Systems and methods for measuring patient pulmonary pressure - Patents.com

Abstract

The present technology is directed to systems and methods for measuring patient lung pressure within a patient during pressure-controlled or volume-controlled ventilation. For example, the present technology includes operating a ventilator insufflator at a first speed during the inhalation phase of a breath to direct gas along a flow path from the ventilator to the patient, and operating the insufflator at a second speed, less than the first speed, after the inhalation phase and before the exhalation phase of a breath to achieve a zero-flow condition in the flow path during which gas is neither flowing into nor out of the patient's lungs. During the zero-flow condition, the pressure in the flow path is equal to, or at least approximately equal to, the patient lung pressure. Thus, pressure can be measured at any location along the flow path during the zero-flow condition to determine the patient lung pressure.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Application No. 63 / 175,405, filed April 15, 2021, and entitled “SYSTEMS AND METHODS FOR MEASURING PATIENT LUNG PRESSURE IN VOLUME-CONTROLLED VENTILATION,” the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present technology is directed generally to ventilator systems and methods of use, and specifically to measuring patient pulmonary pressure and other physiological metrics. [Background technology]

[0003] Mechanical ventilators are typically connected to a patient using a patient circuit. Once connected to the patient, the ventilator drives inspired gas into the patient's lungs to help the patient breathe. Gas flow can be controlled using either pressure-controlled ventilation or volume-controlled ventilation. In pressure-controlled ventilation, the ventilator delivers air to the patient until a predetermined pressure is reached. Once the predetermined pressure is reached, an exhalation valve in the patient circuit opens, reducing the pressure in the patient circuit and allowing gas to flow out of the patient's lungs and exit the patient circuit via the exhalation valve. In volume-controlled ventilation, the ventilator delivers a predetermined volume of air to the patient. Once the predetermined volume of air has been delivered to the patient, the flow rate is reduced and air naturally flows out of the patient's lungs and back towards the ventilator. Summary of the Invention [Means for solving the problem]

[0004] The present technology is generally directed to systems and methods for measuring patient lung pressure during pressure-controlled or volume-controlled mechanical ventilation. In some embodiments, the technology further provides systems and methods for calculating patient static compliance and / or patient airway resistance based on the measured patient lung pressure. For example, the present technology includes operating a ventilator insufflator at a first speed during the inhalation phase of a breath to direct gas along a flow path from the ventilator to the patient, and operating the insufflator at a second speed, less than the first speed, after the inhalation phase and before the exhalation phase of a breath to achieve a zero-flow condition in the flow path during which gas is neither flowing into nor out of the patient's lungs. During the zero-flow condition, the pressure in the flow path is equal to, or at least approximately equal to, the patient lung pressure. Thus, pressure can be measured at any location along the flow path during the zero-flow condition to determine the patient lung pressure. The measured patient lung pressure can then be used to automatically calculate the patient static compliance and / or the patient airway resistance. As described in detail herein, such measurements may assist in monitoring the patient's lung health during ventilation, selecting appropriate therapy levels for the patient, or the like.

[0005] Patient lung pressure (e.g., the pressure within the patient's lungs at any given time during the breathing cycle) fluctuates throughout the inhalation / exhalation breathing cycle. For example, the pressure within the patient's lungs generally increases during the inhalation phase of a breath as air moves into the lungs, expanding them. At the transition between the inhalation and exhalation phases, the patient lung pressure is generally at or near its peak value (e.g., also known as plateau pressure). The patient lung pressure then decreases during the exhalation phase as air moves out of the lungs and the lungs contract.

[0006] Patient lung pressure cannot be measured directly during a standard inhalation / exhalation breathing cycle. This is because patient lung pressure is generally not equal to the pressure at the patient connection (or any other location along the flow path between the ventilator and the patient's mouth) during ventilation due to the resistance of the patient's airway (e.g., trachea). For example, the pressure at the patient's mouth will generally exceed the patient lung pressure at any given moment during the inhalation phase (e.g., due to the patient airway resistance), and the pressure at the patient's mouth will generally be below the patient lung pressure at any given moment during the exhalation phase (e.g., also due to the patient airway resistance). Thus, measuring the pressure at the patient's mouth (or another location along the flow path between the ventilator and the patient's mouth) during the inhalation or exhalation phase does not provide an accurate estimate of the patient lung pressure. Therefore, patient lung pressure cannot be measured by simply placing a pressure sensor on the patient connection at the patient's mouth.

