Control scheme for mechanical cough

Abstract

The present disclosure relates to a control scheme for a system including a mechanical cough function and a corresponding method. In addition to numerous benefits, the present disclosure can reduce, if not eliminated, retrograde displacement of secretions within the patient's airway during the mechanical cough mode.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to control schemes and corresponding methods for systems including mechanical coughing functionality. BACKGROUND

[0002] Respiratory ventilation can be characterized as including both an inspiration phase and an expiration phase. During the inspiration phase, inspiratory gas is drawn into the lungs, while during the expiration phase, expiratory gas is expelled from the lungs.

[0003] Mechanical ventilators are used to assist respiration. Conventional ventilators typically push inspiratory gas, including oxygen, into a patient's lungs. Many patients using a ventilator also require other types of assistance related to treating and maintaining their airways and lungs. For example, some patients can use a nebulizer to deliver medication to their lungs and / or airways. In addition, some patients can require assistance in clearing secretions from their lungs and / or airways.

[0004] Some patients can also require coughing assistance. To use some known coughing assistance devices, which can be referred to as mechanical insufflation-exsufflation (MIE) devices, a patient must disconnect from a mechanical ventilation and connect to a separate device. After performing a coughing assistance or MIE maneuver, the patient must disconnect from the MIE device and reconnect to the mechanical ventilation. Typically, suctioning of the patient's airway is also performed after the patient has disconnected from the MIE device and reconnected to the mechanical ventilation to remove secretions that were not adequately cleared from the patient's airway during the MIE maneuver. SUMMARY

[0005] In some aspects, the technology described herein relates to a system comprising: a respiratory device configured to deliver a fluid to a patient, wherein the respiratory device is operable in a mechanical coughing mode; and a controller configured to issue one or more commands to the respiratory device such that, during an insufflation phase of the mechanical coughing mode, (i) a flow rate of the fluid conducted by the respiratory device to the patient is substantially constant throughout the insufflation phase, or (ii) the flow rate of the fluid conducted by the respiratory device to the patient gradually increases throughout the insufflation phase.

[0006] In some aspects, the technology described herein relates to a system wherein, during an insufflation phase of the mechanical coughing mode, a flow rate of the fluid conducted by the respiratory device to the patient is substantially constant throughout the insufflation phase.

[0007] In some aspects, the technology described herein relates to a system wherein, during an insufflation phase of the mechanical coughing mode, a flow rate of the fluid conducted by the respiratory device to the patient gradually increases throughout the insufflation phase.

[0008] In some aspects, the technology described herein relates to a system, wherein the controller is configured to issue one or more commands to the respiratory device such that, during the insufflation phase of the mechanical coughing pattern, the pressure of the fluid conducted by the respiratory device to the patient substantially follows a line having a constant positive slope.

[0009] In some aspects, the technology described herein relates to a system, wherein the controller is configured to issue one or more commands to the respiratory device such that, during the insufflation phase of the mechanical coughing pattern, the pressure of the fluid conducted by the respiratory device to the patient oscillates relative to the line.

[0010] In some aspects, the technology described herein relates to a system, wherein the controller is configured to issue one or more commands to the respiratory device such that, during the insufflation phase of the mechanical coughing pattern, the flow rate of the fluid conducted by the respiratory device to the patient substantially follows a line having a constant positive slope.

[0011] In some aspects, the technology described herein relates to a system, wherein the controller is configured to issue one or more commands to the respiratory device such that, during the insufflation phase of the mechanical coughing pattern, the flow rate of the fluid conducted by the respiratory device to the patient oscillates relative to the line.

[0012] In some aspects, the technology described herein relates to a system, further comprising: a connection; and a patient interface connected to the connection, wherein the respiratory device is configured to conduct the flow to the patient via the connection through the patient interface.

[0013] In some aspects, the technology described herein relates to a system, further comprising: a pressure sensor; and a flow rate sensor, wherein the controller is configured to interpret a signal from the pressure sensor as the pressure of the fluid conducted by the respiratory device to the patient and to interpret a signal from the flow rate sensor as the flow rate of the fluid conducted by the respiratory device to the patient.

[0014] In some aspects, the technology described herein relates to a system, wherein the respiratory device is operable in a ventilation mode.

