Continuous positive airway pressure (CPAP) equipment and ventilation pressure control methods

Abstract

This application relates to a continuous positive airway pressure (CPAP) device and a method for controlling ventilation pressure. The minimum operating pressure is determined by acquiring a preset treatment pressure and a target pressure drop. The device monitors the patient's respiratory phase transitions in real time and employs different pressure regulation strategies for the inspiratory and expiratory phases. During the inspiratory phase, the ventilation pressure is smoothly adjusted from the preset treatment pressure to the minimum operating pressure and maintained to reduce inspiratory effort. During the expiratory phase, the ventilation pressure is gradually increased from the minimum operating pressure to ensure that the ventilation pressure returns to the preset treatment pressure at the end of the expiratory phase, maintaining airway support and avoiding the risks of airway closure and central apnea. This application improves patient comfort during CPAP therapy, enhances treatment compliance, and simultaneously ensures airway support while reducing the risks of airway closure and central apnea.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a continuous positive airway pressure ventilation device and a ventilation pressure control method. Background Technology

[0002] Continuous positive airway pressure (CPAP) is the mainstream treatment for obstructive sleep apnea. It works by continuously delivering positive airway pressure to maintain airway patency and prevent apnea. However, in clinical practice, patients commonly experience discomfort such as difficulty inhaling and high expiratory resistance. These problems significantly affect patient adherence to treatment, thereby reducing its effectiveness.

[0003] Current comfort-oriented pressure control technologies have several shortcomings. While traditional expiratory pressure release techniques can reduce pressure and expiratory resistance during the expiratory phase, this weakens airway support. Especially at the end of expiration, when lung volume is at its lowest and the airway is most prone to collapse, depressurization significantly increases the risk of airway closure and central apnea, and fails to effectively address the problem of labored inspiration. Inspiratory segmented depressurization techniques, which have emerged in recent years, have made some attempts to address the problem of labored inspiration, but the step-like pressure changes can lead to patient-ventilator asynchrony, causing discomfort and failing to adequately meet clinical needs. Therefore, developing a ventilation pressure control technology that effectively solves the above problems is of significant practical importance. Summary of the Invention

[0004] Based on this, the purpose of this application is to provide a continuous positive airway pressure (CPAP) device and a ventilation pressure control method to improve patient comfort during CPAP treatment, enhance treatment compliance, and at the same time ensure airway support and reduce the risk of airway closure and central sleep apnea.

[0005] The ventilation pressure control method described in this application is applied to a continuous positive airway pressure (CPAP) ventilation system, and the method includes the following steps:

[0006] Obtain the preset treatment pressure and the target pressure drop; determine the minimum working pressure based on the preset treatment pressure and the target pressure drop; Real-time monitoring of the patient's respiratory phase switching status; When the respiratory phase is detected to switch from the expiratory phase to the inspiratory phase, the ventilation pressure is smoothly adjusted from the preset treatment pressure to the minimum working pressure and maintained at the minimum working pressure until the end of the inspiratory phase. When the respiratory phase changes from inspiratory to expiratory phase, the ventilation pressure is gradually increased from the minimum working pressure to maintain the ventilation pressure at the end of the expiratory phase at the preset treatment pressure.

[0007] This application also provides a continuous positive airway pressure ventilation device, including a processor, a memory, and a computer-readable program stored in the memory, wherein the computer-readable program, when executed by the processor, implements the steps of the method described in any one of the embodiments of this application.

[0008] This application applies to continuous positive airway pressure (CPAP) devices. First, a preset treatment pressure and target pressure reduction are obtained, and a minimum operating pressure is determined. This step combines the baseline pressure required for treatment with the pressure reduction range set to reduce inspiratory effort, precisely planning the minimum achievable pressure value during the inspiratory phase, providing key parameters for subsequent pressure regulation. Real-time monitoring of the patient's respiratory phase transitions allows for timely detection of changes in respiratory rhythm, serving as a trigger signal for pressure regulation. When a transition from expiratory to inspiratory phase is detected, the ventilation pressure is smoothly adjusted from the preset treatment pressure to the minimum operating pressure and maintained until the end of the inspiratory phase. This smooth pressure reduction avoids asynchrony between the patient and the device caused by sudden pressure changes, reducing inspiratory resistance and making inspiratory processes easier. When a transition from inspiratory to expiratory phase occurs, the ventilation pressure is gradually increased from the minimum operating pressure, maintaining the preset treatment pressure at the end of the expiratory phase. This gradual pressure increase ensures sufficient airway support throughout the expiratory phase, effectively preventing airway collapse, especially at the end of expiration, and reducing the risk of airway closure and central sleep apnea. Through the above-mentioned sequential and precise technical means, the embodiments of this application effectively reduce the patient's difficulty in inhalation while ensuring airway support, and improve the patient's comfort and treatment compliance during continuous positive airway pressure ventilation.

[0009] To better understand and implement this application, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0010] Figure 1 This is a schematic flowchart of the ventilation pressure control method according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a continuous positive airway pressure ventilation device according to an embodiment of this application. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings. Wherein, when the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0012] It should be understood that the embodiments described below do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0013] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application are also intended to include the plural forms unless the context clearly indicates otherwise. Furthermore, in the description of this application, unless otherwise stated, “a plurality” means two or more. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items, for example, A and / or B, which can represent: A alone, A and B together, and B alone; the character “ / ” generally indicates that the preceding and following objects are in an “or” relationship.

[0014] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, this information should not be limited to these terms, and these terms are only used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Depending on the context, the word "if" as used in this application can be interpreted as "when," "when," or "in response to determination."

