Ventilator and method for adjusting pressure rise time

Abstract

A ventilation device and a pressure rise time adjusting method, the method comprising: obtaining ventilation parameters (100) of a patient in a pressure rise process in ventilation, the ventilation parameters comprising at least one of airway flow rate and airway pressure, the pressure rise process being a process in which the airway pressure changes from an initial pressure value to a target pressure value in the same breathing cycle; obtaining at least one parameter feature (200) of the ventilation parameters related to the pressure rise time, the pressure rise time being a set time length in which the airway pressure rises from the initial pressure value to the target pressure value in the same breathing cycle; and adjusting the pressure rise time of the ventilation device (300) according to the at least one parameter feature related to the pressure rise time. The pressure rise time can be adjusted in combination with one or more parameter features, so that the pressure rise time can be better adapted to the condition of the patient.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a ventilation device and a method for adjusting the pressure rise time. Background Technology

[0002] Pressure rise time refers to the time it takes for the airway pressure in a patient to rise from its initial value to the target pressure value set by the ventilation equipment (such as a ventilator or anesthesia ventilator) during ventilation. Taking a ventilator as an example, there are currently three typical ways to set the pressure rise time: The first is to set the pressure rise time to a fixed time; the second is to set the pressure rise time as a certain percentage of the inspiratory time, for example, if the patient's inspiratory time is 1.5 seconds, setting the pressure rise time to 20% will result in an actual pressure rise time of 0.3 seconds; the third is to set the pressure rise time using different levels, with each level having a corresponding pressure rise time.

[0003] The appropriate setting of the pressure rise time directly affects the patient's inspiratory flow rate, and flow rate synchronization is one of the important factors in patient-ventilator synchronization during ventilation. In clinical practice, patients' conditions vary, and the pressure rise time should be individually adjusted according to the patient's lung characteristics. The same pressure rise time may be too short for patients with low lung compliance, leading to significant pressure overshoot, while it may be too long for patients with high lung compliance, clearly failing to meet the initial inspiratory flow rate requirement. The current method of setting pressure rise time has the following drawbacks: using a fixed pressure rise time setting cannot meet the ventilation needs of different patients or the same patient at different stages, thus leading to inspiratory pressure overshoot or insufficient initial inspiratory flow rate. An inappropriate pressure rise time setting can lead to several harms: if the pressure rise time is too short, significant pressure overshoot may occur, potentially causing excessively high peak lung pressure, easily leading to lung injury and a pronounced overshoot sensation; if the pressure rise time is too long, insufficient initial inspiratory flow rate may occur, potentially leading to inspiratory insufficiency, exacerbating patient-ventilator asynchrony, and increasing the patient's work of breathing. In summary, the current fixed setting of pressure rise time can easily cause patients to experience pressure overshoot or insufficient inspiratory flow rate, leading to patient-ventilator asynchrony, increased respiratory work, and prolonged ventilator use.

[0004] In order to adapt the pressure rise time to changes in the patient's condition, it is necessary to accurately identify whether the pressure rise time during ventilation is too long or too short. This is one of the problems that ventilation equipment needs to solve or improve. Summary of the Invention

[0005] According to a first aspect, one embodiment discloses a method for adjusting the pressure rise time, comprising:

[0006] The ventilation parameters are obtained during the pressure rise process of the patient during ventilation. The ventilation parameters include at least one of airway flow rate and airway pressure. The pressure rise process is the process in which the airway pressure changes from an initial pressure value to a target pressure value within the same respiratory cycle.

[0007] Acquire at least one parameter characteristic of the ventilation parameters regarding pressure rise time, wherein the pressure rise time is a set time during which the airway pressure rises from an initial pressure value to a target pressure value within the same respiratory cycle;

[0008] The pressure rise time of the ventilation device is adjusted according to the at least one parameter characteristic regarding the pressure rise time.

[0009] According to a second aspect, one embodiment discloses a ventilation device, comprising:

[0010] The patient interface is used to connect to the patient's respiratory system;

[0011] A respiratory support device is used to provide respiratory support power during ventilation, delivering respiratory support gas to the patient.

[0012] A processor for performing the methods described in the first aspect.

[0013] According to a third aspect, one embodiment discloses a computer-readable storage medium including a program that can be executed by a processor to implement the method described in the first aspect.

[0014] The above embodiments obtain at least one parameter feature of the ventilation parameters regarding the pressure rise time. Each parameter feature can independently determine whether the pressure rise time is appropriate. Different parameter features can also be combined to jointly determine whether the pressure rise time is appropriate. When the pressure rise time is inappropriate, corresponding adjustments are made so that the ventilation pressure rise time can be adapted to the patient's changing condition. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a ventilator according to one embodiment;

[0016] Figure 2 This is a waveform of airway pressure during one respiratory cycle in one embodiment.

[0017] Figure 3 This is a waveform diagram of airway pressure at different pressure rise times in one embodiment.

[0018] Figure 4 This is a waveform diagram of airway pressure when the pressure rise time is too long, according to one embodiment.

[0019] Figure 5This is a waveform diagram of airway pressure when the pressure rise time is too short, according to one embodiment.

[0020] Figure 6 This is a waveform diagram of airway pressure when the pressure rise time is too long, as shown in another embodiment.

[0021] Figure 7 This is a diagram of airway pressure waveform when the pressure rise time is too long, according to another embodiment.

[0022] Figure 8 This is a waveform diagram of airway flow rate when the pressure rise time is too long, according to one embodiment.

[0023] Figure 9 This is a waveform diagram of airway flow rate when the pressure rise time is too short, according to one embodiment.

[0024] Figure 10 A flowchart illustrating a method for adjusting the pressure rise time according to one embodiment;

[0025] Figure 11 A flowchart illustrating one embodiment of adjusting the pressure rise time based on an airway pressure waveform;

[0026] Figure 12 This is a flowchart illustrating one embodiment of adjusting the pressure rise time based on the airway flow rate waveform. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of this application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0028] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0029] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0030] The most crucial concept of this invention lies in effectively selecting the parameter characteristics and their manifestations that best reflect the pressure rise time from airway pressure and airway parameters, and adjusting the pressure rise time based on these characteristics.

