System and method for improved compliance in respiratory therapy

Systems and methods to provide respiratory therapy may determine a target pressure level in a current therapy session on the successful completion and/or compliance of a patient (for example for at least a threshold amount of respiratory therapy) during one or more prior therapy sessions. By gradually increasing the provided pressure level, patients may improve compliance, comfort, and/or other indicators of how well-tolerated the respiratory therapy is for a patient.

The present disclosure pertains to a system and method for providing respiratory therapy through a pressure support device, and, in particular, to improving compliance by gradually increasing one or more pressure levels used during respiratory therapy.

It is well known that some types of respiratory therapy involve the delivery of a flow of breathable gas to the airway of a subject, for example through a positive airway pressure device. It is known that a flow of breathable gas may be pressurized at varying levels of pressure, even during a single therapy session. It is known that one or more algorithms may operate to control and/or adjust the pressure level used in respiratory therapy. It is known that measurements or estimations of various gas parameters can be used in a feedback manner to control and/or adjust the pressure level used in respiratory therapy. It is known that increased pressure levels may not be very comfortable for subjects, in particular subjects that are relatively new to using a positive airway pressure device. It is known that compliance to a respiratory therapy regimen is related to comfort and ease-of-use.

Accordingly, it is an object of one or more embodiments of the present invention to provide a system for providing respiratory therapy to a subject having an airway. The system comprises a pressure generator, one or more sensors, one or more processors, a compliance module, a target module, and a control module. The pressure generator is configured to generate a pressurized flow of breathable gas for delivery to the airway of the subject. The one or more sensors are configured to generated output signals conveying information related to one or more gas parameters of the pressurized flow of breathable gas. The one or more processors are configured to execute processing modules. The compliance module is configured to determine whether the subject successfully completes a threshold amount of respiratory therapy during therapy sessions. The target module is configured to determine a target pressure for the pressurized flow of breathable gas during a current therapy session. The target pressure is based on a prescribed therapy regimen and determinations by the compliance module pertaining to prior therapy sessions. The control module is configured to adjust levels of one or more gas parameters of the pressurized flow of breathable gas based on the determined target pressure.

It is yet another aspect of one or more embodiments of the present invention to provide method for providing respiratory therapy to a subject having an airway. The method comprises generating a pressurized flow of breathable gas for delivery to the airway of the subject; generating output signals conveying information related to one or more gas parameters of the pressurized flow of breathable gas; determining a compliance determination, wherein the compliance determination is based on whether the subject successfully completes a threshold amount of respiratory therapy during a first therapy session; determining a target pressure for the pressurized flow of breathable gas during a second therapy session subsequent to the first therapy session, wherein the target pressure is based on a prescribed therapy regimen and the compliance determination pertaining to the first therapy session; and adjusting levels of one or more gas parameters of the pressurized flow of breathable gas based on the determined target pressure.

It is yet another aspect of one or more embodiments to provide a system configured for providing respiratory therapy to a subject having an airway. The system comprises means for generating a pressurized flow of breathable gas for delivery to the airway of the subject; means for generating output signals conveying information related to one or more gas parameters of the pressurized flow of breathable gas; means for determining a compliance determination, wherein the compliance determination is based on whether the subject successfully completes a threshold amount of respiratory therapy during a first therapy session; means for determining a target pressure for the pressurized flow of breathable gas during a second therapy session subsequent to the first therapy session, wherein the target pressure is based on a prescribed therapy regimen and the compliance determination pertaining to the first therapy session; and means for adjusting levels of one or more gas parameters of the pressurized flow of breathable gas based on the determined target pressure.

FIG. 1schematically illustrates a system100for providing respiratory therapy to a subject106. System100may be implemented as, integrated with, and/or operating in conjunction with a respiratory therapy device. System100measures, determines, and/or estimates whether a subject successfully completed at least a threshold amount of respiratory therapy during a therapy session, and bases the pressure level of a pressure flow of breathable gas thereon. System100gradually increases the provided pressure level in order to improve the quality, comfort, effectiveness, and/or long-term results of the respiratory therapy.

