gas from the conduit assembly and deliver breathable gas to a patient, the interface assembly including a trigger port; Equipped with A gas delivery system is provided, wherein the controller is configured to determine a status of the trigger port by comparing a determined source flow rate (Fs) with a threshold flow rate (Fth) and to operate the flow generator to provide breathable gas to the patient at a pressure based on the determined status of the trigger port.

[0157] In some configurations, the status of a trigger port is either open or closed.

[0158] In some configurations, pressure is provided in either a PIP state or a PEEP state, where the PIP state is higher than the PEEP state, and the PIP state corresponds to the trigger port being closed and the PEEP state corresponds to the trigger port being open.

[0159] In some configurations, the controller is further configured to determine a pressure (P) at a point in the system.

[0160] In some configurations, the threshold flow rate (Fth) is related to L*sqrt(P), where L is a coefficient and P is a mathematically determined pressure at the patient interface of the interface assembly.

[0161] In some configurations, L relates to conductance values ​​associated with two or more outlet points / scenarios of the system.

[0162] In some configurations, L is related to a conductance value associated with the trigger port and a conductance value associated with the minimum expected flow rate through the system with the trigger port closed and no outflow through the patient interface.

[0163] In some configurations, L is related to a conductance value associated with the minimum expected flow through the system with the trigger port closed and no flow through the patient interface, and a conductance value associated with the maximum flow through the patient interface during delivery of PIP.

[0164] In some configurations, the threshold flow (Fth) is further related to the flow in and out of the patient's lungs.

[0165] In some configurations, if Fs < Fth, the trigger port is determined to be closed.

[0166] In some configurations, if Fs > Fth, the trigger port is determined to be open.

[0167] In some configurations, the determination of the status of the trigger port further includes a hysteresis analysis, where the previous status of the trigger port is considered when determining the status of the trigger port.

[0168] In some configurations, the system is - Disconnection and / or improper connection / incomplete connection of the patient interface (collectively "connection problems"), - Disconnection of one or more other components of the system, such as a conduit or humidifier, and / or - Occlusion within or of the system further configured to detect one or more of.

[0169] In some configurations, the system is configured to detect connection problems of the patient interface, and the system is configured to determine an excess flow threshold (F leakth ) indicating connection problems of the patient interface.

[0170] In some configurations, F leakth depends on one or more conductance values and pressure.

[0171] In some configurations, F leakth is further dependent on the flow rate into and out of the patient's lungs.

[0172] In some configurations, when dependent on claim 71, the system may further comprise a source flow rate (Fs) of F leakth If the patient interface connection problem is greater than

[0173] In some configurations, when dependent on claim 36, the system may further comprise a gas flow rate (Fm) of F leakth If the patient interface connection problem is greater than

[0174] In some configurations, if a patient interface connection problem is detected, the system: - setting the source flow rate (Fs) to a fixed flow rate, - setting the flow generator motor speed to a fixed speed; - setting the pressure in the flow generator to a fixed pressure, and / or - Raise an alarm or alert The device is configured to perform one or more of the following:

[0175] In some configurations, the system is configured to detect disconnection of one or more other components of the system, such as a conduit or a humidifier, and the system is configured to determine a conductance corresponding to the one or more other components of the system, determine an overall conductance of the system, and detect disconnection of the one or more other components of the system if the overall conductance of the system is greater than the conductance corresponding to the one or more other components.

[0176] In some configurations, if disconnection of the one or more other components is detected, the system is configured to set a fixed motor speed and / or generate an alarm or alert.

[0177] In some configurations, the system is configured to detect an occlusion in or on the system, and the system is configured to determine a threshold flow value for use in detecting the occlusion.

[0178] In some configurations, the threshold flow value corresponds to the minimum expected flow rate through the system with the trigger port closed and no outflow through the patient interface, and an occlusion is detected if the source flow rate (Fs) is less than the threshold flow value.

[0179] In some configurations, the threshold flow value is derived from a combination of the conductance associated with the minimum expected flow rate through the system with the trigger port closed and no outflow through the patient interface and the pressure at the patient interface, and an occlusion is detected when the source flow rate (Fs) is less than the threshold flow value.

[0180] In some configurations, the threshold flow value is further derived from the patient's actual or approximate lung compliance.

[0181] In some configurations, if a system blockage is detected, the system is configured to set a fixed motor speed and / or generate an alarm or alert.

[0182] Further aspects and advantages of certain embodiments of the present disclosure will become apparent from the following description, which is given by way of example only.

[0183] Various embodiments are depicted in the accompanying drawings for purposes of illustration and should not be construed as limiting the scope of the embodiments in any way. Furthermore, various features of different disclosed embodiments can be combined to form additional embodiments that are part of this disclosure. [Brief description of the drawings]

[0184] [Figure 1]1 illustrates an example of a gas delivery system according to one embodiment of the present disclosure. [Diagram 2] 1 illustrates an example of a conduit assembly and an interface assembly according to one embodiment of the present disclosure. [Figure 3A] Each shows an example of a device according to one embodiment of the present disclosure. [Figure 3B] Each shows an example of a device according to one embodiment of the present disclosure. [Figure 4A] Each illustrates an alternative example of a device according to one embodiment of the present disclosure. [Figure 4B] Each illustrates an alternative example of a device according to one embodiment of the present disclosure. [Diagram 5] 1A-1D show cross-sectional views of one embodiment of a valve used to occlude or unocclude a trigger port of a device with an actuator in various different positions. [Figure 6] FIG. 6 shows a side view of the valve of FIG. 5. [Figure 7] 1 shows a simplified schematic diagram of a gas delivery system according to one embodiment. [Figure 8] 1 shows another simplified schematic diagram of a gas delivery system according to one embodiment. [Figure 9] 1 shows a schematic diagram of control logic implemented in one embodiment of a controller. [Figure 10] 1 shows a schematic diagram of another control logic implemented in one embodiment of the controller. [Figure 11] 13 illustrates yet another example of control logic implemented in one embodiment of a controller. [Figure 12] 1 illustrates an external view of an example of a device and an exemplary flow sensor according to one embodiment. [Figure 13] 13 shows a cross-sectional view of an example of the device and flow sensor of FIG. 12. [Figure 14] FIG. 14 shows an exploded view of the device and flow sensor of FIGS. 12 and 13. [Figure 15] FIG. 14 shows a side cross-sectional view of the device and flow sensor of FIGS. 12 and 13. [Figure 16]FIG. 2 is a simplified schematic diagram of a gas delivery system according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0185] The present disclosure relates to various systems and methods applicable to gas delivery systems arranged to deliver breathable gas to a patient.

[0186] overview FIG. 1 illustrates an example of a gas delivery system 1 according to one embodiment of the present disclosure.

[0187] The gas delivery system 1 is configured to provide respiratory therapy to a patient by delivering breathable gas to the patient's airway. Respiratory therapy can be pressure therapy delivered to the patient to assist breathing and / or treat respiratory disorders. Pressure therapy can include the gas delivery system 1 providing pressure to or near the patient at one or more target pressures over one or more time windows. Pressure therapy can be infant resuscitation therapy, positive airway pressure therapy (PAP), continuous positive airway pressure (CPAP), bilevel positive airway pressure therapy, non-invasive ventilation, bubble CPAP therapy, or another form of pressure therapy. In some configurations, the device can provide bilevel positive airway pressure therapy to achieve infant resuscitation.

[0188] "Pressure therapy" as used in this disclosure refers to a pressure therapy that is approximately 1 cmH 2 "breathable gas" refers to the delivery of breathable gas at a pressure of O or greater to a patient, delivered to mimic the patient's natural breathing cycle and / or delivered in accordance with the patient's breathing cycle to assist the patient in breathing.

[0189] In some configurations, the breathable gas delivered to the patient is or includes oxygen. In some configurations, the gas includes a mixture of oxygen or an oxygen-enriched gas and ambient air. In some configurations, the percentage of oxygen in the delivered gas may be about 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 about 100%. In at least one configuration, the delivered gas may be of atmospheric composition. In at least one configuration, the delivered gas may be atmospheric.