[0007] In some circumstances, patient lung pressure can be assessed using a hold maneuver immediately following the inspiration phase. During the hold maneuver, the exhalation valve in the patient circuit is held in a closed position following the conclusion of the inspiration phase. This creates a zero-flow condition in the patient circuit during which no air flows into or out of the patient's lungs. Because zero flow exists, patient airway resistance does not affect the pressure in the patient's lungs. Thus, the pressure measured during the zero-flow condition (known as the "plateau pressure") along the flow path between the ventilator and the patient represents the patient's peak lung pressure.

[0008] However, not all ventilator systems incorporate an exhalation valve in the patient circuit that can be selectively closed to achieve and maintain a zero-flow condition. The present technology therefore provides a system and method for measuring patient lung pressure, such as in systems without an actively controlled exhalation valve. In particular, as described in detail below, the present technology automatically controls the operation of the insufflator to achieve a zero-flow condition during a hold maneuver, allowing the plateau pressure, and therefore the patient lung pressure, to be measured.

[0009] Assessing the plateau pressure is useful in setting ventilation therapy parameters. A plateau pressure that is too high during or at the end of a holding maneuver (e.g., above about 20 cmH2O, above about 25 cmH2O, above about 30 cmH2O, or another patient-specific parameter) may indicate that the patient's lungs are overinflated, which may cause barotrauma and lead to lung damage. A plateau lung pressure that is too low during or at the end of a holding maneuver may indicate that the patient is not receiving enough air during breathing. Thus, ventilation therapy parameters can be selected to achieve a patient lung pressure (e.g., plateau pressure) at the end of the inspiration phase that is within a clinically acceptable range for a particular patient.

[0010] Patient static compliance (e.g., the distensibility / ability of the lungs to stretch or expand in volume over a given pressure) and patient airway resistance (e.g., the resistance to airflow generated by the patient's anatomy) can also be useful in setting ventilation therapy parameters and / or monitoring the patient's condition. For example, low patient lung compliance may indicate that the patient has "stiff" or fibrotic lungs, while high patient lung compliance may indicate that the patient's lungs are overly compliant. However, like patient lung pressure, patient static compliance and patient airway resistance cannot be measured directly during pressure-controlled or volume-controlled ventilation. However, as described in detail below, the present technology can utilize measured patient lung pressure values ​​to calculate patient compliance and patient airway resistance. [Brief description of the drawings]

[0011] Many aspects of the present technology can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Emphasis instead is placed upon clearly illustrating the principles of the present technology.

[0012] [Figure 1] FIG. 1 is a schematic diagram of a ventilator system configured in accordance with an embodiment of the present technology.

[0013] [Diagram 2] FIG. 2 illustrates flow waveform graphs, pressure waveform graphs, and insufflator velocity graphs over three respiratory cycles generated in accordance with an embodiment of the present technology.

[0014] [Diagram 3] FIG. 3 is an expanded view of a portion of the flow waveform graph, pressure waveform graph, and insufflator velocity graph of FIG. 2 illustrating a hold maneuver for measuring patient lung pressure in accordance with an embodiment of the present technology.

[0015] [Figure 4A] FIG. 4A is a schematic diagram illustrating a ventilator control module configured to perform a hold maneuver to measure patient lung pressure for use with an active patient circuit in accordance with an embodiment of the present technology.

[0016] [Figure 4B] FIG. 4B is a schematic diagram illustrating a ventilator control module configured to perform a hold maneuver to measure patient lung pressure for use with a passive patient circuit in accordance with an embodiment of the present technology.

[0017] [Diagram 5] FIG. 5 is a schematic diagram of a ventilator configured to perform a hold maneuver to measure patient lung pressure and configured in accordance with an embodiment of the present technology.

[0018] [Figure 6] FIG. 6 is a flowchart of a method for measuring patient lung pressure in a patient during ventilation in accordance with an embodiment of the present technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Detailed Description Further aspects and advantages of the present devices, methods and uses will become apparent from the ensuing description, which is given by way of example only.

[0020] The terminology used in the description presented below is intended to be interpreted in its broadest reasonable manner, even when used in conjunction with the detailed description of a specific embodiment of the present technology. Certain terms may be further emphasized below, however, any terminology intended to be interpreted in any limited manner will be clearly and specifically defined as such in this detailed description section. In addition, the present technology may also include other embodiments that are within the scope of the examples but are not described in detail with respect to Figures 1-6.

[0021] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the technology. Thus, appearances of the phrases "in one embodiment" or "in one embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, particular features or characteristics may be combined in any suitable manner in one or more embodiments.

[0022] References throughout this specification to relative terms such as, for example, "generally," "approximately," and "about" are used herein to mean ±10% of the stated value. The term "substantially" or grammatical variations thereof refers to at least about 50%, e.g., 75%, 85%, 95%, or 98%.