[0031] Please refer to Figure 1 The illustrated embodiment provides a schematic diagram of the structural composition of a ventilator. This embodiment uses a ventilator as an example to illustrate the structure of the ventilation equipment. The ventilator includes an air source interface 10, a respiratory assist device 20, a breathing circuit 30, a sensor interface 40, a memory 50, a processor 60, and a display 70. It should be understood that... Figure 1 This is merely an example of a ventilator and does not constitute a limitation on ventilators. Ventilators can include, but are not limited to, those that are more advanced than, those that are designed for use with other devices. Figure 1 Show more or fewer parts, or combinations of certain parts, or different parts.

[0032] The gas source interface 10 is used to connect to a gas source (not shown in the figure) to provide gas. This gas can typically be oxygen or air. In some embodiments, the gas source can be a compressed gas cylinder or a central gas supply source, supplying gas to the ventilator through the gas source interface 10. The supplied gas types include oxygen (O2) and air. The gas source interface 10 may include conventional components such as a pressure gauge, pressure regulator, flow meter, pressure reducing valve, and proportional control protection device, used to control the flow rate of various gases (e.g., oxygen and air). The gas input through the gas source interface 10 enters the breathing circuit 30 and mixes with the existing gas in the breathing circuit 30 to form a gas mixture. In other embodiments, the ventilator itself has a built-in gas source, therefore the gas source interface 10 is not provided.

[0033] The respiratory assist device 20 is used to power the patient's involuntary breathing and maintain airway patency. It drives the gas input from the gas source interface 10 and the mixed gas in the breathing circuit 30 into the patient's respiratory system, and guides the patient's exhaled air into the breathing circuit 30, thereby improving ventilation and oxygenation and preventing hypoxia and carbon dioxide accumulation in the patient's body. In specific embodiments, the respiratory assist device 20 typically includes a mechanical ventilation module, whose airflow channel is connected to the breathing circuit 30. During surgery, when the patient has not regained spontaneous breathing, the mechanical ventilation module provides the power for breathing. In some embodiments, the respiratory assist device 20 also includes a manual ventilation module, whose airflow channel is connected to the breathing circuit 30. During the induction phase before intubation during surgery, the manual ventilation module is typically used to assist the patient's breathing. When the respiratory assist device 20 includes both a mechanical ventilation module and a manual ventilation module, the mechanical or manual ventilation mode can be switched via a mechanical or manual switch (e.g., a three-way valve) to connect the mechanical or manual ventilation module to the breathing circuit 30, thereby controlling the patient's breathing. Those skilled in the art should understand that, depending on specific needs, the ventilator may include only a mechanical ventilation module or a manual ventilation module.

[0034] The breathing circuit 30 includes an inspiratory pathway 30a, an expiratory pathway 30b, and a carbon dioxide absorber 31. The inspiratory pathway 30a and expiratory pathway 30b are connected to form a closed loop, and the carbon dioxide absorber 31 is disposed on the tubing of the expiratory pathway 30b. A mixture of fresh air and gas introduced by the air source interface 10 is input through the inlet of the inspiratory pathway 30a and provided to the patient through the patient interface 33 disposed at the outlet of the inspiratory pathway 30a. The patient interface 33 can be a face mask, a nasal cannula, or an endotracheal tube. In a preferred embodiment, a one-way valve 32 is provided on the inspiratory pathway 30a, which opens during the inspiratory phase and closes during the expiratory phase. A one-way valve 32 is also provided on the expiratory pathway 30b, which closes during the inspiratory phase and opens during the expiratory phase. The inlet of the expiratory pathway 30b is connected to the patient interface 33. When the patient exhales, the exhaled gas enters the carbon dioxide absorber 31 through the expiratory pathway 30b. The carbon dioxide in the exhaled gas is filtered out by the substances in the carbon dioxide absorber 31, and the gas after the carbon dioxide is removed is recirculated into the inspiratory pathway 30a. In some embodiments, a flow sensor and / or a pressure sensor are also provided in the breathing circuit 30 to detect the gas flow rate and / or the pressure in the tubing, respectively.

[0035] Sensor interface 40 is used to receive ventilation parameters of the patient during ventilation collected by the sensor. In this example, the ventilation parameters include at least the patient's airway pressure (Paw) and / or airway flow (Flow). Specifically, the sensor may include a pressure sensor and a flow sensor, and sensor interface 40 is connected to the signal output terminals of the pressure sensor and the flow sensor, respectively.

[0036] In one embodiment, the sensor interface 40 may simply serve as a connector between the sensor output and subsequent circuitry (e.g., processor 60), without processing the signal. Alternatively, the sensor interface 40 may be integrated into the processor 60 as an interface for receiving signals. In another embodiment, the sensor interface 40 may include an amplifier circuit, a filter circuit, and an analog-to-digital (A / D) conversion circuit for amplifying, filtering, and converting the input analog signal, respectively. Of course, those skilled in the art should understand that the connection relationship between the amplifier circuit, filter circuit, and A / D conversion circuit can vary depending on the specific circuit design, and one circuit may be omitted; for example, the amplifier circuit or filter circuit may be omitted, thereby reducing its corresponding functionality.

[0037] The memory 50 can be used to store data or programs, such as data collected by various sensors, data generated by the processor 60, or image frames generated by the processor 60, which can be 2D or 3D images. Alternatively, the memory 50 can store a graphical user interface, one or more default image display settings, or programming instructions for the processor 60. The memory 50 can be a tangible and non-transitory computer-readable medium, such as flash memory, RAM, ROM, EEPROM, etc.

[0038] The processor 60 is used to execute instructions or programs to control various control valves in the breathing assist device 20, the air source interface 10 and / or the breathing circuit 30, or to process the received data to generate the required calculation or judgment results, or to generate visual data or graphics and output the visual data or graphics to the display 70 for display.