[0015] In some aspects, the technology described herein relates to a system, wherein the respiratory device is a ventilator and the controller is configured to issue one or more commands to the ventilator such that the mechanical coughing pattern is initiated periodically.

[0016] In some aspects, the technology described herein relates to a system, wherein the respiratory device is a ventilator or a mechanical insufflation-exsufflation device.

[0017] In some aspects, the technology described herein relates to a method comprising: conducting fluid to a patient using a respiratory device operating in a mechanical coughing mode such that, during an insufflation phase of the mechanical coughing mode, (i) a flow rate of the fluid conducted to the patient by the respiratory device is substantially constant throughout the insufflation phase, or (ii) the flow rate of the fluid conducted to the patient by the respiratory device gradually increases throughout the insufflation phase.

[0018] In some aspects, the technology described herein relates to a method in which a pressure of the fluid conducted to the patient by the respiratory device substantially follows a line having a constant positive slope.

[0019] In some aspects, the technology described herein relates to a method in which a pressure of the fluid conducted to the patient by the respiratory device oscillates relative to the line described above.

[0020] In some aspects, the technology described herein relates to a method in which a flow rate of the fluid conducted to the patient by the respiratory device substantially follows a line having a constant positive slope.

[0021] In some aspects, the technology described herein relates to a method in which a flow rate of the fluid conducted to the patient by the respiratory device oscillates relative to the line described above.

[0022] In some aspects, the technology described herein relates to a method in which the respiratory device is configured to conduct fluid to the patient via a connection through a patient interface.

[0023] In some aspects, the technology described herein relates to a method in which the controller issues one or more commands to the respiratory device in response to a signal from a pressure sensor or a flow rate sensor.

[0024] In some aspects, the technology described herein relates to a method in which the respiratory device is operable in a ventilation mode. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a block diagram illustrating an example system including a ventilator for use with a human patient.

[0026] FIG. 2A is a plot of pressure versus time according to a known control scheme.

[0027] FIG. 2B is a plot of flow rate versus time according to the known control scheme.

[0028] Figure 3A is a plot of pressure versus time according to a first control scheme of the present disclosure.

[0029] Figure 3B is a plot of flow rate versus time according to the first control scheme.

[0030] Figure 4A is a plot of pressure versus time for a second control scheme according to the present disclosure.

[0031] Figure 4B is a plot of flow rate versus time for the second control scheme.

[0032] Figure 5A is a plot of pressure versus time for a third control scheme according to the present disclosure.

[0033] Figure 5B is a plot of flow rate versus time for the third control scheme.

[0034] Figure 6A is a plot of pressure versus time for a fourth control scheme according to the present disclosure.

[0035] Figure 6B is a plot of flow rate versus time for the fourth control scheme. DETAILED DESCRIPTION

[0036] The present disclosure relates to control schemes and corresponding methods for systems that include a mechanical coughing function. Among other benefits, the present disclosure can reduce, if not eliminate, the retrograde displacement of secretions within a patient’s airway during mechanical insufflation-exsufflation (MIE), which is referred to herein as mechanical coughing and sometimes as mechanical assisted coughing.

[0037] Figure 1 is a block diagram schematically illustrating an example system 10 that includes a breathing apparatus 100 having an integrated mechanical coughing function for use by a patient 102, who in examples of the present disclosure is a human patient. In Figure 1 , the breathing apparatus is incorporated into a larger apparatus that also functions as a ventilator. While a ventilator is shown, the present disclosure extends to other breathing apparatuses that are not incorporated into a ventilator, including a dedicated mechanical insufflation-exsufflation (MIE) apparatus. Further, while a particular ventilator is described below and shown in Figure 1 , the present disclosure extends to other ventilator configurations.

[0038] The breathing apparatus 100 can be configured to provide both conventional volume control ventilation and pressure control ventilation. The breathing apparatus 100 has an optional multi-lumen conduit connection 103, a main ventilator connection 104, and a patient oxygen outlet 105. The patient 102 has a patient interface or connection 106 (e.g., a tracheal tube, a nasal mask, an interface tube, etc.) that can be connected to the main ventilator connection 104 and / or the patient oxygen outlet 105 through a patient circuit 110.