[0015] Please refer to Figure 1 The ventilation pressure control method described in this application embodiment is applied to a continuous positive airway pressure ventilation device, and the method includes the following steps: S101: Obtain the preset treatment pressure and the target pressure drop; determine the minimum working pressure based on the preset treatment pressure and the target pressure drop; S102: Real-time monitoring of the patient's respiratory phase switching status; S103: When the respiratory phase is detected to switch from the expiratory phase to the inspiratory phase, the ventilation pressure is smoothly adjusted from the preset treatment pressure to the minimum working pressure and maintained at the minimum working pressure until the end of the inspiratory phase; S104: When the respiratory phase is detected to switch from the inspiratory phase to the expiratory phase, the ventilation pressure is controlled to gradually increase from the minimum working pressure, so that the ventilation pressure at the end of the expiratory phase is maintained at the preset treatment pressure.

[0016] This application applies to continuous positive airway pressure (CPAP) devices. First, a preset treatment pressure and target pressure reduction are obtained, and a minimum operating pressure is determined. This step combines the baseline pressure required for treatment with the pressure reduction range set to reduce inspiratory effort, precisely planning the minimum achievable pressure value during the inspiratory phase, providing key parameters for subsequent pressure regulation. Real-time monitoring of the patient's respiratory phase transitions allows for timely detection of changes in respiratory rhythm, serving as a trigger signal for pressure regulation. When a transition from expiratory to inspiratory phase is detected, the ventilation pressure is smoothly adjusted from the preset treatment pressure to the minimum operating pressure and maintained until the end of the inspiratory phase. This smooth pressure reduction avoids asynchrony between the patient and the device caused by sudden pressure changes, reducing inspiratory resistance and making inspiratory processes easier. When a transition from inspiratory to expiratory phase occurs, the ventilation pressure is gradually increased from the minimum operating pressure, maintaining the preset treatment pressure at the end of the expiratory phase. This gradual pressure increase ensures sufficient airway support throughout the expiratory phase, effectively preventing airway collapse, especially at the end of expiration, and reducing the risk of airway closure and central sleep apnea. Through the above-mentioned sequential and precise technical means, the embodiments of this application effectively reduce the patient's difficulty in inhalation while ensuring airway support, and improve the patient's comfort and treatment compliance during continuous positive airway pressure ventilation.

[0017] The ventilation pressure control method described in this application uses a continuous positive airway pressure (CPAP) device as the implementing entity. A CPAP device is a ventilation therapy device capable of continuously delivering positive air pressure to the patient's airway to maintain airway patency. Specifically, a CPAP device can be a fixed-pressure CPAP device, an automatic pressure-adjustable APAP device, or a modified positive pressure ventilation device with expiratory / inspiratory pressure release functions. Air pressure regulation and respiratory synchronization can be achieved through a fan, sensors, and a control unit.

[0018] The following explains each step.

[0019] For step S101, obtain the preset treatment pressure and the target pressure drop; determine the minimum working pressure based on the preset treatment pressure and the target pressure drop.

[0020] The preset treatment pressure is a baseline pressure value pre-set during continuous positive airway pressure (CPAP) therapy to ensure basic airway patency and maintain normal respiratory function. This pressure value is determined by medical professionals based on a comprehensive assessment of the patient's specific condition and physical status, and serves as the fundamental reference value for overall ventilation pressure control. In one embodiment, the preset treatment pressure can be a fixed treatment pressure determined through sleep titration, a dynamic treatment pressure automatically adjusted by the device, or a target support pressure manually set by the physician or user, used to maintain airway patency at end-expiratory phase.

[0021] The target pressure reduction is a pre-set value representing the amount of pressure reduction required from a preset treatment pressure to reduce the effort exerted by the patient during inhalation. This value needs to be set by comprehensively considering factors such as the patient's inspiratory capacity, comfort needs, and treatment safety. In this embodiment, the target pressure reduction is a parameter representing the amount of pressure reduction the user expects during the inspiratory phase. Specifically, it can be determined in the following ways: a fixed reduction mapped from the pressure release level, a numerical reduction directly input by the user, or an optimal reduction automatically recommended by the device based on tolerance, such as a configurable pressure reduction of 1–4 cmH2O.

[0022] The minimum operating pressure is the lowest safe operating pressure that the ventilation device can reach during the inspiratory phase. It is calculated based on the preset treatment pressure and the target pressure drop, and represents the lowest pressure value that the device can achieve during the patient's inspiratory phase. It is set to improve patient inspiratory comfort while ensuring therapeutic efficacy. In this embodiment, the minimum operating pressure is calculated by subtracting the target pressure drop from the treatment pressure, and is limited by the device's minimum stable operating pressure. This satisfies inspiratory comfort requirements while ensuring the device can normally detect respiration, maintain the air seal, and provide stable air supply.

[0023] The preset treatment pressure in this step is to ensure the basic effectiveness of the treatment and keep the airway open. The target pressure reduction is set based on patient comfort, reducing inspiratory resistance. Determining the minimum operating pressure using these two parameters provides a clear target value for subsequent pressure adjustments during the inspiratory phase, ensuring that pressure regulation meets treatment needs while also considering patient comfort. In terms of implementation, this step can be achieved by medical personnel manually inputting the preset treatment pressure and target pressure reduction values ​​into the ventilation equipment's control system. For example, a dedicated input box can be provided on the ventilation equipment's interface, allowing medical personnel to input the corresponding values ​​based on the patient's specific situation. After receiving these two values, the control system calculates the minimum operating pressure according to a preset algorithm. The algorithm can be a simple subtraction operation: minimum operating pressure = preset treatment pressure - target pressure reduction; or it can consider factors such as the patient's age and weight, employing a more complex formula.

[0024] In one embodiment, step S101, obtaining the preset treatment pressure, includes: Step S1011: Obtain the patient's airway support baseline pressure.

[0025] Airway support baseline pressure refers to the minimum pressure value required to maintain the opening of a patient's airway under normal physiological conditions. This pressure value is determined by a comprehensive assessment of various factors such as the patient's airway physiological characteristics and respiratory status. It is a key pressure indicator to ensure that the patient's airway does not collapse due to its own tissues or external factors during exhalation.