[0039] In this example, after acquiring the ventilation parameters of the patient during the pressure rise process, the processor 60 acquires at least one parameter feature related to the pressure rise time among the ventilation parameters, and then adjusts the pressure rise time of the ventilation device according to the at least one parameter feature related to the pressure rise time.

[0040] The pressure rise process described above refers to the change in airway pressure from the initial pressure value to the target pressure value within the same respiratory cycle. To better understand this process, the pressure rise time is first explained, which is commonly seen in pressure-targeted ventilation modes. In simple terms, when the patient inhales, the ventilator delivers air at high pressure, allowing the patient to inhale a sufficient amount of air. At the end of the inhalation, the ventilator actively reduces the pressure, allowing the patient to exhale waste gas through the pressure difference between the lungs and the external environment. For example, please refer to... Figure 2 The figure shows a schematic diagram of airway pressure waveforms within a respiratory cycle, where PEEP is the positive end-expiratory pressure of the previous respiratory cycle. At the initial stage of the respiratory cycle shown, the patient transitions from the expiratory state of the previous cycle to the inspiratory state of the current cycle. The time it takes for the airway pressure to rise from the initial pressure value to the target pressure value (the airway pressure during inspiratory states, denoted by Pset) within this respiratory cycle is called the pressure rise time. This pressure rise time is used as a ventilation parameter of the ventilation device and can therefore be set directly or indirectly.

[0041] However, in actual ventilation, the changes in the patient's airway pressure do not necessarily perfectly match the set pressure rise time. For example, if the pressure rise time is set to 0.5 seconds on the ventilation equipment, the patient's airway pressure may reach the target pressure value in 0.4 seconds, or it may reach the target pressure value in 0.6 seconds. The process by which the airway pressure actually changes to the target pressure value within a respiratory cycle is the pressure rise process as defined in this application. During this process, the final airway pressure value will be greater than the airway pressure at the beginning of the respiratory cycle, but this does not mean that the airway pressure is always rising. For example, please refer to... Figure 3 In the figure, curve S1 is the airway pressure waveform when the pressure rise time is neither too long nor too short, while curve S2 is an airway pressure waveform when the pressure rise time is too short. Because the pressure rises too quickly, the ventilator will deliver a large flow of gas in a very short time, causing curve S1 to spike and then drop to the target pressure value. Curve S3 is an airway pressure waveform when the pressure rise time is too long.

[0042] At least one of the ventilation parameters mentioned above, which relates to pressure rise time, refers to a parameter characteristic obtained from the ventilation parameters that reflects the rate of pressure rise. An example is given below.

[0043] In some embodiments, the processor 60 first generates an airway pressure waveform based on the airway pressure acquired during the pressure rise process, then acquires the trend of change in the airway pressure waveform, and finally adjusts the pressure rise time of the ventilation device according to this trend. This trend includes, but is not limited to, the slope of the airway pressure waveform curve, the size of the area enclosed by the airway pressure waveform and the template curve, and the change in the area enclosed by the airway pressure waveform and the time axis within two adjacent time windows of equal length. Specifically:

[0044] During the pressure rise process, the processor 60 can acquire the slope of the airway pressure waveform. When the slope changes from positive to negative, the processor 60 compares the airway pressure at the point where the slope changes from positive to negative with the target pressure value. If the airway pressure is lower than the target pressure value, the pressure rise time of the ventilation device is reduced. In other words, if the airway pressure is still lower than the target pressure value during the pressure rise process, the airway pressure waveform will show an error similar to... Figure 4 The decrease shown indicates that the pressure rise time is too long and the pressure rise rate is too slow; therefore, the pressure rise time needs to be reduced. Figure 4 In the diagram, arrow K points to the stage where the slope changes from positive to negative, while Tslope represents the pressure rise time (Tslope also represents the pressure rise time in other diagrams).

[0045] A template curve refers to a curve fitted based on a set pressure rise time. Ideally, after setting the pressure rise time, the patient's airway pressure should change according to this template curve. However, in reality, the patient's airway pressure waveform may deviate from the template curve due to various reasons. The template curve can be obtained through multiple experiments. The area enclosed by the airway pressure waveform and the template curve has positive and negative values. In this embodiment, when the template curve is below the airway pressure waveform, the area enclosed by the airway pressure waveform and the template curve is positive; when the template curve is above the airway pressure waveform, the area enclosed by the airway pressure waveform and the template curve is negative. In this application, the actual airway pressure waveform is represented by Sp, and the template curve is represented by S1 (in...). Figure 2 The middle curve S1 is also a template curve. When the area enclosed by the airway pressure waveform and the template curve is positive, the processor 60 compares the absolute value of the enclosed area with a first threshold. If the absolute value of the enclosed area is greater than the first threshold, the pressure rise time of the ventilation device is increased. For example... Figure 5 As shown in the figure, the airway pressure waveform exceeds the template curve too much during the rise, which means that the pressure rise time is too short and the pressure rise speed is too fast. Therefore, the pressure rise time needs to be increased.

[0046] When the area enclosed by the airway pressure waveform and the template curve is negative, the processor 60 compares the absolute value of the enclosed area with a second threshold. If the absolute value of the enclosed area is greater than the second threshold, the pressure rise time of the ventilation device is reduced. For example, Figure 6 The figure shows a case where the area enclosed by the airway pressure waveform and the template curve is negative. As can be seen from the figure, if the airway pressure waveform deviates too much from the template curve during the pressure rise process, it means that the pressure rise time is too long and the pressure rise rate is too slow. Therefore, it is necessary to reduce the pressure rise time.