[0039] As will be described below, the patient circuit 110 can be implemented as an active patient circuit or a passive patient circuit. Optionally, when the patient circuit 110 is implemented as an active patient circuit, the patient circuit 110 can include one or more ports 111 configured to connect to the optional multi-lumen catheter connection 103. The port(s) 111 allow one or more pressure signals 109 to flow between the optional multi-lumen catheter connection 103 and the patient circuit 110. The pressure signal(s) can be characterized as gas(es) obtained from a source of fluid (and / or gas) for which pressure is to be measured. The obtained gas(es) are at the same pressure as the source of fluid (and / or gas).

[0040] The primary respiratory device 100 connection 104 is configured to provide gas 112 including room air 114 optionally mixed with oxygen. Although identified as "room air," the room air 114 can include air obtained from any source external to the respiratory device 100. The gas 112 can be used as an inspiratory gas (during the inspiratory phase of respiration) or an insufflation gas used during the insufflation phase of a cough. The primary respiratory device 100 connection 104 is configured to receive gas 113, which can include expiratory gas exhaled by the patient 102 during the expiratory phase of a cough.

[0041] The air 114 is received by the respiratory device 100 via a patient intake 116. Oxygen, optionally mixed with the air 114, can be generated internally by the respiratory device 100 and / or received from an optional low-pressure oxygen source 118 (e.g., an oxygen concentrator) and / or an optional high-pressure oxygen source 120. When oxygen is generated internally, the respiratory device 100 can output an exhaust gas (e.g., a nitrogen-enriched gas 122) via an outlet vent 124. Optionally, the respiratory device 100 can include a low-pressure oxygen inlet 126 configured to couple to and receive optional low-pressure oxygen 128 from the optional low-pressure oxygen source 118. The respiratory device 100 can include an optional high-pressure oxygen inlet 130 configured to couple to and receive optional high-pressure oxygen 132 from the optional high-pressure oxygen source 120.

[0042] The patient oxygen outlet 105 is configured to provide a dose or pulse of oxygen 140 to the patient connection 106 (via the patient circuit 110) in synchronization with the patient's respiration. Unlike the gas 112 provided by the primary respiratory device 100 connection 104, the pulse of oxygen 140 does not include air 114.

[0043] The gases 112 and / or oxygen pulses 140 delivered to the patient circuit 110 are thereby conducted to the patient connection 106 as inspiratory or insufflation gases 108, which at least partially conduct those gases into the patient's lung(s) 142. Whenever the patient exhales during an expiratory phase of a breath or an expulsive phase of a cough, exhaled gases 107 enter the patient circuit 110 via the patient connection 106. Thus, the patient circuit 110 can contain one or more of the following gases: the gases 112 provided by the breathing apparatus 100, the oxygen pulses 140, and the exhaled gases 107. For ease of illustration, the gases within the patient circuit 110 will be referred to hereinafter as "patient gases."

[0044] Optionally, the breathing apparatus 100 includes a suction connection 150 configured to couple to an optional suction assembly 152. The breathing apparatus 100 can provide suction 154 to the optional suction assembly 152 via the optional suction connection 150. The suction assembly 152 can be configured to connect to the patient connection 106, a suction piece positionable within the patient connection 106, and / or a drain piece.

[0045] With reference to Figure 1 Optionally, the breathing apparatus 100 includes a nebulizer connection 160 configured to couple to an optional nebulizer assembly 162. The breathing apparatus 100 can provide gases 164 (e.g., air 114) to the optional nebulizer assembly 162 via the optional nebulizer connection 160. The optional nebulizer assembly 162 can be configured to connect to the patient circuit 110.

[0046] Optionally, the breathing apparatus 100 can include an outlet port 166 through which exhaust gases 167 can exit from the breathing apparatus 100.

[0047] The breathing apparatus 100 can be configured to be portable and powered by an internal battery (not shown) and / or an external power source (not shown), such as a conventional wall outlet.

[0048] The breathing apparatus 100 also includes a pressure sensor 170 and a flow rate sensor 172. The locations of the pressure sensor 170 and the flow rate sensor 172 are exemplary and not limiting. Moreover, while both a pressure sensor 170 and a flow rate sensor 172 are shown, the breathing apparatus 100 need not include both a pressure sensor 170 and a flow rate sensor 172, and in one embodiment includes one or the other of the pressure sensor 170 and the flow rate sensor 172.

