Positive airway pressure support system

Abstract

A control system for controlling pressure applied by a pressure source of a positive airway pressure support system is provided. A progressive increase is provided to the pressure applied during a fall-asleep period of a user of the system. Pressure modulation is applied during the progressive increase. A target respiration rate for facilitating the user is modulated.

Description

Technical Field

[0001] The present invention relates to positive airway pressure support systems and, in particular, to systems that provide a gradual increase in pressure as a user is about to sleep. Background Art

[0002] Positive airway pressure (PAP) is the first-line therapy for patients with moderate to severe obstructive sleep apnea (OSA) and is also a recommended intervention for chronic hypercapnic chronic obstructive pulmonary disease (COPD). Obstructive sleep apnea and insomnia are the two most common clinical symptoms seen in adult sleep clinics. Among the subtypes of insomnia, sleep maintenance insomnia (frequent awakenings at night) was found to be the most common type in patients with OSA, and the prevalence of sleep onset insomnia was similar to that of the general population. The prevalence of insomnia is increased in patients with COPD.

[0003] Studies have found that PAP therapy can significantly reduce symptoms of sleep maintenance insomnia, but not symptoms of sleep onset insomnia. Sleep onset insomnia may negatively affect PAP compliance because patients are awake longer and are therefore more likely to experience adverse aspects of the treatment (e.g., mask or airflow discomfort) for a longer period of time.

[0004] Various features of PAP therapy systems are known to improve comfort during PAP therapy and ultimately improve the overall user experience. For example, the use of a ramp pressure curve is often used to gradually increase air pressure over a fixed period of time to allow the patient to fall asleep before using a higher pressure setting (e.g., a therapeutic pressure).

[0005] The ramp delivers pressurized air from a low setting, gradually "ramping" up to the set pressure. The ramp function allows the patient to breathe the pressurized air comfortably while falling asleep. With the ramp function, PAP therapy starts at a low pressure (e.g., 4 cmH2O) and then slowly increases to the preset pressure (i.e., the therapeutic pressure) over a predetermined period of time (e.g., <45 min). However, for some PAP users with sleep-onset insomnia, falling asleep can still be challenging.

[0006] There remains a need for PAP systems to enable users to sleep more comfortably. Summary of the invention

[0007] The invention is defined by the claims.

[0008] According to an example of one aspect of the present invention, there is provided a control system for controlling the pressure applied by a pressure source of a positive airway pressure support system, wherein the control system comprises a controller configured to:

[0009] applying a gradual increase in pressure applied during a sleep period of a user of the system; and

[0010] Pressure modulation is applied during the gradual increase, wherein the modulation is used to facilitate a target breathing rate of the user.

[0011] During the user's attempt to fall asleep, the control system uses the pressure source of the PAP support system to implement a slow paced breathing (SPB) guidance function (i.e., setting a target breathing rate that the user attempts to follow). Pressure modulation means that superimposed on a gradual increase in applied pressure (e.g., a ramp), the pressure switches between higher and lower values ​​to correspond to a target inspiratory timing and a target expiratory timing.

[0012] Slow paced breathing is a breathing technique that aims to slow down the inspiratory and expiratory phases to a controlled rhythm determined by a visual, auditory or kinesthetic pacemaker. Spontaneous breathing in adults typically consists of between 12 and 20 breaths per minute (bpm). SPB of, for example, 6 bpm has been reported to have a positive effect on sleep quality and emotional well-being. The underlying mechanism may be explained by the fact that SPB enhances respiratory sinus arrhythmia, vagal afferent nerve fibers during the inspiratory phase, via stretching of pulmonary afferent nerve fibers and vagal afferent nerve fibers in the short and long term.

[0013] Thus, by promoting a target (low) breathing rate, sleep quality is improved and the user is assisted in falling asleep. Therefore, for patients suffering from sleep-onset insomnia, having PAP support is particularly meaningful. The slow breathing function occurs during the ramp phase of the pressure support, which is also used to assist the user in falling asleep by reducing the discomfort of PAP support when the user is initially about to fall asleep. The pressure source of the PAP system can also be used to provide a rhythmic mechanism for slow breathing. However, additional rhythmic mechanisms, such as auditory or tactile instructions for slow breathing, can be provided in addition.

