WO2023019551A1

WO2023019551A1 - Ventilation device, and method for adjusting pressure rise time

Info

Publication number: WO2023019551A1
Application number: PCT/CN2021/113783
Authority: WO
Inventors: 朱锋; 万聪颖; 刘京雷; 周小勇
Original assignee: 深圳迈瑞生物医疗电子股份有限公司
Priority date: 2021-08-20
Filing date: 2021-08-20
Publication date: 2023-02-23
Also published as: CN117642200A

Abstract

A ventilation device, and a method for adjusting a pressure rise time. The method comprises: obtaining ventilation parameters of a patient in a pressure rise process during ventilation (100), the ventilation parameters comprising at least one of an airway flow rate and an airway pressure, and the pressure rise process being a process in which the airway pressure is finally changed to a target pressure value from an initial pressure value in a same respiratory cycle; obtaining at least one parameter feature related to the pressure rise time in the ventilation parameters (200), the pressure rise time being a set duration in which the airway pressure rises from the initial pressure value to the target pressure value in the same respiratory cycle; and adjusting the pressure rise time of the ventilation device according to the at least one parameter feature related to the pressure rise time (300). The pressure rise time may be adjusted in conjunction with one or more parameter features such that the pressure rise time can be better adapted to the patient's situation.

Description

Ventilation equipment and method for adjusting pressure rise time

technical field

The invention relates to the technical field of medical equipment, in particular to a ventilator and a method for adjusting the pressure rise time.

Background technique

The pressure rise time refers to the time for the patient's airway pressure to rise from the initial pressure value to the target pressure value set by the ventilation device during the ventilation process of the ventilation device (such as a ventilator or anesthesia ventilator). Taking the ventilator as an example, there are currently three typical settings for the pressure rise time of the ventilator: the first is to set the pressure rise time to a certain time; the second is to set the pressure rise time to a certain percentage of the inspiratory time, For example, the patient's inspiratory time is 1.5s, if the pressure rise time is set to 20%, the actual pressure rise time is 0.3s; the third is to set the pressure rise time in different gears, each gear has a corresponding pressure rise time.

The reasonable setting of the above-mentioned pressure rise time directly affects the patient's inspiratory flow rate, and flow rate synchronization is one of the important factors for man-machine synchronization during ventilation. In clinical practice, the patient's condition is changing, and the setting of the pressure rise time should be adjusted individually according to the patient's lung characteristics, because the same pressure rise time may be too short for patients with low lung compliance. It leads to obvious pressure overshoot, and it may be too long for patients with high lung compliance, obviously unable to meet the flow rate demand at the beginning of inspiration. The defect of the current setting method of pressure rise time is: use a fixed pressure rise time The time setting cannot meet the ventilation needs of different patients or different stages of the same patient, which will lead to overshoot of inspiratory pressure or insufficient initial inspiratory flow rate. However, if the pressure rise time is set unreasonably, it will cause many hazards: if the pressure rise time is too short, there will be obvious pressure overshoot, which may cause the peak pressure of the patient's lungs to be too high, which will easily lead to lung damage and obvious overshoot feeling; if If the pressure rise time is too long and the initial inspiratory flow rate is insufficient, it may lead to insufficient inspiratory flow of the patient, aggravate the man-machine confrontation, and increase the patient's work of breathing. To sum up, the current setting method of the pressure rise time is fixed, which may easily cause the patient's pressure overshoot or the initial inspiratory flow rate to be insufficient, resulting in man-machine confrontation, increasing the patient's work of breathing and prolonging the use time of the ventilator.

In order to be able to adapt the pressure rise time to the patient’s condition change, what needs to be done is to be able to accurately identify whether the pressure rise time is too long or too short during the ventilation process, and this is also a problem to be solved or improved in the current ventilation equipment one.

Contents of the invention

According to the first aspect, an embodiment discloses a method for adjusting the pressure rise time, including:

Obtain the ventilation parameters of the patient during the pressure rise process during ventilation, the ventilation parameters include at least one of airway flow rate and airway pressure, and the pressure rise process is the final change of the airway pressure from the initial pressure value in the same breathing cycle The process to the target pressure value;

Obtaining at least one parameter characteristic of the ventilation parameters about the pressure rise time, the pressure rise time being the set time period for the airway pressure to rise from the initial pressure value to the target pressure value in the same breathing cycle;

The pressure rise time of the ventilation device is adjusted as a function of the at least one pressure rise time-related parameter characteristic.

According to a second aspect, an embodiment discloses a ventilation device, comprising:

Patient interface for connection to the patient's respiratory system;

Respiratory assistance device for providing respiratory support power during ventilation to deliver respiratory support gas to the patient

A processor configured to execute the method as described in the first aspect.

According to a third aspect, an embodiment discloses a computer-readable storage medium, including a program, and the program can be executed by a processor to implement the method described in the first aspect.

The above-mentioned embodiment obtains at least one parameter feature about the pressure rise time among the ventilation parameters, each parameter feature can at least independently determine whether the pressure rise time is appropriate, and different parameter features can also jointly determine whether the pressure rise time is appropriate, and in When the pressure rise time is inappropriate, corresponding adjustments are made, so that the ventilation pressure rise time can be adapted to the changing condition of the patient.