[0190] In relation to infant resuscitation, while in utero, the fetal lungs are filled with fluid and oxygen comes from the blood vessels of the placenta. At birth, compression of the lungs by the birth canal aids in the transition to continuous breathing after birth. Infant breathing is also aided by the presence of surfactant coating the alveoli to reduce surface tension. The need for infant resuscitation can arise in a variety of circumstances, as discussed further below.

[0191] Most infants tolerate passage through the birth canal for an average number of uterine contractions, but the few who do not may require assistance to establish normal breathing at birth. Resuscitation may also be required if there are signs of significant fetal distress during labor, if the baby is delivered before 25 weeks of gestation (particularly since surfactant production does not begin until 24 weeks and continues until 34 weeks of gestation), if the baby is delivered vaginally in a breech position, if there is maternal infection, or in the case of multiple pregnancies. Additionally, there are transitions during birth that require medical intervention, especially if the baby is delivered before 39 weeks of gestation.

[0192] Generally speaking, the gas delivery system 1 comprises a respiratory apparatus 100, a conduit assembly 200 including one or more interconnected tubes, and an interface assembly including a patient interface 340 arranged to communicate with the patient's airway. In some embodiments, a device 320 fluidly couples the conduit assembly 200 to the patient interface 340. The device 320 may be part of the patient interface 340 or may be a device made separately from the interface 340 and later coupled to the interface 340 in use. In at least some embodiments, the device 320 includes a suitable connector or structure that allows the device 320 to fluidly couple to an inlet of the patient interface 340 at one end and to a connector of the conduit assembly 200 at the other end. In some embodiments, the device 320 and the patient interface 340 are collectively referred to as an interface assembly in this disclosure.

[0193] 2 shows an example of a conduit assembly 200 connected to an interface assembly. The conduit assembly 200 includes interconnecting tubes 210, 312 that are coupled to each other via connectors 211, 212. The tube 210 can be arranged to connect to a source gas stream via another suitable connector 201.

[0194] 1 , the respiratory apparatus 100 may include a flow generator 110, an optional humidifier 120 that humidifies gas generated by the flow generator 110, and an associated controller 130 that governs operation of the flow generator 110 and / or the humidifier 120 (if present). In at least one embodiment, the flow generator 110 may be in the form of a blower 110.

[0195] The controller 130 of the respiratory apparatus 100 may include an associated user interface 140 including, for example, a display and input devices such as buttons, a touch screen, etc. The controller 130 is configured or programmed to control and / or interact with components of the gas delivery system 1, such as one or more of: operating the flow generator 110 to generate a flow of gas for delivery to the patient, operating the humidifier 120 (if present) to humidify and / or heat the generated gas flow, receiving one or more inputs from the sensors 30, 31, 32, 33 and / or the user interface 140 for reconfiguration and / or user defined operation of the gas delivery system 1, and outputting information to an operator on a display.

[0196] The controller 130 may control the respiratory apparatus 100 to generate a gas flow at a desired pressure or at a desired flow rate. In particular, the controller 130 controls the flow generator 110 to generate a gas flow at a desired pressure and / or flow rate.

[0197] The controller 130 may also control the humidifier 120 (if present) to humidify and / or heat the gas flow to an appropriate level. The gas flow is directed through the conduit assembly 200 and the patient interface 340 to the patient. The controller 130 may control the humidifier heating element of the humidifier 120 and / or the heating element 220 of the conduit 210 to heat the gas to and / or maintain it at a desired temperature. The controller 130 may be programmed with or may determine a suitable target temperature and / or humidity of the gas flow. The controller 130 may be programmed with or may determine a suitable target temperature and / or humidity of the gas flow and may control the flow rate and / or pressure to the target temperature and / or humidity using one or more of the humidifier heating element, the conduit heating element 220 and the flow generator 110. The target temperature and / or humidity of the heated gas may be set to achieve a desired level of treatment and / or comfort of the patient.

[0198] The operational sensors 30, 31, 32, and 33 may be located at various locations on the respiratory apparatus 100 and / or the conduit assembly 200 and / or the patient interface 340. One or more outputs from the sensors 30, 31, 32, 33 may be monitored by the controller 130 to assist the controller 130 in operating the gas delivery system 1 in a manner that provides an optimal therapy. In some configurations, providing an optimal therapy includes meeting the inhalation demands of the patient. In at least one configuration, providing an optimal therapy includes providing a first target pressure to the patient at a first time point and providing a second target pressure to the patient at a second time point.

[0199] The respiratory apparatus 100 may have a transmitter 150, a receiver 150 and / or a transceiver 150 to enable the controller 130 to receive transmitted signals from the sensors 30, 31, 32, 33 and / or to control various components of the gas delivery system 1. The controller 130 may receive transmitted signals from sensors associated with or control components including, but not limited to, the flow generator 110, the humidifier 120 or the humidifier heating element 220. As mentioned above, the gas delivery system 1 comprises a conduit assembly 200 for receiving breathable gas from the respiratory apparatus 100 and directing the gas flow to the patient interface 340.

[0200] In at least one configuration, the patient interface 340 can be in the form of a sealing patient interface. In at least one configuration, the patient interface 340 can be in the form of a respiratory mask, or an endotracheal tube, or a laryngeal mask. The patient interface 340 can be configured to deliver breathable gas to the patient's airway via a seal or cushion on the patient end 26 that forms an airtight seal in or around the patient's nose and / or mouth. The patient interface 340 can be an oronasal, nasal, direct nose and / or oral patient interface that forms an airtight seal between the patient end 26 and the patient's nose and / or mouth. In at least one embodiment, the seal or cushion can be held in place on the patient's face by headgear. In at least one embodiment, the patient interface 340 can be held on the patient's face by an operator, who may be a medical professional. Such a sealing patient interface can be used to deliver pressure therapy to the patient. Alternative patient interfaces can also be used, such as those that include nasal prongs. In some examples, the nasal prongs can be sealing or non-sealing.

[0201] The neonatal interface may be any interface, as described above, configured for use with a neonatal The neonatal interface may be configured to at least partially, and preferably substantially, seal around the patient's nose and mouth.

[0202] In some embodiments, a device 320 is provided for use in the gas delivery system 1 to trigger the respiratory apparatus 100 at a patient end remote from the respiratory apparatus 100 to adjust the pressure of the gas delivered to the patient, i.e., triggering occurs at the patient end via the device 320, without directly changing the settings of the respiratory apparatus 100. Figures 3A, 3B, 4A and 4B show two types of such devices, sometimes referred to as T-piece devices.

[0203] As mentioned above, existing breathing apparatus are often configured to operate based on a fixed gas flow source that delivers a flow of breathable gas at a constant rate. By blocking or unblocking the PEEP orifice of the T-piece device, different pressures of breathable gas can be provided to the patient. In addition, in existing T-piece devices, both the "PIP" and "PEEP" pressures depend at least in part on the source flow rate and interface leakage. This means that manual adjustments of the fixed gas flow source or the breathing apparatus may be required to maintain the delivered pressure at a desired level. In some cases, the delivered pressure may switch to a different setting due to "false triggers" such as patient breathing, coughing, patient movement, mask inflation, hose bending, and leaks. The present disclosure aims to ameliorate one or more of the problems faced by such systems, or at least provide a useful alternative. According to the embodiments disclosed herein, the breathing apparatus is remotely triggered to deliver breathable gas to the patient at a target pressure level by blocking or unblocking a trigger port of a device of the breathing system, which causes the breathing apparatus to configure its setting.