[0014] A gradual increase in pressure (e.g., a ramp), for example, from a first pressure (e.g., 4 cmH2O=400 Pa) to a therapeutic pressure (e.g., 10 cmH2O=1 kPa). Different therapeutic pressures may be used, and, for example, the therapeutic pressure may be set at different levels for different users. For example, the target respiratory rate is a low respiratory rate, such as about 6 bpm.

[0015] For example, the controller is further configured to receive the user's current breathing rate from a breathing rate sensor.

[0016] The current breathing rate is used as a feedback parameter, for example, to control the level of the target breathing rate to make it suitable for the user's initial breathing rate and / or the user's current breathing rate, and to monitor whether the user is able to obtain the user's currently set target breathing rate. For example, if the current breathing rate is already lower than the desired breathing rate, the slow-paced breathing function is not needed. Therefore, the system can have an operating mode that does not use the slow-paced breathing function (pressure modulation).

[0017] For example, the controller is configured to apply pressure modulation for promoting a target breathing rate that is dependent on the user's current breathing rate. Thus, the target breathing rate may be made achievable for the user because it takes into account the user's current breathing rate.

[0018] For example, at the end of the progressive increase in applied pressure, there is a desired breathing rate to be achieved, and the controller is configured to:

[0019] In a first mode, if the current breathing rate is below a first threshold (A) and above a desired breathing rate, the desired breathing rate is set as a target breathing rate; and

[0020] In the second mode, if the current respiratory rate is higher than the threshold value, the target respiratory rate is set to a target value higher than the desired respiratory rate, and it is changed to the first mode when the current respiratory rate reaches the target value.

[0021] If the user has a breathing rate that is sufficiently close to the desired breathing rate, the desired slow-paced breathing rate can be the target value directly. If the user has a higher breathing rate, an additional higher breathing rate target value is set, and a subsequent reduction from the additional higher breathing rate target value to the desired breathing rate will be necessary.

[0022] The second mode may include a set of thresholds, wherein if the current breathing rate is above a maximum threshold, the controller is configured to set the target breathing rate to a maximum target value, change to a lower target value when the current breathing rate reaches the current target value, and change to the first mode when the current breathing rate reaches a minimum target value for the second mode.

[0023] Before reaching the desired end target value (ie the desired breathing rate), there may be one or more steps from the highest target value to one or more intermediate target values. In one example, there are two target values ​​before the desired breathing rate.

[0024] For example, one or more target breathing rates are set based on the user's initial breathing rate or default breathing rate. The target breathing rate may evolve over time to make progress toward a desired slow-paced breathing rate easier to achieve for a particular user.

[0025] For example, in the third mode, if the user cannot follow one or more target values ​​of the second mode and is still awake, the controller is configured to progressively and / or gradually reduce the target breathing rate from the starting value toward the desired breathing rate. This will occur if the second mode has been applied for a predetermined length of time.

[0026] For example:

[0027] If the current breathing rate is below the first threshold and above the desired breathing rate, the starting value in the third mode includes a target value (β3) that depends on the desired breathing rate (α) and the user's breathing rate and is greater than the desired breathing rate; and

[0028] If the current breathing rate is above the first threshold, the starting value in the third mode comprises a target value that is higher than the desired breathing rate of the second mode.

[0029] For example, the target value β3 is:

[0030] β3=α+a×(BR_user-α)

[0031] Thus, if the breathing rate is above the first threshold, the same target value as in the second mode can be used. However, if the breathing rate is already below the first threshold, a new starting target value is set (not immediately equal to the desired breathing rate as is the case for the first mode).

[0032] For example, the gradual reduction may be to reduce the target breathing rate at a fixed rate of change (e.g., a change of 0.5 bpm per minute). In one embodiment, the target breathing rate may be gradually reduced to the desired breathing rate. This will make the user more comfortable with the change in breathing rate.

[0033] For example, the controller is configured to determine a difference between a user's current breathing rate and a target breathing rate, thereby determining a measure of how well the user is able to follow the target breathing rate, and:

[0034] before the time period threshold has been reached, if the user is unable to follow the target breathing rate well enough and has not fallen asleep, ending the pressure modulation; and

[0035] If the user is able to follow the target breathing rate well enough but has not fallen asleep before the time period threshold has been reached, continuing pressure modulation; and

[0036] When the time period threshold has been reached or after the user has fallen asleep, the pressure modulation ends.