A therapy “session” of using system100may be defined as a period of substantially uninterrupted therapeutic usage of system100, not to exceed some upper threshold of (consecutive) hours. The upper threshold may be, for example, about 10 hours, about 12 hours, about 16 hours, about 24 hours and/or other time periods. If the respiratory therapy is used to treat sleeping disorders, the related session length may correspond to the sleeping pattern of a subject. A typical session length may thus be about eight hours. Alternatively, and/or simultaneously, a therapy session may be defined as a period of substantially uninterrupted therapeutic usage of system100, not to span less than some lower threshold of (consecutive) units of time, and/or at least a minimum period of time apart from a previous session. The lower threshold may be, for example, about 15 minutes, about 30 minutes, about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours and/or other time periods. For example, a minute of usage may be too short to be regarded as a session. For example, two 3-hour periods of usage separated by a 10-minute gap may be regarded as one session rather than two sessions. Individual therapy sessions may have a beginning and an end. Individual therapy sessions may form a sequence of therapy sessions, such that the current therapy sessions may be distinguished from one or more prior therapy sessions. Prior therapy sessions may also be referred to as previous therapy sessions.

In some embodiments, one or more operative levels (e.g. pressure, volume, etc.) are adjusted on a relatively ongoing manner (e.g., between individual breaths, every few breaths, every few seconds, every minute, etc.) during an individual therapy session to titrate the therapy.

System100includes one or more of a pressure generator140, a delivery circuit180, one or more sensors142, an electronic storage130, a user interface120, a processor110, a compliance module111, a target module112, a control module113, a sleep detection module114, a swallow detection module115, and/or other components.

Pressure generator140of system100inFIG. 1may be integrated, combined, coupled, and/or connected with a (positive) airway pressure device (PAP/CPAP/BiPAP®/etc.). Pressure generator140may be configured to provide a pressurized flow of breathable gas for delivery to the airway of subject106, e.g. via an output or outlet of pressure generator140, and/or via a delivery circuit180. Delivery circuit180may sometimes be referred to as subject interface180. Subject106may initiate one or more phases of respiration. Respiratory therapy may be implemented as pressure control, pressure support, volume control, and/or other types of support and/or control. For example, to support inspiration, the pressure of the pressurized flow of breathable gas may be adjusted to an inspiratory pressure. Alternatively, and/or simultaneously, to support expiration, the pressure and/or flow of the pressurized flow of breathable gas may be adjusted to an expiratory pressure. Adjustments may be made numerous times in implementations using auto-titrating for providing respiratory support through the delivery of the pressurized flow of breathable gas. In addition to alternating between multiple levels, the inhalation pressure level may ramp up or down according to a predetermined slope (absolute and/or relative, e.g. dependent on breathing rate) for any specified section of a phase. Similar features may be available for exhalation phases. The pressure levels may be either predetermined and fixed, follow a predetermined dynamic characteristic, or they may dynamically change from breath-to-breath or night-to-night depending on sensed breathing, breathing disorder, or other physiological characteristics. Pressure generator140is configured to adjust one or more of pressure levels, flow, humidity, velocity, acceleration, and/or other parameters of the pressurized flow of breathable gas, e.g. in substantial synchronization with the breathing cycle of subject106.

A positive airway pressure device may be configured such that one or more gas parameters of the pressurized flow of breathable gas are controlled in accordance with a therapeutic respiratory regimen for subject106. The one or more gas parameters include one or more of flow, volume, retrograde volume, pressure, humidity, velocity, acceleration, (intentional) gas leak, and/or other parameters. System100may be configured to provide types of therapy including therapy where a subject performs inspiration and/or expiration of his own accord and/or where the device provides negative airway pressure.

A pressurized flow of breathable gas is delivered from pressure generator140to the airway of subject106via a delivery circuit180. Delivery circuit180may include a conduit182and/or a subject interface appliance184. Conduit182may include a flexible length of hose, or other conduit, either in single-limb or dual-limb configuration that places subject interface appliance184in fluid communication with pressure generator140. Conduit182forms a flow path through which the pressurized flow of breathable gas is communicated between subject interface appliance184and pressure generator140. Conduit182may comprise a standard 22 mm diameter hose (other common diameters range between ¾″ and 1″) or, in certain embodiments, a much smaller diameter hose that is in the range of • of a standard size hose. Such a hose, which may be referred to as a restricted flow hose or limited flow hose, (for example, having a diameter ranging between ¼″ and •″, or alternatively between 6 mm and 9 mm) has a greater resistance to gas flow and allows/requires a lower peak flow, typically of less than 50% compared to a standard size hose (in some embodiments between 20%-30% of the peak flow through a standard size hose). Less flow and less energy are required when using a smaller hose to operate the system, in a manner described herein, to provide respiratory therapy. Additionally, such a system may be smaller and/or less obtrusive.