[0047] Please continue to refer to Figure 7 , Figure 7 The system divides the pressure rise time into two adjacent time windows of equal length. The latter time window is defined as the first time window T1, and the former time window is defined as the second time window T2. The processor 60 obtains the first area enclosed by the airway pressure waveform and the time axis within the first time window T1, and the second area enclosed by the airway pressure waveform and the time axis within the second time window T2, and then compares the first area and the second area. It should be noted that the airway pressure waveform should be above the time axis during the pressure rise process, so the first area and the second area do not need to be positive or negative. When the first area is larger than the second area, and the difference between the two is greater than a preset area threshold, it means that the airway pressure waveform changes too quickly, which is a result of the pressure rise time being too short. Therefore, the pressure rise time of the ventilation equipment should be increased. Conversely, when the first area is smaller than the second area, and the difference between the two is greater than the preset area threshold, it means that the airway pressure waveform changes too slowly, which is a result of the pressure rise time being too long. Therefore, the pressure rise time of the ventilation equipment should be decreased.

[0048] All of the above methods can reflect the changing trend of airway pressure waveform, which can be seen to include both the rate of change and the direction of change.

[0049] In some embodiments, after acquiring the airway pressure, the processor 60 does not generate an airway pressure waveform based on the airway pressure. Instead, it acquires the airway pressure peak value, which is the maximum value of the airway pressure during the pressure rise process. The processor 60 then acquires the difference between the airway pressure peak value and the target pressure value, and adjusts the pressure rise time of the ventilation device based on this difference. This difference can be used to reflect the degree of difference between the airway pressure peak value and the target pressure value. If the airway pressure peak value is greater than the target pressure value, and the difference between the two is large, it can be considered that the patient's airway pressure rises too rapidly during the pressure rise process, meaning the pressure rise time is too short. Therefore, the pressure rise time of the ventilation device is increased.

[0050] The above-mentioned difference relationship can be simply obtained by subtracting the peak airway pressure from the target pressure value. In some embodiments, the difference relationship is also characterized by pressure overshoot, which is calculated according to the following formula:

[0051]

[0052] Where σ is the pressure overshoot, P max P represents the peak airway pressure during the pressure rise process. set The target pressure value is used. After obtaining the pressure overshoot, it can be compared with the overshoot threshold. If the pressure overshoot is greater than the overshoot threshold, the pressure rise time of the ventilation equipment is increased. The overshoot threshold is also a preset value. When the pressure overshoot is too large, the airway pressure waveform may show the following: Figure 5 The spike shown.

[0053] In addition, the appropriateness of the pressure rise time can be determined by the time it takes for the airway pressure to rise to a certain set pressure value. For example, the appropriateness of the pressure rise time can be determined by the time it takes for the airway pressure to rise to half of the target pressure value.

[0054] In some embodiments, the processor 60 first generates an airway flow velocity waveform based on the airway flow velocity obtained during the pressure rise process, then acquires the curve morphology characteristics of the airway flow velocity waveform, and adjusts the pressure rise time of the ventilation device according to these curve morphology characteristics. The curve morphology characteristics of the airway flow velocity waveform are used to characterize the shape of the airway flow velocity waveform. That is, the shape of the airway flow velocity waveform is used to identify whether the pressure rise time is too long or too short. Specifically:

[0055] In some embodiments, the curve shape of the airway flow rate waveform can be characterized by the area between the initial airway flow rate and the peak airway flow rate between the initial value and the peak value of the airway flow rate. Similar to the initial pressure value of the airway pressure, the initial airway flow rate refers to the airway flow rate at the start of the pressure rise time, and the peak airway flow rate is the maximum value of the airway flow rate during the pressure rise process. Figure 8 The dashed line shown is the velocity line, denoted by L1. This velocity line connects the initial value of the airway velocity to the peak value of the airway velocity. The area between the airway velocity waveform and the velocity line also has a positive or negative sign. When the airway velocity waveform is above the velocity line, the area between the airway velocity waveform and the velocity line is positive. If the area between the airway velocity waveform and the velocity line is positive and its absolute value is greater than the fifth threshold (e.g., ...), the area between the airway velocity waveform and the velocity line is negative. Figure 8 In the case shown above, the pressure rise time of the ventilation equipment should be reduced. When the above situation occurs, the airway flow rate waveform usually has a large arc during the rise, which is caused by the excessive pressure rise time. Therefore, it is necessary to reduce the pressure rise time.

[0056] In some embodiments, the ratio of the flow rate decrease time (Tdown) to the flow rate increase time (Tup) can be used to characterize the curve shape of the airway flow rate waveform. The flow rate increase time (Tup) is the time it takes for the airway flow rate to rise from a first flow rate value to its peak value during a pressure increase. The flow rate decrease time (Tdown) is the time it takes for the airway flow rate to decrease from its peak value to a second flow rate value during a pressure increase. The first and second flow rate values ​​are equal. In other words, the ratio of the flow rate decrease time (Tdown) to the flow rate increase time (Tup) is the ratio of the time required for the airway flow rate to rise from a certain value to its peak value during a pressure increase to the time required to decrease from its peak value to the same value. This ratio also reflects the shape of the airway flow rate. For example, as... Figure 9 As shown in the figure, the ratio between the flow rate decrease time Tdown and the flow rate increase time Tup is greater than the third threshold. The overall airway flow rate waveform appears to have a steep increase and a gentler decrease, exhibiting a clear "deceleration wave" characteristic. This shape indicates that the pressure rise rate is too fast, therefore the pressure rise time of the ventilation equipment needs to be increased. Figure 8 In the middle, the ratio between the flow rate drop time Tdown and the flow rate rise time Tup is less than the fourth threshold, and the overall airway flow rate waveform looks like a smooth arc. This shape indicates that the pressure rise rate is too slow, so it is necessary to reduce the pressure rise time of the ventilation equipment.

[0057] The above parameters can be used together to determine whether the pressure rise time is too long or too short.

[0058] It should be noted that the above thresholds are not fixed and can be dynamically changed based on at least one of the following parameters: target pressure value, current pressure rise time, ventilator compliance and resistance, respiratory time constant, patient type, peak inspiratory flow rate, etc.

