Positive end-expiratory pressure measurement method and device based on pressure waveform and breathing machine

Abstract

The application is suitable for the technical field of medical devices, and provides a positive end-expiratory pressure identification method and device based on a pressure waveform and a breathing machine. Real-time pressure values of a breathing machine pipeline Y end are collected, a real-time pressure slope is obtained by deriving the real-time pressure values with respect to time, if the real-time pressure slope satisfies a first preset condition, a pressure value at a time when the last time the first preset condition is satisfied before expiration is taken as a value of the positive end-expiratory pressure, wherein the first preset condition is that an absolute value of the real-time pressure slope is less than a first threshold value, and finally, mean filtering is performed on a positive end-expiratory pressure reference value in multiple breathing cycles to obtain the value of the positive end-expiratory pressure. The application can accurately identify the positive end-expiratory pressure by reducing the interference of spontaneous breathing, so as to meet the accuracy requirement of the positive end-expiratory pressure reference value for inspiratory pressure triggering, thereby avoiding the problem that the calculated positive end-expiratory pressure is sucked into the patient and collapses, resulting in the inability to identify patient triggering.

Description

Technical Field

[0001] This invention belongs to the field of medical devices, and in particular relates to a method, device and ventilator for calculating end-expiratory positive pressure based on pressure waveform. Background Technology

[0002] In mechanical ventilation, we typically focus on three basic questions: when to start ventilation, how to deliver ventilation, and when to start exhalation. The timing of initiating ventilation is called triggering, and traditional triggering methods include time-triggered, pressure-triggered, and flow-triggered ventilation. Time-triggered ventilation involves the ventilator receiving a start-up command at a pre-set time point and initiating ventilation accordingly. Pressure-triggered and flow-triggered ventilation involve setting a trigger sensitivity before ventilation begins. When the pressure in the tubing drops to the set sensitivity, or the flow rate rises to the set sensitivity, the ventilator receives the ventilation command, controls the opening and closing of the inspiratory and expiratory valves, and begins ventilation. This brief process is called pressure-triggered or flow-triggered ventilation.

[0003] Positive End Expiratory Pressure (PEEP) is the baseline pressure maintained by a ventilator to keep the patient's lungs and chest cavity in a certain open state. Appropriate PEEP can open collapsed alveoli, making ventilation easier and improving ventilation efficiency. PEEP is also an important benchmark for calculating pressure drop values, especially in some ventilators that lack flow monitoring and only monitor pressure. These ventilators primarily use pressure-triggered delivery and cannot accurately control PEEP by setting a value, or the ventilator adjusts PEEP via a circuit knob, and the control unit cannot obtain the PEEP setting value. In these cases, accurate PEEP measurement becomes even more crucial.

[0004] In existing technologies, the pressure value corresponding to 2 / 3 of the expiration time or the pressure value corresponding to the end of the expiration time is usually directly selected as the positive end-expiratory pressure (PEP). Both of these methods are greatly affected by spontaneous breathing. The first method, when the pressure drop waveform is relatively flat during the patient's expiration phase, is prone to misinterpreting the pressure drop before the pressure reaches a stable level during the expiration phase as pressure triggering, that is, identifying the PEP too early, resulting in misjudgment and trigger sensitivity, leading to incorrect delivery commands. The second method is prone to identifying the PEP value too low, making it difficult for the patient to inhale the set trigger sensitivity, thus failing to trigger the PEP.

[0005] Therefore, in ventilators with pure pressure monitoring, there is an urgent need for a method that can accurately identify positive end-expiratory pressure to meet the inspiratory pressure triggering conditions, in order to ensure that the ventilator delivers air and the patient’s spontaneous breathing are synchronized, and to avoid false triggering or difficulty in triggering. Summary of the Invention

[0006] This invention provides a method for calculating positive end-expiratory pressure (PEAP) based on pressure waveforms, aiming to solve the technical problem of false triggering or difficulty in triggering PEAP in ventilators due to inaccurate identification.

[0007] To address the aforementioned technical problems, in a first aspect, embodiments of the present invention provide a method for calculating end-expiratory positive pressure based on pressure waveforms, comprising:

[0008] Collect the real-time pressure value at the Y end of the ventilator tubing;

[0009] The real-time pressure slope is obtained by differentiating the real-time pressure value with respect to time.

[0010] If the real-time pressure slope meets the first preset condition, then the pressure value at the last time the first preset condition is met before the end of exhalation is taken as the positive end-expiratory pressure value, wherein the first preset condition is that the absolute value of the real-time pressure slope is less than a first threshold.

[0011] Furthermore, after the real-time pressure slope meets the first preset condition, the method further includes:

[0012] If the real-time pressure slope meets the second preset condition, then the pressure value at the first moment within the current time window when the second preset condition is met for the first time is taken as the positive end-expiratory pressure value, wherein the second preset condition is that the real-time pressure slope is less than the second threshold.