[0204] 3A, 3B, 4A, 4B, each device 320 includes an inlet 324 arranged to receive breathable gas from the respiratory apparatus 100 via the conduit assembly 200, and an outlet 325 connected to a patient interface 340 during delivery of respiratory therapy. Each device 320 also includes a trigger port 322 arranged to be blocked or unblocked by an object, such as the finger of an operator or medical professional, during delivery of respiratory therapy to the patient. The trigger port 322 also forms an exhaust port for the device 320. When the trigger port 322 is blocked, most or all of the breathable gas received from the flow generator 110 is delivered to the patient via the patient interface 340 and the gas delivery system 1 delivers breathable gas to the patient at a first pressure. When the blockage is removed from the trigger port 322, the trigger port 322 acts as an exhaust vent, allowing a portion of the breathable gas to exit the internal cavity of the device 320 into the ambient air, and the gas delivery system 1 delivers the breathable gas to the patient at a second pressure. The T-piece device 320 may also include an optional valve, for example a duckbill valve 323, which may be used for the insertion of ancillary equipment such as a gas sampling device or a catheter for fluid clearance or surfactant delivery.

[0205] In at least some configurations, the trigger port 322 can be arranged to be blocked or unblocked by a valve that includes a movable actuator, where movement of the actuator adjusts the flow path through the valve. Exemplary embodiments of such a valve are shown in Figures 5 and 6. Figure 5 shows various cross-sectional views of the valve 50 with the actuator 502 in various different operating positions, and Figure 6 shows an exterior side view of the valve 50.

[0206] The valve 50 includes a housing 501 having a first opening 512 and a second opening 511 at opposite ends of the housing 501. The first opening 512 can be in fluid communication with the trigger port 322 in use, and the second opening 511 is configured to movably receive the actuator 502. The housing 501 includes a body extending between the first opening 512 and the second opening 511, the body defining a hollow cavity. A sidewall of the body tapers from the second opening 511 towards the first opening 512, the first opening 512 being of smaller diameter than the second opening 511. As shown in FIG. 6, the sidewall of the body defines a plurality of openings 503 configured to allow gas from within the gas delivery system 1 to flow depending on the relative position between the actuator 502 and the housing 501.

[0207] As shown, the actuator 502 is arranged to move between a raised position and an inserted position to adjust the size of the gas flow path through the valve 50. In the raised position, gas can flow into the first opening 512 of the housing 501 and then exit the gas delivery system 1 to the surrounding atmosphere through the plurality of openings 503. This has the effect of lowering the pressure delivered to the patient compared to when the actuator 502 is in the inserted position. In the inserted position, the actuator 502 is lowered into the housing 501 to block the first opening 512 of the housing 501. This blocks the air flow path through the valve 50 and prevents air from escaping the gas delivery system through the valve 50 and the trigger port 322, thereby increasing the pressure delivered to the patient. When the actuator 502 is in the raised position, the pressure of the breathable gas delivered to the patient corresponds to PEEP, and when the actuator 502 is in the inserted position, the pressure of the breathable gas delivered to the patient corresponds to PIP. As the actuator 502 is repeatedly moved between these positions, a pressure between PEEP and PIP is delivered to the patient.

[0208] The valve 50 can include a deformable membrane 504 that assists in the movement of the actuator 501. As shown in Figure 5, the membrane 504 forms a chamber that extends between a second opening 511 in the housing 501 and a shoulder of the actuator 502. The membrane 504 is configured to bias the actuator 502 to a raised position when no external force is applied to the actuator 502. When a compressive force is applied to the actuator 502, for example by an operator, the membrane 504 begins to deform. Once the actuator 502 has moved beyond a deflection point of the membrane 504, it moves or snaps into a fully inserted position.

[0209] The mechanism by which the membrane 504 allows the actuator 502 to be biased to the raised position and snaps into the inserted position is controlled by the elasticity and geometry of the material used to construct the membrane 504. The membrane 504 includes a first member 504a and a second member 504b that are joined at an angle. The joint 504c between the two members acts as a flexible hinge, allowing the relative bending movement of the two members of the membrane. When the actuator 502 is in the raised position and both members 504a and 504b are stationary. This is the stable resting position of the membrane 504. When the actuator 502 is pressed down, the membrane 504 begins to stretch or deform until it reaches a deflection point. When the actuator 502 moves beyond this deflection point, the elasticity of the membrane causes it to snap into the inserted position. This is the semi-stable position of the membrane 504. When the force applied to the actuator 502 is removed, the membrane 504 returns to the stable position. The valve 50, and particularly its membrane 504, provides improved control of occlusion and unocclusion of the trigger port 322 by allowing the gas flow path through the valve 50 to be gradually altered and by providing tactile feedback to the operator using the valve 50.

[0210] The valve 50 may also be provided with a guide member 506 that helps maintain the actuator 502 in an upright orientation as it moves between its raised and inserted positions. Figure 5 shows one example of such a guide member 506, which is formed as a vertical rod and positioned below the tapered end of the actuator 502. A receiving groove or recess 508 is formed in the lower end of the actuator 502 to receive the guide member 506 as the actuator 502 moves to its inserted position.

[0211] A connector portion 509 may also be formed at the base of the valve 50 to allow a connection to be made between the valve 50 and the trigger port 322 .

[0212] It should be understood that the valve 50 shown in Figures 5 and 6 is for illustrative purposes only, to demonstrate that occlusion and unocclusion of the trigger port 322 can be accomplished via the valve 50 instead of using an operator's finger. Other examples of valves suitable for use with the trigger port 322 of a T-piece device are referenced in U.S. Provisional Patent Application No. 63 / 269,289, the contents of which are incorporated herein by reference in their entirety.

[0213] The configuration of device 320 of Figures 3A-4B allows for one-handed operation during respiratory therapy, i.e., by blocking or unblocking trigger port 322 of device 320, and gas delivery system 1 delivers breathable gas to the patient at first and second pressures to mimic the patient's respiratory cycle, typically at 30-60 breaths per minute.

[0214] In at least some embodiments, the pressure of the breathable gas delivered to the patient is controlled by operating the flow generator 110 of the breathing apparatus 100 at a required motor speed. More specifically, if a higher pressure needs to be delivered to the patient, the motor speed increases, and if a lower pressure needs to be delivered, the motor speed decreases. The motor of the flow generator 110 can be used to power a fan / impeller. Thus, when the motor operates at a higher speed, the blower fan also rotates at a higher speed, and a higher pressure of breathable gas is delivered to the patient, raising the pressure inside the patient interface 340 to the required level. When the motor operates at a lower rotational speed, the blower fan will rotate at a lower speed, thereby lowering the pressure of the breathable gas delivered to the patient, and thereby lowering the pressure inside the patient interface 340 to the required level.

[0215] In some embodiments, the first pressure level is delivered to or near the patient termination 26 at a first time point or during a first time window. The first pressure level can be delivered to or near the patient termination 26 once interface mating is confirmed and / or after control signals are generated by the controller 130 that are used to configure the flow generator 110 to set its motor speed, as described above.

[0216] Similarly, a second pressure level can be delivered to or near the patient termination 26 at a second time or during a second time window. Once interface mating is confirmed and / or after a control signal is generated by the controller 130 that is used to configure the flow generator 110 to set its motor speed, the second pressure level can be delivered to or near the patient termination 26. The controller 130 can attempt and continuously control the flow generator 110 such that the gas delivery system 1 continuously provides breathable gas to the patient at the first and second pressure levels to mimic the patient's breathing cycle. Typically, 30-60 breathing cycles per minute are provided to the patient during a respiratory therapy. In some applications, the patient's breathing cycle is manually determined by the clinician. It should be understood that the number of breathing cycles per minute required is highly dependent on the type of therapy to be provided to the patient, the patient's condition (age, respiratory condition), and may vary from patient to patient.

[0217] In at least one embodiment, the first pressure level is equal to the desired PIP. Preferably, the second pressure is 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 cmH2O, and useful values ​​are within these ranges. A higher PIP may be required for the first few breathing cycles (to clear the airways and initiate aeration of the lungs) and / or if the patient does not respond positively to the initially given respiratory therapy. In addition, the level of pressure required for resuscitation usually varies from patient to patient, depending on factors such as lung maturity, the presence or absence of lung disease, disorders, etc. The pressure ranges mentioned above are merely a guideline, and in practice the pressure needs to be adjusted individually depending on the patient's response.