[0023] FIG. 1 is a schematic diagram of a ventilation system 100 ("system 100") configured in accordance with an embodiment of the present technology for providing ventilation therapy to a patient 102. System 100 includes a ventilator 110, a patient circuit 106, and a patient connection 104. Ventilator 110 can be coupled to patient 102 via patient circuit 106 and patient connection 104. For example, patient circuit 106 can include a conduit or lumen (e.g., tubing) for transporting gas to and / or from patient 102. Patient circuit 106 can include a passive patient circuit or an active patient circuit, such as those described in U.S. Patient Nos. 10,518,059 and 10,105,509, the disclosures of which are incorporated herein by reference in their entireties and for all purposes. The patient connection 104 can be any suitable interface that is coupled to the patient circuit 106 for delivering gas to the patient 102, such as a full rebreather mask, a partial rebreather mask, a nasal mask, a mouthpiece, a tracheal tube, or the like.

[0024] The ventilator 110 may include a ventilation assembly 120 having an insufflator 122 for providing inhaled gas (e.g., "air 126") to the patient 102. The air 126 is received by the ventilator 110 via a patient air intake 124 that is coupled to the ventilation assembly 120. Although identified as "air," one skilled in the art will understand that the air 126 may include ambient air or pressurized air obtained from any source external to the ventilator 110. The air 126 may also optionally include enriched oxygen as described in U.S. Pat. Nos. 10,245,406 and 10,315,002, the disclosures of which are incorporated herein by reference in their entireties and for all purposes.

[0025] The insufflator 122 controls the flow rate of air 126 to the patient 102. For example, during the inspiratory phase of the breathing cycle, the insufflator 122 can direct air 126 to the patient 102 via a flow path that includes the patient air intake 124, the ventilation assembly 120, the main ventilator connection 116, the patient circuit 106, and the patient connection 104. The operation of the insufflator during the expiratory phase depends on the mode of therapy provided by the system 100. For example, in an embodiment in which the system 100 is configured to provide positive end-expiratory pressure (PEEP or EPAP) therapy, the insufflator 122 also directs air 126 to the main ventilator connection 116 during the expiratory phase. This maintains positive pressure in the patient's airway during the expiratory phase, which may reduce the risk that the patient's lungs will collapse during exhalation. In some embodiments, the ventilator 110 may receive exhaled gases during the expiratory phase. The ventilator 110 may exhaust exhaled gases via the patient air intake 124 and / or may have a separate outlet port (not shown) for ventilating the patient exhaled gases.

[0026] The system 100 may further include one or more sensors, such as a flow sensor 118 and / or a pressure sensor 119. The flow sensor 118 may be positioned at any suitable location along the flow path between the patient air intake 124 and the patient connection 104. For example, in the illustrated embodiment, the flow sensor 118 is positioned between the patient air intake 124 and the ventilation assembly 120. Regardless of its location, the flow sensor 118 is configured to measure the flow rate of gas (e.g., in liters per minute, or LPM) between the patient air intake 124 and the patient 102. Similarly, the pressure sensor 119 may be positioned at any suitable location to measure pressure in the flow path between the patient air intake 124 and the patient 102. For example, the pressure sensor 119 may be positioned in the ventilator 110 between the ventilation assembly 120 and the main ventilator connection 116. In embodiments in which the patient circuit 106 is an active patient circuit, the system 100 may optionally include a secondary flow sensor 105 proximate to the patient 202 .

[0027] The ventilator 110 may further include a control module 112 for controlling the operation of the ventilator 110. In particular, the control module 112 may generate one or more signals for controlling the operation of the ventilation assembly 120, such as to automatically control the speed of the insufflator 122 (e.g., to provide a suitable flow rate of air 126 to the patient and / or to synchronize the operation of the ventilator 110 with the patient's breathing). For example, the control module 112 may instruct the insufflator 122 to operate at a first rate during the inspiratory phase of a breath and at a second rate, slower than the first rate, during the expiratory phase of a breath. The control module 112 may also receive signals from the flow sensor 118 and / or the pressure sensor 119. For example, in volume-controlled ventilation, the control module 112 may receive a signal from the flow sensor 118 during the inspiratory phase and automatically and in real time calculate the volume of air delivered to the patient during the inspiratory phase based on the received signal. Once the calculated volume reaches a predetermined threshold, the control module 112 can control the ventilation assembly 120 to initiate the expiratory phase (e.g., by slowing down the speed of the insufflator 122). Still further, as will be described in detail with respect to Figures 2-6, the control module 112 can also automatically control the speed of the insufflator 122 based on a signal received from the flow sensor 118 to achieve a zero flow condition in the flow path during a hold maneuver in order to measure patient lung pressure.