Description of drawings

Fig. 1 is the structural representation of a kind of ventilator of embodiment;

Fig. 2 is a waveform diagram of airway pressure in a breathing cycle in an embodiment;

Fig. 3 is a waveform diagram of airway pressure under different pressure rise times of an embodiment;

Fig. 4 is an embodiment of the airway pressure waveform when the pressure rise time is too long;

Fig. 5 is a waveform diagram of airway pressure when the pressure rise time is too short in an embodiment;

FIG. 6 is a waveform diagram of airway pressure when the pressure rise time is too long in another embodiment;

Fig. 7 is a waveform diagram of airway pressure when the pressure rise time is too long in another embodiment;

Fig. 8 is a waveform diagram of airway flow velocity when the pressure rise time is too long in an embodiment;

Fig. 9 is a waveform diagram of airway flow velocity when the pressure rise time is too short in an embodiment;

Fig. 10 is a flow chart of an embodiment of a method for adjusting the pressure rise time;

Fig. 11 is a flowchart of an embodiment of adjusting the pressure rise time according to the airway pressure waveform;

Fig. 12 is a flow chart of adjusting the pressure rise time according to the airway flow velocity waveform according to an embodiment.

Detailed ways

The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings. Wherein, similar elements in different implementations adopt associated similar element numbers. In the following implementation manners, many details are described for better understanding of the present application. However, those skilled in the art can readily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, and methods. In some cases, some operations related to the application are not shown or described in the description, this is to avoid the core part of the application being overwhelmed by too many descriptions, and for those skilled in the art, it is necessary to describe these operations in detail Relevant operations are not necessary, and they can fully understand the relevant operations according to the description in the specification and general technical knowledge in the field.

In addition, the characteristics, operations or characteristics described in the specification can be combined in any appropriate manner to form various embodiments. At the same time, the steps or actions in the method description can also be exchanged or adjusted in a manner obvious to those skilled in the art. Therefore, various sequences in the specification and drawings are only for clearly describing a certain embodiment, and do not mean a necessary sequence, unless otherwise stated that a certain sequence must be followed.

The serial numbers assigned to components in this document, such as "first", "second", etc., are only used to distinguish the described objects, and do not have any sequence or technical meaning. The "connection" and "connection" mentioned in this application all include direct and indirect connection (connection) unless otherwise specified.

The most critical idea of the present invention is to effectively select the parameter characteristics and its expression form that can best reflect the pressure rise time from the airway pressure and airway parameters, and adjust the pressure rise time based on this.

Please refer to the embodiment shown in FIG. 1 , which provides a schematic diagram of the structural composition of a ventilator. In this embodiment, a ventilator is taken as an example to illustrate the structure of the ventilator. The ventilator includes an air source interface 10 , a breathing assistance 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 FIG. 1 is only an example of a ventilator, and does not constitute a limitation to the ventilator. The ventilator may include more or less components than those shown in FIG. 1, or combine certain components, or different components .

The gas source interface 10 is used to connect with a gas source (not shown in the figure), and the gas source is used to provide gas. Usually, oxygen, air and the like can be used as the gas. In some embodiments, the gas source can be a compressed gas cylinder or a central gas supply source, which supplies gas to the ventilator through the gas source interface 10, and the types of gas supply include oxygen O ₂ and air. The gas source interface 10 may include conventional components such as a pressure gauge, a pressure regulator, a flow meter, a pressure reducing valve, and a proportional regulation and protection device, which are respectively used to control the flow of various gases (such as oxygen and air). The gas input from the gas source interface 10 enters the breathing circuit 30 and forms a mixed gas with the original gas in the breathing circuit 30 . In some other embodiments, the ventilator itself has its own air source, so the air source interface 10 is not provided.

The breathing assistance device 20 is used to provide power for the patient's involuntary breathing and maintain the airway, that is, to drive the gas input from the gas source interface 10 and the mixed gas in the breathing circuit 30 to the patient's respiratory system, and to drain the gas exhaled by the patient. To the breathing circuit 30, thereby improving ventilation and oxygenation, preventing hypoxia of the patient's body and accumulation of carbon dioxide in the patient's body. In a specific embodiment, the respiratory assistance device 20 generally includes a mechanically controlled ventilation module, and the airflow channel of the mechanically controlled ventilation module communicates with the breathing circuit 30 . In the state that the patient has not recovered spontaneous breathing during the operation, the mechanically controlled ventilation module is used to provide breathing power for the patient. In some embodiments, the breathing assistance device 20 further includes a manual ventilation module, and the airflow channel of the manual ventilation module communicates with the breathing circuit 30 . During the induction phase prior to intubating a patient during a procedure, it is often necessary to assist the patient to breathe using a manual ventilation module. When the breathing assistance device 20 includes both a mechanically controlled ventilation module and a manual ventilation module, the mechanically controlled or manual ventilation mode can be switched through a mechanically controlled or manually controlled switch (such as a three-way valve), so that the mechanically controlled ventilation module or the manual ventilation module The module communicates with the breathing circuit 30 to control the breathing of the patient. Those skilled in the art should understand that the ventilator may only include a mechanically controlled ventilation module or a manual ventilation module according to specific requirements.

The breathing circuit 30 includes an inspiratory passage 30a, an exhalation passage 30b and a carbon dioxide absorber 31. The inspiratory passage 30a and the exhalation passage 30b are connected to form a closed circuit, and the carbon dioxide absorber 31 is arranged on the pipeline of the exhalation passage 30b. The mixed gas of fresh air introduced by the air source interface 10 is input through the inlet of the inhalation passage 30a, and provided to the patient through the patient interface 33 arranged at the outlet of the inhalation passage 30a. Patient interface 33 may be a mask, nasal or endotracheal tube. In a preferred embodiment, the inhalation passage 30a is provided with a one-way valve 32, and the one-way valve 32 is opened during the inhalation phase and closed during the exhalation phase. The exhalation channel 30b is also provided with a one-way valve 32, which is closed during the inhalation phase and opened during the exhalation phase. The inlet of the exhalation passage 30b communicates with the patient interface 33. When the patient exhales, the exhaled gas enters the carbon dioxide absorber 31 through the exhalation passage 30b, and the carbon dioxide in the exhaled gas is filtered out by the substances in the carbon dioxide absorber 31. The carbon dioxide filtered gas is recirculated into the inhalation passage 30a. In some embodiments, a flow sensor and/or a pressure sensor are also provided in the breathing circuit 30 for detecting the gas flow and/or the pressure in the pipeline respectively.

