Respiratory apparatus and system for providing gases

Abstract

A respiratory apparatus for providing a flow of gas is provided, having a flow generator configured to generate the flow of gas, and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function, modify the defined compensation function based on the user input, and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

Description

[0001] RESPIRATORY APPARATUS AND SYSTEM FOR PROVIDING GASES

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to respiratory apparatus for providing a flow of gas, methods for controlling a respiratory apparatus for providing a flow of gas, and respiratory systems for providing a flow of gas.

[0004] BACKGROUND

[0005] Breathing assistance apparatuses are used in various environments such as hospital, medical facility, residential care, or home environments to deliver a flow of gases to users or patients. A breathing assistance or respiratory therapy apparatus (collectively, “respiratory apparatus” or “respiratory device”) may be used to deliver supplementary oxygen or other gases with a flow of gases, and / or a humidification apparatus to deliver heated and humidified gases. A respiratory apparatus may allow adjustment and control over characteristics of the gases flow, including flow rate, temperature, gases concentration, humidity, pressure, etc. Sensors, such as flow sensors and / or pressure sensors are used to measure characteristics of the gases flow.

[0006] SUMMARY

[0007] In a first aspect, the present disclosure broadly includes a respiratory apparatus for providing a flow of gas, the respiratory apparatus comprising: a flow generator configured to generate the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0008] In some configurations, the defined compensation function is a pressure drop function.

[0009] In some configurations, the controller is configured to modify the defined compensation function and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function in response to receiving the data during delivery of the flow of gas to a patient.

[0010] In some configurations, the defined compensation function is dependent on a flow rate of the flow of gas.

[0011] In some configurations, for modifying the defined compensation function, the controller is configured to apply at least one modifier value to the defined compensation function.

[0012] In some configurations, for modifying the defined compensation function, the controller is configured to apply the at least one modifier value to the defined compensation function as a whole.

[0013] In some configurations, the defined compensation function comprises a plurality of terms, and, for modifying the defined compensation function, the controller is configured to apply the at least one modifier value to one or more terms of the plurality of terms.

[0014] In some configurations, the target pressure comprises a target inspiratory pressure, or the target pressure comprises a target expiratory pressure, or the target pressure comprises a target constant pressure for inspiration and expiration.

[0015] In some configurations, the respiratory apparatus further comprises a user interface operatively coupled to the controller. In some configurations, the user interface comprises a graphical user interface.

[0016] In some configurations, the respiratory apparatus is configured to receive the data from an external device.

[0017] In some configurations, the respiratory apparatus further comprises one or more sensors configured to determine a pressure of the flow of gas at an outlet of the flow generator.

[0018] In some configurations, the controller is configured to modify the defined compensation function based on the user input to maintain at least a substantially consistent pressure at a point along the flow path, the point being downstream of the flow generator.

[0019] In a second aspect, the present disclosure broadly includes a method for controlling a respiratory apparatus for providing a flow of gas, the method comprising: in response to a controller of the respiratory apparatus receiving data indicative of a user input, the user input being indicative of a modification to a defined compensation function for compensating for a pressure drop in the flow of gas relative to a target pressure along a flow path of the flow of gas, wherein the flow of gas is generated by a flow generator of the respiratory apparatus under control of the controller according to the target pressure and based at least partly on the defined compensation function, modifying the defined compensation function based on the user input; and controlling the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0020] In some configurations, the defined compensation function is a pressure drop function.

[0021] In some configurations, the method comprises modifying the defined compensation function and controlling the flow generator to generate the flow of gas based at least partly on the modified defined compensation function in response to receiving the data during delivery of the flow of gas to a patient. In some configurations, the defined compensation function is dependent on a flow rate of the flow of gas.

[0022] In some configurations, modifying the defined compensation function comprises applying at least one modifier value to the defined compensation function.

[0023] In some configurations, applying the at least one modifier value to the defined compensation function comprises applying the at least one modifier value to the defined compensation function as a whole.

[0024] In some configurations, the defined compensation function comprises a plurality of terms, and applying the at least one modifier value to the defined compensation function comprises applying the at least one modifier value to one or more terms of the plurality of terms.

[0025] In some configurations, the target pressure comprises a target inspiratory pressure, or the target pressure comprises a target expiratory pressure, or the target pressure comprises a target constant pressure for inspiration and expiration.

[0026] In some configurations, the method further comprises receiving the user input provided by a user via a user interface of the respiratory apparatus.

[0027] In some configurations, receiving the user input via the user interface comprises receiving the user input via a graphical user interface of the respiratory apparatus.

[0028] In some configurations, the method comprises receiving the data from an external device.

[0029] In some configurations, the method further comprises determining a pressure of the flow of gas at an outlet of the flow generator. In some configurations, modifying the defined compensation function based on the user input comprises modifying the defined compensation function to maintain at least a substantially consistent pressure at a point along the flow path, the point being located downstream of the flow generator.

[0030] In a third aspect, the present disclosure broadly includes a respiratory system for providing a flow of gas, the respiratory system comprising: a flow generator configured to generate the flow of gas; a breathing conduit configured to be operatively coupled to the flow generator to receive the flow of gas; a patient interface configured to be operatively coupled to the breathing conduit to receive the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0031] In some configurations, the defined compensation function is a pressure drop function.

[0032] In some configurations, the controller is configured to modify the defined compensation function and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function in response to receiving the data during delivery of the flow of gas to a patient.

[0033] In some configurations, the defined compensation function is dependent on a flow rate of the flow of gas. In some configurations, for modifying the defined compensation function, the controller is configured to apply at least one modifier value to the defined compensation function.

[0034] In some configurations, for modifying the defined compensation function, the controller is configured to apply the at least one modifier value to the defined compensation function as a whole.

[0035] In some configurations, the defined compensation function comprises a plurality of terms, and, for modifying the defined compensation function, the controller is configured to apply the at least one modifier value to one or more terms of the plurality of terms.

[0036] In some configurations, wherein the target pressure comprises a target inspiratory pressure, or wherein the target pressure comprises a target expiratory pressure, or wherein the target pressure comprises a target constant pressure for inspiration and expiration.

[0037] In some configurations, the respiratory system further comprises a user interface operatively coupled to the controller.

[0038] In some configurations, the user interface comprises a graphical user interface.

[0039] In some configurations, the respiratory system is configured to receive the data from an external device.

[0040] In some configurations, the respiratory system further comprises one or more sensors configured to determine a pressure of the flow of gas at an outlet of the flow generator.

[0041] In some configurations, the controller is configured to modify the defined compensation function based on the user input to maintain at least a substantially consistent pressure at a point along the flow path, the point being located downstream of the flow generator.

[0042] In some configurations, the point is located downstream of the breathing conduit. In some configurations, the patient interface comprises a sealed patient interface.

[0043] In a fourth aspect, the present disclosure broadly includes a respiratory apparatus for providing a flow of gas, the respiratory apparatus comprising: a flow generator configured to generate the flow of gas, the flow generator comprising a motor; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and control, based at least partly on the modified defined compensation function, a speed of the motor for the flow generator to generate the flow of gas to compensate for at least part of the pressure drop.

[0044] In a fifth aspect, the present disclosure broadly includes a respiratory apparatus for providing a flow of gas, the respiratory apparatus comprising: a flow generator configured to generate the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of an increment in the flow of gas through the flow path: modify the defined compensation function based on the user input; and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0045] In a sixth aspect, the present disclosure broadly includes a respiratory apparatus for providing a flow of gas, the respiratory apparatus comprising: a flow generator configured to generate the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of an increment in a perceived pressure at a patient: modify the defined compensation function based on the user input; and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0046] In a seventh aspect, the present disclosure broadly includes a respiratory apparatus for providing a flow of gas, the respiratory apparatus comprising: a flow generator configured to generate the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and control the flow generator to increase a flow rate of the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0047] In an eighth aspect, the present disclosure broadly includes a respiratory apparatus for providing a flow of gas, the respiratory apparatus comprising: a flow generator configured to generate the flow of gas, the flow generator comprising a motor; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and increase, based at least partly on the modified defined compensation function, a speed of the motor for the flow generator to increase pressure of the flow of gas to be provided to a patient to compensate for at least part of the pressure drop.

[0048] In a ninth aspect, the present disclosure broadly includes a respiratory apparatus for providing a flow of gas, the respiratory apparatus comprising: a flow generator configured to generate the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and increase a flow rate output of the flow generator based at least partly on the modified defined compensation function to increase pressure of the flow of gas to be provided to a patient to compensate for at least part of the pressure drop.