[0013] Furthermore, after the real-time pressure slope meets the first preset condition, the method further includes:

[0014] If the real-time pressure slope satisfies a third preset condition, and the duration for which the real-time pressure slope satisfies the third preset condition is greater than or equal to a preset value, then the pressure value when the duration equals the preset value is taken as the positive end-expiratory pressure value, wherein the third preset condition is that the absolute value of the real-time pressure slope is less than a set third threshold.

[0015] Furthermore, the method also includes:

[0016] If the real-time pressure slope does not meet the first preset condition, then the set proportional coefficient is obtained;

[0017] Based on the proportionality coefficient and the exhalation time, the moment when the exhalation phase transitions to the inhalation phase is determined, and the pressure value at the moment when the exhalation phase transitions to the inhalation phase is used as the value of the positive end-expiratory pressure.

[0018] Furthermore, the method also includes:

[0019] Obtain the positive end-expiratory pressure values ​​over multiple respiratory cycles;

[0020] The end-expiratory positive pressure (PEP) values ​​within multiple respiratory cycles are subjected to mean filtering, and the PEP values ​​are updated based on the result of the mean filtering.

[0021] Secondly, the present invention also provides a device for calculating end-expiratory positive pressure based on pressure waveform, comprising:

[0022] The real-time pressure acquisition unit is used to acquire the real-time pressure value at the Y end of the ventilator tubing;

[0023] The real-time pressure slope calculation unit is used to obtain the real-time pressure slope by differentiating the real-time pressure value with respect to time.

[0024] The first positive end-expiratory pressure (PEAP) acquisition unit is used to acquire the pressure value at the last time the first preset condition is met before the end of expiration as the PEAP value when the real-time pressure slope meets the first preset condition, wherein the first preset condition is that the absolute value of the real-time pressure slope is less than a first threshold.

[0025] Furthermore, the device also includes:

[0026] The proportional coefficient acquisition unit is used to acquire a set proportional coefficient when the real-time pressure slope does not meet the first preset condition.

[0027] The second positive end-expiratory pressure (PEAP) acquisition unit is used to determine the moment when the expiration phase transitions to inhalation based on the proportionality coefficient and the expiration time, and to use the pressure value at the moment when the expiration phase transitions to inhalation as the value of the PEAP.

[0028] Thirdly, the present invention also provides a ventilator, comprising:

[0029] The pressure sampling tube is used to collect the real-time pressure value at the Y end of the ventilator tubing;

[0030] One or more processors, working individually or collectively, are used to perform the following steps:

[0031] The real-time pressure slope is obtained by differentiating the real-time pressure value with respect to time.

[0032] If the real-time pressure slope meets the first preset condition, then the pressure value at the last time the first preset condition is met before the end of exhalation is taken as the positive end-expiratory pressure value, wherein the first preset condition is that the absolute value of the real-time pressure slope is less than a first threshold.

[0033] as well as

[0034] A memory used to store data.

[0035] Fourthly, the present invention also provides a computer-readable storage medium storing program instructions that, when executed by a processor, implement the steps of the end-expiratory positive pressure calculation method based on pressure waveform according to any one of claims 1 to 5.

[0036] This invention reduces the interference of spontaneous breathing by judging the real-time pressure slope based on preset conditions for obtaining the positive end-expiratory pressure (PEAP) value, determining the PEAP baseline value according to the priority of the preset conditions, and then performing mean filtering to obtain the PEAP value. This enables accurate identification of PEAP to meet the accuracy requirements of the PEAP baseline value for inspiratory pressure triggering, ensuring synchronization between ventilator delivery and the patient's spontaneous breathing, and avoiding problems of false triggering or difficulty in triggering. Attached Figure Description

[0037] To more clearly illustrate the solutions in this invention, the accompanying drawings used in the description of the embodiments of this invention will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 This is a flowchart of an embodiment of the end-tidal positive pressure calculation method based on pressure waveform provided by the present invention;

[0039] Figure 2 This is a flowchart of another embodiment of the end-expiratory positive pressure calculation method based on pressure waveform provided by the present invention;

[0040] Figure 3 This is a flowchart of another embodiment of the end-tidal positive pressure calculation method based on pressure waveform provided by the present invention;

[0041] Figure 4 This is a schematic diagram of the end-expiratory positive pressure measurement device based on pressure waveform provided by the present invention;

[0042] Figure 5 This is a schematic diagram of the structure of a ventilator provided by the present invention. Detailed Implementation

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings are used to distinguish different objects and not to describe a particular order.