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

In one embodiment, the sensor interface 40 may only serve as a connector between the sensor output terminal and subsequent circuits (such as the processor 60 ), without signal processing. The sensor interface 40 can also be integrated into the processor 60 as an interface of the processor 60 for receiving signals. In another embodiment, the sensor interface 40 may include an amplification circuit, a filter circuit and an A/D conversion circuit, which are used to respectively amplify, filter and analog-to-digital conversion the input analog signal. Of course, those skilled in the art should understand that the connection relationship between the amplifier circuit, the filter circuit and the A/D conversion circuit can be changed according to the specific design of the circuit, and a certain circuit can also be reduced, for example, the amplifier circuit or the filter circuit can be reduced, thereby reducing its corresponding function.

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

The processor 60 is used to execute instructions or programs, control the various control valves in the breathing assistance device 20, the gas source interface 10 and/or the breathing circuit 30, or process the received data to generate required calculations or judgments As a result, visualization data or graphics are either generated and output to display 70 for display.

In this example, after obtaining the ventilation parameters of the patient's pressure rise process during ventilation, the processor 60 obtains at least one parameter feature about the pressure rise time among the ventilation parameters, and then according to at least one parameter feature about the pressure rise time, Adjust the pressure rise time of the ventilator.

The above pressure rise process is the process of the patient’s airway pressure changing from the initial pressure value to the target pressure value in the same respiratory cycle. In order to better understand the pressure rise process, the pressure rise time is first explained. The pressure rise time is often used in the pressure target type ventilation mode. Generally speaking, when the patient inhales, the ventilator sends air at high pressure, and the patient can inhale enough air through the pressure. At the end of the patient's inhalation, the ventilator actively reduces the pressure, allowing the patient to exhale the exhaust gas in the body through the pressure difference between the lung and the outside world. For example, please refer to Fig. 2, which is a schematic diagram of the airway pressure waveform in a breathing cycle, where PEEP is the positive end-expiratory pressure of the previous breathing cycle. In the initial stage of the breathing cycle shown in the figure, the patient changes from the exhalation state in the previous breathing cycle to the inhaling state in this breathing cycle, and the airway pressure in this breathing cycle rises from the initial pressure value to the target pressure value (the patient is in the The time of the airway pressure in the inspiratory state (expressed by Pset) is the pressure rise time, and the pressure rise time is used as a ventilation parameter of the ventilation device, so it can be set directly or indirectly.

However, in actual ventilation, the change of the patient's airway pressure does not necessarily coincide with the set pressure rise time. For example, if the pressure rise time is set to 0.5s on the ventilation device, the patient's airway pressure may pass through 0.4 s to reach the target pressure value, or the airway pressure of the patient may reach the target pressure value in 0.6 s. The process in which the airway pressure actually changes to the target pressure value in a breathing cycle is the pressure rising process defined in this application. In this process, the airway pressure will eventually reach a pressure value greater than airway pressure, but this does not mean that airway pressure is always rising. For example, please refer to Fig. 3, the curve S1 in this figure is the airway pressure waveform when the pressure rise time is neither too long nor too short, and the curve S2 is a kind of airway pressure waveform when the pressure rise time is too short, Because the pressure rises too fast, the ventilator will deliver a large flow of gas in a short period of time, making the curve S1 peak and then drop to the target pressure value, while the curve S3 is a gas when the pressure rises for too long pressure waveform.

At least one parameter characteristic of the above ventilation parameters related to the pressure rise time refers to a parameter characteristic obtained from the ventilation parameters and capable of reflecting the speed of the pressure rise time. An example is given below.

In some embodiments, the processor 60 first generates the airway pressure waveform according to the acquired airway pressure during the pressure rise process, then obtains the change trend of the airway pressure waveform, and finally adjusts the pressure rise time of the ventilation device according to the change trend. The variation trend includes but not limited to the slope of the curve of the airway pressure waveform, the size of the area enclosed by the airway pressure waveform and the template curve, and the area enclosed by the airway pressure waveform and the time axis in two adjacent time windows of the same length The change. in particular:

During the pressure rise process, the processor 60 can obtain the curve slope of the airway pressure waveform. When the curve slope changes from a positive value to a negative value, the processor 60 compares the airway pressure and the target pressure when the curve slope changes from a positive value to a negative value. Values are compared, if the airway pressure is less than the target pressure value, the pressure rise time of the ventilator is reduced. That is to say, if the airway pressure is still lower than the target pressure value during the pressure rise process, the airway pressure waveform will drop as shown in Figure 4, which means that the pressure rise time is too long and the pressure rise speed is too slow , so it is necessary to reduce the pressure rise time. In Figure 4, the arrow K points to the stage where the slope changes from positive to negative, and Tslope represents the pressure rise time (Tslope also represents the pressure rise time in other figures).