[0026] This step can obtain the pressure value in several ways. One method is to use specialized airway pressure monitoring equipment, such as a respiratory monitor with a high-precision pressure sensor, connected to the patient's airway. While the patient is breathing naturally, the pressure data required to maintain airway patency is monitored and recorded over a period of time. Statistical analysis of this data, such as taking the average or median, yields the patient's baseline airway support pressure. Another method is to combine the patient's physiological parameters, such as age, weight, lung function indicators (e.g., vital capacity, forced expiratory volume in one second), and medical history, using a pre-established mathematical model or algorithm to calculate the baseline airway support pressure.

[0027] Step S1012: The airway support reference pressure is determined as the preset treatment pressure; wherein the preset treatment pressure is used to maintain the patient's airway open state during the expiratory phase.

[0028] After obtaining the patient's airway support baseline pressure, it is directly used as the preset treatment pressure. This is because the airway support baseline pressure is the minimum pressure required to maintain airway occupancy. Using it as the preset treatment pressure ensures that during treatment, when the patient is in the expiratory phase, just enough pressure is provided to maintain airway occupancy, preventing airway collapse due to insufficient pressure or unnecessary burden or discomfort to the patient due to excessive pressure. For example, if the patient's airway support baseline pressure is measured or calculated to be 10 cmH2O, then the preset treatment pressure is set to 10 cmH2O, and the treatment device is set and adjusted according to this pressure value.

[0029] This embodiment first obtains the patient's airway support baseline pressure and then sets it as the preset treatment pressure to maintain the patient's airway patency during the expiratory phase. This allows for precise determination of the required treatment pressure based on the patient's individual airway physiological characteristics. Because the pressure is set based on the patient's actual airway support needs, it ensures that just the right pressure is provided during the expiratory phase, effectively preventing airway collapse, ensuring smooth breathing, and improving treatment efficacy.

[0030] In one embodiment, step S101, obtaining the target pressure drop, includes: Step S1013: Obtain the pressure relief level set by the user.

[0031] Pressure release level is a rating system set by the user based on their own feelings, treatment needs, or doctor's advice, used to measure the degree of pressure release. Different pressure release levels correspond to different pressure drops, providing users with an intuitive and convenient way to control the extent of pressure reduction.

[0032] In practical implementation, a dedicated pressure release level selection area can be set up on the treatment device with an operating interface, such as using a knob, button, or touchscreen. Users can select different pressure release levels according to their needs by rotating the knob, pressing the corresponding button, or clicking on the touchscreen. For example, if the treatment device has five levels from 1 to 5, a user who feels the current air pressure is too high and wants to significantly reduce it can select level 5; if they only want to fine-tune the air pressure, they can select level 1. Alternatively, the treatment device can be connected to a mobile terminal application. The user sets the pressure release level on the application interface, and then the application transmits the setting information to the treatment device.

[0033] Step S1014: Determine the target pressure drop based on the pressure drop corresponding to the pressure release level.

[0034] The treatment device pre-stores a table mapping pressure release levels to pressure drop amplitudes. Upon receiving the user-set pressure release level, the device consults this table to find the corresponding pressure drop amplitude, thus determining the target pressure drop amplitude. For example, the table might look like this: Pressure release level 1 corresponds to a pressure drop amplitude of 2 cmH2O, level 2 to 4 cmH2O, level 3 to 6 cmH2O, level 4 to 8 cmH2O, and level 5 to 10 cmH2O. If the user sets the pressure release level to 3, the treatment device will determine the target pressure drop amplitude to be 6 cmH2O by consulting the table. This mapping can be set and optimized based on extensive clinical trial data, patient feedback, and medical expert advice to ensure that different pressure drop amplitudes meet the needs of different users in different situations.

[0035] This embodiment obtains the pressure release level set by the user and determines the target pressure drop based on the corresponding pressure drop, fully considering the user's personalized needs. Users can flexibly set the pressure release level according to their actual feelings, such as breathing comfort and tolerance to pressure changes, thereby achieving precise control over the pressure drop.

[0036] In one embodiment, step S101, which determines the minimum working pressure based on the preset treatment pressure and the target pressure drop, includes: Step S1015: Subtract the target pressure drop from the preset treatment pressure to obtain the target minimum working pressure.

[0037] Step S1016: Obtain the minimum reference operating pressure of the continuous positive airway pressure ventilation device; compare the value of the target minimum operating pressure with the minimum reference operating pressure. The minimum reference operating pressure is the lowest pressure limit that a continuous positive airway ventilation device must maintain to ensure stable and normal operation. This value is determined by factors such as the device's hardware performance and design parameters, and is the basic pressure to ensure the normal operation of all components of the device and the stable delivery of airflow.

[0038] This step can be done by consulting the equipment's parameter manual or directly reading the minimum reference operating pressure from the equipment's control system. When the equipment leaves the factory, the manufacturer sets the minimum reference operating pressure based on the equipment's hardware characteristics and design requirements, and stores it in the equipment's storage unit. For example, the minimum reference operating pressure of a certain continuous positive airway pressure (CPAP) device is 3 cmH2O. Comparing the target minimum operating pressure with the minimum reference operating pressure is to determine whether the initially calculated target minimum operating pressure meets the requirements for normal equipment operation. A simple comparison algorithm can be used: if the target minimum operating pressure is greater than the minimum reference operating pressure, proceed to step S1017; if the target minimum operating pressure is less than the minimum reference operating pressure, proceed to step S1018.

[0039] Step S1017: If the target minimum working pressure is greater than or equal to the minimum reference operating pressure, then the target minimum working pressure is determined as the minimum working pressure.