[0037] Once the user follows the target breathing rate with the assistance of the slow paced breathing function, the slow paced breathing function may continue until the user falls asleep (and therefore may no longer follow the guidance), or the slow paced breathing function may stop after a preset time. If the user cannot follow the target breathing rate, the pressure modulation may also end (as it does not work for that user) and a different mode may be used. The pressure modulation may end immediately upon detecting that the user has fallen asleep or at a fixed time thereafter.

[0038] For example, the controller is configured to implement:

[0039] There is no first overall system mode of gradual increase;

[0040] a second overall system mode with a gradual increase but without pressure modulation; and

[0041] A third overall system mode with a gradual increase and with pressure modulation.

[0042] Thus, the control system can be used in different ways for different users, depending on the user's need or desire for pressure ramping and the user's need for slow paced breathing assistance.Thus, the controller can perform conventional control methods as well as the novel method of the present invention.

[0043] For example, the controller is configured to select one or more target breathing rates (e.g., initial target values) for pressure modulation based on a category of the user, where the category is associated with the user's default breathing rate. Thus, the target breathing rate can start at a level suitable for a particular user, and the user is defined by category (e.g., fast breather, medium breather, slow breather).

[0044] For example, a default breathing rate is sensed when the system is initially used, and the category of the user is derived from the sensed breathing rate.

[0045] The pressure modulation may include a first pressure for an inhalation phase of the breathing cycle and a decrease from the first pressure to a second pressure for an exhalation phase of the breathing cycle.

[0046] For example, modulation produces an inspiratory pressure followed by a gradual pressure increase (ie, a ramp) and a lower expiratory pressure.

[0047] For example, modulation provides a drop in pressure for exhalation (eg, 1 to 2 cmH2O). The amount of the pressure drop may be fixed or may depend on the underlying ramp pressure, so that, for example, the amount of the pressure drop may be greater when the ramp pressure is greater.

[0048] The ramping pressure may be a smooth monotonic increase in pressure, or the ramping pressure may occur in steps.

[0049] The present invention also provides a positive airway pressure support system, comprising:

[0050] stressors; and

[0051] A control system as defined above for controlling the pressure applied by the pressure source.

[0052] The present invention also provides a method for controlling the pressure applied by a pressure source of a positive airway pressure support system, comprising:

[0053] applying a gradual increase in pressure applied during a sleep period of a user of the system; and

[0054] Pressure modulation is applied during the gradual increase, wherein the modulation is used to facilitate a target breathing rate of the user.

[0055] The invention also provides a computer program comprising computer program code means adapted to implement the method defined above when the program is run on a controller of a positive airway pressure support system defined above.

[0056] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] For a better understanding of the invention, and to show more clearly how it may be put into practice, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0058] Figure 1 A graph showing the pressure applied by a positive airway pressure (PAP) system over time, using the most basic embodiment of the present invention;

[0059] Figure 2 A graph showing the pressure applied by a positive airway pressure (PAP) system over time, using a more complex embodiment of the present invention;

[0060] Figure 3 A first portion of a flow chart for explaining the operation of a pressure control system is shown;

[0061] Figure 4 shows the different overall system modes that can be enabled, as follows Figure 3 Flowchart of

[0062] Figure 5 A first part of a flow chart is shown for explaining the different steps of the slow paced breathing function;

[0063] Figure 6 It shows how to determine when to stop the slow-paced breathing guidance for the situation where the user has fallen asleep or has not fallen asleep yet;

[0064] Figure 7 Breathing rate categories are shown;

[0065] Figure 8 An example of a user's breathing rate and a target breathing rate for a first scenario is shown:

[0066] Fig. 9 An example of a user's breathing rate and a target breathing rate for a second scenario is shown;

[0067] Fig.10 An example of the user's breathing rate and the target breathing rate for the third scenario is shown:

[0068] Fig.11 An example of a user's breathing rate and a target breathing rate for a fourth scenario is shown;

[0069] Fig.12 A positive airway pressure support system is shown. DETAILED DESCRIPTION

[0070] The present invention will be described with reference to the accompanying drawings.

[0071] It should be understood that when indicating exemplary embodiments of devices, systems and methods, the detailed description and specific examples are for illustrative purposes only and are not intended to limit the scope of the invention. These and other features, aspects and advantages of the devices, systems and methods of the present invention will be better understood from the following description, the appended claims and the accompanying drawings. It should be understood that the drawings are schematic only and are not drawn to scale. It should also be understood that the same reference numerals are used in the drawings to indicate the same or similar parts.