[0049] The pressure sensor 170 and the flow rate sensor 172 are configured to generate signals that are respectively interpreted by the controller 180 as the pressure and flow rate of the fluid conducted to the patient 102. While Figure 1Only one of each of the pressure sensor 170 and the flow rate sensor 172 is shown, but the respiratory device 100 can include additional pressure and / or flow rate sensors. The controller 180 is configured to follow one or more of a plurality of control schemes and issue one or more commands to the respiratory device 100, and in particular to one or more components of the respiratory device 100, such as the motor of the compressor and / or one or more valves, to adjust the pressure and / or flow rate of the fluid conducted to the patient 102.

[0050] The controller 180 includes a memory connected to one or more processors. The memory is configured to store various tables, algorithms, and instructions executable by the processor(s). The processor(s) can be implemented by one or more microprocessors, microcontrollers, application specific integrated circuits ("ASICs"), digital signal processors ("DSPs"), combinations or sub-combinations thereof, and / or the like. The processor(s) can be integrated into a circuit that powers the processor(s), such as a conventional circuit board. The processor(s) can include internal memory and / or the memory can be coupled to the processor(s). The present disclosure is not limited by the specific hardware components used to implement the processor(s) and / or the memory.

[0051] The memory is a computer readable medium including instructions or computer executable components that are executed by the processor(s). The memory can be implemented using both temporary and / or non-temporary memory components. The memory can be coupled to the processor(s) by an internal bus.

[0052] The memory can include random access memory ("RAM") and read only memory ("ROM"). The memory contains instructions and data that control the operation of the processor(s). The memory can also include a basic input / output system ("BIOS") that contains the basic routines that help to transfer information between elements within the respiratory device 100.

[0053] Optionally, the memory can include internal and / or external memory devices, such as a hard disk drive, a floppy disk drive, and an optical storage device (e.g., CD-ROM, R / W CD-ROM, DVD, etc.). The respiratory device 100 can also include one or more I / O interfaces (not shown), such as a serial interface (e.g., RS-232, RS-432, etc.), an IEEE-488 interface, a universal serial bus ("USB") interface, a parallel interface, etc., for communicating with removable memory devices, such as a flash drive, an external floppy disk drive, etc. In an example, the controller 180 is disposed entirely within the respiratory device 100.

[0054] The processor(s) are configured to execute software that implements the processes and control schemes discussed herein, including interpreting information from the one or more sensors 170, 172 and issuing one or more corresponding commands to execute the control schemes discussed herein. Such software can be implemented by instructions stored in memory.

[0055] While Figure 1 particular embodiments of the respiratory device 100 have been shown in the Figure 1 embodiments shown in the

[0056] A known control scheme will now be described with reference to Figures 2A and 2B. Figures 2A and 2B represent a device, such as a ventilator or MIE device, conducting fluid to a patient when operating in a mechanical cough mode. In this disclosure, the term “fluid” when used herein to refer to fluid conducted by the device relative to the patient encompasses gas, such as air or patient gas, and any particles or other matter that can be entrained or suspended in that gas, such as water, medicament or secretions.

[0057] Figure 2A is a plot of pressure of fluid conducted by the device to the patient versus time, and Figure 2B is a plot of flow rate of fluid conducted by the device to the patient versus time during the same cycle.

[0058] Prior art devices conduct fluid to the patient following a pressure control line 200 by targeting a set pressure. The flow rate of fluid conducted to the patient follows line 202. Starting from an insufflation phase that occurs during a time period labelled insufflation time in Figures 2A and 2B, the prior art device starts conducting fluid to the patient at time T1 so that the pressure initially exhibits a relatively steep positive slope. The slope of the control line 200 gradually decreases while remaining positive until an intermediate time T i the set insufflation pressure is reached. In one example, the set insufflation pressure is set by a physician. Between times T i and T2, the pressure remains at the set insufflation pressure, T2 being the time at which the insufflation phase ends. When compared to the flow rate conducted to the patient between times T i and T2, the result of the steep initial pressure is a relatively high flow rate conducted to the patient between times T1 and T i The prior art device then completes the cycle by performing an exhalation phase, a pause phase which is optional, and then, if required, repeating the cycle until the secretions have been advanced within the airway to a point that can be removed via suction or natural drainage.