[0028] The ventilator 110 may further include a user interface 114. The user interface 114 is configured to accept input from a user (e.g., a patient, a caregiver, a clinician, or other user associated with the patient 102) and provide the input to the control module 112. The inputs accepted via the user interface 114 may include ventilator settings, parameters of operation, modes of operation, and the like. In certain examples, as described in more detail with respect to FIG. 5, a user may initiate a hold maneuver using the user interface 114 to measure patient lung pressure. The user interface 114 may further be configured to display information to the user and / or patient, including selected ventilator settings, parameters of operation, modes of operation, physiological parameters, and the like. The user interface 114 may be any suitable user interface known in the art, such as a touch screen having a digital display of ventilator settings and operating parameters.

[0029] The system 100 may optionally include additional features and functions other than those described above. For example, the system 100 may include one or more of an oxygen assembly for providing supplemental oxygen to the patient 102, a cough assist assembly for providing cough assistance to the patient 102, a nebulizer assembly for providing drug therapy to the patient, a suction assembly for providing suction to the patient 102, or the like. In some embodiments, one or more of the aforementioned assemblies (e.g., a cough assist assembly) may be integrated into the ventilator 110 such that the system 100 may provide multiple respiratory therapies to the patient 102 without disconnecting the patient from the patient circuit 106. Additional features of ventilators suitable for use with the present technology are described in U.S. Pat. No. 9,956,371, the disclosure of which is incorporated herein by reference in its entirety and for all purposes.

[0030] As described below with respect to Figures 2-6, system 100 can be used to measure and / or calculate patient lung pressure, patient static compliance, and / or patient airway resistance during mechanical ventilation. In particular, patient lung pressure can be measured by controlling operation of insufflator 122 to reduce net flow in system 100 to zero following an inspiration phase. Patient static compliance and patient airway resistance can be calculated using the measured patient lung pressure.

[0031] 2 includes a first graph 210 showing a representative flow waveform over three breathing cycles 200a-c during volume-controlled ventilation (e.g., using the system 100 shown in FIG. 1), a second graph 220 showing a representative pressure waveform over the same three breathing cycles 200a-c, and a third graph 230 showing the insufflator (e.g., the insufflator 122 shown in FIG. 1) speed over the same three breathing cycles 200a-c. The first cycle 200a and the third cycle 200c are standard breathing cycles having an inspiratory phase I immediately followed by an expiratory phase E. In the first cycle 200a and the third cycle 200c, the flow rate transitions from a positive value during inspiration phase I to a negative value during expiration phase E, the pressure rises during inspiration phase I and drops during expiration phase E, and the insufflator has a burst of velocity during inspiration phase I and drops to a consistent level during expiration phase E to maintain positive end-expiratory pressure.

[0032] Unlike the first and third cycles 200a and 200c, the second cycle 200b includes a hold maneuver that is used to measure peak patient lung pressure (e.g., plateau pressure) according to an embodiment of the present technology. FIG. 3 is an expanded view of the second cycle 200b showing the hold maneuver, with the other cycles omitted for clarity. Like the first and third cycles 200a and 200c, the second cycle 200b includes an inspiratory phase I and an expiratory phase E. However, the second cycle 200b also includes a zero-flow phase F between the inspiratory phase I and the expiratory phase E. During the zero-flow phase F, the insufflator is set (e.g., automatically set) to a speed that achieves and maintains zero flow in the flow path between the patient air intake 124 and the patient 102, as described in detail below. Because the flow rate is zero, during the zero-flow phase F the pressure generally plateaus at a value below the maximum pressure observed at the end of the inspiration phase, but above the baseline pressure observed at the end of the expiration phase (P in FIG. 3 ). PLAT It is worth noting that the plateau pressure P in the flow channel during the zero flow phase F PLAT is equal to, or at least approximately equal to, the pressure in the patient's lungs. This is because, with the flow rate set to zero, the effects of any patient airway resistance and patient circuit resistance are negated and therefore have no effect on the pressure. Thus, the pressure measured anywhere along the flow path (e.g., at the ventilation assembly 120, along the patient circuit 106, or at the patient connection 104) is equal to the patient lung pressure. Thus, the plateau pressure P, measured during and / or at the end of the zero-flow phase F, is PLAT is equal to, or at least approximately equal to, the patient lung pressure regardless of where the measurement is taken.