[0059] The processor 60 can automatically increase or decrease the pressure rise time as described above, or it can output prompts for adjusting the pressure rise time, such as displaying relevant prompts on the display 70, to remind medical staff to manually adjust the pressure rise time. Once the pressure rise time is adjusted, the ventilator will increase the pressure according to the adjusted pressure rise time in the next respiratory cycle. This pressure rise time adjustment process can occur within each respiratory cycle of the patient. For example, in the first respiratory cycle, the ventilator increases the pressure according to the initially set pressure rise time, adjusting the pressure rise time based on the characteristics of the ventilation parameters. In the second respiratory cycle, the ventilator increases the pressure according to the pressure rise time adjusted in the first respiratory cycle, and so on, adjusting the pressure rise time again based on the characteristics of the ventilation parameters. In the third respiratory cycle, the ventilator increases the pressure again according to the pressure rise time adjusted in the second respiratory cycle, and so on. The pressure rise time can be adjusted by increasing or decreasing a fixed time value, or by changing a fixed percentage of the current pressure rise time each time. This fixed time value and fixed percentage can also be determined based on the characteristics of the ventilation parameters.

[0060] In some embodiments, the processor 60 acquires at least one of the patient's positive end-expiratory pressure (PEEP) and target pressure value, respiratory rate, and respiratory time constant, and determines the adjustment range of pressure rise time based on at least one of the PEEP and target pressure value, respiratory rate, and respiratory time constant. In the process of automatically adjusting the pressure rise time, the patient's physiological condition can be taken into account, and the pressure rise time can be set within an appropriate range.

[0061] This invention also provides a method for adjusting the pressure rise time, please refer to... Figure 10 The steps include:

[0062] Step 100: Obtain ventilation parameters during the pressure rise process of the patient during ventilation. Ventilation parameters include at least one of airway flow rate and airway pressure.

[0063] The pressure rise process described above refers to the change in airway pressure from the initial pressure value to the target pressure value within the same respiratory cycle. To better understand this process, the pressure rise time is first explained, which is commonly seen in pressure-targeted ventilation modes. In simple terms, when the patient inhales, the ventilator delivers air at high pressure, allowing the patient to inhale a sufficient amount of air. At the end of the inhalation, the ventilator actively reduces the pressure, allowing the patient to exhale waste gas through the pressure difference between the lungs and the external environment. For example, please refer to... Figure 2As shown in the figure, this is a schematic diagram of the airway pressure waveform during a respiratory cycle, where PEEP is the positive end-expiratory pressure of the previous respiratory cycle. At the initial stage of the respiratory cycle shown, the patient transitions from the expiratory state of the previous respiratory cycle to the inspiratory state of the current respiratory cycle. The time it takes for the airway pressure to rise from the initial pressure value to the target pressure value (the airway pressure of the patient during inspiration, denoted as Pset) within this respiratory cycle is the pressure rise time. This pressure rise time is used as a ventilation parameter of the ventilation device and can therefore be set directly or indirectly.

[0064] However, in actual ventilation, the changes in the patient's airway pressure do not necessarily perfectly match the set pressure rise time. For example, if the pressure rise time is set to 0.5 seconds on the ventilation equipment, the patient's airway pressure may reach the target pressure value in 0.4 seconds, or it may reach the target pressure value in 0.6 seconds. The process by which the airway pressure actually changes to the target pressure value within a respiratory cycle is the pressure rise process as defined in this application. During this process, the final airway pressure value will be greater than the airway pressure at the beginning of the respiratory cycle, but this does not mean that the airway pressure is always rising. For example, please refer to... Figure 3 In the figure, curve S1 is the airway pressure waveform when the pressure rise time is neither too long nor too short, while curve S2 is an airway pressure waveform when the pressure rise time is too short. Because the pressure rises too quickly, the ventilator will deliver a large flow of gas in a very short time, causing curve S1 to spike and then drop to the target pressure value. Curve S3 is an airway pressure waveform when the pressure rise time is too long.

[0065] Step 200: Obtain at least one parameter characteristic related to pressure rise time from the ventilation parameters.

[0066] This parameter characteristic refers to the parameter characteristics obtained from ventilation parameters that can reflect the rate of pressure rise.

[0067] Step 300: Adjust the pressure rise time of the ventilation equipment according to at least one parameter characteristic related to the pressure rise time. The following example illustrates how to adjust the pressure rise time.

[0068] In some embodiments, the pressure rise time is adjusted, such as Figure 11 The steps shown are as follows:

[0069] Step 310a: Generate an airway pressure waveform based on the airway pressure obtained during the pressure rise process.

[0070] Step 320a: Obtain the trend of airway pressure waveform changes.

[0071] The trends in this step include, but are not limited to, the slope of the airway pressure waveform, the size of the area enclosed by the airway pressure waveform and the template curve, and the changes in the area enclosed by the airway pressure waveform and the time axis within two adjacent time windows of the same length.

[0072] The aforementioned template curve refers to a curve fitted based on a set pressure rise time. Ideally, after setting the pressure rise time, the patient's airway pressure should change according to this template curve. However, in reality, the patient's airway pressure waveform may sometimes deviate from the template curve due to various reasons. The template curve can be obtained through multiple experiments. The area enclosed by the airway pressure waveform and the template curve has positive and negative values. In this embodiment, when the template curve is below the airway pressure waveform, the area enclosed by the airway pressure waveform and the template curve is positive; when the template curve is above the airway pressure waveform, the area enclosed by the airway pressure waveform and the template curve is negative.

[0073] The airway pressure waveform should be above the time axis during the pressure rise process. Therefore, the area enclosed by the airway pressure waveform and the time axis can be considered to have no positive or negative value or to always be positive.

[0074] Step 330a: Adjust the pressure rise time of the ventilation equipment according to the changing trend of the airway pressure waveform.