[0072] The present invention provides a control system for controlling the pressure applied by a pressure source of a positive airway pressure support system. A gradual increase is provided to the pressure applied during a sleep period of a user of the system. Pressure modulation is applied during the gradual increase. The modulation is used to promote a target breathing rate of the user.

[0073] Figure 1 A graph showing the pressure applied by a positive airway pressure (PAP) system over time, using the most basic embodiment of the present invention, is shown. The pressure increases along a ramp from a low level (such as 4 cmH2O=400Pa) at the start of the ramp to a therapeutic (treated) pressure (such as 10 cmH2O=1 kPa) at the end of the ramp. As shown, the ramp time has a duration, for example, in the range of 5 minutes to 45 minutes, and when the user of the PAP system attempts to fall asleep, the ramp time is the sleep onset phase.

[0074] During part or all of the ramp phase, there is a modulation time period (MTP). The modulation time period is a phase that provides guidance for slow-paced breathing. For example, the MTP has a duration of 5 to 20 minutes, and the MTP is used until the user falls asleep. If the user cannot fall asleep during the MTP, the PAP will continue to follow the ramp pressure or therapeutic (therapeutic) pressure without the slow-paced breathing guided by the pressure modulation.

[0075] Slow rhythm breathing guidance is provided as the modulation to ramp pressure, so that there is alternation between the stage of higher pressure and the stage of lower pressure. During the inhalation phase of guiding the user to perform the breathing cycle, a higher first pressure is used, and for the exhalation phase of the breathing cycle, there is a decline from a higher pressure to a lower second pressure. In the example shown, pressure is modulated so that the original slope is the maximum pressure, and as an example, modulation is therefore the pressure reduction of the square wave shape subtracted from the ramp curve. However, alternatively, the modulation of pressure can be an increase higher than the ramp, or an increase and reduction compared with the ramp.

[0076] The resulting waveform has a characteristic frequency (corresponding to a square wave curve as an example) and corresponds to the target breathing rate, i.e. the number of breaths per minute. Figure 1 In the simplest example of , the waveform sets a fixed and constant target breathing rate of 6 bpm. This target breathing rate is an example of a desired breathing rate for slow rhythmic breathing.

[0077] Figure 2 A graph showing the pressure applied by a positive airway pressure (PAP) system over time using a more complex embodiment of the invention is shown. For example, a target breathing rate is set by modulation of the pressure applied by the PAP system, evolving from a starting value of 12 bpm (i.e., a breathing rate calculated based on the user's actual breathing rate; if the user has a higher breathing rate, the modulation will start at a higher breathing rate) to 6 bpm (i.e., the target breathing rate). This approach provides a reduction in the breathing rate that the user is trying to follow.

[0078] The manner in which different target breathing rates may be set and how they evolve over time will be discussed in more detail below.

[0079] Figure 3 A first portion of a flow chart is shown for explaining the operation of one example of a pressure control system.

[0080] In step 1.0, the parameters of the PAP therapy are set, including the treatment pressure (P_treatment), the target slow breathing rate (α, e.g. 6 bpm), the preferred slow breathing category (if any), and the MTP time (T_preset). This step is performed before the first PAP use of the prescribed PAP therapy and does not require frequent changes.

[0081] In step 1.1, each treatment begins with the user putting on the device.

[0082] In step 1.2, the user turns on the PAP device. Pressurized air is then generated by the PAP device and delivered to the connected tube and mask. In step 1.3, the device detects a pressure change indicating that the mask has been put on, and then initiates the preset PAP therapy.

[0083] Figure 4 shows the different overall system modes that can be enabled, as follows Figure 3 Flowchart of the process.

[0084] In step 1.4, if the slow breathing function is set to OFF and the pressure ramp function is set to OFF, the preset PAP therapy will start immediately with P_treatment (no ramp and no slow breathing guidance). This situation can be considered to include the first overall system mode without gradual pressure increase.

[0085] If the pressure ramp function is set to ON, PAP delivers pressurized air from a low setting (eg, 4 cmH2O), gradually ramping up to the set pressure P_treatment.

[0086] If the slow breathing function is not turned ON, a conventional smooth (or stepped) pressure ramp is followed in step 1.5. In this step, the PAP system delivers pressurized air using the above ramp curve. This situation can be considered as a second overall system mode with gradual pressure increase but without pressure modulation for slow breathing guidance.