[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0046] In mechanical ventilation, positive end-expiratory pressure (PEEP) is a crucial factor in ventilator pressure triggering. Generally, ventilators aiming to improve patient-ventilator interaction and reduce patient-ventilator asynchrony must have an inspiratory triggering function to synchronize ventilator-delivered air with the patient's spontaneous breathing. Some low-end ventilators only monitor pressure, not flow rate. Because they can only monitor pressure waveforms, the only way for such ventilators to trigger patient responses is through pressure triggering. However, the PEEP setting on these ventilators may rely on a circuit knob, preventing the machine from accurately acquiring the set PEEP value. When using pressure triggering, PEEP is a critical benchmark for determining when pressure drops below the set value to activate triggering. When the pressure falls below the set PEEP value, triggering is recognized.

[0047] When only a pure pressure waveform is available, in addition to using positive end-expiratory pressure (PEEP) as a reference to identify inspiratory pressure, another method to identify inspiratory trigger is through the slope of the pressure. For example, if the pressure drops to a certain value within a fixed time window, a sufficient slope will be generated to identify trigger. However, this is not suitable for patients taking slow, deep breaths, which may result in very low pressure being reached without triggering. Considering this situation, this invention proposes a method for calculating PEEP based on pressure waveform to meet the inspiratory pressure triggering conditions, thereby ensuring synchronization between ventilator delivery and the patient's spontaneous breathing, and avoiding false triggering or difficulty in triggering.

[0048] Example 1

[0049] Please see Figure 1 A flowchart of an embodiment of the end-tidal positive pressure measurement method based on pressure waveform provided by the present invention includes:

[0050] In step S1, the real-time pressure value at the Y end of the ventilator tubing is collected;

[0051] It is understood that, in the embodiments of the present invention, during breathing using a mechanical ventilation device, there is an inspiratory valve in the inspiratory tubing and an expiratory valve in the expiratory tubing. Both tubings are connected to the patient via a ventilator tubing, which is typically a Y-shaped tubing; therefore, the end of the tubing connected to the patient is usually referred to as the Y-end of the tubing. At the end of expiration, when both the inspiratory and expiratory valves are closed, the tubing becomes a sealed container. When the patient inhales, the pressure inside the tubing decreases. When the pressure drops to the set trigger sensitivity, the ventilator receives a ventilation command, opens the inspiratory valve, and begins delivering air. This brief process is called pressure triggering.

[0052] In some implementations, the ventilator is equipped with a pressure sampling tube at the Y-end of the tubing. This tube allows for real-time acquisition of the pressure value at the Y-end of the ventilator tubing. The real-time pressure can be acquired via the pressure sampling tube or other sensors capable of obtaining real-time pressure values; no limitation is made here.

[0053] In step S2, the real-time pressure slope is obtained by differentiating the real-time pressure value with respect to time.

[0054] It is understood that, in the embodiments of the present invention, there are many ways to differentiate the real-time pressure value with respect to time. The real-time pressure slope can be obtained by linear fitting, low-pass filtering, Kalman filtering, or other differentiation methods in digital signal processing. No limitation is made here.

[0055] It is understood that, in the embodiments of the present invention, for example, by means of linear fitting, a time window of a time period such as 50ms can be preset, the time period corresponding to 10 real-time pressure value points is selected as a 50ms time window, the 10 real-time pressure value points within the 50ms time window are linearly fitted by a linear function, and then the real-time pressure slope is obtained by taking the derivative with respect to time.

[0056] In other implementations, the parameters of the linear function can be obtained by using fast least squares, approximating discrete data with analytical expressions, or other linear function fitting methods. The real-time pressure slope is a parameter that represents how fast the real-time pressure value changes over time.

[0057] Understandably, in some implementations, by fitting a linear function to points such as 10 real-time pressure values ​​within a preset time window using the least squares method, the resulting slope value is assumed to be the slope corresponding to the median of these 10 points. As the time window slides, the pressure slope that changes over time can be obtained. The pressure slope obtained by fitting a linear function within each time window is called the real-time pressure slope.

[0058] In step S3, if the real-time pressure slope meets the first preset condition, the pressure value at the last time the first preset condition is met before the end of exhalation is taken as the positive end-expiratory pressure value, wherein the first preset condition is that the absolute value of the real-time pressure slope is less than a first threshold.

[0059] Understandably, in some implementations, after obtaining a real-time pressure slope with a certain noise resistance, the expiratory time set in the machine-controlled breathing is obtained, such as 3 to 5 seconds. After waiting for 2 / 3 of the expiratory time to arrive, the real-time pressure slope is then judged to meet the preset conditions for the positive end-expiratory pressure value. That is, the pressure is assumed to have dropped after 2 / 3 of the expiratory time before triggering is allowed, to prevent the pressure value from dropping under machine-controlled pressure and being mistakenly judged as the patient inhaling.