[0049] The following configurations are applicable to the fourth, fifth, sixth, seventh, eighth and ninth aspects.

[0050] In some configurations, the defined compensation function is a pressure drop function.

[0051] In some configurations, the controller is configured to modify the defined compensation function in response to receiving the data during delivery of the flow of gas to a patient.

[0052] In some configurations, the defined compensation function is dependent on a flow rate of the flow of gas.

[0053] In some configurations, for modifying the defined compensation function, the controller is configured to apply at least one modifier value to the defined compensation function. In some configurations, for modifying the defined compensation function, the controller is configured to apply the at least one modifier value to the defined compensation function as a whole.

[0054] In some configurations, the defined compensation function comprises a plurality of terms, and, for modifying the defined compensation function, the controller is configured to apply the at least one modifier value to one or more terms of the plurality of terms.

[0055] In some configurations, wherein the target pressure comprises a target inspiratory pressure, or wherein the target pressure comprises a target expiratory pressure, or wherein the target pressure comprises a target constant pressure for inspiration and expiration.

[0056] In some configurations, the respiratory apparatus further comprises a user interface operatively coupled to the controller.

[0057] In some configurations, the user interface comprises a graphical user interface.

[0058] In some configurations, the respiratory apparatus is configured to receive the data from an external device.

[0059] In some configurations, the respiratory apparatus further comprises one or more sensors configured to determine a pressure of the flow of gas at an outlet of the flow generator.

[0060] In some configurations, the controller is configured to modify the defined compensation function based on the user input to maintain at least a substantially consistent pressure at a point along the flow path, the point being downstream of the flow generator.

[0061] In a tenth aspect, the present disclosure broadly includes a method for controlling a respiratory apparatus for providing a flow of gas, the method comprising: in response to a controller of the respiratory apparatus receiving data indicative of a user input, the user input being indicative of a modification to a defined compensation function for compensating for a pressure drop in the flow of gas relative to a target pressure along a flow path of the flow of gas, wherein the flow of gas is generated by a flow generator of the respiratory apparatus under control of the controller according to the target pressure and based at least partly on the defined compensation function, modifying the defined compensation function based on the user input; and controlling, based at least partly on the modified defined compensation function, a speed of a motor of the flow generator for the flow generator to generate the flow of gas to compensate for at least part of the pressure drop.

[0062] In an eleventh aspect, the present disclosure broadly includes a method for controlling a respiratory apparatus for providing a flow of gas, the method comprising: in response to a controller of the respiratory apparatus receiving data indicative of a user input, the user input being indicative of an increment in the flow of gas through a flow path of the flow of gas, wherein the flow of gas is generated by a flow generator of the respiratory apparatus under control of the controller according to a target pressure and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along the flow path, modifying the defined compensation function based on the user input; and controlling the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0063] In a twelfth aspect, the present disclosure broadly includes a method for controlling a respiratory apparatus for providing a flow of gas, the method comprising: in response to a controller of the respiratory apparatus receiving data indicative of a user input, the user input being indicative of an increment in a perceived pressure at a patient, wherein the flow of gas is generated by a flow generator of the respiratory apparatus under control of the controller according to a target pressure and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along the flow path, modifying the defined compensation function based on the user input; and controlling the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0064] In a thirteenth aspect, the present disclosure broadly includes a method for controlling a respiratory apparatus for providing a flow of gas, the method comprising: in response to a controller of the respiratory apparatus receiving data indicative of a user input, the user input being indicative of a modification to a defined compensation function for compensating for a pressure drop in the flow of gas relative to a target pressure along a flow path of the flow of gas, wherein the flow of gas is generated by a flow generator of the respiratory apparatus under control of the controller according to the target pressure and based at least partly on the defined compensation function, modifying the defined compensation function based on the user input; and controlling the flow generator to increase a flow rate of the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0065] In a fourteenth aspect, the present disclosure broadly includes a method for controlling a respiratory apparatus for providing a flow of gas, the method comprising: in response to a controller of the respiratory apparatus receiving data indicative of a user input, the user input being indicative of a modification to a defined compensation function for compensating for a pressure drop in the flow of gas relative to a target pressure along a flow path of the flow of gas, wherein the flow of gas is generated by a flow generator of the respiratory apparatus under control of the controller according to the target pressure and based at least partly on the defined compensation function, modifying the defined compensation function based on the user input; and increasing, based at least partly on the modified defined compensation function, a speed of a motor of the flow generator for the flow generator to increase pressure of the flow of gas provided to a patient to compensate for at least part of the pressure drop.

[0066] In a fifteenth aspect, the present disclosure broadly includes a method for controlling a respiratory apparatus for providing a flow of gas, the method comprising: in response to a controller of the respiratory apparatus receiving data indicative of a user input, the user input being indicative of a modification to a defined compensation function for compensating for a pressure drop in the flow of gas relative to a target pressure along a flow path of the flow of gas, wherein the flow of gas is generated by a flow generator of the respiratory apparatus under control of the controller according to the target pressure and based at least partly on the defined compensation function, modifying the defined compensation function based on the user input; and increasing a flow rate output of the flow generator based at least partly on the modified defined compensation function to increase pressure of the flow of gas provided to a patient to compensate for at least part of the pressure drop.

[0067] The following configurations are applicable to the tenth, eleventh, twelfth, thirteenth, fourteenth and fifteenth aspects.

[0068] In some configurations, the defined compensation function is a pressure drop function.

[0069] In some configurations, the method comprises modifying the defined compensation function in response to receiving the data during delivery of the flow of gas to a patient.

[0070] In some configurations, the defined compensation function is dependent on a flow rate of the flow of gas.

[0071] In some configurations, modifying the defined compensation function comprises applying at least one modifier value to the defined compensation function.

[0072] In some configurations, applying the at least one modifier value to the defined compensation function comprises applying the at least one modifier value to the defined compensation function as a whole.

[0073] In some configurations, the defined compensation function comprises a plurality of terms, and applying the at least one modifier value to the defined compensation function comprises applying the at least one modifier value to one or more terms of the plurality of terms.

[0074] In some configurations, wherein the target pressure comprises a target inspiratory pressure, or wherein the target pressure comprises a target expiratory pressure, or wherein the target pressure comprises a target constant pressure for inspiration and expiration.

[0075] In some configurations, the method further comprises receiving the user input provided by a user via a user interface of the respiratory apparatus.

[0076] In some configurations, receiving the user input via the user interface comprises receiving the user input via a graphical user interface of the respiratory apparatus.

[0077] In some configurations, the method comprises receiving the data from an external device.

[0078] In some configurations, the method further comprises determining a pressure of the flow of gas at an outlet of the flow generator.

[0079] In some configurations, modifying the defined compensation function based on the user input comprises modifying the defined compensation function to maintain at least a substantially consistent pressure at a point along the flow path, the point being located downstream of the flow generator.

[0080] In a sixteenth aspect, the present disclosure broadly includes a respiratory system for providing a flow of gas, the respiratory system comprising: a flow generator configured to generate the flow of gas, the flow generator comprising a motor; a breathing conduit configured to be operatively coupled to the flow generator to receive the flow of gas; a patient interface configured to be operatively coupled to the breathing conduit to receive the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and control, based at least partly on the modified defined compensation function, a speed of the motor for the flow generator to generate the flow of gas to compensate for at least part of the pressure drop.

[0081] In a seventeenth aspect, the present disclosure broadly includes a respiratory system for providing a flow of gas, the respiratory system comprising: a flow generator configured to generate the flow of gas; a breathing conduit configured to be operatively coupled to the flow generator to receive the flow of gas; a patient interface configured to be operatively coupled to the breathing conduit to receive the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of an increment in the flow of gas through the flow path: modify the defined compensation function based on the user input; and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0082] In an eighteenth aspect, the present disclosure broadly includes a respiratory system for providing a flow of gas, the respiratory system comprising: a flow generator configured to generate the flow of gas; a breathing conduit configured to be operatively coupled to the flow generator to receive the flow of gas; a patient interface configured to be operatively coupled to the breathing conduit to receive the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of an increment in a perceived pressure at a patient: modify the defined compensation function based on the user input; and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0083] In a nineteenth aspect, the present disclosure broadly includes a respiratory system for providing a flow of gas, the respiratory system comprising: a flow generator configured to generate the flow of gas; a breathing conduit configured to be operatively coupled to the flow generator to receive the flow of gas; a patient interface configured to be operatively coupled to the breathing conduit to receive the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and control the flow generator to increase a flow rate of the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0084] In a twentieth aspect, the present disclosure broadly includes a respiratory system for providing a flow of gas, the respiratory system comprising: a flow generator configured to generate the flow of gas, the flow generator comprising a motor; a breathing conduit configured to be operatively coupled to the flow generator to receive the flow of gas; a patient interface configured to be operatively coupled to the breathing conduit to receive the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and increase, based at least partly on the modified defined compensation function, a speed of the motor for the flow generator to increase pressure of the flow of gas to be provided to a patient to compensate for at least part of the pressure drop.