[0075] In some embodiments, when the curve slope changes from positive to negative, the airway pressure at the point of transition can be compared with the target pressure value. If the airway pressure is lower than the target pressure value, the pressure rise time of the ventilation device is reduced. In other words, if the airway pressure remains below the target pressure value during the pressure rise process, the airway pressure waveform will exhibit the following characteristics: Figure 4 The decrease shown indicates that the pressure rise time is too long and the pressure rise rate is too slow; therefore, the pressure rise time needs to be reduced. Figure 4 In the diagram, arrow K points to the stage where the slope changes from positive to negative, while Tslope represents the pressure rise time (Tslope also represents the pressure rise time in other diagrams).

[0076] In some embodiments, when the area enclosed by the airway pressure waveform and the template curve is positive, the absolute value of the enclosed area can be compared with a first threshold. If the absolute value of the enclosed area is greater than the first threshold, the pressure rise time of the ventilation device is increased. For example... Figure 5As shown in the figure, the airway pressure waveform exceeds the template curve excessively during its ascent, indicating that the pressure rise time is too short and the pressure rise rate is too fast, thus requiring an increase in the pressure rise time. When the area enclosed by the airway pressure waveform and the template curve is negative, the absolute value of this area can be compared to a second threshold. If the absolute value of the enclosed area is greater than the second threshold, the pressure rise time of the ventilation equipment should be reduced. For example, Figure 6 The figure shows a case where the area enclosed by the airway pressure waveform and the template curve is negative. As can be seen from the figure, if the airway pressure waveform deviates too much from the template curve during the pressure rise process, it means that the pressure rise time is too long and the pressure rise rate is too slow. Therefore, it is necessary to reduce the pressure rise time.

[0077] In some embodiments, please refer to Figure 7 , Figure 7 The pressure rise time is divided into two adjacent time windows of equal length. The latter time window is defined as the first time window T1, and the former time window is defined as the second time window T2. The first area enclosed by the airway pressure waveform and the time axis within the first time window T1, and the second area enclosed by the airway pressure waveform and the time axis within the second time window T2, are then compared. When the first area is larger than the second area, and the difference between them is greater than a preset area threshold, it means the airway pressure waveform is changing too quickly, which is a result of an insufficient pressure rise time. Therefore, the pressure rise time of the ventilation equipment should be increased. Conversely, when the first area is smaller than the second area, and the difference between them is greater than the preset area threshold, it means the airway pressure waveform is changing too slowly, which is a result of an excessively long pressure rise time. Therefore, the pressure rise time of the ventilation equipment should be decreased.

[0078] All of the above methods can reflect the changing trend of airway pressure waveform, which can be seen to include both the rate of change and the direction of change.

[0079] In some embodiments, after obtaining the airway pressure, instead of generating an airway pressure waveform, the peak airway pressure is obtained, which is the maximum value of the airway pressure during the pressure rise process. Then, the difference between the peak airway pressure and the target pressure value is obtained, and the pressure rise time of the ventilation device is adjusted based on this difference. This difference can be used to reflect the degree of difference between the peak airway pressure and the target pressure value. If the peak airway pressure is greater than the target pressure value, and the difference between the two is large, it can be considered that the patient's airway pressure rises too rapidly during the pressure rise process, meaning the pressure rise time is too short; therefore, the pressure rise time of the ventilation device is increased.

[0080] The above-mentioned difference relationship can be simply obtained by subtracting the peak airway pressure from the target pressure value. In some embodiments, the difference relationship is also characterized by pressure overshoot, which is calculated according to the following formula:

[0081]

[0082] Where σ is the pressure overshoot, P max P represents the peak airway pressure during the pressure rise process. set The target pressure value is used. After obtaining the pressure overshoot, the pressure overshoot can be compared with the overshoot threshold. If the pressure overshoot is greater than the overshoot threshold, the pressure rise time of the ventilation equipment is increased. The overshoot threshold is also a preset value.

[0083] In some embodiments, the pressure rise time is adjusted, such as Figure 12 The steps shown are as follows:

[0084] Step 310b: Generate an airway flow velocity waveform based on the airway flow velocity obtained during the pressure rise process.

[0085] Step 320b: Obtain the curve morphology features of the airway flow velocity waveform. The curve morphology features are used to characterize the shape of the airway flow velocity waveform.

[0086] In some embodiments, the curve shape of the airway flow rate waveform can be characterized by the area between the initial airway flow rate and the peak airway flow rate between the initial value and the peak value of the airway flow rate. Similar to the initial pressure value of the airway pressure, the initial airway flow rate refers to the airway flow rate at the start of the pressure rise time, and the peak airway flow rate is the maximum value of the airway flow rate during the pressure rise process. Figure 8 The dashed line shown represents the velocity line, which connects the initial value and peak value of the airway velocity. Furthermore, the area between the airway velocity waveform and the velocity line has a positive or negative sign. When the airway velocity waveform is above the velocity line, the area between the airway velocity waveform and the velocity line is positive.

[0087] In other embodiments, the ratio of the flow rate decrease time Tdown to the flow rate increase time Tup can be used to characterize the curve shape of the airway flow rate waveform. The flow rate increase time Tup is the time it takes for the airway flow rate to rise from a first flow rate value to the peak flow rate during the pressure increase process, and the flow rate decrease time Tdown is the time it takes for the airway flow rate to fall from the peak flow rate to a second flow rate value during the pressure increase process. The first flow rate value and the second flow rate value are equal. In other words, the ratio of the flow rate decrease time Tdown to the flow rate increase time Tup is the ratio of the time required for the airway flow rate to rise from a certain value to the peak value during the pressure increase process to the time required for the flow rate to fall from the peak value to the same value. The shape of the airway flow rate can also be reflected from this ratio.

[0088] Step 330b: Adjust the pressure rise time of the ventilation equipment according to the curve shape characteristics of the airway flow rate waveform.

[0089] If the area between the airway flow velocity waveform and the flow velocity line is positive and the absolute value is greater than the fifth threshold, then the pressure rise time of the ventilation equipment should be reduced. When the above situation occurs, the airway flow velocity waveform usually has a large arc during the rise, which is caused by the excessive pressure rise time. Therefore, it is necessary to reduce the pressure rise time.