[0040] When the target minimum working pressure is greater than or equal to the minimum reference operating pressure, it means that the target minimum working pressure calculated in the preliminary calculation can meet the basic needs of patient treatment (considering the preset treatment pressure and the target pressure drop) and will not be lower than the minimum pressure required for normal operation of the equipment. Therefore, the target minimum working pressure can be directly used as the minimum working pressure.

[0041] Step S1018: If the target minimum working pressure is less than the minimum reference operating pressure, then the minimum reference operating pressure is determined as the minimum working pressure.

[0042] When the target minimum operating pressure is lower than the minimum reference operating pressure, it means that operating the equipment at the target minimum operating pressure may cause the equipment to malfunction, such as unstable airflow or component damage. To ensure the normal operation of the equipment, the minimum reference operating pressure is used as the minimum operating pressure in this case.

[0043] This embodiment first calculates the target minimum operating pressure and then compares it with the minimum reference operating pressure of the continuous positive airway pressure (CPAP) device to determine the appropriate minimum operating pressure, comprehensively considering both patient treatment needs and equipment operational requirements. On one hand, calculating the target minimum operating pressure based on the preset treatment pressure and target pressure drop allows for personalized adjustments according to the patient's specific condition and user needs, meeting the pressure change requirements of different patients during treatment and improving treatment comfort and effectiveness. On the other hand, comparing it with the minimum reference operating pressure ensures that the equipment operates within a safe and stable pressure range under all circumstances, avoiding equipment malfunction or failure due to excessively low pressure.

[0044] For step S102, the patient's respiratory phase switching status is detected in real time.

[0045] Respiratory phase transitions refer to the moment and direction of the change in respiratory motion between two phases (expiration and inspiration). Specifically, it refers to the change in the patient's breathing process from inspiration to expiration, or vice versa. This can be identified through airflow, pressure, or flow signals and is used to trigger inspiratory depressurization and expiratory pressurization. Accurate detection of respiratory phase transitions is crucial for achieving precise ventilation pressure control.

[0046] Real-time detection of respiratory phase transitions is crucial for precise ventilation pressure control. Only by accurately determining whether the patient is currently in the inspiratory or expiratory phase can the ventilation pressure be adjusted according to the appropriate strategy. This can be achieved using various sensors for real-time detection. In one embodiment, a flow sensor is used to determine the respiratory phase by detecting changes in airway flow. During inspiration, airway flow is positive and gradually increases; during expiration, airway flow is negative and gradually decreases. When the flow changes from negative to positive, it indicates a transition from expiration to inspiration; when it changes from positive to negative, it indicates a transition from inspiration to expiration. In another embodiment, a pressure sensor can be used to detect changes in airway pressure, and the respiratory phase transition status can be determined based on the characteristics of the pressure curve. Furthermore, some advanced ventilation devices may combine data from multiple sensors and employ intelligent algorithms for comprehensive judgment, improving detection accuracy.

[0047] In one embodiment, step S102, which involves real-time detection of the patient's respiratory phase switching state, includes: Step S1021: Real-time detection of airflow data at the patient's airway.

[0048] Airflow data is the volume or mass of air passing through a cross section of a patient's airway per unit time. It can intuitively reflect the strength and changes of airflow during a patient's breathing and is an important basis for judging the respiratory status.

[0049] Airflow abrupt change characteristics refer to the changes in airflow rate during the transition from inspiratory to expiratory phases or vice versa during a patient's breathing process. Specifically, these can include abrupt changes in airflow amplitude, reversal of flow direction, and sharp changes in the rising / falling edge. These characteristics are used to accurately identify the timing of respiratory phase transitions and are a core basis for respiratory synchronization control. For example, when the breath ends and transitions to expiration, the airflow direction changes, and the flow rate changes from an increasing trend to a decreasing trend; this change in the direction and rate of flow rate change is a manifestation of airflow abrupt change characteristics.

[0050] This step can be achieved by installing a high-precision airflow sensor at the connection point of the patient's airway. For example, installing an airflow sensor at the connection point between the patient's breathing mask and the breathing tubing can accurately measure the airflow entering or exiting the patient's airway through the mask with each breath. The sampling frequency can reach tens of times per second or even higher to ensure the real-time nature and accuracy of the data.

[0051] Step S1022: Extract the airflow change characteristics of the airflow flow data, and determine the breathing phase switching state based on the airflow change characteristics.

[0052] After receiving airflow data, specific algorithms are used to extract airflow abrupt change features. A common method is to calculate the first or second derivative of the airflow data. The first derivative reflects the rate of change of airflow; when the value of the first derivative changes from positive to negative or vice versa, it may indicate a change in airflow direction, i.e., a possible shift in respiratory phase. The second derivative reflects the change in the rate of change of airflow; when the second derivative shows a significant peak or trough, it often indicates a critical moment of airflow abrupt change. After extracting the airflow abrupt change features, they are matched against preset rules. If the detected airflow abrupt change features match the characteristic pattern from inspiration to expiration, the patient is determined to be transitioning from the inspiration phase to the expiration phase; conversely, if they match the characteristic pattern from expiration to inspiration, the patient is determined to be transitioning from the expiration phase to the inspiration phase.

[0053] This embodiment determines the respiratory phase switching state by real-time detection of airflow data at the patient's airway and extracting abrupt airflow changes, achieving high accuracy and real-time performance. Accurate identification of respiratory phase switching states is crucial for respiratory therapy equipment, allowing it to adjust operating parameters promptly according to different respiratory stages, improving patient comfort and treatment effectiveness. Simultaneously, real-time detection and accurate judgment ensure that the equipment remains synchronized with the patient's breathing rhythm, avoiding equipment malfunctions due to incorrect phase judgment and guaranteeing the safety and effectiveness of respiratory therapy.

[0054] In one embodiment, step S102, which involves real-time detection of the patient's respiratory phase switching state, includes: Step S1023: Detect the inspiratory duration and expiratory duration of the patient in this respiratory cycle; the inspiratory duration and expiratory duration are used for ventilation pressure control in the next respiratory cycle.