[0060] Understandably, in specific implementation, the preset condition for obtaining the end-expiratory positive pressure value is that this invention judges the pressure change during the expiratory phase based on the changes in the real-time pressure slope. For example, when the real-time pressure slope meets certain conditions, it reflects the existence of a pressure stability region with a relatively long duration. When the real-time pressure slope meets certain conditions, a sudden drop in pressure value will occur in a short period of time. Thus, the change in the real-time pressure slope can be used to identify when the patient reaches the stability phase at the end of expiration. Finally, the value of the end-expiratory stable pressure is used as the benchmark value for pressure triggering.

[0061] It is understandable that there may be one or more preset conditions for obtaining the positive end-expiratory pressure (PEP) value. Under different preset conditions, different methods are used to obtain the PEP value. The method of obtaining the PEP value can be direct assignment or calculation, and there is no limitation here.

[0062] It is understood that, in the specific implementation of this embodiment, the absolute value of the real-time pressure slope is calculated based on the obtained real-time pressure slope, and the absolute value of the real-time pressure slope is compared with the set first threshold. When the absolute value of the real-time pressure slope is less than the set first threshold, the real-time pressure slope meets the preset condition one, and the end-expiratory positive pressure value can be obtained according to the preset condition one.

[0063] Specifically, in this embodiment, the first threshold is set to 2K0, which is selected according to the actual situation of the ventilator. For example, depending on the ventilator, K0 can be set to 0.8 cmH2O / s, then the corresponding first threshold is 1.6 cmH2O / s; or K0 can be set to 1 cmH2O / s or 1.2 cmH2O / s, then the corresponding first threshold is 2 cmH2O / s or 2.4 cmH2O / s, depending on the actual situation of the respiratory rate or other parameters set by the ventilator.

[0064] Specifically, in this embodiment, if the absolute value of the real-time pressure slope is less than the set 2K0, then the pressure value at the last time the absolute value of the real-time pressure slope is less than 2K0 before the end of exhalation is obtained.

[0065] Specifically, in this embodiment, the time for the end of exhalation can be a time set by the ventilator, such as 3-5 seconds, or it can be a time period from the point when the inhalation phase transitions to exhalation to the point when the trigger is successfully identified as the exhalation time.

[0066] Specifically, in this embodiment, after the absolute value of the real-time pressure slope is less than 2K0, the real-time pressure slope is continuously acquired, and it is continuously determined whether the absolute value of the acquired real-time pressure slope is less than 2K0 again. If the condition is met for the second time, the pressure value acquired when the condition is met for the second time is overwritten with the pressure value stored when the condition is met for the first time. When it is determined that the absolute value of the real-time pressure slope is less than 2K0 when the condition is met for the third time, the pressure value acquired when the condition is met for the third time is overwritten with the pressure value stored when the condition is met for the second time. And so on, until the pressure value is acquired when the absolute value of the real-time pressure slope is less than 2K0 for the last time before the end of exhalation.

[0067] By setting a preset condition, if the absolute value of the last real-time pressure slope before the end of expiration is less than the first threshold, the pressure value is obtained. This is mainly because, based on the ventilator settings and the patient's actual situation, when the pressure slope is relatively gentle, this method of obtaining the pressure value can basically ensure the reliability of the obtained positive end-expiratory pressure, thereby ensuring the stability of pressure triggering.

[0068] Example 2

[0069] Please see Figure 2 A flowchart of another embodiment of the end-expiratory positive pressure calculation method based on pressure waveform provided by the present invention. This embodiment is similar to... Figure 1The difference in the illustrated embodiment is that, in step S3, if the real-time pressure slope meets the first preset condition, it is further determined whether the second preset condition is met. If it is met, the pressure value obtained in step S4 is used as the end-expiratory positive pressure value to replace the original value. Figure 1 The positive end-tidal pressure value obtained in step 3.

[0070] Specifically, in step S4, if the real-time pressure slope meets the second preset condition, the pressure value at the first moment within the current time window when the second preset condition is met for the first time is taken as the positive end-expiratory pressure value, wherein the second preset condition is that the real-time pressure slope is less than the second threshold.

[0071] In a specific embodiment, the absolute value of the real-time pressure slope is calculated based on the obtained real-time pressure slope. The absolute value of the real-time pressure slope is compared with a set first threshold 2K0. When the absolute value of the real-time pressure slope is less than the set first threshold 2K0, the real-time pressure slope is continued to be obtained. It is then determined whether the real-time pressure slope will be less than the second threshold -8K0 after the absolute value of the real-time pressure slope is less than the first threshold 2K0. If it is, the real-time pressure slope meets the second preset condition, and the end-expiratory positive pressure value can be obtained according to the second preset condition.

[0072] Specifically, in this embodiment, the second threshold is set to -8K0. For example, if K0 is set to 1cmH2O / s, the corresponding second threshold is -8cmH2O / s. Alternatively, K0 can be set to 0.8cmH2O / s, in which case the corresponding second threshold is -6.4cmH2O / s. The specific choice depends on the actual situation of the respiratory rate or other parameters set by the ventilator.