Subject interface appliance184of system100inFIG. 1is configured to deliver the pressurized flow of breathable gas to the airway of subject106. As such, subject interface appliance184may include any appliance suitable for this function. In some embodiments, subject interface appliance184is configured to be removably coupled with another interface appliance being used to deliver respiratory therapy to subject106. For example, subject interface appliance184may be configured to engage with and/or be inserted into an endotracheal tube, a tracheotomy portal, and/or other interface appliances. In one embodiment, subject interface appliance184is configured to engage the airway of subject106without an intervening appliance. In this embodiment, subject interface appliance184may include one or more of an endotracheal tube, a nasal cannula, a tracheotomy tube, a nasal mask, a nasal/oral mask, a full-face mask, a total facemask, and/or other interface appliances that communicate a flow of gas with an airway of a subject. The present disclosure is not limited to these examples, and contemplates delivery of the pressurized flow of breathable gas to subject106using any subject interface.

Electronic storage130of system100inFIG. 1comprises electronic storage media that electronically stores information. The electronic storage media of electronic storage130may include one or both of system storage that is provided integrally (i.e., substantially non-removable) with system100and/or removable storage that is removably connectable to system100via, for example, a port (e.g., a USB port, a FireWire port, etc.) or a drive (e.g., a disk drive, etc.). Electronic storage130may include one or more of optically readable storage media (e.g., optical disks, etc.), magnetically readable storage media (e.g., magnetic tape, magnetic hard drive, floppy drive, etc.), electrical charge-based storage media (e.g., EPROM, EEPROM, RAM, etc.), solid-state storage media (e.g., flash drive, etc.), and/or other electronically readable storage media. Electronic storage130may store software algorithms, information determined by processor110, information received via user interface120, and/or other information that enables system100to function properly. For example, electronic storage130may record or store timing information (including duration of inhalation phases and exhalation phases as well as transitional moments), one or more (breathing) parameters and/or other parameters (as discussed elsewhere herein), pressure levels, information indicating whether the subject successfully completed at least a threshold amount of prescribed respiratory therapy, information indicating whether a respiratory event (including Cheyne-Stokes respiration, central sleep apnea, obstructive sleep apnea, hypopnea, snoring, hyperventilation, and/or other respiratory events) occurred, information indicating adequacy of treatment, and/or other information. For example, stored information may be organized per day, per week, per therapy session, and/or in other ways. Electronic storage130may be a separate component within system100, or electronic storage130may be provided integrally with one or more other components of system100(e.g., processor110).

User interface120of system100inFIG. 1is configured to provide an interface between system100and a user (e.g., user108, subject106, a caregiver, a therapy decision-maker, etc.) through which the user can provide information to and receive information from system100. This enables data, results, and/or instructions and any other communicable items, collectively referred to as “information,” to be communicated between the user and system100. An example of information that may be conveyed to user108is a report detailing compliance information and/or occurrences of respiratory events throughout a period during which the subject is receiving therapy. Examples of interface devices suitable for inclusion in user interface120include a keypad, buttons, switches, a keyboard, knobs, levers, a display screen, a touch screen, speakers, a microphone, an indicator light, an audible alarm, and a printer. Information may be provided to user108or subject106by user interface120in the form of auditory signals, visual signals, tactile signals, and/or other sensory signals.

It is to be understood that other communication techniques, either hard-wired or wireless, are also contemplated herein as user interface120. For example, in one embodiment, user interface120may be integrated with a removable storage interface provided by electronic storage130. In this example, information is loaded into system100from removable storage (e.g., a smart card, a flash drive, a removable disk, etc.) that enables the user(s) to customize system100. Other exemplary input devices and techniques adapted for use with system100as user interface120include, but are not limited to, an RS-232 port, RF link, an IR link, modem (telephone, cable, Ethernet, internet or other). In short, any technique for communicating information with system100is contemplated as user interface120.