The template curve refers to the curve fitted based on the set pressure rise time. After the pressure rise time is set, the airway pressure of the patient changes according to the template curve under ideal conditions. Of course, in actual situations, A patient's airway pressure waveform inevitably deviates from this template curve at times due to various reasons. The template curve can be obtained by multiple experiments. The size of the area enclosed by the airway pressure waveform and the template curve is positive or negative. 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 a positive value; when the template curve is above the airway pressure waveform, the area formed by the airway pressure waveform and the template curve is positive. The enclosed area is a negative value. In this application, the actual curve of the airway pressure waveform is denoted by Sp, and the template curve is denoted by S1 (curve S1 is also a template curve in FIG. 2 ). When the area enclosed by the airway pressure waveform and the template curve is a positive value, the processor 60 compares the absolute value of the enclosed area with the first threshold, and if the absolute value of the enclosed area is greater than the first threshold, increase Pressure rise time for large ventilators. For example, as shown in Figure 5, it can be seen from the figure that the airway pressure waveform exceeds the template curve too much during the rising process, which means that the pressure rising time is too short and the pressure rising speed is too fast, so the pressure rising time needs to be increased .

And when the area enclosed by the airway pressure waveform and the template curve is a negative value, the processor 60 compares the absolute value of the enclosed area with the second threshold, and if the absolute value of the enclosed area is greater than the second threshold, then Reduce the pressure rise time of the ventilator. For example, Figure 6 shows a situation where the area enclosed by the airway pressure waveform and the template curve is a negative value. It can be seen from the figure that if the airway pressure waveform deviates from the template curve below Too much means that the pressure rise time is too long and the pressure rise speed is too slow, so the pressure rise time needs to be reduced.

Please continue to refer to Figure 7. In Figure 7, two adjacent and equal-length time windows are divided in the pressure rise time, wherein the latter time window is defined as the first time window T1, and the former time window is defined as the first time window T1. Two time windows T2, the processor 60 obtains the first area enclosed by the airway pressure waveform and the time axis in the first time window T1, and obtains the area enclosed by the airway pressure waveform and the time axis in the second time window T2 second area, and then compare the first area to 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 may not be positive or negative. When the first area is greater than the second area, and the difference between the two is greater than the preset area threshold, it means that the change speed of the airway pressure waveform is too fast, which is the result of the pressure rise time being too short, so increase The pressure rise time of the ventilation device, and 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 change speed of the airway pressure waveform is too slow, which means that the pressure rise time is too long. As a result, the pressure rise time of the ventilator is reduced.

All of the above methods can reflect the change trend of the airway pressure waveform, and it can be seen that the change trend can include both the change speed and the change direction.

In some embodiments, after the airway pressure is acquired, the processor 60 does not generate the airway pressure waveform according to the airway pressure, but acquires the peak value of the airway pressure, which is the airway pressure during the pressure rise process , and the post-processor 60 obtains the difference relationship between the peak airway pressure and the target pressure value, and then adjusts the pressure rise time of the ventilator according to the difference relationship, which can be used to reflect the peak airway pressure The degree of difference from 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, which means that the pressure rise time is too short, so the increase The pressure rise time of the ventilator.

The above-mentioned difference relationship can be obtained simply by making a difference between the peak value of the airway pressure and the target pressure value. In some embodiments, the difference relationship is also represented by the pressure overshoot, and the pressure overshoot is calculated according to the following formula:

Among them, σ is the pressure overshoot, P _max is the peak airway pressure during the pressure rise process, and P _set is the target pressure value. After the pressure overshoot is obtained, 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 ventilator is increased, and the overshoot threshold is also a preset value. . When the pressure overshoot is too large, the airway pressure waveform may have a sharp peak as shown in FIG. 5 .

In addition, it is also possible to judge whether the pressure rise time is appropriate according to the time when the airway pressure rises to a certain set pressure value, for example, judge whether the pressure rise time is appropriate according to the time when the airway pressure rises to half of the target pressure value.

In some embodiments, the processor 60 first generates the airway flow velocity waveform according to the airway flow velocity acquired during the pressure rise process, and then acquires the curve shape characteristics of the airway flow velocity waveform, and adjusts the pressure rise of the ventilation device according to the curve shape characteristics Time, where the curve shape feature of the airway flow waveform is used to characterize the shape of the airway flow waveform. That is to say, whether there is too long pressure rise time or too short pressure rise time is identified through the shape of the airway flow velocity waveform. in particular:

In some embodiments, the curve shape characteristics of the airway flow velocity waveform can be characterized by the area between the airway flow velocity waveform and the flow velocity line between the initial value of the airway flow velocity and the peak value of the airway flow velocity, wherein, the initial pressure value of the airway pressure Similarly, the initial value of the airway flow rate refers to the airway flow rate at the beginning of the pressure rise time, and the peak value of the airway flow rate is the maximum value of the airway flow rate during the pressure rise process. The dotted line shown in Figure 8 is the flow rate connecting line, and L1 indicates that the flow velocity connection line is the connection line between the initial value of the airway flow velocity and the peak value of the airway flow velocity, and the area between the airway flow velocity waveform and the flow velocity connection line is also positive or negative. When the airway flow velocity waveform is above the flow velocity connection line, the area between the airway flow velocity waveform and the flow velocity connection line is a positive value. 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 (such as the situation shown in Figure 8), then reduce the pressure rise time of the ventilation device. When the above situation occurs, usually the airway The arc of the flow velocity waveform is too large when it rises, and this is caused by the long pressure rise time, so the pressure rise time needs to be reduced.