[0218] In one embodiment, the second pressure level is equal to the desired PEEP. The second pressure may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 cmH 2 The second pressure may be about 5 cmH2O, and useful values ​​can be selected in any of these ranges (e.g., about 1 to about 15, about 1 to about 14, about 1 to about 13, about 1 to about 12, about 1 to about 11, about 1 to about 10, about 1 to about 9, about 1 to about 8, about 1 to about 7, about 1 to about 6, about 1 to about 5, about 2 to about 8, about 2 to about 6, about 2 to about 5, about 3 to about 8, about 3 to about 5, about 4 to about 8, about 4 to about 7, about 4 to about 5, about 5 to about 8, or about 6 to about 8 cmH2O). The second pressure may be about 5 cmH2O, but can be set according to, for example, the patient's requirements and / or the clinician's preferences.

[0219] In some embodiments, the device 320 can be configured to be removably connected to the conduit assembly 200 and / or to the patient interface 340 for ease of replacement and cleaning after use. In some embodiments, the device 320 can be permanently connected to the conduit 312 of the conduit assembly 200 and / or to the patient interface 340. In some embodiments, the device 320 can be an integral part of the patient interface 340.

[0220] Control Method According to the present disclosure, there is provided a method of controlling the patient gas delivery system 1 described above by determining a source gas flow rate, determining a delivered gas flow rate, calculating the difference between the source gas flow rate and the delivered gas flow rate, and causing the gas delivery system 1 to deliver breathable gas to the patient at a pressure based on the calculated difference between the source gas flow rate and the delivered gas flow rate.

[0221] In an alternative embodiment, the present disclosure provides a method of delivering breathable gas to a patient via an interface assembly, the interface assembly including a trigger port 322, the method including determining a status of the trigger port 322 by determining a source gas flow rate generated by a gas delivery system 1 and a delivered gas flow rate delivered to the interface assembly, and causing the gas delivery system 1 to deliver breathable gas to the patient at a pressure based on the determined status of the trigger port 322.

[0222] Both of the above methods involve determining a source gas flow rate and a delivered gas flow rate, and then using these two measurements to operate the gas delivery system 1 so that breathable gas is delivered to the patient at a suitable pressure level.

[0223] FIG. 7 shows a simplified schematic diagram of a gas delivery system 1 that can be used to implement one or both of the methods described above. The gas delivery system 1 includes a flow generator 110, in this example a blower, arranged to generate breathable gas to be delivered to a patient. For ease of illustration, both the conduit assembly 200 and the patient interface 340 are omitted from FIG. 7. The operation of the flow generator 110 is controlled by an associated controller 130. The gas delivery system 1 further includes a number of sensors 141, 321 arranged to measure source gas flow and delivered gas flow. In one embodiment, the sensor 321 can also be used to determine the pressure of the breathable gas in the patient interface 340.

[0224] A pressure sensor may be provided to measure the pressure of the breathable gas in the patient interface 340. The pressure sensor may be located at a suitable sensing location for it to measure the pressure of the breathable gas in the device 320 or in the patient interface 340. The pressure sensor may be a strain gauge, capacitance, electromagnetic type pressure sensor. Depending on its configuration, the sensor may be located entirely in the gas flow path and may return its measurements to the controller 130 via wired or wireless communication. Alternatively, suitable pressure tapping points may be formed in the device 320 or the patient interface 340, and the pressure sensor components may be positioned to obtain pressure measurements via the pressure tapping points. For example, the device 320 or the patient interface 340 may be provided with a gas bypass channel or a pressure sensing port. One or more pressure sensing tubes may then establish a fluid connection between the pressure tapping points and a sensing element located outside the device 320 and the patient interface 340.

[0225] The readings of sensors 141 and 321 are received or calculated by controller 130 to make decisions regarding the status of trigger port 322 and the level of pressure to be delivered to the patient, and corresponding control signals are then generated and transmitted from controller 130 to flow generator 110 to enable the flow generator 110 to set its motor speed.

[0226] For completeness, it is noted that it is within the scope of the present invention that in addition to or instead of using the detected flow rate and / or pressure, the motor speed of the flow generator 110 is used as a factor in determining the current status of the trigger port 322. By way of example, the motor speed of the flow generator 110 may be provided by an associated motor module. The controller 130 may be in signal communication with the motor module. If the characteristics of the motor and other components of the system (such as the patient interface, the conduit assembly, and the trigger port) are known, then predicted values ​​(in terms of motor speed and flow rate, and / or motor speed and pressure) corresponding to the open and closed status of the trigger port are also known (or can be calculated). For example, using this methodology, the controller may first determine whether the flow generator 110 is currently delivering PEEP or PIP pressure to the patient, and then based on the pressure being delivered to the patient, the controller 130 may determine the current status of the trigger port 322.

[0227] More specifically, the source gas flow rate is the flow rate of breathable gas generated by the flow generator 110 and delivered to the conduit assembly 200. This is the first flow rate determined by the controller 130 and is denoted as Fs throughout this disclosure. The first flow rate can be determined by a first sensor 141, which can be a flow sensor located at least partially in the fluid path near the flow generator 110. The measurement of the flow sensor 141 is transmitted to the controller 130 via a wired or wireless sensing circuit. In one embodiment, the sensor 141 can be a pressure sensor, the measurement of which can be converted to the first flow rate based on the relationship between pressure and flow rate. In at least some embodiments, the pressure sensor can include one or more pressure sensing tubes in fluid communication with the breathable gas as it enters the conduit assembly 200. The one or more sensing tubes deliver the flow rate of breathable gas to a corresponding sensing element in the controller 130, at which point a flow rate determination is performed.

[0228] The delivered gas flow rate refers to the flow rate of breathable gas delivered to the patient interface 340. This is the second flow rate determined by the controller 130 and is denoted as Fm throughout this disclosure. Fm includes the breathable gas inhaled by the patient during respiratory therapy, but also includes any interface leakage (if any). The difference between Fs and Fm is independent of interface leakage and other system noise sources (such as the patient coughing), and represents the breathable gas flow rate through the trigger port 322. Thus, this difference (i.e., Fs-Fm) should be small when the trigger port 322 is occluded, i.e., in a closed state, and should be at a higher value that is approximately equal to the amount of breathable gas flowing through the trigger port 322 when the trigger port 322 is unoccluded (in an open state). The controller 130 determines or calculates this difference (Fs-Fm) and then uses this difference to determine what state the trigger port 322 is currently in or whether the status of the trigger port 322 has changed.

[0229] FIG. 8 is a schematic diagram of the gas delivery system 1, including arrows showing the direction of gas flow within the gas delivery system 1 and the associated flow rates that the controller 130 uses to implement its control functions of the flow generator 110. As shown, the source gas flow rate Fs, i.e., the flow rate of breathable gas generated by the flow generator 110 and delivered to the conduit assembly 200, is measured based on the flow characteristics of the breathable gas near the flow generator 110 end. In comparison, the delivered gas flow rate Fm, i.e., the flow rate of breathable gas delivered to the patient interface 340, is measured based on the flow characteristics of the breathable gas near the patient end, preferably at or near the device 320 itself. FIG. 8 also shows two pressure measurements, namely the source pressure Ps and the mask pressure Pm (or interface pressure). These pressure measurements may be made directly by the first sensor 141 and the second sensor 321, as further described below, or they may be measured by additional pressure sensors.

[0230] Similar to the first sensor 141 described above, the second sensor 321 may be an integrated sensor, with measurements taken by the sensor 321 being transmitted back to the controller 130 via wired lines or via wireless signal transmission. In some embodiments, the second sensor 321 may be configured to include a sensing component (e.g., a flow restriction such as a diaphragm or deflectable flap) located in the gas flow path or at the pressure tap location, and a pneumatic connection established by one or more pressure sensing tubes located outside the cavity of the device 320 and patient interface 340. This will be described below with reference to Figures 12-16, which show one exemplary embodiment of the device 320 including a differential pressure sensor.