[0059] The present disclosure controls the breathing apparatus 100 in a mechanical coughing mode in which the fluid conducted to the patient 102 does not exhibit a relatively steep, sudden pressure and flow rate at the onset of the insufflation phase as in the prior art apparatus of Figures 2A and 2B. Rather, in the present disclosure, the controller 180 is configured to issue one or more commands to the breathing apparatus 100 such that the pressure of the fluid conducted to the patient 102 by the breathing apparatus 100 gradually increases throughout the insufflation phase of the mechanical coughing mode. An example control scheme will now be described.

[0060] In a first example control scheme, as shown in Figure 3A and Figure 3B the controller 180 is configured to issue one or more commands to the breathing apparatus 100 such that the pressure of the fluid conducted to the patient 102 by the breathing apparatus 100 during the insufflation phase of the mechanical coughing mode substantially follows a control line 300 having a constant positive slope. This approach has the effect that at the end of the insufflation, the flow of fluid conducted to the patient is maintained at substantially the lowest level required to reach the set pressure, thereby minimizing or eliminating movement of secretions towards the patient’s lungs during the insufflation phase.

[0061] In the present disclosure, the term “control line” is used to refer to a line that represents a target of active control of the breathing apparatus 100, as opposed to, for example, the line 302 in Figure 3B which is a line representing a change in another flow characteristic as a result of the breathing apparatus 100 actively following the control line 300. The control line can be embodied as an algorithm and / or lookup table on the software of the controller 180. In some embodiments, the control line is pressure, and in other embodiments, the control line is flow rate. The controller 180 is configured to interpret signals from one or both of the sensors 170, 172 and issue various commands to components of the breathing apparatus 100 to substantially follow the control line corresponding to a particular control scheme. The term “substantially follow”, when used in relation to the controller 180 controlling the breathing apparatus 100 in a manner that substantially follows a control line, is used to refer to the controller 180 actively attempting to follow the control line within acceptable deviations and tolerances in the art.

[0062] Continuing with the embodiments of Figure 3A and Figure 3B where the control line 300 relates to pressure, at time T1 the pressure is zero, and at time T2 the pressure is equal to the set insufflation pressure. Again, the set insufflation pressure can be set by a physician. Because the control line 300 has a constant positive slope, the pressure conducted to the patient 102 gradually increases at a constant rate throughout the insufflation phase. Thus, with reference to Figure 3BThe flow rate represented by line 302 is substantially constant between times T1 and T2, and presents a slope of zero. It should be noted that the slope of line 302 is based on the lung compliance of the particular patient, and can not always present a slope of zero. Moreover, in one example, the amplitude of line 302 is less than the flow rate in the prior art device of FIG. 2B. In Figure 3A and Figure 3B In, the patient 102 does not experience a variable flow rate, including an initially relatively large flow rate as shown in FIG. 2B, which reduces, if not eliminates, the likelihood of retrograde displacement of secretions during the insufflation phase. Retrograde displacement is the movement of secretions within the airway of the patient 102 in a direction toward the lungs 142 of the patient 102 and away from the respiratory device 100. In another aspect, forward displacement is movement toward the respiratory device 100. Unless otherwise described, the expelling and pausing phases of the present disclosure (again, the pausing phase is optional) are controlled substantially similar to their control in FIGS. 2A and 2B. If necessary, the cycle is repeated, and the secretions are naturally expelled or removed using suction.

[0063] Figure 4A and Figure 4B FIG. 2D illustrates another example control scheme. In this example, the controller 180 is configured to issue one or more commands to the respiratory device 100 such that the flow rate of fluid conducted by the respiratory device 100 to the patient 102 during the insufflation phase of the mechanical coughing mode substantially follows a control line 402 having a constant positive slope. In particular, unlike the examples of Figure 3A and Figure 3B the respiratory device 100 is controlled to provide a particular flow rate as opposed to a particular pressure. The control line 402 is such that at time T1, the flow rate is zero, and at time T2, the flow rate has increased to the point where the pressure indicated at line 400 is equal to the set insufflation pressure. Alternatively, the flow rate can increase until the flow rate is equal to another physician set value, such as a peak insufflation flow (PIF), which can range between about 10-120 liters per minute (LPM). Because the flow rate is gradually increasing at a constant rate throughout the insufflation phase, the pressure follows the line 400 with a gradually increasing steepness, and in particular presents a gradually increasing positive slope between times T1 and T2.