[0090] If the ratio between the velocity decrease time (Tdown) and the velocity increase time (Tup) is greater than the third threshold, then the pressure rise time is increased. For example... Figure 9 As shown in the figure, the ratio between the flow rate decrease time (Tdown) and the flow rate increase time (Tup) is greater than the third threshold. The overall airway flow rate waveform appears to have a steep increase and a gentler decrease, exhibiting a clear "deceleration wave" characteristic. This shape indicates that the pressure rise rate is too fast, therefore the pressure rise time of the ventilation equipment needs to be increased. If the ratio between the flow rate decrease time (Tdown) and the flow rate increase time (Tup) is less than the fourth threshold, then the pressure rise time should be decreased. For example... Figure 8 In the middle, the ratio between the flow rate drop time Tdown and the flow rate rise time Tup is less than the fourth threshold, and the overall airway flow rate waveform looks like a smooth arc. This shape indicates that the pressure rise rate is too slow, so it is necessary to reduce the pressure rise time of the ventilation equipment.

[0091] The above parameters can be used together to determine whether the pressure rise time is too long or too short.

[0092] It should be noted that the above thresholds are not fixed and can be dynamically changed based on at least one of the following parameters: target pressure value, current pressure rise time, ventilator compliance and resistance, respiratory time constant, patient type, peak inspiratory flow rate, etc.

[0093] The increase and decrease of pressure rise time mentioned above can be automatically adjusted by the ventilation equipment, or prompts can be displayed on the ventilation equipment's display 70 to encourage medical staff to manually adjust the pressure rise time. Once the pressure rise time is adjusted, the ventilation equipment will increase the pressure according to the adjusted rise time in the next respiratory cycle. This adjustment process can occur within each respiratory cycle of the patient. For example, in the first respiratory cycle, the ventilation equipment increases the pressure according to the initially set pressure rise time, adjusting the rise time based on the characteristics of the ventilation parameters. In the second respiratory cycle, the ventilation equipment increases the pressure according to the rise time adjusted in the first cycle, and then adjusts the rise time again based on the characteristics of the ventilation parameters. In the third respiratory cycle, the ventilation equipment again increases the pressure according to the rise time adjusted in the second cycle, and so on. The pressure rise time can be adjusted by increasing or decreasing a fixed time value, or by changing a fixed percentage of the current pressure rise time each time. Both the fixed time value and the fixed percentage can be determined based on the parameter characteristics of the ventilation parameters mentioned above.

[0094] In some embodiments, at least one of the patient's positive end-expiratory pressure (PEEP) and target pressure value, respiratory rate, and respiratory time constant can be obtained, and the adjustment range of pressure rise time can be determined based on at least one of the PEEP and target pressure value, respiratory rate, and respiratory time constant. In the process of automatically adjusting pressure rise time, the patient's physiological condition can be taken into account, and the pressure rise time can be set within an appropriate range.

[0095] The above method effectively adjusts the pressure rise time based on different parameters of airway pressure and airway flow rate, so that the pressure rise time can be adapted to the patient's condition for better ventilation.

[0096] The above examples illustrate the present invention and are only intended to aid in understanding the invention, not to limit it. Those skilled in the art can make variations to the specific embodiments described above based on the spirit of the invention.

Claims

1. A ventilation device, characterized in that ,include: The patient interface is used to connect to the patient's respiratory system; A respiratory support device is used to provide respiratory support power during ventilation in order to deliver respiratory support gas to the patient. Processor, used for: Acquire ventilation parameters during the pressure rise process of a patient during ventilation, wherein the ventilation parameters include at least one of airway flow rate and airway pressure, and the pressure rise process is the process by which the airway pressure changes from an initial pressure value to a target pressure value within the same respiratory cycle; Acquire at least one parameter characteristic of the ventilation parameters regarding pressure rise time, wherein the pressure rise time is a set time during which the airway pressure rises from an initial pressure value to a target pressure value within the same respiratory cycle; Adjusting the pressure rise time of the ventilation device based on at least one parameter characteristic regarding pressure rise time includes: An airway pressure waveform is generated based on the airway pressure obtained during the pressure rise process; the trend of change of the airway pressure waveform is obtained; and the pressure rise time of the ventilation device is adjusted according to the trend of change of the airway pressure waveform; wherein, the trend of change of the airway pressure waveform is characterized by at least one of the following parameter features: the size of the area enclosed by the airway pressure waveform and the template curve, and the change of the area enclosed by the airway pressure waveform and the time axis within two adjacent time windows of the same length; or... Based on the airway flow velocity obtained during the pressure rise process, an airway flow velocity waveform is generated; the curve morphology characteristics of the airway flow velocity waveform are obtained, and the curve morphology characteristics are used to characterize the shape of the airway flow velocity waveform; the pressure rise time of the ventilation device is adjusted according to the curve morphology characteristics of the airway flow velocity waveform.

2. The ventilation device of claim 1, wherein, The trend of the airway pressure waveform is also characterized by the following parameters: The slope of the airway pressure waveform curve.

3. The ventilation device of claim 2, wherein, The processor adjusts the pressure rise time of the ventilation device according to the slope of the airway pressure waveform, including: When the slope of the curve changes from a positive value to a negative value, the airway pressure is compared with the target pressure value; If the airway pressure is less than the target pressure value, then the pressure rise time of the ventilation device is reduced.

4. The ventilation device of claim 1, wherein, The processor adjusts the pressure rise time of the ventilation device based on the area enclosed by the airway pressure waveform and the template curve, including: When the area enclosed by the airway pressure waveform and the template curve is positive, the absolute value of the enclosed area is compared with a first threshold. If the absolute value of the enclosed area is greater than the first threshold, the pressure rise time of the ventilation device is increased. When the area enclosed by the airway pressure waveform and the template curve is negative, the absolute value of the enclosed area is compared with a second threshold. If the absolute value of the enclosed area is greater than the second threshold, the pressure rise time of the ventilation device is reduced. When the template curve is below the airway pressure waveform, the area enclosed by the airway pressure waveform and the template curve is positive; when the template curve is above the airway pressure waveform, the area enclosed by the airway pressure waveform and the template curve is negative.