[0055] A respiratory cycle refers to the time required for a patient to complete one full respiratory process, which includes the inhalation phase and the exhalation phase.

[0056] Inspiratory duration refers to the length of time a patient experiences from the start of inspiration to the end of inspiration during a respiratory cycle. It reflects the speed and force of the patient's inhalation and is important for assessing respiratory function and developing appropriate ventilation strategies.

[0057] Expiratory duration refers to the time a patient experiences from the start of exhalation to the end of exhalation during the respiratory cycle. Expiratory duration also reflects the characteristics of the patient's exhalation process and is related to factors such as the amount of gas expelled from the lungs and airway resistance.

[0058] This embodiment, by real-time monitoring of the inspiratory and expiratory durations of the current respiratory cycle and adjusting the ventilation pressure for the next respiratory cycle accordingly, can more accurately match the patient's respiratory needs. Compared to traditional fixed ventilation pressure modes or methods that adjust pressure based on only a single parameter, this method, which dynamically adjusts based on respiratory duration, can better adapt to changes in the patient's respiratory status and improve ventilation effectiveness.

[0059] In one embodiment, step S1023, which involves detecting the duration of inhalation and exhalation in the current respiratory cycle of the patient, includes: Step S10231: Obtain the first moment when the respiratory phase switches from the expiratory phase to the inspiratory phase, and the second moment when the respiratory phase switches from the inspiratory phase to the expiratory phase; determine the inspiratory duration of this respiratory cycle based on the time difference between the second moment and the first moment.

[0060] This step can be achieved using sensors installed in the patient's airway. For example, a flow sensor can measure the airflow rate through the airway in real time. During the expiratory phase, airflow exits the lungs, and the flow direction is negative; as the inspiratory phase begins, airflow enters the lungs, and the flow direction becomes positive. By monitoring the change in airflow direction, the first moment of transition from the expiratory to the inspiratory phase can be determined. Similarly, when inspiration ends and expiration begins, the airflow direction changes again, thus determining the second moment of transition from the inspiratory to the expiratory phase.

[0061] Step S10232: Obtain the third moment when the respiratory phase switches from the expiratory phase to the inspiratory phase of the next respiratory cycle; determine the expiratory duration of the current respiratory cycle based on the time difference between the third moment and the second moment.

[0062] Continue using the flow sensor described above. When the current exhalation ends and the next respiratory cycle begins in the inspiratory phase, the airflow direction or airway pressure will undergo another significant change. By monitoring these changes, the third moment when the respiratory phase transitions from the expiratory phase to the inspiratory phase of the next respiratory cycle can be determined.

[0063] This embodiment determines the duration of inspiratory and expiratory breathing by precisely acquiring the timing of respiratory phase transitions, providing a crucial and accurate data foundation for subsequent ventilation pressure control. By utilizing a flow sensor to monitor changes in airflow or pressure within the airway in real time, the switching points of respiratory phases can be captured promptly and accurately, thereby precisely calculating the duration of inspiratory and expiratory breathing. This precise duration data allows the respiratory therapy device to dynamically and precisely adjust the ventilation pressure for the next respiratory cycle based on the patient's actual breathing situation in the current cycle. For example, if a short inspiratory duration is detected, indicating rapid inhalation, the device can rapidly increase the ventilation pressure during the inspiratory phase of the next respiratory cycle to provide more sufficient pressure support and help the patient inhale smoothly. Conversely, if a long expiratory duration indicates potential difficulty in exhalation, the device can appropriately reduce the pressure during the expiratory phase of the next respiratory cycle to reduce expiratory resistance and facilitate gas expulsion. Such dynamic adjustments better adapt to the patient's constantly changing respiratory state, improving ventilation effectiveness, enhancing patient comfort, and thus improving the effectiveness of respiratory therapy and patient compliance, providing more scientific and precise support for the treatment of respiratory diseases.

[0064] For step S103, when the respiratory phase is detected to switch from the expiratory phase to the inspiratory phase, the ventilation pressure is smoothly adjusted from the preset treatment pressure to the minimum working pressure and maintained at the minimum working pressure until the end of the inspiratory phase.

[0065] Ventilation pressure is the pressure of gas delivered to a patient's airway by a continuous positive airway pressure (CPAP) device. By adjusting the ventilation pressure, a patient's breathing condition can be improved, and diseases such as obstructive sleep apnea can be treated.

[0066] This step smoothly adjusts the ventilation pressure from the preset therapeutic pressure to the minimum working pressure during the inspiratory phase, effectively reducing inspiratory resistance in patients. Smooth adjustment avoids abrupt pressure changes, reduces patient-ventilator asynchrony, and makes the patient more comfortable. Maintaining the minimum working pressure until the end of the inspiratory phase ensures that the patient enjoys low inspiratory resistance throughout the entire inspiratory process, improving inspiratory smoothness. This is significant for improving respiratory function, especially for patients with significant inspiratory difficulty. In terms of implementation, a proportional-integral-derivative (PID) control algorithm can be used to achieve smooth adjustment of the ventilation pressure. The PID controller calculates the control signal based on the difference between the current ventilation pressure and the minimum working pressure, as well as the rate of change of the difference, and adjusts the output pressure of the ventilation device to gradually decrease it from the preset therapeutic pressure to the minimum working pressure. During the decrease, the PID parameters are adjusted to ensure the smoothness of the pressure change and avoid sudden pressure changes. Once the ventilation pressure reaches the minimum working pressure, the control system continuously monitors the respiratory phase and maintains this pressure value until the end of the inspiratory phase is detected.

[0067] In one embodiment, step S103, which involves smoothly adjusting the ventilation pressure from a preset treatment pressure to a minimum working pressure, includes: Step S1031: Obtain the inspiratory duration corresponding to the previous respiratory cycle.