[0087] If the slow breathing function is ON, the user's breathing rate is detected in step 1.6. This detected breathing rate BR_user is compared with the desired breathing rate α. This is the user's target breathing rate and is determined by the PAP device by delivering Figure 1 and Figure 2 The rhythm achieved by the stepped lower and higher pressure levels is shown.

[0088] If the detected breathing rate BR_user is above α, a pressure ramp with SPB modulation is initiated in step 1.7. The PAP system delivers pressurized air in SPB mode, gradually ramping up from a low initial setting to treatment P_treatment, and with modulation of the pressure ramp to provide breathing guidance.

[0089] In step 1.8, the therapeutic pressure is reached at the end of the pressure ramp.

[0090] As mentioned above Figure 1 and Figure 2 As shown, there are different possible patterns for slow-paced breathing function.

[0091] Figure 5 The first part of a flow chart for explaining the different steps of the slow paced breathing function is shown. In particular, Figure 5 Three SPB modes are shown: fixed frequency, adaptive stepped frequency, and adaptive (dynamic) frequency.

[0092] The guided target breathing rate used in various SPB modes is based on the user's breathing rate (BR_user). BR_user can be measured by a sensor such as a pressure sensor installed in a PAP device.

[0093] In a first step 2.0, the user's initial breathing rate BR_user is measured. In this particular example, the user is placed in one of three categories based on two thresholds A and B for the user's initial (i.e., resting) breathing rate (or the user can manually select a category regardless of the user's breathing rate BR_user).

[0094] The first category is slow breathers, where the breathing rate is within the target slow paced breathing rate α (or Figure 3 0) and a first threshold A. As discussed below, users in this category follow a fixed frequency program.

[0095] The second category is mesobeat breathers, where the breathing rate is between a first threshold A and a second, higher threshold B. As discussed below, users in this category follow an adaptive step frequency program.

[0096] The third category is fast breathers, where the breathing rate is above the second threshold B. As discussed below, users in this category also follow the adaptive step rate program, but with more steps before the target breathing rate reaches the desired ending breathing rate.

[0097] As discussed further below, the adaptive (dynamic) frequency mode may be used when the user has not fallen asleep after the adaptive stepped frequency. The user may also choose to start in the adaptive frequency mode.

[0098] For example, threshold A is the lower limit of the normal breathing rate and threshold B is the upper limit of the normal breathing rate. For example, the normal breathing rate may be 6 to 12 bpm.

[0099] like Figure 5 As shown in Figure 3 In step 1.0, you can select which mode to follow (regardless of the user's breathing rate). Figure 5 The meaning of "or 1.0 PAP setting" in .

[0100] Line 50 illustrates that the adaptive (dynamic) frequency mode may be manually activated by the user, thereby proceeding directly to step 2.30.

[0101] The initiation of the slow breathing function can be done manually or automatically.

[0102] For manual start, the SPB mode can be manually pre-selected in the device settings before PAP therapy (in step 1.0). The user can start in fixed frequency mode, adaptive step frequency or adaptive (dynamic) frequency mode and continue with the pre-selected mode until the SPB function ends, regardless of which breathing category the user has.

[0103] For Auto-Start, SPB mode is automatically selected prior to PAP therapy based on the user's real-time (initial) breathing rate (BR_user) and therefore the user's breathing rate category.

[0104] When the breathing rate BR_user falls into the slow breather category, a fixed frequency (mode 1) is selected in step 2.1: the PAP system starts the pressure ramp at a preset target frequency α and starts the SPB mode. The preset target frequency α is the expected slow rhythm breathing rate. Then, the PAP pressure waveform example is as follows Figure 1 For example, let the user BR_user with 11bpm follow Figure 8 A fixed frequency of 6bpm for the example shown in .

[0105] When BR_user falls into the moderate breather category, the adaptive stepped frequency mode is selected in step 2.2. The PAP system starts the pressure ramp with an initial target breathing rate β1 and starts the SPB mode. The initial target breathing rate β1 can be selected based on the initial user breathing rate BR_user. When checking whether the user is able to follow the target value β1, the target value β1 is sustained for a short time. If the user is able to follow the target value β1, the process proceeds to step 2.1, thereby using the fixed frequency mode, in which the target value is set to the desired final slow-paced breathing rate α. In the adaptive stepped frequency mode, the target value β1 is immediately changed to the desired final slow-paced breathing rate α without a gradual change process.