[0085] In a twenty first aspect, the present disclosure broadly includes a respiratory system for providing a flow of gas, the respiratory system comprising: a flow generator configured to generate the flow of gas; a breathing conduit configured to be operatively coupled to the flow generator to receive the flow of gas; a patient interface configured to be operatively coupled to the breathing conduit to receive the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and increase a flow rate output of the flow generator based at least partly on the modified defined compensation function to increase pressure of the flow of gas to be provided to a patient to compensate for at least part of the pressure drop.

[0086] The configurations disclosed herein are applicable also to the sixteenth, seventeenth, eighteenth, nineteenth, twentieth, and twenty first aspects. For example, the defined compensation function is a pressure drop function.

[0087] BRIEF DESCRIPTION OF THE DRAWINGS

[0088] These and other features, aspects, and advantages of the present disclosure are described with reference to the drawings of certain embodiments, which are intended to schematically illustrate certain embodiments and not to limit the disclosure. Figure 1 shows a schematic view of a respiratory system for providing a flow of gas, according to various embodiments.

[0089] Figure 2 is a schematic block diagram illustrating an exemplary communications system involving a respiratory apparatus and an external device.

[0090] Figure 3 shows a flow chart illustrating a method for controlling a respiratory apparatus for providing a flow of gas, according to various embodiments.

[0091] Figure 4 shows a flow chart illustrating a method for controlling a respiratory apparatus for providing a flow of gas, according to various embodiments.

[0092] Figure 5 shows a plot illustrating pressure drop as a function of flow rate.

[0093] Figure 6 shows a plot illustrating the target pressure at the patient and compensation for the pressure drop at the patient.

[0094] Figure 7 shows a plot illustrating the target pressure at the patient and compensation for the pressure drop at the patient.

[0095] Figures 8 to 11 illustrate various embodiments of patient interfaces, each in side and front views on a patient.

[0096] DETAILED DESCRIPTION

[0097] Although certain examples are described below, those of skill in the art will appreciate that the disclosure extends beyond the specifically disclosed examples and / or uses and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the disclosure herein disclosed should not be limited by any particular examples described below.

[0098] In a pressure-controlled respiratory device or system, a flow of gas (or gases) is generated by a flow generator (e.g., a blower) in the device. The flow generator is controlled to achieve a target pressure. After leaving the flow generator, the gas or gases flow may pass through one or more sections of the device that is downstream of the flow generator (including, for example, a humidifier), through a tube (or breathing conduit), through an (patient) interface, and to or into a patient. As the gas flow moves (or flows or traverses) along this (flow) path, the flow of gas experiences resistance. This resistance results in a pressure drop between the device and the patient. In other words, the pressure at the patient side, Ppatient, is less than the pressure at the device side, Poevice.

[0099] Some pressure-controlled respiratory devices or systems may not include a pressure sensor at the patient end. In such systems, the controller or processor of the respiratory device (or respiratory apparatus) may use a pressure measured by a sensor in the device and an approximated (or estimated) pressure drop to calculate (or determine) the patientend pressure. The calculated patient-end pressure may then be used by the controller to determine whether or not one or more parameters, e.g., the blower speed, need to be altered to keep the patient-end pressure as close to the (pressure) set point as possible. This may mean that, as a result of the change(s) made, the pressure of the flow of gases at the patient side may be changed (e.g., increased) to more closely match or align with the set point to compensate for the pressure drop resulting from the flow resistance during normal device operation. The closer the controller can keep the patient-end pressure to the set point (or target pressure), the closer the therapy will be to what was prescribed for the patient. Further, if the pressure drop is not compensated, the lower pressure of the flow of gases experienced by the patient may cause discomfort to the patient. Therefore, the more accurate the approximation of the pressure drop, the better.

[0100] The techniques disclosed herein may provide a respiratory apparatus having a controller that may, in response to receiving one or more user inputs, control operation of the respiratory apparatus to compensate for a pressure drop that may occur as a result of resistance experienced by a flow of gas(es) along the flow path. The respiratory apparatus may receive user input(s) via a user interface (UI) on the respiratory apparatus or in communication with the respiratory apparatus, including, for example, remotely via use of an external device that is in communication with the respiratory apparatus. The UI on the respiratory apparatus may include a graphical UI (GUI), a display screen, including, for example, a touchscreen, a (physical) input device such as a knob, a dial, a switch, a lever, a sliding bar, a button, etc. Figure 1 shows a schematic view of a respiratory system 250 for providing a flow of gas (represented by dashed arrow 213), according to various embodiments. The respiratory system 250 includes a flow generator 212 configured to generate the flow of gas 213, a breathing conduit 254 configured to be operatively coupled to the flow generator 212 to receive the flow of gas 213 (from the flow generator 212), a patient interface 256 configured to be operatively coupled to the breathing conduit 254 to receive the flow of gas 213 (from the breathing conduit 254), and a controller 214 configured to control the flow generator 212 to generate the flow of gas 213 according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas 213 relative to the target pressure along a flow path of the flow of gas 213. The flow generator 212 and the controller 214 may be or may form part of a respiratory apparatus 210 of the respiratory system 250. The controller 214 is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function, modify the defined compensation function based on the user input, and control the flow generator 212 to generate the flow of gas 213 based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0101] In other words, a respiratory system 250 is provided. The respiratory system 250 includes a respiratory apparatus 210 having a flow generator 212 to generate a flow of gas 213, and a controller 214. The controller 214 may be operatively coupled to the flow generator 212, as represented by the dashed line in Figure 1. The respiratory apparatus 210 / respiratory system 250 may be used for pressure-controlled therapy.

[0102] The respiratory system 250 further includes a breathing conduit 254 configured to be operatively coupled or fluidly connected to the flow generator 212 to receive the flow of gas 213. The breathing conduit 254 may be removably coupled to the flow generator 212. The breathing conduit 254 may include a heating element or a heater.

[0103] The breathing conduit 254 may include a device end coupler / connector that may connect to the respiratory apparatus 210 or the flow generator 212. The flow generator 212 may be housed in a housing of the respiratory apparatus 210 and the breathing conduit 254 may be connected to an outlet of the housing via the device end coupler / connector.

[0104] The respiratory system 250 further includes a patient interface 256 configured to be operatively coupled or fluidly connected to the breathing conduit 254 to receive the flow of gas 213. The patient interface 256 may convey the flow of gas 213 to a patient.

[0105] The patient interface 256 may be worn or used by a patient. The patient interface 256 may be positioned over an airway of the patient. The patient interface 256 may be removably coupled to the breathing conduit 254. The breathing conduit 254 and the patient interface 256 may include complementary connectors that form a fluid connection.

[0106] When operatively coupled together, the flow generator 212, the breathing conduit 254 and the patient interface 256 are in fluid communication with each other to convey the flow of gases 213 from the flow generator 212 to the patient interface 256.

[0107] The controller 214 is configured to control the flow generator 212 to generate the flow of gas 213 according to a target pressure (or set pressure), and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas 213 relative to the target pressure along a flow path of the flow of gas 213.

[0108] The target pressure may include a pressure that is prescribed by a clinician or a medical professional for a patient that is to use the respiratory apparatus 210, e.g., during a therapy session. The prescribed pressure by the clinician may be a pressure that is considered to be therapeutically effective for the patient.

[0109] The target pressure may be set or defined for the patient.

[0110] The target pressure may be set or defined by a user. The user may be a patient, a clinician, a healthcare professional (e.g., a doctor, a nurse, etc.), a technician, or others. In response to data indicative of a user input being received, the user input being indicative of a modification to the defined compensation function, the controller 214 is further configured to modify the defined compensation function based on (or according to) the user input, and control the flow generator 212 to generate the flow of gas 213 based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0111] As the flow of gas 213 propagates or flows along the flow path, the gas flow 213 experiences resistance, and, consequently, there is a pressure drop in the gas flow 213 downstream of the flow generator 212 along the flow path. The pressure drop may increase along the flow path. This may mean that a patient may experience the gas flow 213 at a pressure that is less than the target pressure that is desired for the patient. By compensating for the pressure drop, there may be a more consistent pressure that is experienced by the patient and / or the pressure of the flow of gas 213 experienced by the patient may be closer to or reach the target pressure. Compensation of the pressure drop may also improve patient comfort.