One or more sensors142of system100inFIG. 1are configured to generate output signals conveying measurements related to gas parameters of respiratory airflow, parameters related to airway mechanics, and/or other parameters. Gas parameters may include flow, (airway) pressure, humidity, velocity, acceleration, and/or other gas parameters. Output signals may convey measurements related to respiratory parameters. Sensor142may be in fluid communication with conduit182and/or subject interface appliance184. Sensor142may generate output signals related to physiological parameters pertaining to subject106. Parameters may be associated with the state and/or condition of an airway of subject106, the breathing of subject106, the gas breathed by subject106, the composition of the gas breathed by subject106, the delivery of the gas to the airway of subject106, and/or a respiratory effort by the subject. For example, a parameter may be related to a mechanical unit of measurement of a component of pressure generator140(or of a device that pressure generator140is integrated, combined, or connected with) such as valve drive current, rotor speed, motor speed, blower speed, fan speed, or a related measurement that may serve as a proxy for any of the parameters listed herein through a previously known and/or calibrated mathematical relationship.

The illustration of sensor142including two members inFIG. 1is not intended to be limiting. In some hardware configurations, system100may use only one sensor142. The individual sensor142may be located at or near subject interface appliance184, or at other locations. In some hardware configurations, system may include a sensor142at or near an output of pressure generator140. The illustration of a sensor142at or near subject interface appliance184and a sensor142at or near an output of pressure generator140is not intended to be limiting. Resulting signals or information from one or more sensors142may be transmitted to processor110, user interface120, electronic storage130, and/or other components of system100. This transmission may be wired and/or wireless.

The one or more sensors142may be configured to generate output signals in an ongoing manner during a therapy session. This may include generating signals intermittently, periodically (e.g. at a sampling rate), continuously, continually, at varying intervals, and/or in other ways that are ongoing during at least a portion of a therapy session. For example, in some embodiments, the generated output signals may be considered as a vector of output signals, such that a vector includes multiple samples of information conveyed related to one or more gas parameters and/or other parameters. Different parameters may be related to different vectors. A particular parameter determined in an ongoing manner from a vector of output signals may be considered as a vector of that particular parameter.

Processor110of system100inFIG. 1is configured to provide information processing capabilities in system100. As such, processor110includes one or more of a digital processor, an analog processor, a digital circuit designed to process information, an analog circuit designed to process information, a state machine, and/or other mechanisms for electronically processing information. Although processor110is shown inFIG. 1as a single entity, this is for illustrative purposes only. In some embodiments, processor110includes a plurality of processing units.

As is shown inFIG. 1, processor110is configured to execute one or more computer program modules. The one or more computer program modules include one or more of compliance module111, target module112, control module113, sleep detection module114, swallow detection module115, therapy amount module116, randomness module117, and/or other modules. Processor110may be configured to execute modules111-117by software; hardware; firmware; some combination of software, hardware, and/or firmware; and/or other mechanisms for configuring processing capabilities on processor110.

It should be appreciated that although modules111-117are illustrated inFIG. 1as being co-located within a single processing unit, in embodiments in which processor110includes multiple processing units, one or more of modules111-117may be located remotely from the other modules. The description of the functionality provided by the different modules111-117described herein is for illustrative purposes, and is not intended to be limiting, as any of modules111-117may provide more or less functionality than is described. For example, one or more of modules111-117may be eliminated, and some or all of its functionality may be incorporated, shared, integrated into, and/or otherwise provided by other ones of modules111-117. Note that processor110may be configured to execute one or more additional modules that may perform some or all of the functionality attributed below to one of modules111-117.

One or more modules of system100inFIG. 1may be configured to determine one or more gas parameters, breathing parameters, and/or other parameters from output signals generated by sensor(s)142, for example in an ongoing manner. The one or more gas parameters may include and/or be related to one or more of (peak) flow rate, flow rate, (tidal) volume, pressure, temperature, humidity, velocity, acceleration, gas composition (e.g. concentration(s) of one or more constituents such as, e.g., CO2), thermal energy dissipated, (intentional) gas leak, and/or other measurements related to the (pressurized) flow of breathable gas. One or more gas parameters may be determined at different locations and/or positions within system100, including within pressure generator140, at or near an output of pressure generator140, within subject interface180, at or near the point of engagement between pressure generator140and subject interface180, within conduit182, at or near an input of conduit182, at or near an output of conduit182, within subject interface appliance184, at or near an input of subject interface appliance184, at or near an output of subject interface appliance184, and/or at other locations and/or positions within system100.