In some embodiments, the ratio of the flow rate drop time Tdown to the flow rate rise time Tup can be used to characterize the curve shape characteristics of the airway flow velocity waveform, and the flow rate rise time Tup is the increase of the airway flow rate from the first flow rate value to the airway flow rate during the pressure rise process. The time of the peak flow velocity, the flow velocity drop time Tdown is the time when the airway flow velocity peak value drops to the second flow velocity value during the pressure rise process, where the first flow velocity value and the second flow velocity value are equal, that is to say, the flow velocity drop time Tdown and the flow velocity The ratio of the rise time Tup is the ratio of the time required for the airway flow rate to rise from a certain value to the peak value and the time required to drop from the peak value to the same value during the pressure rise process. The airway flow rate can also be reflected from this ratio shape. For example, as shown in Figure 9, the ratio between the flow velocity drop time Tdown and the flow velocity rise time Tup in this figure is greater than the third threshold, and the airway flow velocity waveform as a whole seems to have a steeper rising process, while the falling process has a gentle slope, showing an obvious The characteristic of the "deceleration wave" of the "deceleration wave", this shape indicates that the pressure rise rate is too fast, so the pressure rise time of the ventilator needs to be increased. However, in Fig. 8, the ratio between the flow velocity drop time Tdown and the flow velocity rise time Tup is less than the fourth threshold value, and the airway flow velocity waveform as a whole looks like a circular arc shape with a smooth transition, which indicates that the pressure rise rate is relatively slow, so it is necessary to Reduce the pressure rise time of the ventilator.

The characteristics of the above parameters can cooperate with each other to determine whether the pressure rise time is too long or too short.

It should be noted that the above-mentioned various thresholds are not fixed, and each threshold can be determined according to parameters such as target pressure value, current pressure rise time, compliance and resistance monitored by the ventilator, respiratory time constant, patient type, peak inspiratory flow rate, etc. At least one of the dynamic changes.

The increase and decrease of the pressure rise time mentioned above can be automatically increased or decreased by the processor 60, and prompt information for adjusting the pressure rise time can also be output, such as displaying relevant prompts on the display 70 information to prompt medical personnel to manually adjust the pressure rise time. After the pressure rise time is adjusted, the ventilator will raise the pressure according to the adjusted pressure rise time in the next breathing cycle. The adjustment process of the above-mentioned pressure rise time can occur in each breathing cycle of the patient. For example, in the first breathing cycle, the ventilator raises the pressure according to the initially set pressure rising time, and in the first breathing cycle according to the ventilation parameters In the second breathing cycle, the ventilator increases the pressure according to the pressure rising time adjusted in the first breathing cycle, and in this process adjusts the pressure rising time according to the parameter characteristics of the ventilation parameters. , in the third breathing cycle, the ventilator increases the pressure according to the adjusted pressure rise time in the second breathing cycle, and so on. The adjustment of the pressure rise time can be increased or decreased according to a fixed time value, or a fixed percentage of the current pressure rise time can be changed each time. The fixed time value and the fixed percentage can also be determined based on the parameter characteristics of the above-mentioned ventilation parameters.

In some embodiments, the processor 60 acquires at least one of the difference between the patient's positive end-expiratory pressure and the target pressure value, the respiratory rate, and the respiratory time constant, and according to the difference between the positive end-expiratory pressure and the target pressure value, At least one of the difference, the respiratory rate, and the respiratory time constant determines the adjustment range of the pressure rise time. In the process of automatically adjusting the pressure rise time, the patient's physiological condition can be considered, and the pressure rise time can be set within an appropriate range.

The present invention also provides a method for adjusting the pressure rise time, please refer to Figure 10, including steps:

Step 100, acquiring the ventilation parameters of the patient during the pressure rise process during the ventilation. Ventilation parameters include at least one of airway flow rate and airway pressure.

The above pressure rise process is the process of the patient’s airway pressure changing from the initial pressure value to the target pressure value in the same respiratory cycle. In order to better understand the pressure rise process, the pressure rise time is first explained. The pressure rise time is often used in the pressure target type ventilation mode. Generally speaking, when the patient inhales, the ventilator sends air at high pressure, and the patient can inhale enough air through the pressure. At the end of the patient's inhalation, the ventilator actively reduces the pressure, allowing the patient to exhale the exhaust gas in the body through the pressure difference between the lung and the outside world. For example, please refer to FIG. 2 , which is a schematic diagram of the airway pressure waveform in a respiratory cycle, wherein PEEP is the positive end-expiratory pressure of the previous respiratory cycle. In the initial stage of the breathing cycle shown in the figure, the patient changes from the exhalation state in the previous breathing cycle to the inhaling state in this breathing cycle, and the airway pressure in this breathing cycle rises from the initial pressure value to the target pressure value (the patient is in the The time of the airway pressure in the inspiratory state (expressed by Pset) is the pressure rise time, and the pressure rise time is used as a ventilation parameter of the ventilation device, so it can be set directly or indirectly.

Step 200, acquiring at least one parameter characteristic of the ventilation parameters related to the pressure rise time.

The parameter feature refers to a parameter feature obtained from ventilation parameters and capable of reflecting the speed of pressure rise time.

Step 300. Adjust the pressure rise time of the ventilator according to at least one parameter characteristic about the pressure rise time. The following specific examples illustrate how to adjust the pressure rise time.

In some embodiments, adjusting the pressure rise time, as shown in Figure 11, includes steps:

Step 310a, generating an airway pressure waveform according to the acquired airway pressure during the pressure rise process.

Step 320a, acquiring the variation trend of the airway pressure waveform.

The changing trend in this step includes, but is not limited to, the slope of the curve of the airway pressure waveform, the size of the area enclosed by the airway pressure waveform and the template curve, and the difference between the airway pressure waveform and the time axis in two adjacent time windows of the same length. Changes in the surrounding area.