[0112] For generating the flow of gas 213 based at least partly on the modified defined compensation function, the flow generator 212 may, under control of the controller 214, modify or vary one or more parameters (e.g., flow rate, pressure, etc.) of the flow of gas 213. For example, at least one of the flow rate or the pressure of the flow of gas 213 may be increased.

[0113] A user may provide the user input via a user interface (UI) 216 of the respiratory apparatus 210 or via an external or remote device (see, for example, 220, Figure 2).

[0114] The respiratory apparatus 210 may further include a housing. The flow generator 212 and the controller 214 may be arranged within the housing.

[0115] In some configurations, the defined compensation function is or includes a pressure drop function (or a flow resistance function or flow conductance function). The pressure drop function defines how much the pressure of the flow of gas 213 may drop across, for example, the breathing conduit 254.

[0116] In some configurations, a pressure sensor may be provided at or with the patient interface 256. This facilitates determination of the pressure of the flow of gas 213 at or close to the patient wearing the patient interface 256.

[0117] The techniques disclosed herein allow for a manually adjustable defined compensation function or pressure drop (or loss) function. The adjustment may be made by a user (e.g. , a patient and / or a clinician) via a user input. Such manual adjustment may be facilitated with the provision of an optional pressure sensor at or with the patient interface 256.

[0118] In some configurations, modifying the defined compensation function or the pressure drop function increases the pressure delivered to the patient, i.e., pressure is boosted.

[0119] The controller 214 may modify the defined compensation function and may control the flow generator 212 to generate the flow of gas 213 based at least partly on the modified defined compensation function in response to receiving the data during delivery of the flow of gas to a patient. This may mean that the controller 214 may receive the data indicative of the user input during a therapy session, i.e., while the patient is undergoing therapy or in the midst of using the respiratory apparatus 210. This allows changes to be made without disrupting or interrupting the therapy session.

[0120] The defined compensation function may include or may be a mathematical function or an algorithm. As a non-limiting example, the defined compensation function may include or may be a polynomial function, e.g., a second-order polynomial function.

[0121] The defined compensation function may include or may be a look up table. The defined compensation function may be dependent on a flow rate of the flow of gas 213. In other words, the defined compensation function may be a function of the flow rate of the flow of gas 213.

[0122] The defined compensation function may be one of a plurality of defined compensation functions. The defined compensation function may be a function selected from a plurality of defined compensation functions.

[0123] The defined compensation function or the plurality of defined compensation functions may be accessible to the controller 214.

[0124] The defined compensation function or the plurality of defined compensation functions may be stored in a memory of the controller 214 or a memory of the respiratory apparatus 210.

[0125] The controller 214 may, for modifying the defined compensation function, apply at least one modifier value to the defined compensation function.

[0126] The controller 214 may, for modifying the defined compensation function, apply the at least one modifier value to the defined compensation function as a whole. For example, the modifier value may be added to the defined compensation function as a whole, or the defined compensation function as a whole may be multiplied by the modifier value.

[0127] The defined compensation function may include at least one term, and, for modifying the defined compensation function, the controller 214 may be configured to apply the at least one modifier value to the at least one term. The at least one term may include a coefficient, and the at least one modifier value may be applied to the coefficient, e.g., the modifier value may be added to the coefficient, or multiplied with the coefficient. In some configurations, the defined compensation function may include a plurality of terms, and, the controller 214 may, for modifying the defined compensation function, apply the at least one modifier value to one or more terms of the plurality of terms.

[0128] The plurality of terms may include two or more terms, each term having a coefficient, and the at least one modifier value may be applied to one or more of the coefficients. For example, the modifier value may be added to or multiplied with one or more of the coefficients. Different modifier values may be applied to different coefficients.

[0129] The plurality of terms may include at least one term having a coefficient, and a constant term, and the at least one modifier value may be applied to the coefficient and / or the constant term. For example, the modifier value may be added to the coefficient and / or the constant term, or multiplied with the coefficient and / or the constant term. Different modifier values may be applied to the coefficient and the constant term.

[0130] The defined compensation function may be predetermined (or predefined or calibrated) based on the pressure drop that is determined (or calculated) for respective flow rates of a plurality of (different) flow rates of the flow of gas 213, for example, by performing a flow sweep to determine the pressure drop for a range of flow rates. This may mean that the pressure drop may be a function of the flow rate of the flow of gas 213.

[0131] In one configuration, the target pressure may include or may be a target inspiratory pressure.

[0132] In another configuration, the target pressure may include or may be a target expiratory pressure.

[0133] In a further configuration, the target pressure may include or may be a target constant pressure for inspiration and expiration. The different types of target pressures may allow for BiLevel pressure therapy and CPAP therapy.

[0134] The target pressure may be configurable.

[0135] The respiratory apparatus 210 may further include a user interface (UI) 216 operatively coupled to the controller 214. The UI 216 may be configured for a user to provide the user input. The user may be a patient, a healthcare professional (e.g., a doctor, a nurse, etc.), a technician, or others.

[0136] The UI 216 may be integrated with a housing of the respiratory apparatus 210.

[0137] The UI 216 may include a graphical user interface (GUI) (e.g., including a touchscreen) and / or one or more physical input devices (e.g., at least one of a knob, a dial, a switch, a lever, a sliding bar, or a button). User inputs may be provided via the UI 216, for example, to modify the defined compensation function and / or to request a boost of pressure for the patient.

[0138] The respiratory apparatus 210 may (further) receive the data from an external device (e.g., 220, see Figure 2). This may be via wired or wireless communication with the external device. The respiratory apparatus 210 may include a receiver or a receiving module to receive the data.

[0139] The external device may include a (user) communications device (e.g., a mobile phone, a tablet, etc.), a computer, a server, a touchscreen, etc.

[0140] Referring to Figure 2 as a non-limiting example, in some configurations, the user input may be provided via an App or application 222 that is resident on a user communications device 220. The App (or application) 222 may be specific to the respiratory apparatus 210. In one non-limiting example, the data indicative of the user input may then be transmitted to the respiratory apparatus 210 directly by the user communications device 220, e.g., via Bluetooth. In another non-limiting example, the data indicative of the user input may then be transmitted by the user communications device 220, via a network (e.g., the Internet) 224, to a server 226 for onward transmission, via another network or the same network 224, to the respiratory apparatus 210.

[0141] In some configurations, the user input may be inputted directly into the respiratory apparatus 210 via the UI 216 (e.g., a GUI) of the respiratory apparatus 210, and this information may be transmitted to the server 226 for recording. This information may be included in a report that may be accessed by a clinician, e.g., a doctor, nurse, or another authorised party such as a dealer.

[0142] The respiratory apparatus 210 may further include one or more sensors configured to determine a pressure of the flow of gas 213 at an outlet of the flow generator 212. The one or more sensors may include at least one pressure sensor.

[0143] The respiratory apparatus 210 may further include one or more sensors for determining or sensing a flow rate of the flow of gas 213.

[0144] The controller 214 may be operatively coupled to the sensor(s). The controller 214 may receive data indicative of at least one of the pressure or the flow rate of the flow of gas 213.

[0145] The sensor (s) may be arranged at or proximal to an outlet of the flow generator 212.

[0146] The sensor(s) may be arranged at or within a housing of the respiratory apparatus 210.

[0147] The respiratory apparatus 210 may further include a humidifier configured to humidify the flow of gas 213. The humidifier may further heat the flow of gas 213. The humidifier may be located downstream of the flow generator 212. The humidifier may be integrated into the same housing as the flow generator 212, or may be a separate humidifier. In some examples, the humidifier helps to humidify the flow of gases 213 provided to the patient to fully saturate the gases, e.g., at 37 deg dew point.

[0148] The controller 214 may control the humidifier to control a humidity level of the flow of gas 213. This may improve patient comfort.

[0149] The controller 214 may modify the defined compensation function based on the user input to maintain at least a substantially consistent pressure at a point along the flow path, the point being downstream of the flow generator 212. In this way, a more consistent pressure may be maintained at the point downstream of the flow generator 212. As non-limiting examples, the point may be located within or downstream of the breathing conduit 254 connected to the respiratory apparatus 210, or the point may be the point of delivery of the flow of gas 213 to the patient, e.g., at or close to the respiratory airways of the patient.