[0073] Furthermore, if the second preset condition is met, the pressure value at the first moment within the current time window is obtained when the real-time pressure slope is less than the second threshold -8K0 for the first time.

[0074] Specifically, in this embodiment, if the absolute value of the real-time pressure slope is less than 2K0, and after the absolute value of the real-time pressure slope is less than 2K0, the real-time pressure slope becomes less than -8K0, then when the real-time pressure slope becomes less than -8K0 for the first time, the pressure value at the first moment within the current time window is obtained.

[0075] Specifically, in this embodiment, the time window is a time period with a preset length of 50ms. Ten time points are set within the 50ms time window. As the time window slides, the pressure slope that changes over time can be obtained. The pressure slope within any 50ms time window is the slope corresponding to the median value of the 10 time points within the time window. When the real-time pressure slope is less than -8K0 for the first time, the pressure value of the first time point within the current time window is obtained.

[0076] By setting a second preset condition, when the real-time pressure slope first falls below a second threshold, the pressure value at the first point in the time window is obtained. Since this condition applies after a relatively stable pressure level, where the pressure drops rapidly due to strong spontaneous breathing, the pressure before this drop can be used as the positive end-expiratory pressure (PEAP). This requires the patient to inhale with a certain intensity, allowing the pressure slope to clearly identify the interval where spontaneous breathing begins. The pressure before spontaneous breathing is then marked as PEAP, and obtaining the pressure value at the first point in the time window ensures more accurate pressure triggering, preventing false triggering or failure to trigger.

[0077] Example 3

[0078] Please see Figure 3 A flowchart of another embodiment of the end-expiratory positive pressure calculation method based on pressure waveform provided by the present invention. This embodiment is similar to... Figure 1 The difference in the illustrated embodiment is that it further determines whether a third preset condition is met. If met, the pressure value obtained in step S5 is used as the positive end-expiratory pressure value to replace the original value. Figure 1 The positive end-tidal pressure value obtained in step 3.

[0079] In step S5, if the real-time pressure slope satisfies a third preset condition, and the duration for which the real-time pressure slope satisfies the third preset condition is greater than or equal to a preset value, then the pressure value when the duration is equal to the preset value is taken as the end-expiratory positive pressure value, wherein the third preset condition is that the absolute value of the real-time pressure slope is less than a set third threshold.

[0080] In a specific embodiment, the absolute value of the real-time pressure slope is calculated based on the obtained real-time pressure slope. The absolute value of the real-time pressure slope is compared with a set third threshold K0. When the absolute value of the real-time pressure slope is less than the set third threshold K0, the real-time pressure slope is continued to be obtained. It is then determined whether, after the absolute value of the real-time pressure slope is less than the first threshold 2K0, the duration of the absolute value of the real-time pressure slope being less than the third threshold K0 is greater than or equal to a preset value T0. If this occurs, the real-time pressure slope meets the third preset condition, and the end-expiratory positive pressure value can be obtained based on the third preset condition.

[0081] Specifically, in this embodiment, the third threshold is set to K0. For example, K0 can be set to 1 cmH2O / s, 0.8 cmH2O / s, or 1.2 cmH2O / s, depending on the actual situation of the respiratory rate or other parameters set by the ventilator.

[0082] Specifically, in this embodiment, the preset value of the duration is to determine whether there is a region with a stable pressure value. Therefore, using a certain amount of time as the preset value T0 of the duration, it is possible to be very certain that the pressure value reaching a certain duration is the band where the positive end-expiratory pressure is maintained.

[0083] Specifically, in this embodiment, if the absolute value of the real-time pressure slope is less than K0, and the duration of the absolute value of the real-time pressure slope being less than K0 is greater than or equal to a preset value, then the pressure value when the duration is equal to the preset value is obtained.

[0084] Specifically, in this embodiment, the third threshold is set to K0. For example, K0 can be set to 1 cmH2O / s, 0.8 cmH2O / s, or 1.2 cmH2O / s, depending on the actual situation of the respiratory rate or other parameters set by the ventilator.

[0085] Specifically, in this embodiment, the preset value of the duration is to determine whether there is a region with a stable pressure value. Therefore, using a certain amount of time as the preset value of the duration can ensure that the pressure value that reaches a certain duration is the band where the positive end-expiratory pressure is maintained.

[0086] By setting a third preset condition, the pressure value is obtained when the duration equals the preset value. Since the pressure can maintain a small fluctuation range within a certain period of time during the exhalation phase, it is considered that the period is in the stable phase of exhalation. Therefore, obtaining the pressure value during this period as the end-expiratory positive pressure baseline value can further ensure the accuracy of pressure triggering.

[0087] Example 4

[0088] This invention provides a method for calculating end-expiratory positive pressure based on pressure waveforms, the method further comprising:

[0089] If the real-time pressure slope does not meet the first preset condition, then the set proportional coefficient is obtained;

[0090] Based on the proportionality coefficient and the exhalation time, the moment when the exhalation phase transitions to the inhalation phase is determined, and the pressure value at the moment when the exhalation phase transitions to the inhalation phase is used as the value of the positive end-expiratory pressure.