[0068] Step S1032: Based on the preset treatment pressure, the minimum working pressure, and the inhalation duration, a pressure adjustment curve is generated using a preset exponential variation model.

[0069] The preset exponential change model is a pre-defined mathematical model used to achieve a smooth, non-linear transition of ventilation pressure. It describes the functional relationship in which ventilation pressure changes exponentially over time. Specifically, its pressure change curve model, based on an exponential function, is generated according to parameters such as treatment pressure, minimum working pressure, and inspiratory duration. This ensures a rapid initial decrease in pressure followed by a gradual decrease, achieving smooth regulation of ventilation pressure without abrupt changes and better reflecting physiological breathing.

[0070] Step S1033: Based on the pressure regulation curve, the ventilation pressure is smoothly adjusted from the preset treatment pressure to the minimum working pressure in real time.

[0071] This embodiment obtains the inspiratory duration of the previous respiratory cycle and uses a preset exponential variation model to generate a continuous nonlinear pressure regulation curve, thereby smoothly adjusting the ventilation pressure from the preset therapeutic pressure to the minimum working pressure. It fully considers the individual differences and dynamic changes in patient breathing, as different patients have different inspiratory durations; the pressure regulation curve generated according to the inspiratory duration better matches the patient's actual respiratory needs. Compared with traditional linear pressure regulation methods, the continuous nonlinear pressure regulation curve makes the changes in ventilation pressure smoother, avoiding discomfort caused by sudden pressure changes and improving patient breathing comfort. Simultaneously, this precise pressure regulation better maintains the patient's airway patency, providing sufficient therapeutic pressure during the inspiratory phase to ensure ventilation and oxygenation, and reducing pressure during the expiratory phase to reduce expiratory resistance, thereby improving the effectiveness of respiratory therapy and helping to improve the patient's respiratory function and quality of life.

[0072] In one embodiment, the preset exponential change model is: P(t) = Ptarget ΔPactual×(1 e^( k t / (β Ti)));where P(t) is the current target pressure, Ptarget is the preset treatment pressure, ΔPactual is the actual pressure drop, k is the curve parameter, β is the adaptive time factor, Ti is the inhalation duration, and t is the time after the start of inhalation; the curve parameter k is determined according to the pressure release level. The higher the pressure release level, the larger the value of k, which is used to control the rate and magnitude of pressure drop, so that the pressure quickly approaches the minimum value according to an exponential law, ensuring a smooth and natural pressure drop.

[0073] Step S1033, which involves smoothly adjusting the ventilation pressure from the preset treatment pressure to the minimum working pressure in real time according to the pressure regulation curve, includes: Get the maximum system setting reduction; Calculate the difference between the preset treatment pressure and the minimum working pressure to obtain the actual pressure drop. The adaptive time factor is obtained by calculating the ratio between the actual pressure drop and the system's maximum set pressure drop. Multiply the adaptive time factor by the inhalation duration to obtain the total pressure smoothing adjustment time; When the time after the start of inhalation is less than or equal to the total duration of pressure smoothing, smooth pressure reduction is performed according to the preset exponential change model. If the time after the start of inhalation is greater than the total duration of pressure smoothing, maintain the minimum working pressure until the end of the inhalation phase.

[0074] For step S104, when the respiratory phase is detected to switch from the inspiratory phase to the expiratory phase, the ventilation pressure is controlled to gradually increase from the minimum working pressure so that the ventilation pressure at the end of the expiratory phase is maintained at the preset treatment pressure.

[0075] This step involves gradually increasing the ventilation pressure during the expiratory phase and maintaining it at the preset therapeutic pressure at the end of the expiratory phase. This ensures sufficient airway support throughout the expiration process. Especially at the end of the expiratory phase, when lung volume is at its lowest and the airway is most prone to collapse, maintaining the preset therapeutic pressure effectively prevents airway closure and reduces the risk of central sleep apnea. The gradual pressure increase also avoids discomfort caused by sudden pressure rises, improving patient tolerance to treatment. Similar to the pressure regulation during the inspiratory phase, when the respiratory phase shifts from inspiration to expiration, the ventilation equipment's control system can use a PID control algorithm or other suitable control algorithm to gradually adjust the output pressure of the ventilation equipment based on the difference between the current ventilation pressure and the preset therapeutic pressure, gradually increasing it from the minimum operating pressure to the preset therapeutic pressure. During the increase, the pressure change must also be kept smooth to avoid sudden pressure changes that could cause patient discomfort. By appropriately setting the parameters of the control algorithm, the ventilation pressure is accurately maintained at the preset therapeutic pressure at the end of the expiratory phase.

[0076] In one embodiment, step S104, which involves controlling the ventilation pressure to gradually increase from the minimum operating pressure, includes: Step S1041: Obtain the expiratory duration of the previous respiratory cycle.

[0077] Step S1042: Divide the exhalation duration into time periods to obtain multiple continuous time phases.

[0078] Time segmentation refers to dividing the exhalation duration into multiple consecutive time segments according to certain rules. Each time segment has a specific duration, so as to carry out personalized pressure rebound control in different segments.

[0079] The pressure recovery rate refers to the speed at which ventilation pressure rises over time in each time period, usually expressed as a numerical value of pressure increase per unit time, such as cmH2O / s. Different pressure recovery rates affect the smoothness and speed of ventilation pressure recovery.

[0080] Step S1043: Configure the corresponding pressure recovery rate for each time stage; gradually increase the ventilation pressure according to the pressure recovery rate corresponding to each time stage.