One or more modules of system100may derive one or more breathing parameters from one or more determined gas parameters and/or generated output signals. The one or more breathing parameters may include one or more of respiratory rate, breathing period, inhalation time or period, exhalation time or period, respiration flow curve shape, transition time from inhalation to exhalation and/or vice versa, transition time from peak inhalation flow rate to peak exhalation flow rate and/or vice versa, respiration pressure curve shape, maximum proximal pressure drop (per breathing cycle and/or phase), and/or other breathing parameters. Alternatively, and/or simultaneously, vectors of parameters may be derived in an ongoing manner during a therapy session from vectors of generated output signals and/or other (vectors of) determined parameters.

Therapy amount module116is configured to determine the amount of provided respiratory therapy subject106completed successfully during therapy sessions. The amount may be determined on a per-session basis. In some embodiments, the amount of respiratory therapy may be cumulative, such that multiple shorter periods of successful completion with the provided respiratory therapy may be added together to reach a total amount for a particular therapy session, so long as the shorter periods are part of the same therapy session. Alternatively, and/or simultaneously, in some embodiments, the amount of respiratory therapy may need to be reached in a consecutive, continuous, and/or substantially uninterrupted manner within one therapy session. Combinations and/or variations of both approaches to determine the total amount per therapy session are considered within the scope of this disclosure. Various and varying standards to determine whether respiratory therapy is considered “completed successfully” may be implemented. Successful completion may for example be based on detecting whether subject106removed subject appliance interface184during respiratory therapy. Successful completion may for example be based on one or more of detections of occurrences of respiratory events, determinations of randomness and/or variability in breathing patterns (e.g. by randomness module117), detections of occurrences of temporary flow limitations, and/or other factors. Determinations by therapy amount module116may be performed and/or updated in an ongoing manner during a therapy session.

Compliance module111is configured to obtain a threshold amount of respiratory therapy, e.g. through user interface120. Compliance module111is further configured to determine whether subject106successfully completed at least a threshold amount of respiratory therapy during a therapy session by comparing the obtained threshold amount to an amount as determined by therapy amount module116.

Randomness module117may be configured to determine a measure of randomness in the breathing pattern of subject106during at least part of a therapy session. Randomness may be determined through statistical analysis of a variability (and/or other statistical operation) of the duration of inhalations, the duration of exhalations, any other breathing parameter, and/or combinations thereof. If respiratory therapy is well-tolerated, the randomness may be lower than moments or periods during which the respiratory therapy is not well-tolerated. If subject106is struggling to endure and/or undergo a particular type or setting of provided respiratory therapy, the determined randomness in the breathing pattern may indicate this in a quantitative manner.

In some embodiments, a patient-specific baseline for a measure of randomness may be determined during a low level of pressure or even no pressure. Such a baseline of randomness may subsequently be compared, during a subsequent therapy session, with a randomness in the breathing pattern during at least part of the subsequent therapy session. A particular increase in randomness may indicate that the current respiratory therapy (e.g. at the current pressure level) is not well-tolerated, not comfortable, not completed successfully, and/or not compliant for the purpose of a determination by compliance module111. In some implementations, compliance determinations by compliance module111may be based on one or more determinations by randomness module117. Determinations by randomness module117may be performed and/or updated in an ongoing manner during a therapy session.

By way of illustration,FIG. 2Aillustrates a graph20of a randomness index (along the X-axis) in a breathing pattern of a particular subject versus pressure level (along the Y-axis) of, e.g., a pressurized flow of breathable gas being provided during respiratory therapy. Minimum pressure22may indicate a lower threshold for a target pressure level for respiratory therapy, or a pressure offset to be applied to a target pressure level being provided during a therapy session. Maximum pressure21may indicate an upper threshold for a target pressure level for respiratory therapy, or a pressure offset to be applied to a target pressure level being provided during a therapy session. As indicated inFIG. 2A, responsive to a measured, determined, and/or estimated randomness in the breathing pattern of a particular subject during a given therapy session at or near the value of a minimum randomness23, e.g. a baseline randomness as established using the provision of no or low pressure, (and possibly in conjunction with one or more other factors and/or considerations) the system and/or an algorithm described herein (seeFIG. 2B) may be configured to determine that the particular subject successfully completed respiratory therapy at the target pressure level and may further be configured to adjust the target pressure for one or more subsequent therapy sessions. For example, the current target pressure level may be increased and/or offset by a value similar to and/or the same as maximum pressure21for the subsequent therapy session. Alternatively, and/or simultaneously, a compliance determination may be favorably affected by a low index of randomness, for example such that a smaller amount of respiratory therapy qualifies as being compliant in conjunction with a low index of measured, determined, and/or estimated randomness.