The template curve above refers to the curve fitted based on the set pressure rise time. After the pressure rise time is set, the airway pressure of the patient changes according to the template curve in an ideal state. Of course, in the actual situation , the patient's airway pressure waveform will inevitably deviate from the template curve sometimes due to various reasons. The template curve can be obtained by multiple experiments. The size of the area enclosed by the airway pressure waveform and the template curve is positive or negative. 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 a positive value; when the template curve is above the airway pressure waveform, the area formed by the airway pressure waveform and the template curve is positive. The enclosed area is a negative value.

The airway pressure waveform should be above the time axis during the pressure rise process, so the area enclosed by the airway pressure waveform and the time axis can be considered to be non-positive or always positive.

Step 330a, adjust the pressure rise time of the ventilator according to the change trend of the airway pressure waveform.

In some embodiments, when the slope of the curve changes from a positive value to a negative value, the airway pressure when the slope of the curve changes from a positive value to a negative value can be compared with the target pressure value, and if the airway pressure is lower than the target pressure value, then decrease Pressure rise time for small ventilators. That is to say, if the airway pressure is still lower than the target pressure value during the pressure rise process, the airway pressure waveform will drop as shown in Figure 4, which means that the pressure rise time is too long and the pressure rise speed is too slow , so it is necessary to reduce the pressure rise time. In Figure 4, the arrow K points to the stage where the slope changes from positive to negative, and Tslope represents the pressure rise time (Tslope also represents the pressure rise time in other figures).

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 the first threshold, and if the absolute value of the enclosed area is greater than the first threshold , then increase the pressure rise time of the ventilator. For example, as shown in Figure 5, it can be seen from the figure that the airway pressure waveform exceeds the template curve too much during the rising process, which means that the pressure rising time is too short and the pressure rising speed is too fast, so the pressure rising time needs to be increased . And when the area enclosed by the airway pressure waveform and the template curve is a negative value, the absolute value of the enclosed area can be compared with the second threshold, and if the absolute value of the enclosed area is greater than the second threshold, then decrease The pressure rise time of the ventilator. For example, Figure 6 shows a situation where the area enclosed by the airway pressure waveform and the template curve is a negative value. It can be seen from the figure that if the airway pressure waveform deviates from the template curve below Too much means that the pressure rise time is too long and the pressure rise speed is too slow, so the pressure rise time needs to be reduced.

In some embodiments, please refer to FIG. 7. In FIG. 7, two adjacent and equal-length time windows are divided in the pressure rise time, wherein the latter time window is defined as the first time window T1, and the former time window When defined as the second time window T2, the first area enclosed by the airway pressure waveform and the time axis in the first time window T1 can be obtained, and the area enclosed by the airway pressure waveform and the time axis in the second time window T2 can be obtained. The resulting second area, and then compare the first area with the second area. When the first area is greater than the second area, and the difference between the two is greater than the preset area threshold, it means that the change speed of the airway pressure waveform is too fast, which is the result of the pressure rise time being too short, so increase The pressure rise time of the ventilation device, and 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 change speed of the airway pressure waveform is too slow, which means that the pressure rise time is too long. As a result, the pressure rise time of the ventilator is reduced.

In some embodiments, after the airway pressure is obtained, the airway pressure waveform may not be generated according to the airway pressure, but the peak value of the airway pressure is obtained, and the peak value of the airway pressure is the maximum value of the airway pressure during the pressure rise process. value, and then obtain the difference relationship between the peak airway pressure and the target pressure value, and then adjust the pressure rise time of the ventilation device according to the difference relationship, the difference relationship can be used to reflect the difference between the peak airway pressure and the target pressure value the difference between. 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, which means that the pressure rise time is too short, so the increase The pressure rise time of the ventilator.

Among them, σ is the pressure overshoot, P _max is the peak airway pressure during the pressure rise process, and P _set is the target pressure value. After the pressure overshoot is obtained, 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 ventilator is increased, and the overshoot threshold is also a preset value. .

In some embodiments, adjusting the pressure rise time, as shown in Figure 12, includes the steps of:

Step 310b: Generate an airway flow velocity waveform according to the airway flow velocity acquired during the pressure rise process.

Step 320b. Obtain the curve shape feature of the airway flow velocity waveform, which is used to characterize the shape of the airway flow velocity waveform.

In some embodiments, the curve shape characteristics of the airway flow velocity waveform can be characterized by the area between the airway flow velocity waveform and the flow velocity line between the initial value of the airway flow velocity and the peak value of the airway flow velocity, wherein, the initial pressure value of the airway pressure Similarly, the initial value of the airway flow velocity refers to the airway flow velocity at the beginning of the pressure rise time, and the peak value of the airway flow velocity is the maximum value of the airway flow velocity during the pressure rise process. The dotted line shown in Figure 8 is the flow velocity connection line. The connecting line is the connecting line between the initial value of the airway flow velocity and the peak value of the airway flow velocity, and the area between the airway flow velocity waveform and the connecting line of the flow velocity is also positive or negative. When the airway flow velocity waveform is above the flow velocity connection line, the area between the airway flow velocity waveform and the flow velocity connection line is a positive value.