[0081] This embodiment acquires the expiratory duration of the previous respiratory cycle and divides it into time segments, configuring corresponding pressure recovery rates for each time segment to gradually increase the ventilation pressure. It fully considers the dynamic changes in the patient's expiratory process and the characteristics of different stages, enabling personalized pressure recovery control based on the patient's actual respiratory condition. Compared to the traditional single pressure recovery rate method, configuring different pressure recovery rates for different time segments makes the ventilation pressure recovery smoother and more natural, avoiding discomfort caused by excessively fast or slow pressure recovery, and improving the patient's breathing comfort. Simultaneously, this precise pressure recovery control better maintains the patient's airway patency, ensuring the continuity and effectiveness of respiratory therapy, helping to improve the patient's respiratory function, and enhancing the quality and effect of respiratory therapy.

[0082] In one embodiment, the plurality of consecutive time phases include the pre-expiratory phase, the mid-expiratory phase, and the end-expiratory phase; The pre-expiratory phase refers to the initial stage of the patient's expiratory process. During this stage, the patient's expiratory action has just begun, the airflow changes drastically in the airway, and the pressure fluctuations are relatively large. Usually, the patient's exhalation is relatively rapid, and it is the initial period of the expiratory cycle.

[0083] The mid-expiratory phase, following the early expiratory phase, is a relatively stable stage in the patient's expiratory process. During this phase, the patient's expiratory rhythm is stable, and the changes in airflow and pressure within the airway are relatively regular, without the dramatic fluctuations seen in the earlier phase.

[0084] The end of the expiratory phase is the final stage of the patient's expiratory process. At this time, the patient's expiratory force gradually weakens, the airflow speed in the airway slows down, and the pressure gradually stabilizes, approaching the end of exhalation.

[0085] In one embodiment, the first part of the expiratory phase is 0% to 30% of the expiratory progress, the middle part of the expiratory phase is 30% to 90% of the expiratory progress, and the last part of the expiratory phase is 90% to 100% of the expiratory progress; the ventilation pressure at the end of the expiratory phase is maintained at a preset treatment pressure.

[0086] Step S1043 is the step of configuring the corresponding pressure recovery rate for each time stage, including: Step S10431: For the first part of the expiratory phase, configure the pressure recovery rate to be zero.

[0087] During the initial phase of expiration, the airway pressure undergoes rapid adjustment due to the significant airflow impact at the start of expiration. If the pressure recovery rate is not zero at this stage, the ventilatory pressure will begin to rise, interfering with the pressure changes generated by the patient's own expiration. This could lead to airway pressure instability, increasing the patient's breathing discomfort and even affecting the normal progress of respiratory therapy. Therefore, the pressure recovery rate is set to zero, meaning that no active pressure recovery occurs during this phase, allowing the patient to naturally complete the airway pressure adjustment at the beginning of expiration.

[0088] Step S10432: For the mid-expiratory phase, configure it as the first preset recovery rate.

[0089] During the mid-expiratory phase, patients' breathing is relatively stable, and airway pressure changes are also relatively regular. At this point, setting the first preset recovery rate allows the ventilatory pressure to recover at a relatively stable and appropriate speed, avoiding discomfort caused by an excessively rapid recovery or disruption to subsequent respiratory cycles due to an excessively slow recovery. The specific value of the first preset recovery rate can be determined through extensive clinical trials and data analysis, combined with feedback on respiratory parameters and comfort levels from different patients.

[0090] Step S10433: Configure the second preset recovery rate for the end of the expiratory phase.

[0091] At the end of the expiratory phase, the patient's expiratory force weakens, and airway pressure tends to stabilize. At this point, a second preset recovery rate is configured, typically lower than the first preset recovery rate. This allows the ventilation pressure to rise more gradually before the end of expiration, avoiding a sudden pressure increase that could cause discomfort to the patient, while ensuring a smooth return to an appropriate level to prepare for the next respiratory cycle. Determining the second preset recovery rate also requires comprehensive consideration of factors such as the patient's respiratory status and comfort.

[0092] This embodiment divides the expiratory process into three phases: the pre-expiratory phase, the mid-expiratory phase, and the post-expiratory phase, and configures different pressure recovery rates for each phase. A zero pressure recovery rate is configured for the pre-expiratory phase to avoid interference with the drastic changes in airway pressure during the patient's initial exhalation, ensuring airway pressure stability and reducing patient discomfort. A first preset recovery rate is configured for the mid-expiratory phase, allowing the ventilation pressure to recover at a stable and appropriate rate, meeting the pressure change requirements of respiratory therapy while also considering patient comfort. A second preset recovery rate, lower than the first preset rate, is configured for the post-expiratory phase, allowing the ventilation pressure to recover more gently before the end of exhalation, further improving patient comfort and ensuring a smooth recovery of ventilation pressure to an appropriate level, thus guaranteeing a successful next respiratory cycle. Taking into full account the characteristics of different stages of the patient's exhalation process, the system achieves optimized control of ventilation pressure rise through precise pressure rise rate configuration, thereby improving the quality and effectiveness of respiratory therapy and enhancing patients' tolerance and compliance with respiratory therapy.

[0093] In one embodiment, during the first N respiratory cycles after treatment initiation, the inspiratory pressure smoothing adjustment of the ventilation pressure control method of this application is not executed; instead, an initial stabilization control strategy is adopted. Starting from the (N+1)th respiratory cycle, the ventilation pressure control method is executed normally, entering the complete pressure control process of steps S101 to S104. Here, N is used to ensure that the initial respiratory parameters stabilize before entering pressure release control. In one embodiment, N is a fixed number of cycles preset by the system, pre-configured at the factory, used to stabilize respiratory parameter detection in the early stages of treatment initiation. Preferably, N is 5, meaning that the first 5 respiratory cycles after treatment initiation are a warm-up and stabilization phase, during which inspiratory pressure smoothing adjustment is not enabled; starting from the 6th respiratory cycle, the complete ventilation pressure control process of steps S101 to S104 is executed.