As further indicated inFIG. 2A, responsive to a measured, determined, and/or estimated randomness in the breathing pattern of a particular subject during a given therapy session at or near the value of a maximum randomness24, (and possibly in conjunction with one or more other factors and/or considerations) the system and/or an algorithm described herein (seeFIG. 2B) may be configured to determine that the particular subject successfully completed respiratory therapy at the target pressure level and may further be configured to adjust the target pressure for one or more subsequent therapy sessions. For example, the current target pressure level may be decreased and/or offset by a value similar to and/or the same as minimum pressure22for the subsequent therapy session. Alternatively, and/or simultaneously, a compliance determination may be negatively affected by a high index of randomness, for example such that a threshold amount of respiratory therapy fails to qualify as being compliant in conjunction with a high index of measured, determined, and/or estimated randomness.

Target module112is configured to determine a target pressure for the pressurized flow of breathable gas during a current therapy session. The target pressure may be in accordance with a therapy regimen, and may dynamically change and/or titrate during one or more therapy sessions. For example, the therapy regimen may prescribe a particular pressure level. The target pressure may further be based on one or more determinations by compliance module111pertaining to one or more prior therapy sessions. For example, target module112may start therapy using a below-prescription pressure level (such as e.g. a minimum pressure level) as the target pressure that is below the prescribed pressure level. Responsive to subject106successfully completing a threshold amount of respiratory therapy during one or more therapy sessions using the below-prescription pressure level, target module112may gradually increase the target pressure level for subsequent therapy sessions, e.g. using small increments such as 1 cm-H2O. Through repeated and gradual increments of the target pressure level over the course of multiple therapy sessions, and assuming continued successful completion by subject106as described previously, the target pressure determined by target module112will eventually reach the prescribed pressure level of the therapy regimen. In some embodiments, responsive to subject106failing to successfully complete at least a threshold amount of respiratory therapy during a particular therapy session at a particular target pressure level, target module112may be configured to maintain and/or reduce the target pressure level for a subsequent therapy session, which may depend on the value of the current target pressure level in relation to the prescribed pressure level. Target module112may be configured to implement an algorithm to determine the target pressure, as well as increasing and/or reducing the target pressure, as described herein. The target pressure may be adjusted as the prescribed pressure level changes.

By way of illustration,FIG. 2Billustrates an exemplary algorithm used to provide respiratory therapy to a particular subject, and, in particular, to determine a target pressure level for a current therapy session. Note that similar algorithms using more or fewer steps may be envisioned within the scope of this disclosure. Note that the examples provided in relation toFIG. 2Bare not intended to be limiting in any way. At a step201, the prescribed pressure level is checked against a threshold level of, for example, 11 cm-H2O. Other threshold levels are contemplated. If the prescribed pressure level is higher than the threshold level, the algorithm may continue at a step202, otherwise at a step207. At step207, the target pressure level is set to the prescribed pressure level. At step202, the target pressure level is set to a predetermined fraction of the prescribed pressure level, such as 50%. Other fractions or functions of the prescribed pressure level are contemplated. After step207and/or step202, the algorithm may continue at a step203. At step203, the target pressure level is used to provide a pressurized flow of breathable gas during the current therapy session. In some embodiments, a therapy session may coincide with provided respiratory therapy during an entire night, e.g. covering all or most of the period the particular subject is sleeping. After step203, the algorithm may continue at a step204. At step204, compliance by the particular subject is checked to verify whether the particular subject successfully completed at least a threshold amount of respiratory therapy during the therapy session provided and/or administered during step203. If the particular subject was successful, as determined at step204, the algorithm may continue at a step205, otherwise at a step209. At step209, the current target pressure level is checked against a lower threshold level of, for example, 5 cm-H2O. Other lower threshold levels are contemplated. If the current target pressure level is below the lower threshold level, the algorithm may continue at a step211, otherwise at a step210. At step211, a healthcare provider and/or other qualified medical personnel may be notified. At step210, the target pressure level may be reduced, e.g. by an amount of 1 cm-H2O. Other fixed and/or variable amounts for reducing the target pressure level are contemplated. Responsive to this reduction, the algorithm may continue at step203for a subsequent therapy session. At step205, responsive to the particular subject successfully completing at least a threshold amount of respiratory therapy as determined at step204, the current target pressure may be compared to the prescribed pressure level. If these pressure levels are equal and/or similar, the algorithm may continue at a step208, indicating standard respiratory therapy. Otherwise, the algorithm may continue at a step206. Step206the target pressure level may be increased, e.g. by an amount of 1 cm-H2O. Other fixed and/or variable amounts for increasing the target pressure level are contemplated. Responsive to this increase, the algorithm may continue at step203for a subsequent therapy session.