[0033] The third graph 230c illustrates operation of the insufflator 122 to maintain zero flow during a zero flow phase F (e.g., no gas is flowing into or out of the patient's lungs). It is important to note that the insufflator 122 cannot simply be turned off or even returned to its baseline speed to achieve zero flow. If the insufflator 122 were turned off immediately after the inspiration phase I, the patient's lungs would contract and air would flow out of the patient's lungs and into the patient circuit, resulting in a negative flow (e.g., flow toward the ventilation assembly 120). If the insufflator 122 were returned to its baseline speed immediately after the inspiration phase I, such as in the first and third cycles 200a and 200c, the patient's lungs would still contract during a normal expiration event and air would flow out of the patient's lungs and into the patient circuit, also resulting in a negative flow. If the insufflator 122 is maintained at or near that speed during inspiration phase I, it will continue to move air into the patient's lungs, resulting in a positive flow rate (e.g., flow toward the patient). Thus, to achieve zero flow, the insufflator 122 operates at an intermediate speed during zero flow phase F, which is between its peak speed during inspiration phase I and its baseline speed during expiration phase E.

[0034] In particular, the system 100 can measure the flow rate (e.g., via the flow sensor 118) and automatically control the insufflator 122 based on the measured flow rate to achieve and maintain a zero-flow state. For example, FIG. 4A is a flow chart illustrating a first ventilator control module 112a configured to automatically control the speed of the insufflator for use with an active patient circuit and achieve a zero-flow state during a hold maneuver. For a hold maneuver, a flow rate reference value (e.g., a target flow rate) is set to zero. Based on the flow rate reference value and the pressure measured at the insufflator outlet, the control module 412a can estimate an insufflator speed suitable for achieving the flow rate reference value (e.g., using a look-up table having a predetermined correlation between pressure, flow rate, and insufflator speed). The first PI controller can also compare the measured flow rate with the flow rate reference value and determine whether the flow rate is at the flow rate reference value. The second PI controller can automatically control the speed of the insufflator to the estimated speed (e.g., by controlling the duty cycle of the motor driving the insufflator). Once the insufflator is operating at the estimated speed, the first PI controller can further fine-tune the insufflator speed to achieve and maintain the flow rate reference value.

[0035] 4B is a flow chart illustrating a second ventilator control module 112b configured to automatically control the insufflator speed for use with a passive patient circuit and achieve a zero-flow condition during a hold maneuver. The second ventilator control module 112b may be substantially similar to the first ventilator control module 112a, described above with respect to FIG. 4B. However, unlike the first ventilator control module 112a, the second ventilator control module 112b uses a patient estimated flow rate to control the insufflator speed to account for any leaks in the passive patient circuit or at the patient connection.

[0036] As explained above, maintaining a zero-flow condition in system 100 following inspiration phase I causes the pressure in the flow path to equalize with the pressure in the patient's lungs. Thus, the pressure measured along the flow path during zero-flow phase F (e.g., plateau pressure) is equal to, or at least approximately equal to, the patient's lung pressure.

[0037] Once the patient pulmonary pressure is measured, the patient static compliance and the patient airway resistance can be calculated using modifications of the following equations, where P is pressure, Q is flow, and R is the patient pulmonary pressure. p is the patient airway resistance, and V t is the tidal volume, and C L is the patient lung compliance. [ka]

[0038] During the hold maneuver, pressure P is the patient lung pressure P L where flow rate Q is zero and patient airway resistance R p is therefore invalid. t is known based on the volume of air delivered to the patient during the inspiration phase. Therefore, patient static compliance can be calculated using the following equation: [ka] Once the patient static compliance has been calculated, the patient airway resistance can also be calculated.

[0039] In some embodiments, system 100 can automatically determine patient lung pressure, patient static compliance, and / or patient airway resistance once a hold maneuver is initiated. For example, control module 112 can include a computing module that automatically measures patient lung pressure during a hold maneuver and then automatically calculates patient static compliance and patient airway resistance based on the measured patient lung pressure. System 100 can then display (e.g., using user interface 114) the patient lung pressure, patient static compliance, and / or patient airway resistance.

[0040] 5 is a schematic diagram of the user interface 114 of the ventilator 110 of FIG. 1 illustrating a user-input hold operation control 550 (e.g., a button, switch, toggle, etc.) for initiating a hold maneuver. In operation, a user can activate (e.g., press) the hold operation control 550 to initiate a hold maneuver that maintains a zero-flow state to measure patient lung pressure. For example, when a user activates the hold operation control 550, the control module 112 (FIG. 1) can automatically control the operation of the insufflator 122 to achieve a zero-flow state within the system 100, as described above. In some embodiments, the hold maneuver continues for as long as the user activates (e.g., presses) the hold operation control 550, subject to a maximum hold period described below.

[0041] In some embodiments, the user interface 114 can display a pressure waveform graph 552 in real time. Thus, when the user activates the hold maneuver control 550, the user can simultaneously view the pressure waveform graph and ensure that the plateau pressure is achieved before releasing the hold maneuver control 550 and terminating the hold maneuver (hold maneuver pressure waveform not shown in FIG. 5). The user interface 114 can also display a most recently measured plateau pressure metric 554 and a most recently calculated static compliance metric 556.