5. The ventilation device of claim 1, wherein, The processor adjusts the pressure rise time of the ventilation device based on the change in the area enclosed by the airway pressure waveform and the time axis within two adjacent time windows of equal length, including: Obtain the first area enclosed by the airway pressure waveform and the time axis within the next time window; Obtain the second area enclosed by the airway pressure waveform and the time axis within the previous time window; When the first area is larger than the second area, and the difference between the two is greater than a preset area threshold, the pressure rise time of the ventilation device is increased. When the first area is smaller than the second area, and the difference between the two is greater than a preset area threshold, the pressure rise time of the ventilation device is reduced.

6. The ventilation device of claim 1, wherein, The morphological characteristics of the airway flow velocity waveform are characterized by at least one of the following parametric features: The area between the initial airway flow rate and the peak airway flow rate, defined as the area between the airway flow rate waveform and the flow rate line, wherein the initial airway flow rate is the airway flow rate at the start of the pressure rise time, the peak airway flow rate is the maximum value of the airway flow rate during the pressure rise process, and the flow rate line is the line connecting the initial airway flow rate and the peak airway flow rate; and The ratio between the flow rate decrease time and the flow rate increase time, wherein the flow rate increase time is the time during which the airway flow rate increases from a first flow rate value to the peak flow rate during the pressure increase process, and the flow rate decrease time is the time during which the peak flow rate of the airway decreases to a second flow rate value during the pressure increase process, wherein the first flow rate value and the second flow rate value are equal.

7. The ventilation device as described in claim 6, characterized in that, The processor adjusts the pressure rise time of the ventilation device based on the curve morphology characteristics of the airway flow rate waveform, including: If the ratio between the flow rate decrease time and the flow rate rise time is greater than the third threshold, then the pressure rise time of the ventilation device is increased. If the ratio between the flow rate decrease time and the flow rate rise time is less than a fourth threshold, or if the area between the airway flow rate waveform and the flow rate line is positive and its absolute value is greater than a fifth threshold, then the pressure rise time of the ventilation device is reduced. Wherein, when the airway flow rate waveform is above the flow rate line, the area between the airway flow rate waveform and the flow rate line is positive.

8. The ventilation device as described in claim 1, characterized in that, The processor adjusts the pressure rise time of the ventilation device based on the at least one parameter characteristic related to the pressure rise time, and further includes: The peak airway pressure is obtained, which is the maximum value of the airway pressure during the pressure rise process; Obtain the relationship between the difference between the peak airway pressure and the target pressure value; The pressure rise time of the ventilation device is adjusted based on the difference between the peak airway pressure and the target pressure value.

9. The ventilation device as described in claim 8, characterized in that, The processor adjusts the pressure rise time of the ventilation device based on the difference between the peak airway pressure and the target pressure value, including: The pressure overshoot is calculated based on the peak airway pressure and the target pressure value. The pressure overshoot is calculated according to the following formula: ,in, For pressure overshoot, This refers to the peak airway pressure during the pressure rise process. The target pressure value; The pressure rise time of the ventilation device is adjusted according to the pressure overshoot.

10. The ventilation device as described in claim 9, characterized in that, The processor adjusts the pressure rise time of the ventilation device according to the pressure overshoot, including: The pressure overshoot is compared with the overshoot threshold. If the pressure overshoot is greater than the overshoot threshold, the pressure rise time of the ventilation device is increased.

11. The ventilation device as described in claim 1, characterized in that, The processor is also used for: Obtain at least one of the following: the difference between the patient's positive end-expiratory pressure and the target pressure value, respiratory rate, and respiratory time constant; The adjustment range of the pressure rise time is determined based on at least one of the difference between the positive end-expiratory pressure and the target pressure value, the respiratory rate, and the respiratory time constant. Within the range of the pressure rise time adjustment, the pressure rise time of the ventilation device is adjusted.

12. The ventilation device as described in claim 1, characterized in that, The processor adjusts the pressure rise time of the ventilation device based on the at least one parameter characteristic related to the pressure rise time, and further includes: Based on the at least one parameter characteristic regarding pressure rise time, identify whether the pressure rise time is too long or too short. If the pressure rise time is too long or too short, a prompt will be made to adjust the pressure rise time or to automatically adjust the pressure rise time.

13. A computer-readable storage medium, characterized in that, Includes a program that can be executed by a processor to implement the following methods: Acquire ventilation parameters during the pressure rise process of a patient during ventilation, wherein the ventilation parameters include at least one of airway flow rate and airway pressure, and the pressure rise process is the process by which the airway pressure changes from an initial pressure value to a target pressure value within the same respiratory cycle; Acquire at least one parameter characteristic of the ventilation parameters regarding pressure rise time, wherein the pressure rise time is a set time during which the airway pressure rises from an initial pressure value to a target pressure value within the same respiratory cycle; Adjusting the pressure rise time of the ventilation device based on at least one parameter characteristic regarding pressure rise time includes: An airway pressure waveform is generated based on the airway pressure obtained during the pressure rise process; the trend of change of the airway pressure waveform is obtained; and the pressure rise time of the ventilation device is adjusted according to the trend of change of the airway pressure waveform; wherein, the trend of change of the airway pressure waveform is characterized by at least one of the following parameter features: the size of the area enclosed by the airway pressure waveform and the template curve, and the change of the area enclosed by the airway pressure waveform and the time axis within two adjacent time windows of the same length; or... Based on the airway flow velocity obtained during the pressure rise process, an airway flow velocity waveform is generated; the curve morphology characteristics of the airway flow velocity waveform are obtained, and the curve morphology characteristics are used to characterize the shape of the airway flow velocity waveform; the pressure rise time of the ventilation device is adjusted according to the curve morphology characteristics of the airway flow velocity waveform.

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