[0106] When the breathing rate BR_user falls into the fast breather category, an adaptive step frequency is also selected in step 2.3, but at a higher initial target value. The PAP system starts a pressure ramp at a higher preset target frequency β2 and starts the SPB mode. When checking whether the user is able to follow the target value β2, this target value β2 is maintained for a short time. If the user is able to follow the target value β2, the process proceeds to step 2.2, thereby setting a new lower target value β1. Once the target value β1 can be followed, the process proceeds to step 2.1 again. For the change from target value β2 to target value β1 and the change from target value β1 to the desired final slow-paced breathing rate α, these two changes occur immediately without a gradual change process.

[0107] The values ​​of β1 and β2 depend on the user's initial breathing rate. For example:

[0108] β1=α+a×(BR_user-A)

[0109] β2=α+b×(BR_user-A)

[0110] a∈(0,1),b∈(0,1),a <b.

[0111] The value (BR_user-A) is a measure of the amount by which the user's breathing rate exceeds the lower limit of the normal breathing rate range.

[0112] By way of example, a=0.5, b=0.7, and Figure 8 and Fig. 9 These values ​​are used in the examples in . This approach ensures that a user with a higher breathing rate can start with a relatively high breathing rate, so the user can adjust to a slower breathing rate more comfortably.

[0113] When the user cannot follow these two modes (fixed frequency or stepped frequency) and is still awake, the adaptive (dynamic) frequency mode is activated. This mode uses a larger number of smaller decreases in the target breathing rate. Thus achieving a gradual and gradual smooth change in the target breathing rate.

[0114] like Figure 5 As shown, if sleep is not detected and the difference BR_Δ (between the current breathing rate and the target breathing rate) exceeds a threshold value (such as 1 bpm), steps 2.1, 2.2 and 2.3 end and the process proceeds to step 2.30.

[0115] The current breathing rate is detected in step 2.30.

[0116] If the user's breathing rate is below threshold A (but above the desired breathing rate α), then in step 2.4, the target breathing rate starts from a new target value β3 and then gradually decreases to α. For example:

[0117] β3=α+a×(BR_user-α)

[0118] If the user's breathing rate is between threshold A and threshold B, then in step 2.6 the target breathing rate starts from value β1 and then gradually decreases to α.

[0119] If the user's breathing rate is above threshold B, then in step 2.5 the target breathing rate starts from value β2 and then gradually decreases to α.

[0120] For example, the taper process used in the third mode has a constant target breathing rate reduction rate, such as a reduction rate of 0.5 bpm per minute (see Fig.11 ).

[0121] Thus, the adaptive frequency mode gradually reduces the target breathing rate until the target breathing rate is the desired ending breathing rate for slow paced breathing, ie, α. The starting point depends on the current breathing rate.

[0122] If the user has fallen asleep, the slow-paced breathing guidance ends.

[0123] Figure 6 It shows how to determine when to stop the slow pace breathing guidance for the situation where the user has not fallen asleep yet. Figure 6 Next Figure 5 .

[0124] After executing the SPB mode for a fixed time, if the user is able to follow the SPB mode (for example, if BR_Δ is in the range of 0 to 1) and is still awake, SPB will continue until T_preset is reached. This situation is shown in step 3.1. If the user is able to follow the SPB mode and still has not fallen asleep when the maximum time T_preset is reached, the SPB mode stops in step 3.2.

[0125] If the user cannot follow the SPB pattern (eg if BR_Δ>1) and is still awake, SPB will also stop in step 3.2.

[0126] If the user is unable to follow the SPB pattern (eg if BR_Δ>1) but nevertheless falls asleep, SPB will stop in step 3.2.

[0127] As explained above, if the time of slow rhythm breathing exceeds a threshold value T_preset, the process proceeds to step 3.2. This threshold value T_preset can be defined at the beginning of the therapy. The maximum time of SPB and therefore T_preset should be shorter than the ramp phase.

[0128] As mentioned above, determining whether the target breathing rate can be followed is based on the value of BRΔ. After starting each SPB pattern, BR_Δ is calculated based on the difference between the guided rate and BR_user within a fixed time. If BR_Δ = [0, 1], the user can follow the current SPB pattern, otherwise not.

[0129] For detection of sleep, falling asleep during PAP therapy is detected in a known manner based on changes in respiratory rate, flow, and events (ie, large standard deviations in respiratory rate, detection of lower flows, and apnea events).