[0094] Please refer to Figure 2 This application also provides a continuous positive airway pressure ventilation device 301, including: a processor 302, a memory 303, and a computer program 304 stored in the memory 303 and executable on the processor 302. When the processor 302 executes the computer program 304, it implements the steps of the method as described in any one of the embodiments of this application.

[0095] The processor 302 may include one or more processing cores. The processor 302 connects to various parts within the continuous positive airway pressure (CPAP) device 301 via various interfaces and lines. It executes various functions and processes data of the CPAP device 301 by running or executing instructions, programs, code sets, or instruction sets stored in the memory 303, and by calling data stored in the memory 303. Optionally, the processor 302 may be implemented using at least one of the following hardware forms: Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), and Programmable Logic Array (PLA). The processor 302 may integrate one or a combination of several of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and Modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content displayed on the touchscreen; and the modem handles wireless communication. It is understood that the modem may also be implemented as a separate chip without being integrated into the processor 302.

[0096] The memory 303 may include random access memory (RAM) or read-only memory. Optionally, the memory 303 may include a non-transitory computer-readable storage medium. The memory 303 may be used to store instructions, programs, code, code sets, or instruction sets. The memory 303 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch instructions), instructions for implementing the various method embodiments described above, etc.; the data storage area may store data involved in the various method embodiments described above, etc. Optionally, the memory 303 may also be at least one storage device located remotely from the aforementioned processor 302.

[0097] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this application, and this application also intends to include these modifications and variations.

Claims

1. A method of ventilation pressure control, characterized by, Applied to continuous positive airway pressure (CPAP) devices, the method includes the following steps: Obtain the preset treatment pressure and the target pressure drop; determine the minimum working pressure based on the preset treatment pressure and the target pressure drop; Real-time monitoring of the patient's respiratory phase switching status; When the respiratory phase is detected to switch from the expiratory phase to the inspiratory phase, the ventilation pressure is smoothly adjusted from the preset treatment pressure to the minimum working pressure and maintained at the minimum working pressure until the end of the inspiratory phase. When the respiratory phase changes from inspiratory to expiratory phase, the ventilation pressure is gradually increased from the minimum working pressure to maintain the ventilation pressure at the end of the expiratory phase at the preset treatment pressure.

2. The ventilation pressure control method according to claim 1, characterized in that, The steps for smoothly adjusting the ventilation pressure from the preset treatment pressure to the minimum working pressure include: Obtain the inspiratory duration corresponding to the previous respiratory cycle; A pressure regulation curve is generated based on the preset treatment pressure, the minimum working pressure, and the inhalation duration using a preset exponential variation model. Based on the pressure regulation curve, the ventilation pressure is smoothly adjusted from the preset treatment pressure to the minimum working pressure in real time.

3. The ventilation pressure control method according to claim 1, characterized in that, The steps for gradually increasing the ventilation pressure from the minimum operating pressure include: Obtain the duration of expiration in the previous respiratory cycle; The exhalation duration is divided into time periods to obtain multiple continuous time phases; Configure corresponding pressure recovery rates for each time stage; gradually increase the ventilation pressure based on the corresponding pressure recovery rates for each time stage.

4. The ventilation pressure control method according to claim 3, characterized in that, The multiple consecutive time phases include the first phase of the expiratory phase, the middle phase of the expiratory phase, and the last phase of the expiratory phase; The steps for configuring the corresponding pressure recovery rate for each time stage include: For the first phase of expiration, the pressure recovery rate is set to zero. For the mid-expiratory phase, the first preset recovery rate is configured; For the end of the expiratory phase, the second preset recovery rate is configured.

5. The ventilation pressure control method according to claim 2 or 3, characterized in that, The steps for real-time monitoring of a patient's respiratory phase transitions include: The duration of inhalation and exhalation in the current respiratory cycle of the patient is detected; the duration of inhalation and exhalation are used for ventilation pressure control in the next respiratory cycle.

6. The ventilation pressure control method according to claim 5, characterized in that, The steps for measuring the duration of inspiratory and expiratory breathing in a patient's current respiratory cycle include: Obtain the first moment when the respiratory phase switches from the expiratory phase to the inspiratory phase, and the second moment when the respiratory phase switches from the inspiratory phase to the expiratory phase; determine the inspiratory duration of this respiratory cycle based on the time difference between the second moment and the first moment; Obtain the third moment when the respiratory phase switches from the expiratory phase to the inspiratory phase of the next respiratory cycle; determine the expiratory duration of the current respiratory cycle based on the time difference between the third moment and the second moment.

7. The ventilation pressure control method according to any one of claims 1 to 4, characterized in that, The steps to obtain the target pressure drop include: Get the user-defined stress relief level; The target pressure drop is determined based on the pressure drop corresponding to the pressure release level.

8. The ventilation pressure control method according to any one of claims 1 to 4, characterized in that, The step of determining the minimum working pressure based on the preset treatment pressure and the target pressure drop includes: Subtracting the target pressure drop from the preset treatment pressure yields the target minimum working pressure. Obtain the minimum reference operating pressure of the continuous positive airway pressure ventilation device; compare the value of the target minimum operating pressure with that of the minimum reference operating pressure; If the target minimum operating pressure is greater than or equal to the minimum reference operating pressure, then the target minimum operating pressure is determined as the minimum operating pressure; If the target minimum operating pressure is less than the minimum reference operating pressure, then the minimum reference operating pressure is determined as the minimum operating pressure.

9. The ventilation pressure control method according to any one of claims 1 to 4, characterized in that, The steps for real-time monitoring of a patient's respiratory phase transitions include: Real-time monitoring of airflow data at the patient's airway; Extract the airflow abrupt change characteristics from the airflow flow data, and determine the breathing phase switching state based on the airflow abrupt change characteristics.

10. A continuous positive airway pressure device, characterized by It includes a processor, a memory, and a computer-readable program stored in the memory, which, when executed by the processor, implements the steps of the method as described in any one of claims 1-9.

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