[0042] The user can thus use the user interface 114 to initiate a hold maneuver and measure the patient lung pressure (e.g., on-demand measurements) at various times throughout the day. The duration of the hold maneuver can be preset (e.g., 1 second, 2 seconds, 3 seconds, 4 seconds, 5 seconds, or 6 seconds) or controlled by the user, as described above. For patient safety, the system 100 can include a maximum hold duration (e.g., 6 seconds) after which the system 100 reverts to standard ventilation even if the user keeps the hold maneuver control 550 activated. In some embodiments, the system 100 can automatically initiate a hold maneuver at preset intervals. For example, the system 100 can be programmed to initiate a hold maneuver once per day, twice per day, three times per day, four times per day, five times per day, six times per day, etc.

[0043] Although the above-described systems and techniques for measuring patient lung pressure and calculating patient static compliance and patient airway resistance have been described with respect to system 100, those skilled in the art will appreciate that the same techniques may be utilized with other ventilation systems that operate using an insufflator. Thus, the present technology is not limited to system 100.

[0044] The present technology further includes a method for measuring patient lung pressure. For example, FIG. 6 is a flow chart of a method 600 for measuring patient lung pressure in a patient during pressure-controlled or volume-controlled ventilation. The method 600 can begin in step 602 by operating a ventilator insufflator (e.g., insufflator 122 of system 100) at a first rate during the inspiratory phase of a breath. The first rate can be sufficient to direct gas from the ventilator to the patient through a flow path, which can include a patient circuit and a patient connection. During the inspiratory phase, gas is delivered at a flow rate sufficient to inflate the patient's lungs.

[0045] After the inspiratory phase and before the expiratory phase of the breath, the method 600 can continue in step 604 by operating the insufflator at a second speed that is less than the first speed to achieve a zero-flow condition in the flow path (e.g., to prevent the patient from exhaling). This can include, for example, measuring the flow rate of gas in the flow path (e.g., using flow sensor 118 of system 100) and automatically adjusting the speed of the insufflator based on the measured flow rate to achieve and maintain the zero-flow condition. The zero-flow condition can be maintained for about 1 second to about 6 seconds, such as for about 1 second, about 2 seconds, about 3 seconds, about 4 seconds, about 5 seconds, or about 6 seconds.

[0046] The method 600 further includes measuring a plateau pressure during the zero-flow state in step 606. This may include measuring the pressure using, for example, a pressure sensor located in the ventilator. Notably, as explained above, the plateau pressure measured during the zero-flow state is equal to, or at least approximately equal to, the patient lung pressure. The measured plateau pressure may thus be displayed to the user as the patient lung pressure. The patient static compliance may also be calculated using the measured patient lung pressure, as explained above. Similarly, the patient airway resistance may be calculated using the calculated static compliance, as also explained above. After the plateau pressure is measured in step 606, the method 600 may continue by operating the insufflator at a third speed, which is less than the second speed, and allowing the user to exhale gas delivered during the inspiratory phase of the breath. EXAMPLES