[0130] Figure 7 The breathing rate categories described above are shown.

[0131] Slow breathers are in the range of α (eg, 6) to A (eg, 12) (if their resting rate is below α, they do not need SPB guidance).

[0132] Moderate breathers are in the range of A (eg, 12) to B (eg, 20).

[0133] Fast breathers are higher than B (e.g. 20).

[0134] Figure 8 An example of a user breathing rate (curve 80) and a target breathing rate (curve 82) is shown for the following scenario: In this scenario, the user's breathing rate BR_user is detected to be 11 bpm ( Figure 7The SPB mode is automatically set to a breathing target value α=6bpm. The user will try to slow down the breathing rate until the user reaches 6bpm and follows 6bpm during the user's awake time. When the user falls asleep, the user's breathing rate increases. Failure to follow the SPB target breathing rate and falling asleep are detected by the device, and when sleep is detected, the SPB mode stops and therapy continues, following an unmodulated ramp. When the SPB mode ends, the target breathing rate can be considered to be zero.

[0135] Fig. 9 An example of a user breathing rate (curve 90) and a target breathing rate (curve 92) is shown for the following alternative scenario: In this alternative scenario, the user's breathing rate BR_user is detected to be 20 bpm ( Figure 7 The SPB mode is automatically set to βl = 10 bpm. The user will attempt to slow down the breathing rate until the user reaches 10 bpm (becoming a moderate breather). Figure 7 ). After that, the SPB target value is automatically set to α=6bpm. The user will try to slow down the breathing rate until the user reaches 6bpm and follows 6bpm during awake time. When the user falls asleep, his / her breathing rate increases and the SPB pattern stops. When the SPB pattern ends, the target breathing rate can be considered to be zero again.

[0136] Fig.10 An example of a user breathing rate (curve 100) and a target breathing rate (curve 102) is shown for the following alternative scenario: In this alternative scenario, the user's breathing rate BR_user is detected to be 30 bpm ( Figure 7 The user will attempt to slow down the breathing rate until the user reaches 19 bpm (becoming a fast breather). Figure 7 Then, SPB is automatically set to β1=9bpm. The user will try to slow down the breathing rate until the user reaches 9bpm (becoming a slow breather). After that, SPB is automatically set to the breathing target value α=6bpm. The user will try to slow down the breathing rate until the user reaches 6bpm and follows 6bpm during the awake time.

[0137] Fig.11 An example of a user's breathing rate (curve 110) and a target breathing rate (curve 112) when using an adaptive (dynamic) frequency mode is shown. In this case, the user has manually selected to start with an adaptive (dynamic) frequency without going through the fixed and adaptive step frequency modes.

[0138] The user's breathing rate BR_user is detected as 18bpm ( Figure 7The SPB target breathing rate is automatically set to β1 = 9 bpm. The user will try to slow down the breathing rate until the user reaches 9 bpm (becomes Figure 7 Then, SPB decreases gradually over time from 9 bpm until the user reaches 6 bpm (α) (e.g., decreasing at a rate of 0.5 bpm per minute).

[0139] Fig.12 A positive airway pressure support system is shown, comprising a PAP pressure source 120 and a control system 122 for implementing the control method described above. The control system 122 has a ramp generator 124 and a pressure modulator 126.

[0140] The present invention provides a method of controlling the pressure applied by a pressure source of a positive airway pressure support system to apply a gradual increase in the pressure applied during the sleep time period and to apply pressure modulation. The method is preferably implemented in software that controls the pressure source of the positive airway pressure system. The software includes a computer program, i.e., computer program code means, which is executed by a processor that forms part of the control system of the positive airway pressure system. For example, the computer program is implemented as a computer program medium (i.e., a storage device).

[0141] Those skilled in the art can understand and implement changes to the disclosed embodiments when practicing the claimed invention by studying the drawings, the present disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0142] The functions implemented by a processor may be implemented by a single processor or multiple independent processing units, which may be considered to collectively constitute a “processor.” These processing units may be remote from each other in some cases and communicate with each other by wired or wireless means.

[0143] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0144] The computer program may be stored / distributed on an appropriate medium, such as an optical storage medium or a solid-state medium, which is provided together with or as a part of other hardware, but the computer program may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0145] If the term "adapted to" is used in the claims or the description, it should be noted that the term "adapted to" is intended to be equivalent to the term "configured to". If the term "device" is used in the claims or the description, it should be noted that the term "device" is intended to be equivalent to the term "system" and vice versa.