[0231] 9-11 show example control logic that the controller 130 implements to determine whether the trigger port 322 is open or closed, and then the controller 130 uses that determination to operate the flow generator 110 to deliver a target pressure to the patient. In the illustrated example, the flow generator 110 is operated such that the controller 130 repeatedly delivers breathable gas to the patient at a first pressure level and a second pressure level to mimic the patient's breathing cycle. Preferably, the first pressure is higher than the second pressure, and more preferably, the first pressure corresponds to a PIP and the second pressure corresponds to a PEEP.

[0232] For completeness, it should be noted that it is within the scope of the present invention for the system to operate in a "hybrid" mode, where instead of operating exclusively in a pressure-based mode, the controller 130 can be in either a pressure-based mode or a flow-based mode, depending on the status of the trigger port 322. For example, when the trigger port 322 is in an open state, the device can operate in a flow-based (or "flow-controlled") mode, whereby a target flow rate is targeted. When the trigger port is in a closed state, the device can operate in a pressure-based (or "pressure-controlled") mode, whereby a target pressure is targeted.

[0233] In some embodiments, the previous status of the trigger port 322 is stored in the memory of the controller 130. Measurements from the sensors 141, 321 are acquired or received by the controller 130, preferably at a predefined frequency. The controller 130 calculates the difference between the first and second flow rates and then compares the difference to a first threshold flow rate (Fa) and / or a second threshold flow rate (Fb) to determine the current status of the trigger port 322, and then determines whether the status of the trigger port 322 has changed by making a comparison between the current status of the trigger port 322 and the previous status. There are several different ways to determine Fa or Fb, as explained below.

[0234] In some configurations, the first threshold flow rate Fa is determined based on the interface pressure. In some configurations, the first threshold flow rate Fa is calculated from J*sqrt(Pm), as shown in FIG. 11, where Pm is the interface pressure and J is a coefficient determined empirically or during a calibration phase and / or obtained from a database or look-up table built into or accessible to the system. The interface pressure Pm is the pressure of the breathable gas in the patient interface 340 and can be measured by the second sensor 321 or another pressure sensor. Alternatively, the first threshold flow rate Fa may be a predetermined range, such as 0.5-10 L / min. Alternatively, the first threshold flow rate Fa may be set to a constant level / flow rate. In some configurations, the first threshold flow rate Fa is set to a constant flow rate of 1 L / min, as shown in FIG. 10. In at least some configurations, the coefficient J is a coefficient between, for example, 2-6 L / min*cmH2O. -1 / 2 In at least one embodiment, the coefficient J can be, for example, 4.47 L / min*cmH 2 O -1 / 2 Thus, the threshold value Fa is 5 cmH 2 For O Pm, it is 10L / min.

[0235] In some configurations, the second threshold flow rate is calculated based on the interface pressure Pm. In some configurations, the threshold flow rate Fb is calculated from K*sqrt(Pm), as shown in FIG. 9, where Pm is the interface pressure and K is a coefficient determined experimentally or during a calibration phase and / or obtained from a database or look-up table built into or accessible to the system. Alternatively, the second threshold flow rate Fb may be a predetermined range, such as 0.5-10 L / min. Alternatively, the second threshold flow rate may be set to a constant level / flow rate. In some configurations, the second threshold flow rate is set to a value in the range of 1-3 L / min. In at least some configurations, the coefficient K may be calculated from a value in the range of 1-4 L / min*cmH2O, for example. -1 / 2In at least one embodiment, the coefficient K can be, for example, 2.23 L / min*cmH 2 O -1 / 2 Thus, the threshold value Fb can be set to 5 cmH 2 For O Pm, it is 5L / min.

[0236] As discussed further below with reference to the alternative embodiment of FIG. 16, the coefficients J and K may be based on calculated conductance values ​​(Ctrig, Cbias) associated with theoretical "trigger orifice" and "bias orifice". These theoretical orifices are mathematical representations of outlet points / scenario in the gas delivery system 1. The trigger orifice represents outlet through the trigger port 322. The bias orifice represents the minimum expected flow rate through the gas delivery system 1 with the trigger port 322 closed and no outlet through the patient interface 340.

[0237] Exemplarily, the coefficients J and K may each correspond to (Ctrig+Cbias), i.e., the values ​​of J and K may each be equal to Ctrig+Cbias.

[0238] In some embodiments, the first threshold flow rate Fa or the second threshold flow rate Fb may be equal. In some embodiments, the value of Fb may be selected to be slightly greater than Fa to account for the fact that some air may leak out of the trigger port 322 when the trigger port 322 is in a closed state.

[0239] 9, if the flow generator 110 is already delivering PIP, the previous status of the trigger port 322 is closed. "Previous status" refers to the last status recorded by the controller 130. To remotely trigger the flow generator 110 to switch to PEEP, the operator unoccludes the trigger port 322 (e.g., by removing a finger from the trigger port 322 or by using the valve 50 shown in FIGS. 5 and 6), which allows breathable gas to flow through the trigger port 322 and out to the ambient air. The controller 130 compares the calculated difference between Fs and Fm to the threshold flow rate Fb. If the difference is greater than Fb, the controller 130 determines that the trigger port 322 has now changed from a closed state to an open state, and sends a control signal to the flow generator 130 to configure its motor speed so that the delivery pressure is reduced to the PEEP level. The flow generator 110 is maintained at this motor speed until a new control signal is received from the controller 130.

[0240] Similarly, referring to Figures 10 and 11, when the flow generator 110 is already delivering PEEP, the previous status of the trigger port 322 is open. That is, the last recorded status of the trigger port 322 by the controller 130 is open. To remotely trigger the flow generator 110 to switch to PIP, the operator occludes the trigger port 322, for example, by placing a finger in front of the trigger port 322, so that less breathable gas leaks through the trigger port 322 to the ambient air. The controller 130 compares the difference between the calculated Fs and Fm with the threshold flow rate Fa. If the difference is less than Fa, the controller 130 determines that the trigger port 322 has now changed to a closed state and generates a control signal to the flow generator 110 to increase its motor speed so that the delivery pressure rises to the PIP level. The flow generator 110 remains at this level until a new control signal is again received from the controller 130.

[0241] In one embodiment, the controller 130 is configured to vary the pressure between PIP and PEEP over a predetermined time interval to achieve an appropriate respiratory rate or minute ventilation (number of breaths delivered per minute) if the controller 130 determines that the current status of the trigger port 322 has changed from its previous status. In one embodiment, the predetermined time interval is 100-400 ms, or 100-300 ms, or 100-200 ms, or about 150 ms.

[0242] The above mentioned control logic is preferably implemented by suitable software algorithms in the controller 130. Upon or after receiving the measurements from the sensors 141, 321, the controller 130 may further perform appropriate filtering or smoothing calculations on the measurements to remove noise or spurious signals.

[0243] As discussed above, the controller 130 is arranged to determine the source gas flow rate Fs and the delivery gas flow rate Fm based on measurements provided by the sensors 141 and 321. These sensors can take a variety of different forms, such as mass flow sensors, pressure sensors, differential pressure sensors, flow sensors, ultrasonic flow sensors and / or thermistors. In some embodiments, one or both of the sensors 141, 321 include a pressure sensor, and the controller 130 can use the pressure measurements to calculate the first and second flow rates described above.

[0244] In at least some embodiments, the controller 130 and flow generator 110 may be incorporated into the respiratory apparatus 100, which receives a source of breathable gas, for example from a fixed wall source, when delivering respiratory therapy to a patient. The sensors 141 and 321 may be provided at suitable sensing locations outside the housing of the respiratory apparatus 100. In the case of sensors that can obtain measurements via one or more pressure tapping points, such as bypass channels or sensing tubes, they may be housed within the housing of the respiratory apparatus 100.

[0245] In at least some embodiments, one or more of the sensors 141, 321 may be integrated sensors, such that they can be contained entirely within the gas flow path of the gas delivery system 1 and their measurement signals can be transmitted back to the controller 130 via a wireless or wired connection.