[0091] Specifically, in this embodiment, if the real-time pressure slope does not satisfy the condition that the absolute value of the real-time pressure slope is less than the first threshold, a set proportional coefficient is obtained. The proportional coefficient can be set to 90%, 95%, or other proportional coefficients within the range of [90%, 95%].

[0092] Specifically, in some embodiments, the exhalation time can be a time set on the ventilator or the actual exhalation time, where the actual exhalation time refers to a time value between the start of exhalation and the successful recognition of pressure triggering.

[0093] Specifically, in this embodiment, the moment of transition from exhalation to inhalation is determined by multiplying the set proportional coefficient of 95% and the exhalation time of 3 seconds. That is, the pressure value corresponding to the moment of 95% exhalation time is taken as the positive end-expiratory pressure.

[0094] Example 5

[0095] This embodiment provides a method for calculating end-expiratory positive pressure based on pressure waveforms, and further includes:

[0096] Obtain the positive end-expiratory pressure (PEAP) values ​​over multiple respiratory cycles;

[0097] The end-expiratory positive pressure (PEP) values ​​within multiple respiratory cycles are subjected to mean filtering, and the PEP values ​​are updated based on the result of the mean filtering.

[0098] Specifically, in this embodiment, the pressure changes periodically over time with the rhythm of breathing. The judgment and value of the preset conditions are within one respiratory cycle. Therefore, the pressure value obtained when the preset conditions are met is the end-expiratory positive pressure reference value within one respiratory cycle.

[0099] Specifically, in this embodiment, the positive end-expiratory pressure (PEP) baseline value within a respiratory cycle can be obtained by satisfying different preset conditions for the slope. As time changes, the PEP baseline value for multiple respiratory cycles can be obtained. The mean value of the obtained PEP baseline values ​​for multiple respiratory cycles is then filtered to obtain the final PEP value used to achieve pressure triggering.

[0100] Specifically, in this embodiment, the positive end-expiratory pressure (PEAP) baseline value is averaged over multiple cycles, and the average value of the PEAP baseline value is used when triggering. In this way, even if the PEAP is misidentified in some cycles due to pressure fluctuations at the patient end, the stability of the triggering can still be guaranteed.

[0101] This invention relates to a method for calculating positive end-expiratory pressure (PEAP) based on pressure waveforms. It determines the PEAP baseline value by judging the real-time pressure slope according to preset conditions and prioritizing these conditions. Then, it performs mean filtering to obtain the PEAP value, thereby reducing the interference from spontaneous breathing. This method accurately identifies PEAP, meeting the accuracy requirements of the PEAP baseline value for inspiratory pressure triggering, ensuring trigger stability, and ensuring synchronization between ventilator delivery and the patient's spontaneous breathing. This effectively avoids problems such as false triggering or difficulty in triggering.

[0102] Example 6

[0103] Please see Figure 4 , Figure 4 This is a schematic diagram of the end-tidal positive pressure measurement device based on pressure waveform provided by the present invention, as a reference. Figure 1 The implementation of the end-expiratory positive pressure (PEP) calculation method based on pressure waveform is shown in this embodiment. This embodiment provides a device for calculating PEP based on pressure waveform, and the device embodiment is similar to... Figure 1 Corresponding to the method embodiment shown, the apparatus includes:

[0104] The real-time pressure acquisition unit 21 is used to acquire the real-time pressure value at the Y end of the ventilator tubing;

[0105] The real-time pressure slope calculation unit 22 is used to obtain the real-time pressure slope by differentiating the real-time pressure value with respect to time.

[0106] The first positive end-expiratory pressure acquisition unit 23 is used to acquire the pressure value at the last time the first preset condition is met before the end of expiration as the positive end-expiratory pressure value when the real-time pressure slope meets the first preset condition, wherein the first preset condition is that the absolute value of the real-time pressure slope is less than a first threshold.

[0107] The beneficial effect of the positive end-expiratory pressure (PEAP) measuring device 20 based on pressure waveform in this embodiment of the invention is that by setting a preset condition one, the pressure value is obtained when the absolute value of the last real-time pressure slope before the end of expiration is less than a first threshold. This is mainly because, based on the ventilator settings and the patient's actual situation, when the pressure slope is relatively gentle, this method of obtaining the pressure value can basically ensure the reliability of the obtained PEAP, thereby ensuring the stability of pressure triggering.

[0108] Example 7

[0109] In this embodiment, the end-expiratory positive pressure measurement device based on pressure waveform provided by the present invention further includes:

[0110] The proportional coefficient acquisition unit is used to acquire a set proportional coefficient when the real-time pressure slope does not meet the first preset condition.