In some other embodiments, the ratio of the flow rate drop time Tdown to the flow rate rise time Tup can be used to characterize the curve shape characteristics of the airway flow velocity waveform, and the flow rate rise time Tup is the airway flow rate rising from the first flow rate value to The time of the peak flow velocity of the airway, the flow velocity drop time Tdown is the time when the peak flow velocity of the airway drops to the second flow velocity value during the pressure rise process, where the first flow velocity value and the second flow velocity value are equal, that is to say, the flow velocity drop time Tdown The ratio of the flow velocity rise time Tup is the ratio of the time required for the airway flow velocity to rise from a certain value to the peak value and the time required to drop from the peak value to the same value during the pressure rise process. The shape of the flow velocity.

Step 330b, adjust the pressure rise time of the ventilator according to the curve shape characteristics of the airway flow velocity waveform.

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 reduce the pressure rise time of the ventilator. , and this is caused by too long pressure rise time, so it is necessary to reduce the pressure rise time.

On the other hand, if the ratio between the flow rate falling time Tdown and the flow rate rising time Tup is greater than the third threshold, the pressure rising time is increased. For example, as shown in Figure 9, the ratio between the flow velocity drop time Tdown and the flow velocity rise time Tup in this figure is greater than the third threshold, and the airway flow velocity waveform as a whole seems to have a steeper rising process, while the falling process has a gentle slope, showing an obvious Characteristic of a "deceleration wave", this shape indicates a rapid pressure rise and therefore requires an increase in the pressure rise time of the ventilator. If the ratio between the flow rate down time Tdown and the flow rate up time Tup is smaller than the fourth threshold, the pressure up time is decreased. For example, in Figure 8, the ratio between the flow velocity drop time Tdown and the flow velocity rise time Tup is less than the fourth threshold, and the overall airway flow velocity waveform looks like a smooth circular arc. Pressure rise time for small ventilators.

The above mentioned increasing the pressure rise time and decreasing the pressure rise time can be automatically increased or decreased by the ventilator, and a prompt message for adjusting the pressure rise time can also be output, such as displaying relevant information on the display 70 of the ventilator. The prompt information to prompt the medical staff to manually adjust the pressure rise time. When the pressure rise time is adjusted, the ventilator increases the pressure in the next breathing cycle according to the adjusted pressure rise time. The adjustment process of the above-mentioned pressure rise time can occur in each breathing cycle of the patient. For example, in the first breathing cycle, the ventilator raises the pressure according to the initially set pressure rising time, and in the first breathing cycle according to the ventilation parameters In the second breathing cycle, the ventilator increases the pressure according to the pressure rising time adjusted in the first breathing cycle. In this process, the pressure rising time is adjusted according to the parameter characteristics of the ventilation parameters. , in the third breathing cycle, the ventilator increases the pressure according to the adjusted pressure rise time in the second breathing cycle, and so on. The adjustment of the pressure rise time can be increased or decreased according to a fixed time value, or a fixed percentage of the current pressure rise time can be changed each time. The fixed time value and the fixed percentage can also be determined based on the parameter characteristics of the above-mentioned ventilation parameters.

In some embodiments, at least one of the difference between the patient's positive end-expiratory pressure and the target pressure value, the respiratory rate, and the respiratory time constant can also be obtained, and according to the difference between the positive end-expiratory pressure and the target pressure value In the process of automatically adjusting the pressure rise time, the pressure rise time can be set within an appropriate range while taking into account the patient's physiological condition.

The above method effectively adjusts the pressure rise time according to different parameter characteristics of airway pressure and airway flow rate, so that the pressure rise time can be adapted to the patient's condition, so as to better ventilate the patient.

The above uses specific examples to illustrate the present invention, which is only used to help understand the present invention, and is not intended to limit the present invention. For those skilled in the art, the above specific implementation manners may be changed according to the idea of the present invention.

Claims

A method for adjusting pressure rise time, applied to ventilation equipment, characterized in that the method includes:

Obtain the ventilation parameters of the patient during the pressure rise process during ventilation, the ventilation parameters include at least one of airway flow rate and airway pressure, and the pressure rise process is the final change of the airway pressure from the initial pressure value in the same breathing cycle The process to the target pressure value;

Obtaining at least one parameter characteristic of the ventilation parameters about the pressure rise time, the pressure rise time being the set time period for the airway pressure to rise from the initial pressure value to the target pressure value in the same breathing cycle;

The pressure rise time of the ventilation device is adjusted as a function of the at least one pressure rise time-related parameter characteristic.
The adjustment method according to claim 1, wherein the adjusting the pressure rise time of the ventilation device according to the at least one parameter characteristic about the pressure rise time comprises:

generating an airway pressure waveform according to the airway pressure acquired during the pressure rise process;

Obtain the variation trend of the airway pressure waveform;

According to the change trend of the airway pressure waveform, the pressure rise time of the ventilator is adjusted.
The adjustment method according to claim 2, characterized in that, the change trend of the airway pressure waveform is characterized by at least one of the following parameter characteristics:

the slope of the curve of the airway pressure waveform; and

the size of the area enclosed by the airway pressure waveform and the template curve; and

Changes in the area enclosed by the airway pressure waveform and the time axis within two adjacent time windows of the same length.
The adjustment method according to claim 3, wherein adjusting the pressure rise time of the ventilation device according to the curve slope of the airway pressure waveform comprises:

When the slope of the curve changes from a positive value to a negative value, compare the airway pressure with the target pressure value;

If the airway pressure is less than a target pressure value, the pressure rise time of the ventilation device is decreased.
The adjustment method according to claim 3, wherein, according to the size of the area enclosed by the airway pressure waveform and the template curve, adjusting the pressure rise time of the ventilation device includes:

When the area enclosed by the airway pressure waveform and the template curve is a positive value, compare the absolute value of the enclosed area with the first threshold, and if the absolute value of the enclosed area is greater than the first threshold, increase the the pressure rise time of the ventilator;