[0246] In another embodiment, where at least one of the one or more sensors includes an air pressure sensor, one or more sensing ports may be required at suitable locations in the T-piece device 320 to allow for measurement of gas flow. The one or more sensing ports may be positioned to be fluidly connected to one or more components of the sensor, such as a flap, diaphragm, thermistor, etc., some components of the sensor may be located outside of the cavity formed by the T-piece device 320.

[0247] Regardless of what type of sensor is used at the patient end, the sensor is suitable for the systems and methods described herein as long as it can be used to determine the flow rate of breathable gas delivered to the patient interface 340 using one or more of the control methods described above.

[0248] 12-15 show various different views of a device 320 and patient interface 340 incorporating an exemplary sensor arrangement.

[0249] The device 320 includes an inlet 324 for receiving breathable gas from the conduit assembly 200, an outlet 325 arranged to be fluidly coupled to a patient interface 340 in use, and a trigger port 322. A substantially hollow body portion of the device 320 extends between the inlet 324 and the outlet 325. The body portion includes a first member 331 including the trigger port 322. In this particular embodiment, the body portion includes a bend along the length of the body portion that forms an angle, and above the angle the trigger port 322 is located. In other embodiments, the body portion may be configured without a bend, for example the body portion is formed as a substantially straight hollow cavity without a bend along its length, and the trigger port 322 may be located within a sidewall of the body portion or at an end of the body portion. A second member 332 of the body portion is substantially hollow and arranged to be connected to a patient interface 340 in use. The first member 331 and the second member 332 may be permanently joined by ultrasonic welding, adhesive, or overmolding, or may be removably coupled to one another. Figure 14 shows an exploded view of the first member 331 and the second member 332 of the device 320.

[0250] The sensor 321 may be a differential pressure sensor having a flow restriction. The flow restriction creates a pressure drop along the gas flow path, which is used to derive the flow rate of gas flowing through the device 320. For example, the flow restriction may be or include an orifice plate or a deflectable flap. In the example shown in Figures 12-15, the sensor 321 is a differential pressure sensor including a deflectable flap 328 positioned between the first member 331 and the second member 332 described above. The deflectable flap 328 acts as a variable flow restriction for gas passing through the internal cavity of the device 320, creating a difference in gas pressure on either side of the deflectable flap 328, which the controller 130 uses to derive the flow rate of gas flowing through the device 320 (i.e., the deflection of the flap 328 is determined by the pressure difference on either side of the flap 328). It should be understood that the sensor can take many different forms, some requiring multiple such deflectable flaps 328. Additionally, in some sensors, the deflectable flap 328 can be attached to various angle or displacement sensors, such as rotary encoders, strain gauges, Hall effect, and the like, and based on the readings of the angle or displacement sensors, a measurement of differential pressure or flow rate can be derived.

[0251] Referring again to Figures 12-15, a first pressure sensing port 329a and a second pressure sensing port 329b may be formed in the sidewall of the device 320. The pressure sensing ports 329a and 329b are pressure take-off points that form a fluid path between the internal cavity of the device 320 on either side of the deflectable flap 328 and other components of the differential pressure sensor located outside the device 320. In use, a pair of sensing tubes 330a, 330b are mounted over the pressure sensing ports 329a, 329b, respectively. At equilibrium, the pressure of the air in the two sensing tubes 330a, 330b will be equal to the pressure of the air in the device 320 on either side of the flap 328. In its simplest form, the pressure sensing tubes 330a, 330b may be two flexible tubes that form a complete pneumatic connection between the device 320 and a sensing element provided in the controller 130. The controller 130 is programmed to calculate the bidirectional flow rate based on the differential pressure measurements. An air pressure sensor eliminates the need for electrical circuit connections between the device 320 and the controller 130, which may be preferable in some cases.

[0252] For completeness, the following additional points are mentioned in relation to embodiments including one or more pressure taps / sensing ports and one or more pressure sensing tubes. - In some embodiments, the pressure take-off points / pressure sensing ports 329a, 329b can both be located in one of the body portion members 331, 332. For example, they can be located in the first body portion member 331 such that they (and the pressure sensing tube or tubes) can be attached and detached together with the trigger port 322. - More generally, in some embodiments, one or more pressure sensing tubes 330a, 330b may be removably attached to the body portion. They may be removable themselves and / or may be attached to components of the body portion that are themselves removable / separable from other components of the body portion. - In some embodiments, the system may have a "back-up" protocol in place to determine pressure, for example, in the event that there is an occlusion affecting the pressure tap / pressure sensing port and / or one or more pressure sensing tubes. For example, the "back-up" may include estimating pressure at the patient interface based on flow rate. Alternatively or additionally, the system may include additional pressure sensors elsewhere in the system for use as backups.

[0253] Alternative Embodiments FIG. 16 illustrates a gas delivery system 900 according to another exemplary embodiment of the present disclosure.

[0254] In this embodiment, the gas delivery system 900 is configured with one or more sensors 141 proximate the flow generator 110, but in this embodiment, there are no sensors proximate the patient interface 340 (not shown in FIG. 16). That is, in this embodiment, the sensor 321 located near the patient end is omitted. The system 900 configured in this manner is still capable of determining whether a detected flow level corresponds to the trigger port 322 (not shown in FIG. 16) being in an open or closed state, and operating the flow generator 110 (via the controller 130) to control the pressure of breathable gas delivered to the patient interface 340 accordingly.

[0255] Specifically, in such an embodiment, the one or more sensors 141 include at least one flow sensor proximate the flow generator 110 such that the source gas flow rate (Fs) can be determined.

[0256] The one or more sensors 141 may also include a pressure sensor proximate the flow generator 110 to measure the source pressure (Ps), i.e., the pressure proximate the flow generator 110. Alternatively, the pressure (P) proximate the flow generator 110, or anywhere in the system 900, may be mathematically determined based on the flow rate (if a flow sensor is deployed instead of a pressure sensor).

[0257] Within the system 900, there are multiple outflow (or "leak") points / scenarios, e.g., the patient interface 340, the trigger port 322, and the minimum expected flow rate through the system 900 (i.e., the minimum flow rate through the system to ensure safe clearance of gas) with the trigger port closed and no outflow through the patient interface. Each of these can be mathematically approximated by an orifice (not shown in FIG. 16), i.e., the patient interface orifice, the trigger orifice, and the bias orifice, respectively. Each of these theoretical orifices is associated with a conductance value (conductance is a function of the flow through the orifice for a given pressure). The conductance value of each of these theoretical orifices representing the outflow points / scenarios can be mathematically determined (e.g., based on experiment, or determined during a calibration phase and / or obtained from a database or lookup table built into or accessible to the system), and once determined, the conductance value is a known characteristic of the system.

[0258] From this, the dynamic threshold flow rate (Fth) can be determined.

[0259] Fth may be related to L*sqrt(P), where P is a mathematically calculated pressure at the patient interface 340 based on flow rate, and L is a coefficient determined empirically or during a calibration phase and / or obtained from a database or look-up table built into or accessible to the system. In at least some configurations, the coefficient L may be, for example, between 2 and 10 L / min*cmH 2O -1 / 2 In at least one embodiment, L can be, for example, 4.47 L / min*cmH 2 O -1 / 2 This allows P at the interface to be 5cmH 2 If the threshold value is O, then Fth=10 L / min.

[0260] In one embodiment, the coefficient L is given by (Cbias+Ctrig), which is the calculated conductance value of the bias orifice and the trigger orifice. Cbias is, for example, 2.23 L / min*cmH 2 O -1 / 2 This can be calculated as a mask pressure of 5cmH 2 This corresponds to a bias orifice with a bias flow rate of 5 L / min at 0 (according to the formula Cbias=FlowBias / sqrt(P)). Ctrig can be, for example, 2.23 L / min*cmH 2 O -1 / 2 This means that the flow rate through the trigger port 322 is greater than the calculated mask pressure of 5 cmH 2 This corresponds to a trigger orifice of 5 L / min at O ​​(according to the formula Ctrig=FlowTrig / sqrt(P)).