[0064] Figure 4A and Figure 4B The control line 300 and line 302 are shown in for reference. While the control line 402 does exceed the flow rate provided in the control scheme of i and Figure 3A and Figure 3B the control scheme of, the patient 102 never experiences a sharp increase in pressure or flow rate due to the gradually increasing control line 402. Moreover, in this example, the pressure does not exceed the set insufflation pressure. Thus, Figure 4A andFigure 4B The control scheme of FIG. 4 can also reduce, if not eliminate, retrograde displacement of secretions.

[0065] In Figure 4B , the control line 402 begins at time Tl with a flow rate of zero. In another example, the control line 402 can begin at time Tl with a flow rate greater than zero. In this example, the control line 402 can remain substantially flat between times Tl and T2, exhibiting a substantially zero slope. Alternatively, the control line 402 can remain substantially flat while increasing slightly between times Tl and T2.

[0066] Referring to Figure 5A and Figure 5B , another control scheme is disclosed. In this control scheme, the pressure of the fluid conducted by the breathing apparatus 100 to the patient 102 during the insufflation phase of the mechanical coughing pattern substantially follows a control line 500 that oscillates about a line 504 having a constant positive slope. In other words, the control line 500 is analogous to a sinusoidal wave oscillating about an axis, here the line 504. In this example, the line 504 is equivalent to the control line 300 and exhibits a pressure of zero at time Tl and a set insufflation pressure at time T2. The control line 500 oscillates about the line 504 with an amplitude 506. Starting at time Tl, the control line 500 oscillates above the line 504. In this example, the control line 500 completes three oscillations relative to the line 504 between times Tl and T2. The disclosure extends to control lines 500 that complete at least one oscillation between times Tl and T2. The resulting flow rate to the patient 102, represented by line 502, also oscillates about a line 508 with an amplitude 510. In one example, the line 508 is equivalent to the line 302. Oscillating the pressure and / or flow rate in this manner can help loosen secretions within the airway of the patient 102 while also being able to reduce, if not eliminate, the possibility of retrograde secretions displacement.

[0067] Referring to Figure 6A and Figure 6BIn another control scheme, disclosed in FIG. 6, the flow rate of the fluid conducted by the breathing apparatus 100 to the patient 102 during the insufflation phase of the mechanical coughing mode substantially follows a control line 602 that oscillates relative to a line 604 having a constant positive slope. The control line 602 is analogous to a sinusoidal wave oscillating about an axis, here the line 604. In one example, the line 604 is equivalent to the line 402. The control line 602 oscillates relative to the line 604 with an amplitude 606. Starting at time Tl, the control line 602 oscillates above the line 604, and in this example completes three oscillations between times Tl and T2. The resulting pressure of the fluid conducted to the patient 102, represented by the line 600, also oscillates relative to a line 608 with an amplitude 610. In this example, the line 608 exhibits a constant positive slope. In another example, the line 608 is equivalent to the line 400. Again, the oscillations can help to loosen secretions within the airway of the patient 102. In Figure 5A , Figure 5B , Figure 6A and Figure 6B the oscillations are present only during the insufflation phase, however they can also be present during the exsufflation phase or the pause phase.

[0068] In Figure 5A and Figure 6B , despite the oscillations, the control lines 500 and 602 are considered to increase gradually throughout the insufflation phase in the present disclosure because the control lines 500, 602 substantially follow and oscillate about a line that increases gradually throughout the insufflation phase, and because the control lines 500, 602 exhibit a minimum value at time Tl and a maximum value at time T2.

[0069] In one aspect of the present disclosure, the breathing apparatus 100 is capable of periodically functioning in the mechanical coughing mode at preprogrammed intervals. In this aspect, the controller 180 can issue one or more commands to the breathing apparatus 100 such that the breathing apparatus 100 delivers fluid according to one of the control schemes of Figures 3A to 6B between normal operation of the breathing apparatus 100 in the ventilation mode at preprogrammed intervals, such as every hour or every four hours. When operating in this mode, the breathing apparatus 100 can be referred to as operating in an "intermittent coughing" mode.

[0070] It should be understood that terms such as "about", "substantially", and "generally" are not all-inclusive terms and should be interpreted in a manner consistent with the way a person of ordinary skill in the art would interpret these terms.