Control module113is configured to control operation of system100during therapy sessions. Control module113may be configured to control the pressure generator to adjust one or more levels of gas parameters of the pressurized flow of breathable gas in accordance with one or more of a (respiratory) therapy regimen, based on one or more target pressures determined by target module112, based on one or more algorithms that control adjustments and/or changes in the pressurized flow of breathable gas (including, e.g., the algorithm described in relation toFIG. 2B), and/or based on other factors. Referring toFIG. 1, control module113may be configured to control pressure generator140to provide the pressurized flow of breathable gas. Control module113may be configured to control pressure generator140such that one or more gas parameters of the pressurized flow of breathable gas are varied over time in accordance with a respiratory therapy regimen.

One or more parameters based on output signals generated by sensors142may be used by control module113, e.g. in a feedback manner, to adjust one or more therapy modes/settings/operations of system100. Alternatively, and/or simultaneously, signals and/or information received through user interface120may be used by control module113, e.g. in a feedback manner, to adjust one or more therapy modes/settings/operations of system100. Control module113may be configured to time its operations relative to transitional moments in the breathing cycle of a subject, over multiple breath cycles, and/or in any other timing relation.

Sleep detection module114is configured to detect sleep onset of subject106. Determinations of the target pressure by target module112may further be based on whether sleep onset has been detected. For example, once sleep onset has been detected, the target pressure may be gradually increased in order to build up tolerance to increased pressure levels for respiratory therapy. Increased and/or improved tolerance may improve compliance. The target pressure may be decreased to the pre-sleep level once subject106is detected to be awake.

Swallow detection module115is configured to detect swallowing by subject106. Since swallowing air, or aerophagia, may contribute to a reduced level of comfort and/or compliance, the target pressure may be temporarily reduced by target module112during the process of swallowing by subject106in order to reduce aerophagia, and thus improve compliance.

FIG. 3illustrates a method300for providing respiratory therapy to a subject. The operations of method300presented below are intended to be illustrative. In certain embodiments, method300may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed. Additionally, the order in which the operations of method300are illustrated inFIG. 3and described below is not intended to be limiting.

At an operation302, a pressurized flow of breathable gas is generated for delivery to the airway of the subject via an output of the pressure generator. In some embodiments, operation302is performed by a pressure generator similar to or substantially the same as pressure generator140(shown inFIG. 1and described herein).

At an operation304, output signals conveying information related to one or more gas parameters of the pressurized flow of breathable gas are generated. In some embodiments, operation304is performed by one or more sensors similar to or substantially the same as one or more sensors142(shown inFIG. 1and described herein).

At an operation306, a compliance determination is determined. The compliance determination is based on whether the subject successfully completes a threshold amount of respiratory therapy during a first therapy session. In some embodiments, operation306is performed by a compliance module similar to or substantially the same as compliance module111(shown inFIG. 1and described herein).

At an operation308, a target pressure is determined for the pressurized flow of breathable gas during a second therapy session subsequent to the first therapy session. The target pressure is based on a prescribed therapy regimen and the compliance determination pertaining to the first therapy session. In some embodiments, operation308is performed by a target module similar to or substantially the same as target module112(shown inFIG. 1and described herein).

At an operation310, levels of one or more gas parameters of the pressurized flow of breathable gas are adjusted based on the determined target pressure. In some embodiments, operation310is performed by a control module similar to or substantially the same as control module113(shown inFIG. 1and described herein).