[0261] In another embodiment, the factor L may be provided by (Cbias+CmaskMaxPIP), where CmaskMaxPIP is a calculated conductance value associated with an orifice that represents the maximum flow rate through the patient interface during delivery of PIP. In at least one embodiment, CmaskMaxPIP may be, for example, 11.18 L / min*cmH 2 O -1 / 2 which corresponds to a virtual orifice that passes a maximum flow rate (e.g., 50 L / min) at a PIP pressure (e.g., 20 cmH2O) (according to the formula CmaskMaxPIP=FlowmaskMaxPIP / sqrt(PIP)).

[0262] In an alternative embodiment, the dynamic threshold flow rate (Fth) equation can also have a component that takes into account the flow rate into and out of the patient's lungs (i.e., the breathable gas that the patient inhales during respiratory therapy). This can be derived from the measured or approximated lung compliance of the patient. For example, a typical lung compliance for the type of patient being treated can be used as an approximation.

[0263] Thus, by way of example, the equation for the dynamic threshold flow rate (Fth) can be as follows: Fth = L * sqrt(P) + Fpatient(t) where Fpatient(t) is the flow rate into and out of the patient's lungs at the time being considered.

[0264] The source gas flow rate (Fs) can then be compared to the dynamic threshold Fth to determine whether the trigger port 322 is in an open or closed state.

[0265] If Fs < Fth, i.e., if the source gas flow rate Fs is less than the dynamic threshold flow rate Fth, this indicates that the trigger port 322 is in a closed state.

[0266] If Fs > Fth, i.e., if the source gas flow rate Fs is greater than the dynamic threshold flow rate Fth, this indicates that the trigger port 322 is in an open state.

[0267] Optionally, as part of determining whether the trigger port 322 is in an open or closed state, the system 900 can also perform a "hysteresis" analysis, which acts to stabilize the system by preventing unwanted oscillations between the open and closed states of the trigger port 322 based on minor or borderline flow rate variations. If the determination includes a hysteresis analysis, as part of the determination, the system 900 also needs to determine the previous (existing) state of the trigger port 322 immediately prior to the comparison of Fs and Fth.

[0268] In other respects, the system of this embodiment may be substantially as described above with respect to the other embodiments.

[0269] Additional Features In both the dual position sensor (141, 321) and single position sensor (141) embodiments (as shown in Figures 7 and 16, respectively), the system (1, 900) may be further configured to detect one or more of the following: - the patient interface 340 is disconnected (disconnected) or poorly or improperly connected; - other components of the system (in particular the humidifier (120 in FIG. 1) and / or the conduit (210 in FIG. 1)) are disconnected, and / or - Blockage in or on System 1 / 900. If such a condition is detected, the system may be configured to take one or more actions in response, for safety and / or functionality reasons.

[0270] Patient Interface Disconnection Detection A disconnection of the patient interface will result in excessive leakage / flow from the system (ie, greater leakage / flow than when the patient interface is properly attached).

[0271] This can be modeled by treating the excess leak / spill as an additional theoretical orifice in the system. This theoretical orifice has a mathematically determinable conductance value (Cmaskleak) that is a function of the flow rate through this theoretical orifice for a given pressure. In at least one embodiment, Cmaskleak is, for example, 6.71 L / min*cmH 2 O -1 / 2 This means that the flow rate through the orifice is 5cmH 2 This corresponds to a hypothetical mask leak orifice (according to the formula Cmaskleak=FlowMaskLeak / sqrt(P)) which is 15 L / min at a pressure of O.

[0272] From this, the excess flow threshold (F leakth ), for example, as follows: In a single sensor embodiment, F leakth =(Cbias+Ctrig+Cmaskleak)*sqrt(P)+Fpatient(t) In a dual sensor embodiment (sensor at source and interface) F leakth =Cmaskleak*srt(Pm)+Fpatient(t) It can be calculated as follows.

[0273] In at least one embodiment, the leak threshold (F leakth ) can be, for example, 80 L / min, meaning that if the flow rate through the orifice is greater than 80 L / min, then excessive leakage is detected. Similarly, if the flow rate through the orifice is less than 80 L / min, then there is no excessive leakage.

[0274] The actual flow rate in the system is then calculated based on this threshold (F leakth ) to determine whether there is excessive leakage, which would indicate a disconnection of the patient interface. In a single sensor embodiment, excessive leakage is Fs>F leakth If - Stopping excessive leakage Fs <F leakth It will be detected when this happens. In a dual sensor embodiment, excessive leakage is Fm>F leakth is detected if - Stopping excessive leakage Fm <F leakth It will be detected when this happens.

[0275] A similar methodology can be used to detect when the patient interface is not fully or properly connected (where the leak is less than if the patient interface were completely disconnected, but greater than the expected leak).

[0276] If excessive leakage is detected, indicating that the patient interface is disconnected (or poorly / improperly connected), the system can illustratively set the flow rate to a fixed flow rate, the motor to a fixed motor speed, or the pressure to a fixed pressure. These measures can help ensure that the system still provides some level of respiratory assistance, for example, when the patient interface is on the patient's face but improperly / improperly connected. The system can also disable gas delivery or some gas delivery functions if excessive leakage is detected, such as for safety reasons. For example, delivery at a particular pressure based on the detected trigger port status can be disabled. The system can also generate one or more alarms or alerts to ensure that a caregiver, physician, or other interested party is notified of the problem.

[0277] Detection of cleavage of other components A disconnected component can be conceptualized as an extreme case of excessive leakage. Thus, similar to the detection of a disconnected patient interface, the disconnected component (such as the humidifier 120 or the conduit 210) can be approximated as an additional theoretical orifice in the system, whose conductance value (Cdisconnectedcomponent) can be mathematically determined.

[0278] The overall conductance value of the system (Csystem) can be determined as a function of Fs and P, where P is the source pressure, i.e., the pressure adjacent to the flow generator. Specifically, Csystem=Fs / sqrtP It becomes.

[0279] Therefore, detection of the cleaved components is Csystem>Cdisconnectedcomponent It can be detected if

[0280] The system's response to detecting a disconnected component may include setting a fixed motor speed (such as at a minimum speed) as well as generating an alarm or alert.

[0281] In at least one embodiment, Cdisconnectedcomponent is, for example, 70.71 L / min*cmH 2 O -1 / 2 This means that the flow rate through the orifice is 2 cmH 2 This corresponds to a virtual orifice that is 100 L / min at a pressure of O (according to the formula Cdisconnectedcomponent=FlowDisconnectedcomponent / sqrt(P)).

[0282] Detecting occlusions Detection of an occlusion in the system can be detected by comparing the actual flow rate to an appropriate threshold flow rate value. For both the dual position sensor (141, 321) and single position sensor (141) embodiments of the system (1, 900) of the present invention, if the actual flow rate is less than the threshold flow rate value, it may indicate the presence of an occlusion in the system.

[0283] In a single position sensor embodiment, the threshold flow value may correspond to the minimum expected flow rate, discussed above, through the system 900 with the trigger port closed and no outflow through the patient interface. If the actual source flow rate (Fs) is less than this value, this indicates an occlusion.

[0284] In a dual position sensor embodiment, a threshold flow value can be derived from the minimum expected flow rate through the system with the trigger port closed and no other outflow through the patient interface, more specifically, from the associated conductance value Cbias in combination with the interface pressure. This threshold flow value can be compared to Fs, the source flow rate. If Fs is less than the threshold flow value, this indicates an occlusion.

[0285] Optionally, the patient's lung compliance (actual or approximated) may also be included as a factor in determining the threshold flow value for dual-position sensor embodiments.

[0286] The system's response to detecting an obstruction may include setting a fixed motor speed (such as at a minimum speed) as well as generating an alarm or alert.

[0287] term Positive End Expiratory Pressure (PEEP) is also known as Peak End Expiratory Pressure, and in the context of respiratory therapy systems and methods, the two terms are often used interchangeably.