[0111] The second positive end-expiratory pressure (PEAP) acquisition unit is used to determine the moment when the expiration phase transitions to inhalation based on the proportionality coefficient and the expiration time, and to use the pressure value at the moment when the expiration phase transitions to inhalation as the value of the PEAP.

[0112] Specifically, in this embodiment, if the real-time pressure slope does not satisfy the condition that the absolute value of the real-time pressure slope is less than the first threshold, a set proportional coefficient is obtained. The proportional coefficient can be set to 90%, 95%, or other proportional coefficients within the range of [90%, 95%].

[0113] Specifically, in some embodiments, the exhalation time can be a time set on the ventilator or the actual exhalation time, where the actual exhalation time refers to a time value between the start of exhalation and the successful recognition of pressure triggering.

[0114] Specifically, in this embodiment, the moment of transition from exhalation to inhalation is determined by multiplying the set proportional coefficient of 95% and the exhalation time of 3 seconds. That is, the pressure value corresponding to the moment of 95% exhalation time is taken as the positive end-expiratory pressure.

[0115] Example 8

[0116] Please see Figure 5 This invention also provides a ventilator 10, which includes:

[0117] Pressure sampling tube 11 is used to collect the real-time pressure value at the Y end of the ventilator tubing;

[0118] One or more processors 12, working individually or collectively, are used to perform the following steps:

[0119] The real-time pressure slope is obtained by differentiating the real-time pressure value with respect to time.

[0120] If the real-time pressure slope meets the first preset condition, then the pressure value at the last time the first preset condition is met before the end of exhalation is taken as the positive end-expiratory pressure value, wherein the first preset condition is that the absolute value of the real-time pressure slope is less than a first threshold.

[0121] as well as

[0122] Memory 13 is used to store data.

[0123] Specifically, in this embodiment, the processor 12 may be a central processing unit (CPU), controller, microcontroller, microprocessor, or other data processing chip in some embodiments. The processor 12 is typically used to control the overall operation of the ventilator.

[0124] In this embodiment, the processor 12 is used to run computer-readable instructions or process data stored in the memory 13, such as running computer-readable instructions for a ventilator-based method for calculating end-expiratory positive pressure based on pressure waveforms.

[0125] Those skilled in the art will understand that the memory 13 includes at least one type of readable storage medium, including flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, disk, optical disk, etc.

[0126] In some embodiments, memory 13 may be an internal storage unit of the ventilator, such as the hard disk or memory of the ventilator.

[0127] In other embodiments, the memory 13 may also be an external storage device of the ventilator, such as a plug-in hard drive, smart media card (SMC), secure digital (SD) card, flash card, etc.

[0128] Of course, the memory 13 may include both the internal storage unit of the ventilator and its external storage device.

[0129] The beneficial effect of the ventilator 10 in this embodiment of the invention is that by setting different preset conditions, it can cover the changes in pressure values ​​under different conditions. Since waveform changes under different conditions may affect the recognition of pressure triggering, different preset conditions are set to ensure the accuracy of end-expiratory positive pressure values ​​under different conditions, thereby improving the anti-interference ability and reliability of pressure triggering during inspiration.

[0130] Example 8

[0131] This invention also provides a storage medium storing program instructions for executing the above-described method for calculating end-tidal positive pressure based on pressure waveforms.

[0132] The beneficial effect of the storage medium of the present invention is that by setting different preset conditions, it can cover the changes in pressure values ​​under different conditions. Since waveform changes under different conditions may affect the identification of pressure triggering, different preset conditions are set to ensure the accuracy of end-expiratory positive pressure values ​​under different conditions, thereby improving the anti-interference ability and reliability of pressure triggering during inhalation.

[0133] This invention can be used in a wide range of general-purpose or special-purpose computer system environments or configurations.

[0134] Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, and distributed computing environments that include any of the above systems or devices.

[0135] The method of this invention involves acquiring real-time pressure values ​​at the Y-end of the ventilator tubing, performing linear function fitting on the real-time pressure values ​​within a set time window to obtain the real-time pressure slope, determining whether the real-time pressure slope meets preset conditions for PEEP (Positive End-Expiratory Pressure) values, obtaining the pressure value that meets the preset conditions, and determining the PEEP baseline value for a respiratory cycle based on the priority of the preset conditions. The PEEP baseline value is the pressure value that meets the preset conditions. Finally, the PEEP baseline values ​​over multiple respiratory cycles are averaged and filtered to obtain the PEEP value. Therefore, by setting different preset conditions, pressure value changes under different conditions can be covered. Furthermore, different preset conditions are set to ensure the accuracy of PEEP values ​​under different conditions, addressing the potential impact of waveform changes on pressure trigger identification. This satisfies the accuracy requirements of inspiratory pressure triggering for the PEEP baseline value, ensuring synchronization between ventilator delivery and the patient's spontaneous breathing, thereby avoiding false triggering or difficulty in triggering, and improving the anti-interference capability and reliability of inspiratory pressure triggering.