[0047] Several aspects of the present technology are described in the following examples. 1. A method for measuring patient pulmonary pressure in a patient during ventilation using a ventilator connected to the patient by a patient circuit and a patient connection, the method comprising: operating an insufflator of the ventilator at a first speed during an inspiratory phase of a breath to direct gas from the ventilator to the patient along a flow path that includes a patient circuit and a patient connection; operating the insufflator at a second speed less than the first speed after the inspiratory phase and before the expiratory phase of the breath to achieve a zero flow condition in the flow path during which gas is neither flowing into nor flowing out of the patient's lungs; measuring a plateau pressure in the flow path during a zero flow condition, the measured plateau pressure being equal to or approximately equal to the patient's pulmonary pressure; A method comprising: 2. Operating the insufflator at a second speed, less than the first speed, to achieve a zero flow condition; Measuring a gas flow rate in the flow path via a flow sensor; Automatically adjusting the insufflator speed based on the measured gas flow to achieve and maintain a zero flow condition. The method of Example 1, comprising: 3. The method of example 2, wherein the flow sensor is positioned within the ventilator. 4. The method of example 2, wherein the flow sensor is positioned in the patient circuit. 5. The method of any of Examples 1-4, wherein measuring the plateau pressure in the flow path includes measuring the plateau pressure using a pressure sensor positioned in the ventilation device. 6. The method of any of Examples 1-5, wherein operating the insufflator at the second speed includes maintaining a zero flow condition for about 1 second to about 6 seconds. 7. The method of any of Examples 1-6, further comprising automatically calculating patient static compliance based on the measured plateau pressure. 8. The method of example 7, further comprising automatically calculating patient airway resistance based at least in part on the calculated patient static compliance. 9. After the zero-flow condition is achieved and during the expiratory phase of the breath, operating the insufflator at a third speed, the third speed being less than the second speed. The method of any of Examples 1-8, further comprising: 10. A ventilation system comprising: a ventilation assembly having an insufflator configured to control a flow of gas to a patient; A control module configured to control the insufflation device, the control module comprising: one or more processors; a memory storing instructions for performing a hold operation to measure patient lung pressure, the instructions, when executed by the one or more processors, to cause the ventilator system to: operating the insufflator at a first speed during an inspiratory phase of a breath to direct gas from the ventilator to the patient along a flow path that includes a patient circuit and a patient connection; reducing the speed of the insufflator after the inspiratory phase and before the expiratory phase of the breath to achieve a zero flow condition in the flow path during which gas is neither flowing into nor flowing out of the patient's lungs. A memory and a control module including: a pressure sensor configured to measure a plateau pressure in the flow path during a zero flow condition, the measured plateau pressure being equal to or approximately equal to a patient's lung pressure; A ventilation system comprising: 11. Further comprising a flow sensor configured to measure a gas flow rate in the flow path, and the operation of reducing the speed of the insufflator to achieve a zero flow condition further comprises: receiving a signal from a flow sensor indicative of a gas flow rate in the flow path; automatically adjusting the speed of the insufflator based on the received signal to achieve and maintain a zero flow condition; The system of Example 10, comprising: 12. The system of example 10 or 11, wherein the zero flow state is maintained for about 1 second to about 6 seconds. 13. The system of any of Examples 10-12, wherein the operations further include automatically calculating patient static compliance based on the measured plateau pressure. 14. The system of example 13, wherein the operations further include automatically calculating patient airway resistance based at least in part on the calculated patient static compliance. 15. A system as described in any of Examples 10-14, wherein the operations further include further reducing the speed of the insufflator after the zero flow state is achieved and during the exhalation phase to allow patient exhalation. 16. A system described in any of Examples 10-15, further comprising a user display configured to display the plateau pressure measured during the zero flow condition. 17. The system of any of Examples 10-16, further comprising a user input for selectively initiating the operation of a hold operation. conclusion

[0048] The systems and methods described herein can be implemented with and / or distributed across computing architectures. For example, many of the systems described herein include a memory, which stores data, software modules, instructions, or the like. The memory described herein can include one or more of various hardware devices for volatile and non-volatile storage, and can include both read-only and writeable memory. For example, the memory can include random access memory (RAM), various caches, CPU registers, read-only memory (ROM), and writeable non-volatile memory, such as flash memory, hard drives, floppy disks, CDs, DVDs, magnetic storage devices, tape drives, device buffers, and the like. Memory is not a propagating signal that is separate from the underlying hardware, and memory is therefore non-transient. In some embodiments, memory is a non-transient computer-readable storage medium, which stores, for example, programs, software, data, or the like.

[0049] As those skilled in the art will understand from the disclosure herein, various components of the system described above can be omitted without departing from the scope of the technology. Similarly, additional components not explicitly described above can be added to the system without departing from the scope of the technology. For example, while specific embodiments of the technology are described herein for illustrative purposes, it should be understood that well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the technology. Also, while specific embodiments of the technology and examples thereof are described above for illustrative purposes, various equivalent modifications are also possible within the scope of the technology, as those skilled in the art will recognize. For example, while steps are presented in a given order, alternative embodiments may perform steps in a different order. The various embodiments described herein can also be combined to provide further embodiments. Thus, the technology is not limited to the configurations expressly identified herein, but rather encompasses variations and modifications of the systems and methods described.

[0050] Moreover, although advantages associated with some embodiments of the present technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments necessarily exhibit such advantages to fall within the scope of the present technology. Thus, the present disclosure and associated technology may encompass other embodiments not explicitly shown and described herein.

[0051] Unless the context clearly requires otherwise, throughout the description and examples, the words "comprise", "comprising", and the like, should be interpreted in an inclusive or exhaustive sense, as opposed to an exclusive sense, i.e., "including, but not limited to". As used herein, the terms "connected", "coupled", or any variant thereof, mean any connection or coupling, either direct or indirect, between two or more elements, and the coupling of the connections between the elements can be physical, logical, or a combination thereof. In addition, the words "herein", "above", "below", and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above detailed description using singular or plural numbers may also include plural or singular numbers, respectively. As used herein, the phrase "and / or," such as in "A and / or B," refers to A only, B only, and A and B. Furthermore, where a specific completeness to which an embodiment has known equivalents in the art to which it pertains is set forth herein, such known equivalents are deemed to be incorporated herein as if individually set forth.