[0288] Unless the context expressly requires otherwise, words such as "comprise," "comprising," and the like are to be interpreted in an inclusive sense, i.e., "including, but not limited to," as opposed to an exclusive or exhaustive sense. In particular, conditional language used herein, such as "can," "may," "could," "may," "for example," and the like, is intended to generally suggest that some embodiments include certain features, elements, and / or conditions, but not other embodiments, unless expressly specified otherwise or understood otherwise within the context in which it is used. Thus, such conditional language is generally not intended to suggest that features, elements, and / or conditions are necessarily required for one or more embodiments, or that one or more embodiments necessarily include logic for determining whether or not the features, elements, and / or conditions are included or implemented in any particular embodiment, with or without author input or prompting.

[0289] The term "plurality" refers to two or more items. Enumerations of quantities, dimensions, sizes, formulations, parameters, shapes, and other characteristics should be interpreted as if the quantity, dimension, size, formulation, parameter, shape, or other characteristic were preceded by the term "about" or "approximately". The term "about" or "approximately" means that the quantity, dimension, size, formulation, parameter, shape, and other characteristic need not be exact, but may be approximated and / or greater than or less than, as appropriate, to reflect acceptable tolerances, conversion factors, rounding, measurement errors, and the like, and other factors known to those of skill in the art. Enumerations of quantities, dimensions, sizes, formulations, parameters, shapes, and other characteristics should also be interpreted as if the quantity, dimension, size, formulation, parameter, shape, or other characteristic were preceded by the term "substantially". As used herein, the terms "approximately", "about" and "substantially" refer to an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, in some embodiments, as may be dictated by context, the terms "approximately," "about," and "substantially" may refer to an amount that is within 10% or less of a stated amount. The term "generally," as used herein, refers to a value, amount, or characteristic that largely includes or tends toward a particular value, amount, or characteristic. For example, as may be dictated by context, the term "generally linear" may mean that it deviates from exactly parallel by no more than 15°.

[0290] In this specification, numerical data may be expressed or presented in a range format. Such range formats are used merely for convenience and brevity, and therefore should be understood to be interpreted flexibly to include not only the numerical values ​​explicitly recited as the limits of the range, but also to include all individual numerical values ​​or subranges contained within the range, as if each numerical value and subrange were explicitly recited. By way of illustration, a numerical range of "1 to 5" should be interpreted not only to include the explicitly recited values ​​of about 1 to about 5, but also to include each value and subrange within the indicated range. Thus, this numerical range includes individual values ​​such as 2, 3, and 4, and subranges such as "1 to 3," "2 to 4," and "3 to 5." This same principle should also be applied to ranges reciting only one numerical value (e.g., "greater than 1"), regardless of the breadth or characteristics of the range being described.

[0291] For convenience, several items may be presented in a common list. However, these lists should be construed as if each element of the list were individually identified as a separate and unique element. Thus, any individual element of such a list should not be construed as a de facto equivalent of any other element of the same list solely based on being presented in a common group, without any indication to the contrary. Furthermore, when the terms "and" and "or" are used in conjunction with a list of items, these terms should be interpreted broadly in that any one or more of the listed items may be used alone or in combination with other listed items. The term "alternatively" refers to a selection of one of two or more alternatives and is not intended to limit the selection to only the listed alternatives or to only one of the listed alternatives at a time, unless the context clearly dictates otherwise.

[0292] Reference herein to any prior art is not, and should not be construed as, an admission or any form of suggestion that the prior art forms part of the common general knowledge in the field of endeavor in any country throughout the world. Moreover, references to other patent specifications, other external documents, or other sources are generally intended to provide a context for discussing features of certain embodiments. Unless expressly stated otherwise, references to such external documents should not be construed as an admission that such documents or such sources are prior art or form part of the common general knowledge in the art in any jurisdiction.

[0293] The embodiments of the present invention may be broadly stated as being embodied in the parts, elements and features referred to or shown in the specification of this application, either individually or collectively, and in any or all combinations of any two or more of said parts, elements or features, and where specific wholes having known equivalents in the art to which the invention pertains are referred to herein, such known equivalents are deemed to be incorporated herein as if individually set forth.

[0294] Where the above description refers to wholes or components having known equivalents, those wholes are incorporated herein as if individually set forth.

[0295] It should be noted that various variations and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such variations and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. For example, various components can be rearranged as necessary. Accordingly, such variations and modifications are intended to be included within the scope of the present invention. Moreover, not all of the features, aspects and advantages are necessarily required to implement the present invention. Accordingly, the scope of the present invention is intended to be defined solely by the scope of the following claims.

Claims

1. 1. A gas delivery system for delivering breathable gas to a patient, comprising: a breathing apparatus including a flow generator, a controller arranged to control the flow generator, and one or more sensors configured to determine a source flow rate (Fs) from the flow generator; the breathing apparatus is configured to connect to a conduit assembly that delivers the breathable gas from the flow generator to the patient; the respiratory apparatus is configured to connect to an interface assembly arranged to receive the breathable gas from the conduit assembly and deliver the breathable gas to the patient, the interface assembly comprising a trigger port and one or more sensors configured to determine an interface gas flow rate (Fm); the controller is configured to calculate a difference between the source flow rate and the interface gas flow rate, determine a status of the trigger port based on the difference, and operate the flow generator to provide the breathable gas to the patient at a pressure based on the determined status of the trigger port. Gas delivery system.

2. The controller comparing the difference between the source flow rate and the interface gas flow rate (ΔF=Fs-Fm) to a first threshold flow rate (Fa) and / or a second threshold flow rate (Fb); determining a status of the trigger port based on the comparison; The gas delivery system of claim 1 , configured as follows:

3. The gas delivery system of claim 2 , wherein the status of the trigger port comprises an open state or a closed state.

4. The controller Obtaining a previous status of the trigger port, including an open or closed state; comparing the difference between the source flow rate and the interface gas flow rate to a first threshold flow rate Fa if the previous status of the trigger port was open, or comparing the difference between the source flow rate and the interface gas flow rate to a second threshold flow rate Fb if the previous status of the trigger port was closed; determining a current status of the trigger port based on the comparison; Comparing the previous status with the current status to determine if the trigger port status has changed. The gas delivery system of claim 3 further configured as follows:

5. 5. The gas delivery system of claim 3, wherein the trigger port is in the closed state when the difference is less than the first threshold flow rate (.DELTA.F<Fa).

6. 5. The gas delivery system of claim 3, wherein the trigger port is in the open state when the difference is greater than the second threshold flow rate (.DELTA.F>Fb).

7. 5. The gas delivery system of claim 2, wherein the second threshold flow rate is determined based on an interface pressure or calculated from K*sqrt(Pm), where Pm is the interface pressure and K is a coefficient determined experimentally or during a calibration phase.

8. 5. The gas delivery system of claim 2, wherein the first threshold flow rate is determined based on an interface pressure or calculated from Fa=J*sqrt(Pm), where Pm is the interface pressure and J is a coefficient determined experimentally or during a calibration phase.

9. A gas delivery system as described in any one of claims 2 to 4, wherein the second threshold flow rate and / or the first threshold flow rate are within the range of 0.5 to 10 L / min or are set to a constant level.

10. The controller: operating the flow generator to deliver breathable gas to the patient at a first pressure if the trigger port is determined to be in a closed state; If the trigger port is determined to be in an open state, operating the flow generator to deliver breathable gas to the patient at a second pressure. The gas delivery system of any one of claims 2 to 4, further configured as follows:

11. The gas delivery system of claim 10 , wherein the first pressure is greater than the second pressure.

12. 11. The gas delivery system of claim 10, wherein the first pressure corresponds to a peak inspiratory pressure (PIP) and the second pressure corresponds to a positive end-expiratory pressure (PEEP).

13. The gas delivery system of any one of claims 1 to 4, wherein the flow generator is operated by controlling the speed of a motor of the flow generator.

14. A gas delivery system as described in any one of claims 1 to 4, further comprising the conduit assembly.

15. A gas delivery system as described in any one of claims 1 to 4, further comprising the interface assembly.

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