[0150] The defined compensation function may be predetermined based on a breathing conduit and / or a sealed patient interface that the respiratory apparatus 210 may be configured to fluidly communicate with.

[0151] The defined compensation function may be a function selected from a plurality of defined compensation functions. A plurality of breathing conduits and a plurality of sealed patient interfaces may be used with the respiratory apparatus 210, and each of the plurality of defined compensation functions may be associated with a pair of a respective breathing conduit of the plurality of breathing conduits and a respective sealed patient interface of the plurality of sealed patient interfaces. The plurality of defined compensation functions may be stored in a memory of the controller 214 or the respiratory apparatus 210.

[0152] The defined compensation function may be predetermined (or predefined or calibrated) based on the pressure drop that is determined (or calculated) for respective conditions of a plurality of (different) conditions of the breathing conduit. The conditions of the breathing conduit may include the states and / or orientations of the breathing conduit. For example, the breathing conduit may be bent, curled, constricted, etc. In some configurations, the defined compensation function may be

[0153] CtV2+ C2V + C3, Equation (1), where each of C^V2, C2V, and C3is a term of the defined compensation function, umetric flow rate of the flow of gas, are coefficients, and

[0154] C3is a constant term.

[0155] The respiratory apparatus 210 may be a pressure-controlled respiratory apparatus for pressure-controlled therapy, including, e.g., non-invasive ventilation (NIV), bilevel positive airway pressure (BiPAP), etc.

[0156] The respiratory apparatus 210 may be a pressure-controlled respiratory apparatus for pressure-controlled therapy for a respiratory system with a sealed patient interface, and / or a patient interface that is non-invasive. As non-limiting example, the patient interface 256 may include masks (e.g., full-face mask or nasal mask) or nasal pillows.

[0157] As a non-limiting example, in some configurations, as one form of controlling the flow generator 212 to generate the flow of gas 213 based at least partly on the modified defined compensation function, the controller 214 may be configured to control, based at least partly on the modified defined compensation function, a speed of a motor 215 of the flow generator 212 for the flow generator 212 to generate the flow of gas 213 to compensate for at least part of the pressure drop.

[0158] In some configurations, the patient may ask or request for more or additional pressure and the user input, therefore, may be an indication of an increment in a perceived pressure at the patient.

[0159] The patient interface 256 may be any suitable types of sealed patient interfaces, including but not limited to full face masks and nasal masks. Figure 3 shows a flow chart 230 illustrating a method for controlling a respiratory apparatus (e.g., 210, Figure 1) for providing a flow of gas, according to various embodiments.

[0160] In response to a controller of the respiratory apparatus receiving data indicative of a user input, the user input being indicative of a modification to a defined compensation function for compensating for a pressure drop in the flow of gas relative to a target pressure along a flow path of the flow of gas, wherein the flow of gas is generated by a flow generator of the respiratory apparatus under control of the controller according to the target pressure and based at least partly on the defined compensation function, at 232, the defined compensation function is modified based on the user input, and, at 234, the flow generator is controlled to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

[0161] The defined compensation function is or includes a pressure drop function.

[0162] The method may be executed by any controller (e.g., controller 214) disclosed herein. In other words, the method may be carried out in the respiratory apparatus of various embodiments disclosed herein.

[0163] The method may include modifying the defined compensation function at 232 and controlling the flow generator at 234 to generate the flow of gas based at least partly on the modified defined compensation function in response to receiving the data during delivery of the flow of gas to a patient.

[0164] The defined compensation function may be dependent on a flow rate of the flow of gas.

[0165] At 232, at least one modifier value may be applied to the defined compensation function. At 232, the at least one modifier value may be applied to the defined compensation function as a whole.

[0166] The defined compensation function may include a plurality of terms, and, at 232, the at least one modifier value may be applied to one or more terms of the plurality of terms.

[0167] The defined compensation function may be predetermined based on the pressure drop that is determined for respective flow rates of a plurality of flow rates of the flow of gas.

[0168] The target pressure may include a target inspiratory pressure, or a target expiratory pressure, or a target constant pressure for inspiration and expiration.

[0169] The target pressure may be configurable.

[0170] The method may further include receiving the user input provided by a user via a user interface (UI), including, e.g., a graphical user interface (GUI), of the respiratory apparatus.

[0171] The method may include receiving the data from an external device.

[0172] The method may further include determining a pressure of the flow of gas at an outlet of the flow generator.

[0173] At 234, the defined compensation function may be modified to maintain at least a substantially consistent pressure at a point along the flow path, the point being downstream of the flow generator.

[0174] In some configurations of the method, the defined compensation function may be Equation (1). Figure 4 shows a flow chart 240 illustrating a method for controlling a respiratory apparatus (e.g., 210, Figure 1) for providing a flow of gas, according to various embodiments.

[0175] In response to a controller of the respiratory apparatus receiving data indicative of a user input, the user input being indicative of a modification to a defined compensation function for compensating for a pressure drop in the flow of gas relative to a target pressure along a flow path of the flow of gas, wherein the flow of gas is generated by a flow generator of the respiratory apparatus under control of the controller according to the target pressure and based at least partly on the defined compensation function, at 242, the defined compensation function is modified based on the user input, and at 244, based at least partly on the modified defined compensation function, a speed of a motor of the flow generator is controlled for the flow generator to generate the flow of gas to compensate for at least part of the pressure drop.

[0176] It should be appreciated that description relating to the method in the context of the flow chart 230 (Figure 3) may correspondingly be applicable in relation to the method described in the context of the flow chart 240.

[0177] It should be appreciated that description in the context of the respiratory apparatus 210 may correspondingly be applicable in relation to the method for controlling a respiratory apparatus described in the context of the flow charts 230, 240.

[0178] Various embodiments or techniques will now be further described in detail by way of the following non-limiting examples.

[0179] As described above, as a result of resistance experienced by a flow of gas(es) flowing from a respiratory apparatus towards the patient, there is a pressure drop at the patient side. The techniques disclosed herein may enable approximation of the pressure drop to enable compensation to be made to bring the pressure at the patient side, after the pressure drop, back up to a level that is closer to or at the (target) pressure point that has been set for the patient for the patient’s therapy session.

[0180] A non-limiting example of the present disclosure is to approximate the magnitude of the pressure drop that occurs during therapy for a specific respiratory system. This may be carried out prior to using the respiratory system, e.g., during a calibration stage. Herein, the “specific respiratory system” may include or may be a respiratory system having a respiratory apparatus, as well as a breathing conduit (or tube) and a patient interface (e.g., a mask) where the breathing conduit and the patient interface may be configured or designed to operatively couple to the respiratory apparatus for defining the defined compensation function. In a “specific respiratory system”, a specific respiratory apparatus is coupled to a specific breathing conduit and a specific patient interface, and a defined compensation function is associated with the specific respiratory system. The respiratory system changes or is no longer a “specific respiratory system”, for example, when a different breathing conduit and / or a different patient interface is used because the flow path geometry has changed.

[0181] The amount of pressure drop may be approximated by applying a pressure sensor to the patient end of the system in a controlled environment or setting, e.g., in a laboratory or under laboratory conditions, and comparing the readings from the patient-end pressure sensor to readings from a pressure sensor arranged in a respiratory apparatus (that generates flow of gas for the patient) of the system for or at a specific flow rate. The difference between these readings may then be used in Equation (2) to calculate or determine the pressure drop, PLab, under the laboratory conditions:

[0182] ^Ppab Poevice_Lab Ppatient_Lab Equation (2), where Poevice_Lab isthe pressure measured by the sensor in the respiratory apparatus or device, and Ppatient_Lab isthe pressure measured by the sensor applied to the patient end of the system in the laboratory. However, Equation (2) may be an oversimplification as pressure drop is a function of the flow rate through the respiratory system. As a flow of gas travels along the flow path towards the patient, there may be losses due to, for example, friction and changes in flow path geometry that are generally dependent on the flow rate. The losses are generally greater at higher flow rates.