Claims

1. A non-transitory computer readable medium storing instructions for measuring patient pulmonary pressure within a patient during ventilation, the instructions being executable by a control module associated with a ventilator that delivers the ventilation to the patient, the instructions, when executed, performing: operating an insufflator of the ventilator at a first speed during an inspiratory phase of a breath to direct gas from the ventilator to the patient along a flow path that includes a patient circuit and a patient connection; operating the insufflator at a second speed after the inspiratory phase and before the expiratory phase of the breath to achieve a zero flow condition in the flow path during which gas is neither flowing into nor flowing out of the patient's lungs; receiving a measurement of a plateau pressure in the flow path during the zero flow condition, the measured plateau pressure being equal to or approximately equal to the patient's lung pressure; A non-transitory computer readable medium that causes the control module to perform operations including:

2. The operation of operating the blower at the second speed to achieve the zero flow state comprises: receiving a measurement of gas flow rate in the flow path via a flow sensor; automatically adjusting the speed of the insufflator based on the measured gas flow to achieve and maintain the zero flow condition.

2. The non-transitory computer readable medium of claim 1 , comprising:

3. The non-transitory computer readable medium of claim 2 , wherein the flow sensor is positioned within the ventilator.

4. The non-transitory computer readable medium of claim 2 , wherein the flow sensor is positioned in the patient circuit.

5. 10. The non-transitory computer-readable medium of claim 1, wherein the act of measuring the plateau pressure in the flow path comprises measuring the plateau pressure using a pressure sensor positioned in the ventilator.

6. 10. The non-transitory computer readable medium of claim 1, wherein operating the insufflator at the second speed comprises maintaining the zero-flow condition for about 1 second to about 6 seconds.

7. The non-transitory computer-readable medium of claim 1, wherein the operation further includes automatically calculating patient static compliance based on the measured plateau pressure.

8. The non-transitory computer-readable medium of claim 7, wherein the operations further include automatically calculating patient airway resistance based at least in part on the calculated patient static compliance.

9. The non-transitory computer-readable medium of claim 1, wherein the operations further include operating the blower at a third speed after the zero flow state is achieved and during the expiratory phase of the breath, the third speed being less than the second speed.

10. 1. A ventilation system comprising: a ventilation assembly having an insufflator configured to control a flow of gas to a patient; A control module configured to control the insufflation machine, the control module comprising: one or more processors; a memory storing instructions for performing a hold operation to measure patient lung pressure, the instructions, when executed by the one or more processors, comprising: operating the insufflator at a first speed during an inspiratory phase of a breath to direct gas from the ventilator to the patient along a flow path including a patient circuit and a patient connection; controlling a speed of the insufflator after the inhalation phase and before the exhalation phase of the breath to achieve a zero flow condition in the flow path during which gas is neither flowing into nor flowing out of the patient's lungs. a memory for causing the ventilator system to perform operations including a control module including: a pressure sensor configured to measure a plateau pressure in the flow path during the zero flow condition, the measured plateau pressure being equal to or approximately equal to the patient's lung pressure; A ventilation system comprising:

11. a flow sensor configured to measure a gas flow rate in the flow path; The operation of controlling the speed of the insufflator to achieve a zero flow condition further comprises: receiving a signal from the flow sensor indicative of a gas flow rate in the flow path; automatically adjusting the speed of the insufflator based on the received signal to achieve and maintain the zero flow condition. The system of claim 10 , comprising:

12. The system of claim 10, wherein the zero-flow condition is maintained for about 1 second to about 6 seconds.

13. The system of claim 10 , wherein the operations further include automatically calculating a patient static compliance based on the measured plateau pressure.

14. The system of claim 13 , wherein the operations further include automatically calculating a patient airway resistance based at least in part on the calculated patient static compliance.

15. 11. The system of claim 10, wherein the operations further include further reducing a speed of the insufflator after the zero-flow condition is achieved and during the exhalation phase to allow patient exhalation.

16. The system of claim 10 , further comprising a user display configured to display the measured plateau pressure during the zero flow condition.

17. The system of claim 10 , further comprising a user input for selectively initiating operation of the hold operation.

18. The non-transitory computer-readable medium of claim 1, wherein the second speed is less than the first speed.

19. The non-transitory computer-readable medium of claim 1, wherein the operation of operating the blower at the second speed to achieve the zero flow condition includes adjusting the second speed to maintain the zero flow condition.

20. The system described in claim 10, wherein the operation of controlling the speed of the blower to achieve the zero flow condition includes reducing the speed of the blower.

21. The system described in claim 10, wherein the operation of controlling the speed of the blower to achieve the zero flow condition includes adjusting the speed of the blower during the hold operation to maintain the zero flow condition.

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