[0071] While different examples have specific components as illustrated in the figures, embodiments of the present disclosure are not limited to those particular combinations. Some components or features of one example can be used with or in place of other components or features of another example. Additionally, the various figures accompanying this disclosure are not necessarily drawn to scale and some features can be exaggerated or minimized for the sake of clarity.

[0072] Those of ordinary skill in the art will appreciate that the above- described embodiments are exemplary rather than limiting. That is, various modifications are possible that fall within the scope of the claims. To that end, the following claims should be consulted to determine the true scope and content of this disclosure.

Claims

1. A system comprising: A respiratory device configured to deliver fluid to a patient, wherein the respiratory device is capable of operating in a mechanical cough mode; as well as A controller configured to issue one or more commands to the breathing device such that during the blowing phase of the mechanical cough mode, (i) the flow rate of fluid conducted by the breathing device to the patient is substantially constant throughout the blowing phase, or (ii) the flow rate of fluid conducted by the breathing device to the patient gradually increases throughout the blowing phase.

2. The system according to claim 1, wherein, During the blowing-in phase of the mechanical cough mode, the flow rate of fluid transmitted from the respiratory device to the patient is substantially constant throughout the blowing-in phase.

3. The system according to claim 1, wherein, During the blowing-in phase of the mechanical cough mode, the flow rate of fluid transmitted to the patient by the breathing device gradually increases throughout the blowing-in phase.

4. The system according to claim 1, wherein, The controller is configured to issue one or more commands to the breathing device such that during the blowing phase of the mechanical cough mode, the pressure of the fluid transmitted from the breathing device to the patient substantially follows a line with a constant positive slope.

5. The system according to claim 4, wherein, The controller is configured to issue one or more commands to the breathing device such that during the blowing phase of the mechanical cough mode, the pressure of the fluid transmitted from the breathing device to the patient oscillates relative to the line.

6. The system according to claim 1, wherein, The controller is configured to issue one or more commands to the respiratory device such that during the blowing phase of the mechanical cough mode, the flow rate of fluid transmitted from the respiratory device to the patient substantially follows a line with a constant positive slope.

7. The system according to claim 6, wherein, The controller is configured to issue one or more commands to the breathing device such that during the blowing phase of the mechanical cough mode, the flow rate of the fluid transmitted from the breathing device to the patient oscillates relative to the line.

8. The system of claim 1, further comprising: Connectors; as well as A patient interface connected to the connector, wherein the respiratory device is configured to conduct flow to the patient via the connector through the patient interface.

9. The system of claim 8, further comprising: Pressure sensor; as well as A flow rate sensor, wherein the controller is configured to interpret signals from the pressure sensor as pressure of fluid transmitted from the respiratory device to the patient, and to interpret signals from the flow rate sensor as the flow rate of fluid transmitted from the respiratory device to the patient.

10. The system of claim 1, wherein the breathing device is operable in ventilation mode.

11. The system according to claim 1, wherein: The respiratory equipment is a ventilator, and The controller is configured to issue one or more commands to the ventilator, causing the mechanical cough mode to be activated periodically.

12. The system of claim 1, wherein the breathing device is a ventilator or a mechanical blow-in / blow-out device.

13. A method comprising: Fluid is delivered to the patient using a breathing device operating in mechanical cough mode such that during the blowing-in phase of the mechanical cough mode, (i) the flow rate of the fluid delivered to the patient by the breathing device is substantially constant throughout the blowing-in phase, or (ii) the flow rate of the fluid delivered to the patient by the breathing device gradually increases throughout the blowing-in phase.

14. The method of claim 13, wherein the pressure of the fluid transmitted from the respiratory device to the patient substantially follows a line with a constant positive slope.

15. The method of claim 14, wherein the pressure of the fluid transmitted to the patient by the breathing device oscillates relative to the line.

16. The method of claim 13, wherein the flow rate of the fluid transmitted from the respiratory device to the patient substantially follows a line with a constant positive slope.

17. The method of claim 16, wherein the flow rate of the fluid transmitted from the respiratory device to the patient oscillates relative to the line.

18. The method according to claim 13, wherein, The breathing device is configured to deliver fluid to the patient via a connector through a patient interface.

19. The method of claim 18, wherein the controller issues one or more commands to the breathing device in response to a signal from a pressure sensor or a flow rate sensor.

20. The method of claim 13, wherein the breathing device is capable of operating in ventilation mode.

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