[0183] If a pressure-controlled respiratory system, having a pressure-controlled respiratory apparatus, has to increase its flow rate to maintain the target pressure at the patient end (in response to inhalation, for example), the pressure drop may increase. Conversely, if a pressure-controlled respiratory system has to decrease its flow rate to maintain the target pressure at the patient end (in response to exhalation, for example), the pressure drop may decrease. To account for the effect of flow rate on the pressure drop, the process for determining the pressure drop as described above under controlled conditions may be repeated at a number of flow rates across a range of flow rates (e.g., a flow sweep may be performed). Equation (2) may then be used to determine the pressure drop, PLab, at each flow rate for the specific respiratory system. The flow rate and PLabvalues may then be plotted against each other where the data points are arranged in a trend resembling a curve. The flow rate of the gas flow may be measured within the respiratory apparatus. The flow rate through the respiratory apparatus is at least substantially the same as the flow rate through the breathing conduit of the respiratory system (conservation of mass). A non-limiting example of the results that may be obtained for a specific respiratory system under laboratory conditions is shown in Figure 5.

[0184] Using the data points arranged in a curve-like trend in Figure 5 as a non-limiting example, the curve-like trend may be represented or approximated by Equation (3) below, which is a second-order polynomial. Equation (3) may be used to define or form a function or model that represents the pressure drop that occurs at any given flow rate, PLab: Equation (3), where V is the volumetric flow rate of the gas flow, and C2are coefficients and C3is a constant term. Each of C^V2, C2V, and C3may be referred to as a term of Equation (3). The determination in a controlled setting is carried out prior to a respiratory apparatus being used in the field (e.g., during a therapy session). This enables calibration of the respiratory apparatus as the respiratory system of the present disclosure may not have a pressure sensor at the patient end.

[0185] Using Equation (3), the magnitude of the pressure drop may be more accurately approximated over a range of flow rates. This more accurate approximation means that the respiratory system, using Equation (3) as the defined compensation function, may be able to better compensate for pressure drop and maintain close to the target pressure at the patient, as shown in Figure 6.

[0186] Figure 6 provides an illustration of the way in which the pressure at the patient may decrease with increasing flow rate if the pressure drop, which is dependent on the gas flow rate, is not compensated at all (see dashed line 580) and the compensation (a), as represented by arrow 584, that may be required to achieve the target pressure at the patient (see solid line 582). In other words, at a particular flow rate, the pressure at the patient is likely to be lower than the target pressure 582 because of the pressure drop if there is no compensation. If the pressure drop is compensated, the pressure at the patient is increased in magnitude towards the target pressure 582. When the pressure drop is fully compensated (see compensation (a) 584), the pressure 580 at the patient reaches the target pressure 582. The higher the calculated pressure drop, the more the blower in the respiratory apparatus will compensate (e.g., increase pressure).

[0187] Equation (3) may be an effective way to approximate the pressure drop under controlled conditions, where, as a non-limiting example, and C2may be constants, and C3is a constant term. However, the values obtained for Ct, C2, and C3under controlled conditions may not represent the real world conditions. In the real world, outside of the controlled laboratory conditions, e.g., when a patient is undergoing a therapy, the influence of the flow rate on the pressure drop may be dependent on a number of uncontrolled factors. Therefore, in the real world, the values for each of Ct, C2, and C3 for compensation of pressure drop may be different from those determined under the controlled conditions. For example, the values of one or more of Ct, C2, and C3in the real world may be different to the values under controlled conditions depending on the type of breathing conduit and / or patient interface (or specific tube-mask setup) being used for the therapy, the fit of the patient interface to the patient, and / or changing conditions during therapy, e.g., the breathing conduit may be bent or constricted, the patient may have moved or changed position, the patient may be lying on part of the breathing conduit, the patient interface may have shifted while being worn by the patient, etc. It should be appreciated that the values for each of C1, C2, and C3for pressure drop compensation may be different at various points in time during a therapy session because of changing conditions.

[0188] In some therapy cases, the values of , C2, and C3determined under controlled conditions may be adequate. They may result in adequate compensation in the form of a flow ratedependent pressure adjustment enacted by the blower or flow generator during therapy. However, in other cases, the values of Ct, C2, and C3determined under controlled conditions may be inadequate. They may not sufficiently fully compensate for the pressure drop at one or more or all flow rates that the respiratory system may need to employ during pressure-controlled therapy, as shown in the example of Figure 7.

[0189] Figure 7 provides an illustration of the way in which the pressure at the patient may decrease with increasing flow rate if the pressure drop, which is dependent on the gas flow rate, is partially compensated (see dotted line 681) with compensation (p), as represented by arrow 690. A further compensation (see compensation (n), as represented by the arrow 686) may be provided for the pressure at the patient to be able to reach the target pressure (see solid line 682).

[0190] For the techniques described herein, there may be a plurality or different predefined levels of compensation, which, for example, may be manually selected. As a non-limiting example, the UI of the respiratory apparatus may display different levels of compensation that may be selected by the user (e.g., patient or clinician). The partial compensation may present some challenges during therapy, as a clinician or health professional may not know if their patient is actually receiving the target pressure that they have prescribed for their patient. For example, the patient potentially may not be receiving the prescribed pressure or target pressure throughout their entire breath (especially when the flow rate is high during inhalation). Nevertheless, it should be appreciated that, while it may not be optimum, partial compensation for the pressure drop may still provide sufficiently effective therapy.

[0191] Further, it should be appreciated that the flow rate of the flow of gas generated by the respiratory apparatus can change throughout a therapy session. For example, the flow rate during inspiration may be greater than the flow rate during expiration.

[0192] Using Equation (3) as a non-limiting example, the defined compensation function associated with a respiratory apparatus may be C^V2+ C2V + C3. The techniques disclosed herein may allow for adjustment of the defined compensation function, or the values of one or more of C1 ?C2, and C3of the defined compensation function that may enable suitable compensation for the pressure drop that occurs in the gas flow along the flow path from the respiratory apparatus to the patient, i.e., boost mode. The values of one or more or each of Ct, C2, and C3may be increased or decreased. The adjustment may be based on or according to a user input.

[0193] The user may provide a user input for adjusting the defined compensation function, or the values of one or more of Ct, C2, and C3. The user input may be provided via a user interface (UI) of the respiratory apparatus that generates and provides the flow of gas. Additionally or alternatively, the user input may be provided via an external device that the respiratory apparatus can communicate with. The UI may be a graphical UI (GUI), a display screen (e.g., a touchscreen), a (physical) input device, etc. The GUI may include a plurality of graphical elements selectable by the user, and / or at least one slider bar slidable by the user. The user may, for example, tap, touch, make a sliding motion or a circular motion, etc. on one or more parts of the GUI or a touchscreen to make the adjustment to the defined compensation function, or the values of one or more of , C2, and C3. The input device may include a physical input device, e.g., at least one of a knob, a dial, a switch, a lever, a sliding bar, a button, etc. The external device may be a communications device (e.g., a mobile phone, a tablet, etc.), a computer, a server, a touchscreen.

[0194] In some configurations, the user may provide the user input using a one-touch or one- action operation.

[0195] In response to the user providing a user input, one or more modifier values may be applied to the defined compensation function to provide a pressure boost. In this way, a modified defined compensation function may be provided.

[0196] As a non-limiting example, a modifier value may be applied to the defined compensation function as a whole. For example, the modifier value, x, may be added to the defined compensation function as shown in Equation (4), or the defined compensation function may be multiplied by the modifier value, x, as shown in Equation (5).

[0197] Modified defined compensation function = x + ( F2+ C2V + C3) Equation (4), Modified defined compensation function = x(C1V2+ C2V + C3) Equation (5).

[0198] As another non-limiting example, one or more of Ct, C2, and C3of the defined compensation function may be modified individually to provide a modified defined compensation function. A modifier value may be applied to at least one of Ct, C2, or C3. The modifier value may be added to or multiplied with at least one of Ct, C2, or C3. Different modifier values may be applied to Ct, C2, and C3.

[0199] As another non-limiting example, one or more or all of Ct, C2, and C3of the defined compensation function may be modified by adjustment of a (or one) control parameter (e.g., control parameter “A”) associated with the defined compensation function. For example, in response to a user input, a control parameter “A” may be increased by 20%, which may result in an increase in Ctby about 20%, C2by about 18%, and C3by 2%. It should be appreciated that other amounts or percentages may be provided or defined for each of the control parameter “A”, Ct, C2, and C3. Further, it should be appreciated that C1, C2, and C3may be adjusted equally, i.e., by the same amount, or differently, as a result of adjusting the control parameter “A”.

[0200] Based on the defined compensation function that has been modified in response to a user input, the flow generator of the respiratory apparatus is adjusted or controlled to provide a flow of gas in accordance with or based on the modified defined compensation function to compensate for the pressure drop.