When the area enclosed by the airway pressure waveform and the template curve is a negative value, compare the absolute value of the enclosed area with the second threshold, and if the absolute value of the enclosed area is greater than the second threshold, decrease the The pressure rise time of the ventilation device, wherein, when the template curve is below the airway pressure waveform, the area enclosed by the airway pressure waveform and the template curve is a positive value, and when the template curve is below the airway pressure waveform When the waveform is above the waveform, the area enclosed by the airway pressure waveform and the template curve is a negative value.
The adjustment method according to claim 3, wherein, according to the change of the area enclosed by the airway pressure waveform and the time axis in two adjacent time windows of the same length, the pressure rise time of the ventilation device is adjusted, including :

Obtain the first area enclosed by the airway pressure waveform and the time axis in the next time window;

Obtain the second area enclosed by the airway pressure waveform and the time axis in the previous time window;

When the first area is greater than the second area, and the difference between the two is greater than a preset area threshold, increasing the pressure rise time of the ventilation device;

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.
The adjustment method according to claim 1, wherein the adjusting the pressure rise time of the ventilation device according to the at least one parameter characteristic about the pressure rise time comprises:

generating an airway flow velocity waveform according to the airway flow velocity acquired during the pressure rise process;

Obtaining the curve shape feature of the airway flow velocity waveform, the curve shape feature being used to characterize the shape of the airway flow velocity waveform;

The pressure rise time of the ventilator is adjusted according to the curve shape characteristic of the airway flow velocity waveform.
The adjustment method according to claim 7, characterized in that, the curve shape characteristic of the airway flow velocity waveform is characterized by at least one of the following parameter characteristics:

The area between the airway flow velocity waveform and the flow velocity line between the initial value of the airway flow velocity and the peak value of the airway flow velocity, wherein the initial value of the airway flow velocity is the airway flow velocity at the beginning of the pressure rise time, and the airway flow velocity The peak flow velocity is the maximum value of the airway flow velocity during the pressure rise process, and the flow velocity connection line is the connection line between the initial value of the airway flow velocity and the peak value of the airway flow velocity; and

The ratio between the flow rate drop time and the flow rate rise time, wherein the flow rate rise time is the time when the airway flow rate rises from the first flow rate value to the peak value of the airway flow rate during the pressure rise process, and the flow rate drop time is the pressure The time when the peak airway flow velocity drops to the second flow velocity value during the ascent process, wherein the first flow velocity value and the second flow velocity value are equal.
The adjustment method according to claim 8, characterized in that, adjusting the pressure rise time of the ventilation device according to the curve shape characteristics of the airway flow velocity waveform comprises:

increasing the pressure rise time of the ventilator if the ratio between the flow rate fall time and the flow rate rise time is greater than a third threshold;

If the ratio between the flow velocity falling time and the flow velocity rising time is less than the fourth threshold, or 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 decrease The pressure rise time of the ventilator, wherein, when the airway flow velocity waveform is above the flow velocity connection line, the area between the airway flow velocity waveform and the flow velocity connection line is a positive value.
The adjustment method according to claim 1, wherein the adjusting the pressure rise time of the ventilation device according to the at least one parameter characteristic about the pressure rise time comprises:

Acquiring peak airway pressure, where the peak airway pressure is the maximum value of airway pressure during the pressure rise process;

Acquiring the difference relationship between the peak airway pressure and the target pressure value;

The pressure rise time of the ventilator is adjusted according to the difference relationship between the peak airway pressure and the target pressure value.
The adjustment method according to claim 10, characterized in that, adjusting the pressure rise time of the ventilation device according to the difference relationship between the peak value of the airway pressure and the target pressure value comprises:

Calculate the pressure overshoot according to the peak value of the airway pressure and the target pressure value;

The pressure overshoot is calculated according to the following formula:

Among them, σ is the pressure overshoot, P max is the peak airway pressure during the pressure rise process, and P set is the target pressure value;

The pressure rise time of the ventilation device is adjusted according to the pressure overshoot.
The adjustment method according to claim 11, wherein the adjusting the pressure rise time of the ventilation device according to the pressure overshoot comprises:

The pressure overshoot is compared with an overshoot threshold, and if the pressure overshoot is greater than the overshoot threshold, the pressure rise time of the ventilation device is increased.
The adjustment method according to claim 1, characterized in that the method further comprises:

obtaining at least one of a difference between positive end-expiratory pressure of the patient and the target pressure value, a respiratory rate, and a respiratory time constant;

determining an adjustment range of the pressure rise time according to at least one of the difference between the positive end-expiratory pressure and the target pressure value, a respiratory rate, and a respiratory time constant;

Within the adjustment range of the pressure rise time, the pressure rise time of the ventilation device is adjusted.
The adjustment method according to claim 1, wherein the adjusting the pressure rise time of the ventilation device according to the at least one parameter characteristic about the pressure rise time comprises:

Identifying whether there is an excessively long pressure rise time or an excessively short pressure rise time based on the at least one parameter characteristic about the pressure rise time;

If the pressure rise time is too long or the pressure rise time is too short, prompt to adjust the pressure rise time or automatically adjust the pressure rise time.
A ventilator, characterized in that it comprises:

A patient interface for connecting to the patient's respiratory system;

Respiratory assistance devices for providing respiratory support power during ventilation to output respiratory support gas to the patient;

A processor, configured to execute the method according to any one of claims 1-14.
A computer-readable storage medium, characterized by comprising a program, the program can be executed by a processor to implement the method according to any one of claims 1-14.