[0136] It is understood that those skilled in the art can combine various implementation methods in the above embodiments under the guidance of the above examples to obtain technical solutions with multiple implementation methods.

[0137] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for calculating end-expiratory positive pressure based on pressure waveform, characterized in that, include: Collect the real-time pressure value at the Y end of the ventilator tubing; The real-time pressure slope is obtained by differentiating the real-time pressure value with respect to time. If the real-time pressure slope meets the first preset condition, then the pressure value at the last time the first preset condition is met before the end of exhalation is taken as the positive end-expiratory pressure value, wherein the first preset condition is that the absolute value of the real-time pressure slope is less than a first threshold. After the real-time pressure slope meets the first preset condition, the method further includes: If the real-time pressure slope meets the second preset condition, then the pressure value at the first moment within the current time window when the second preset condition is met for the first time is taken as the positive end-expiratory pressure value, wherein the second preset condition is that the real-time pressure slope is less than the second threshold.

2. The method for calculating end-expiratory positive pressure based on pressure waveform as described in claim 1, characterized in that, After the real-time pressure slope meets the first preset condition, the method further includes: If the real-time pressure slope satisfies a third preset condition, and the duration for which the real-time pressure slope satisfies the third preset condition is greater than or equal to a preset value, then the pressure value when the duration equals the preset value is taken as the positive end-expiratory pressure value, wherein the third preset condition is that the absolute value of the real-time pressure slope is less than a set third threshold.

3. The method for calculating end-expiratory positive pressure based on pressure waveform as described in claim 1, characterized in that, The method further includes: If the real-time pressure slope does not meet the first preset condition, then the set proportional coefficient is obtained; Based on the proportionality coefficient and the exhalation time, the moment when the exhalation phase transitions to the inhalation phase is determined, and the pressure value at the moment when the exhalation phase transitions to the inhalation phase is used as the value of the positive end-expiratory pressure.

4. The method for calculating end-expiratory positive pressure based on pressure waveform as described in any one of claims 1 to 3, characterized in that, The method further includes: Obtain the positive end-expiratory pressure values ​​over multiple respiratory cycles; The end-expiratory positive pressure (PEP) values ​​within multiple respiratory cycles are subjected to mean filtering, and the PEP values ​​are updated based on the result of the mean filtering.

5. A device for calculating end-expiratory positive pressure based on pressure waveform, characterized in that, include: The real-time pressure acquisition unit is used to acquire the real-time pressure value at the Y end of the ventilator tubing; The real-time pressure slope calculation unit is used to obtain the real-time pressure slope by differentiating the real-time pressure value with respect to time. The first positive end-expiratory pressure (PEAP) acquisition unit is used to acquire the pressure value at the last time the first preset condition is met before the end of expiration when the real-time pressure slope meets the first preset condition, wherein the first preset condition is that the absolute value of the real-time pressure slope is less than a first threshold. After the real-time pressure slope meets the first preset condition, the first end-expiratory positive pressure acquisition unit is further configured to: If the real-time pressure slope meets the second preset condition, then the pressure value at the first moment within the current time window when the second preset condition is met for the first time is taken as the positive end-expiratory pressure value, wherein the second preset condition is that the real-time pressure slope is less than the second threshold.

6. The end-expiratory positive pressure measurement device based on pressure waveform as described in claim 5, characterized in that, The device further includes: The proportional coefficient acquisition unit is used to acquire a set proportional coefficient when the real-time pressure slope does not meet the first preset condition. The second positive end-expiratory pressure (PEAP) acquisition unit is used to determine the moment when the expiration phase transitions to inhalation based on the proportionality coefficient and the expiration time, and to use the pressure value at the moment when the expiration phase transitions to inhalation as the value of the PEAP.

7. A ventilator, characterized in that, include: The pressure sampling tube is used to collect the real-time pressure value at the Y end of the ventilator tubing; One or more processors, working individually or collectively, are used to perform the following steps: The real-time pressure slope is obtained by differentiating the real-time pressure value with respect to time. If the real-time pressure slope meets the first preset condition, then the pressure value at the last time the first preset condition is met before the end of exhalation is taken as the positive end-expiratory pressure value, wherein the first preset condition is that the absolute value of the real-time pressure slope is less than a first threshold. as well as A memory used to store data; After the real-time pressure slope meets the first preset condition, the processor is further configured to: If the real-time pressure slope meets the second preset condition, then the pressure value at the first moment within the current time window when the second preset condition is met for the first time is taken as the positive end-expiratory pressure value, wherein the second preset condition is that the real-time pressure slope is less than the second threshold.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores program instructions that, when executed by a processor, implement the steps of the end-tidal positive pressure calculation method based on pressure waveforms according to any one of claims 1 to 4.

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