[0201] Depending on the user input, the pressure drop may be partially compensated or fully compensated. For example, the amount of compensation for the pressure drop may depend on the adjustment amount or value corresponding to the user input. Compensation of the pressure drop, even if partially, may increase the efficiency of the therapy provided to the patient, and / or increase the patient comfort.

[0202] While a defined compensation function is prescribed for a specific respiratory system, the defined compensation function remains applicable to be employed for the respiratory apparatus of the specific respiratory system, but using at least one of a breathing conduit or a patient interface that is not part of the defined specific respiratory system. As a nonlimiting example, while a breathing conduit and / or a patient interface may not have been used for defining the defined compensation function for the specific respiratory system, the breathing conduit and / or the patient interface may still be able to be coupled to or work with the respiratory apparatus of the specific respiratory system for use during therapy. While the defined compensation function may not have been prescribed for or may not be optimum for such a situation, nevertheless, the use of the defined compensation function provides an effective approach due to the ability of the user to provide user inputs that modify the defined compensation function to provide compensation for the pressure drop. As described above, conditions may change during a therapy session. For example, the pressure drop may be dependent on how a patient is using a specific breathing conduitpatient interface (or tube-mask) setup. This may include situations where the breathing conduit may be bent, and / or the patient may be lying on the breathing conduit, etc. where these factors may have an effect too. As the defined compensation function for a specific respiratory system may have been calibrated under controlled conditions, and which may not account for all types of conditions that may occur during therapy, the techniques disclosed herein provides an option or ability for the user to make changes during the therapy or on the fly (e.g., to provide a boost). Such an approach enables the defined compensation function to remain applicable under any conditions.

[0203] While the techniques have been described in relation to the defined compensation function of C^V2+ C2V + C3, it should be appreciated that other defined compensation functions may be used. As a non-limiting example, the defined compensation function may be varied by varying a value of the constant term C3. The defined compensation function or the type thereof to be used for a respiratory system may depend on which defined compensation function works most effectively for the respiratory system. Each defined compensation function may be modified by a modifier value as described herein. A defined compensation function may include one term, two terms, three terms, or any higher number of terms. A defined compensation function may include at least one term with a coefficient.

[0204] Further, it should be appreciated that there may be a plurality of defined compensation functions accessible to the respiratory apparatus or the controller thereof. Each defined compensation function may be associated with a respective pair of breathing conduit and patient interface (i.e., a particular breathing conduit-patient interface setup) that may be employed with the respiratory apparatus. A certain defined compensation function may be selected, out of the plurality of defined compensation functions, depending on the pair of breathing conduit and patient interface being employed or operated with the respiratory apparatus. As non-limiting examples, the techniques disclosed herein in relation to compensation for pressure drop may be executed and / or implemented in any suitable sealed respiratory apparatus and / or respiratory systems. As a non-limiting example, the respiratory apparatus used in the sealed system may operate in BiLevel or CPAP mode.

[0205] It should be appreciated that any suitable breathing conduit and / or patient interface may be used in or with the techniques disclosed herein. The patient interface may include any suitable types of sealed patient interfaces for use with respiratory support apparatus and / or systems to provide the boost mode described herein, for example, sealing masks such as full face masks and nasal masks as described below by way of non-limiting examples.

[0206] References in this specification to a patient interface may include a patient interface comprising a full face mask sealing around the mouth and nose of the user (or patient), and / or a patient interface comprising a nasal mask covering only the nose of the user (or patient). Figures 8 to 11 illustrate various different types of patient interfaces that may be used with one or more different systems and / or methods disclosed herein. Figure 8 illustrates a full face interface 201 that includes a nasal cannula 202 and seals around the patient’s nose and mouth, and is supplied with gas flow by conduit 203. Figure 9 illustrates a total face interface 204 that includes a nasal cannula 202 and substantially or fully seals around the patient’s face, including at least the patient’s nose, mouth, and eyes. Figure 10 illustrates a subnasal interface 205 that includes a nasal cannula 202 and seals around the patient’s mouth and nares on the underside of the nose. Figure 11 illustrates a nasal interface 206 that includes a nasal cannula and seals around only the nares of the patient. It should be appreciated that other forms of a nasal delivery portion may be used in place of a nasal cannula. and definitions

[0207] The term ‘comprising’ as used in this specification and claims means ‘consisting at least in part of’ or ‘including, but not limited to’ such that it is to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense. When interpreting each statement in this specification and claims that includes the term “comprising”, features other than that or those prefaced by the term may also be present. Related terms such as “comprise” and “comprises” are to be interpreted in the same manner.

[0208] The term ‘and / or’ means ‘and’ or ‘or’, or both.

[0209] As used herein, the phrase of the form of “at least one of A or B” may include A or B or both A and B. Correspondingly, the phrase of the form of “at least one of A or B or C”, or including further listed items, may include any and all combinations of one or more of the associated listed items.

[0210] The use of ‘(s)’ following a noun means the plural and / or singular forms of the noun.

[0211] Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that features, elements, and / or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and / or steps are included or are to be performed in any particular embodiment.

[0212] In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

[0213] It is noted that the embodiments may be described as a process that is depicted as a flowchart, a flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process is terminated when its operations are completed. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc., in a computer program. When a process corresponds to a function, its termination corresponds to a return of the function to the calling function or a main function.

[0214] The various illustrative logical blocks, modules, circuits, elements, and / or components described in connection with the examples disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic component, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, circuit, and / or state machine. A processor may also be implemented as a combination of computing components, e.g., a combination of a DSP and a microprocessor, a number of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0215] The methods or algorithms described in connection with the examples disclosed herein may be embodied directly in hardware, in a software module executable by a processor, or in a combination of both, in the form of processing unit, programming instructions, or other directions, and may be contained in a single device or distributed across multiple devices. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD- ROM, or any other form of storage medium known in the art. A storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. In its various aspects, embodiments of the disclosure can be embodied in a computer- implemented process, a machine (such as an electronic device, or a general purpose computer or other device that provides a platform on which computer programs can be executed), processes performed by these machines, or an article of manufacture. Such articles can include a computer program product or digital information product in which a computer readable storage medium containing computer program instructions or computer readable data stored thereon, and processes and machines that create and use these articles of manufacture.

[0216] This disclosure may also be said broadly to consist in the parts, elements and features referred to or indicated in this disclosure, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this disclosure relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

[0217] Features, materials, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example are to be understood to be applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The protection is not restricted to the details of any foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0218] For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. The scope of the present disclosure is not intended to be limited by the specific disclosures of embodiments in this section or elsewhere in this specification, and may be defined by claims as presented in this section or elsewhere in this specification or as presented in the future. The language of the claims is to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive.

Claims

CLAIMS1. A respiratory apparatus for providing a flow of gas, the respiratory apparatus comprising: a flow generator configured to generate the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

2. The respiratory apparatus as claimed in claim 1, wherein the defined compensation function is a pressure drop function.

3. The respiratory apparatus as claimed in claim 1 or 2, wherein the controller is configured to modify the defined compensation function and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function in response to receiving the data during delivery of the flow of gas to a patient.

4. The respiratory apparatus as claimed in any one of claims 1 to 3, wherein the defined compensation function is dependent on a flow rate of the flow of gas.

5. The respiratory apparatus as claimed in any one of claims 1 to 4, wherein, for modifying the defined compensation function, the controller is configured to apply at least one modifier value to the defined compensation function.

6. The respiratory apparatus as claimed in claim 5, wherein, for modifying the defined compensation function, the controller is configured to apply the at least one modifier value to the defined compensation function as a whole.

7. The respiratory apparatus as claimed in claim 5, wherein the defined compensation function comprises a plurality of terms, and wherein, for modifying the defined compensation function, the controller is configured to apply the at least one modifier value to one or more terms of the plurality of terms.

8. The respiratory apparatus as claimed in any one of claims 1 to 7, wherein the target pressure comprises a target inspiratory pressure, or wherein the target pressure comprises a target expiratory pressure, or wherein the target pressure comprises a target constant pressure for inspiration and expiration.

9. The respiratory apparatus as claimed in any one of claims 1 to 8, further comprising a user interface operatively coupled to the controller.

10. The respiratory apparatus as claimed in claim 9, wherein the user interface comprises a graphical user interface.

11. The respiratory apparatus as claimed in any one of claims 1 to 10, wherein the respiratory apparatus is configured to receive the data from an external device.

12. The respiratory apparatus as claimed in any one of claims 1 to 11, further comprising one or more sensors configured to determine a pressure of the flow of gas at an outlet of the flow generator.