[0146] Any reference signs in the claims should not be construed as limiting the scope of the present invention.

Claims

1. A control system (122) for controlling the pressure applied by a pressure source of a positive airway pressure support system, wherein the control system comprises a controller (124, 126) configured to: applying a gradual increase to the pressure applied during a sleep period of a user of the system; and Pressure modulation is applied during the gradual increase, wherein the modulation is used to facilitate a target breathing rate of the user.

2. The system of claim 1, wherein the controller is further configured to receive the user's current breathing rate from a breathing rate sensor.

3. The system of claim 2, wherein the controller is configured to apply pressure modulation to facilitate a target breathing rate that is dependent on the current breathing rate of the user.

4. A system according to claim 3, wherein at the end of the progressive increase in the applied pressure, there is a desired breathing rate (α) to be achieved, and wherein the controller is configured to: In a first mode, if the current breathing rate is below a first threshold (A) and above the desired breathing rate, setting the desired breathing rate (α) as the target breathing rate; and In the second mode, if the current breathing rate is higher than a threshold value (A), the target breathing rate is set to a target value (β1) higher than the desired breathing rate (α), and the mode is changed to the first mode when the current breathing rate reaches the target value (β1).

5. A system according to claim 4, wherein the second mode includes a set of thresholds (A, B), wherein if the current respiratory rate is higher than a maximum threshold (B), the controller is configured to set the target respiratory rate to a maximum target value (β2), and to change to a lower target value (β1) when the current respiratory rate reaches the current target value (β2), and to change to the first mode when the current respiratory rate reaches a minimum target value (β1) of the second mode.

6. A system according to claim 4 or 5, wherein one or more target breathing rates are set according to an initial breathing rate or a default breathing rate of the user.

7. The system of claim 4, 5 or 6, wherein the controller is configured to: In a third mode, if the user cannot follow the one or more target values ​​(β1, β2) of the second mode and is still awake, the target breathing rate is gradually reduced from a starting value towards the desired breathing rate (α).

8. The system of claim 7, wherein: If the current breathing rate is lower than the first threshold (A) and higher than the expected breathing rate (α), the starting value in the third mode includes a target value (β3) that depends on the expected breathing rate (α) and the user's breathing rate (BR_user) and is greater than the expected breathing rate; and If the current breathing rate is higher than the first threshold (A), the starting value in the third mode comprises the target value (β1, β2) higher than the desired breathing rate (α) of the second mode.

9. The system according to any one of claims 2 to 8, wherein the controller is configured to determine a difference (BR_Δ) between the current breathing rate of the user and the target breathing rate, thereby determining whether the user is able to follow the target breathing rate, and: before a time period threshold has been reached, if the user is unable to follow the target breathing rate well enough and has not fallen asleep, ending the pressure modulation; as well as before the time period threshold has been reached, if the user is able to follow the target breathing rate well enough but has not fallen asleep, continuing the pressure modulation; as well as The pressure modulation is ended when the time period threshold has been reached or after the user has fallen asleep.

10. The system according to any one of claims 1 to 9, wherein the controller is configured to implement: A first overall system mode without said progressive increase; a second overall system mode having said progressive increase but without said pressure modulation; and A third overall system mode having said gradual increase and having said pressure modulation.

11. The system according to any one of claims 1 to 10, wherein the controller is configured to select one or more target breathing rates for the pressure modulation according to a category of a user, wherein the category is associated with a default breathing rate of the user.

12. The system of any one of claims 1 to 11, wherein the pressure modulation comprises a first pressure for an inspiratory phase of a breathing cycle and a decrease from the first pressure to a second pressure for an expiratory phase of the breathing cycle.

13. A positive airway pressure support system, comprising: Stressors; as well as A control system as claimed in any one of claims 1 to 12, for controlling the pressure applied by the pressure source.

14. A method of controlling the pressure applied by a pressure source of a positive airway pressure support system, comprising: applying a gradual increase to the pressure applied during a sleep period of a user of the system; as well as Pressure modulation is applied during the gradual increase, wherein the modulation is used to facilitate a target breathing rate of the user.

15. A computer program comprising computer program code means adapted to implement the method of claim 14 when said program is run on said controller of said positive airway pressure support system of claim 13.

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