13. The respiratory apparatus as claimed in any one of claims 1 to 12, wherein the controller is configured to modify the defined compensation function based on the user input to maintain at least a substantially consistent pressure at a point along the flow path, the point being downstream of the flow generator.

14. A method for controlling a respiratory apparatus for providing a flow of gas, the method comprising: in response to a controller of the respiratory apparatus receiving data indicative of a user input, the user input being indicative of a modification to a defined compensation function for compensating for a pressure drop in the flow of gas relative to a target pressure along a flow path of the flow of gas, wherein the flow of gas is generated by a flow generator of the respiratory apparatus under control of the controller according to the target pressure and based at least partly on the defined compensation function, modifying the defined compensation function based on the user input; and controlling the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

15. The method as claimed in claim 14, wherein the defined compensation function is a pressure drop function.

16. The method as claimed in claim 14 or 15, wherein the method comprises modifying the defined compensation function and controlling the flow generator to generate the flow of gas based at least partly on the modified defined compensation function in response to receiving the data during delivery of the flow of gas to a patient.

17. The method as claimed in any one of claims 14 to 16, wherein the defined compensation function is dependent on a flow rate of the flow of gas.

18. The method as claimed in any one of claims 14 to 17, wherein modifying the defined compensation function comprises applying at least one modifier value to the defined compensation function.

19. The method as claimed in claim 18, wherein applying the at least one modifier value to the defined compensation function comprises applying the at least one modifier value to the defined compensation function as a whole.

20. The method as claimed in claim 18, wherein the defined compensation function comprises a plurality of terms, and wherein applying the at least one modifier value to the defined compensation function comprises applying the at least one modifier value to one or more terms of the plurality of terms.

21. The method as claimed in any one of claims 14 to 20, wherein the target pressure comprises a target inspiratory pressure, or wherein the target pressure comprises a target expiratory pressure, or wherein the target pressure comprises a target constant pressure for inspiration and expiration.

22. The method as claimed in any one of claims 14 to 21 , further comprising receiving the user input provided by a user via a user interface of the respiratory apparatus.

23. The method as claimed in claim 22, wherein receiving the user input via the user interface comprises receiving the user input via a graphical user interface of the respiratory apparatus.

24. The method as claimed in any one of claims 14 to 23, comprising receiving the data from an external device.

25. The method as claimed in any one of claims 14 to 24, further comprising determining a pressure of the flow of gas at an outlet of the flow generator.

26. The method as claimed in any one of claims 14 to 25, wherein modifying the defined compensation function based on the user input comprises modifying the defined compensation function to maintain at least a substantially consistent pressure at a point along the flow path, the point being located downstream of the flow generator.

27. A respiratory apparatus for providing a flow of gas, the respiratory apparatus comprising: a flow generator configured to generate the flow of gas, the flow generator comprising a motor; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of a modification to the defined compensation function: modify the defined compensation function based on the user input; and control, based at least partly on the modified defined compensation function, a speed of the motor for the flow generator to generate the flow of gas to compensate for at least part of the pressure drop.

28. A respiratory apparatus for providing a flow of gas, the respiratory apparatus comprising: a flow generator configured to generate the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas,wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of an increment in a perceived pressure at a patient: modify the defined compensation function based on the user input; and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

29. The respiratory apparatus as claimed in any one of claims 27 to 28, wherein the defined compensation function is a pressure drop function.

30. The respiratory apparatus as claimed in any one of claims 27 to 29, wherein the controller is configured to modify the defined compensation function in response to receiving the data during delivery of the flow of gas to a patient.

31. The respiratory apparatus as claimed in any one of claims 27 to 30, wherein the defined compensation function is dependent on a flow rate of the flow of gas.

32. The respiratory apparatus as claimed in any one of claims 27 to 31 , wherein, for modifying the defined compensation function, the controller is configured to apply at least one modifier value to the defined compensation function.

33. The respiratory apparatus as claimed in claim 32, wherein, for modifying the defined compensation function, the controller is configured to apply the at least one modifier value to the defined compensation function as a whole.

34. The respiratory apparatus as claimed in claim 32, wherein the defined compensation function comprises a plurality of terms, and wherein, for modifying the defined compensation function, the controller is configured to apply the at least one modifier value to one or more terms of the plurality of terms.

35. The respiratory apparatus as claimed in any one of claims 27 to 34, wherein the target pressure comprises a target inspiratory pressure, or wherein the target pressure comprises a target expiratory pressure, or wherein the target pressure comprises a target constant pressure for inspiration and expiration.

36. The respiratory apparatus as claimed in any one of claims 27 to 35, further comprising a user interface operatively coupled to the controller.

37. The respiratory apparatus as claimed in claim 36, wherein the user interface comprises a graphical user interface.

538. The respiratory apparatus as claimed in any one of claims 27 to 37, wherein the respiratory apparatus is configured to receive the data from an external device.

39. The respiratory apparatus as claimed in any one of claims 27 to 538, further comprising one or more sensors configured to determine a pressure of the flow of gas at an outlet of the flow generator.

40. The respiratory apparatus as claimed in any one of claims 27 to 39, wherein the controller is configured to modify the defined compensation function based on the user input to maintain at least a substantially consistent pressure at a point along the flow path, the point being downstream of the flow generator.

41. A method for controlling a respiratory apparatus for providing a flow of gas, the method comprising: in response to a controller of the respiratory apparatus receiving data indicative of a user input, the user input being indicative of a modification to a defined compensation function for compensating for a pressure drop in the flow of gas relative to a target pressure along a flow path of the flow of gas, wherein the flow of gas is generated by aflow generator of the respiratory apparatus under control of the controller according to the target pressure and based at least partly on the defined compensation function, modifying the defined compensation function based on the user input; and controlling, based at least partly on the modified defined compensation function, a speed of a motor of the flow generator for the flow generator to generate the flow of gas to compensate for at least part of the pressure drop.

42. The method as claimed in any one of claims 41 , wherein the defined compensation function is a pressure drop function.

43. The method as claimed in any one of claims 41 to 42, wherein the method comprises modifying the defined compensation function in response to receiving the data during delivery of the flow of gas to a patient.

44. The method as claimed in claim any one of claims 41 to 43, wherein the defined compensation function is dependent on a flow rate of the flow of gas.

45. The method as claimed in any one of claims 41 to 44, wherein modifying the defined compensation function comprises applying at least one modifier value to the defined compensation function.

46. The method as claimed in claim 45, wherein applying the at least one modifier value to the defined compensation function comprises applying the at least one modifier value to the defined compensation function as a whole.

47. The method as claimed in claim 45, wherein the defined compensation function comprises a plurality of terms, and wherein applying the at least one modifier value to the defined compensation function comprises applying the at least one modifier value to one or more terms of the plurality of terms.

48. The method as claimed in any one of claims 41 to 47, wherein the target pressure comprises a target inspiratory pressure, or wherein the target pressure comprises a target expiratory pressure, or wherein the target pressure comprises a target constant pressure for inspiration and expiration.

49. The method as claimed in any one of claims 41 to 48, further comprising receiving the user input provided by a user via a user interface of the respiratory apparatus.

50. The method as claimed in claim 49, wherein receiving the user input via the user interface comprises receiving the user input via a graphical user interface of the respiratory apparatus.

51. The method as claimed in any one of claims 41 to 50, comprising receiving the data from an external device.

52. The method as claimed in any one of claims 41 to 51, further comprising determining a pressure of the flow of gas at an outlet of the flow generator.

53. The method as claimed in any one of claims 41 to 52, wherein modifying the defined compensation function based on the user input comprises modifying the defined compensation function to maintain at least a substantially consistent pressure at a point along the flow path, the point being located downstream of the flow generator.

54. A respiratory system for providing a flow of gas, the respiratory system comprising: a flow generator configured to generate the flow of gas; a breathing conduit configured to be operatively coupled to the flow generator to receive the flow of gas;a patient interface configured to be operatively coupled to the breathing conduit to receive the flow of gas; and a controller configured to control the flow generator to generate the flow of gas according to a target pressure, and based at least partly on a defined compensation function for compensating for a pressure drop in the flow of gas relative to the target pressure along a flow path of the flow of gas, wherein the controller is further configured to, in response to receiving data indicative of a user input, the user input being indicative of an increment in a perceived pressure at a patient: modify the defined compensation function based on the user input; and control the flow generator to generate the flow of gas based at least partly on the modified defined compensation function to compensate for at least part of the pressure drop.

55. The respiratory system as claimed in any one of claims 54, wherein the defined compensation function is a pressure drop function.

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