CN105194776B - A kind of lung ventilator air flue compress control method - Google Patents

Abstract

The invention discloses a kind of lung ventilator air flue compress control method, it is related to automation control area, the airway pressure of collection is compensated according to the airway pressure force value collected and airway pressure variation tendency by dynamic, lung ventilator is enabled accurately to prejudge airway pressure regulated quantity, to carry out the regulation of adaptability to patient respiration pipeline air pressure, the stability of patient respiration pipeline pressure control is improved, ensure that adaptability of this airway pressure control method in different use environments.

Description

A method for controlling airway pressure of a ventilator

technical field

The invention relates to the field of automatic control, in particular to a method for controlling airway pressure of a ventilator.

Background technique

The PEEP valve is the positive end-expiratory pressure valve, which is mainly used in ventilators to facilitate breathing and ventilation for patients with lung lesions. When the airway opens at the end of expiration, the airway pressure remains above atmospheric pressure to prevent collapse of the alveoli. When PEEP is abnormally increased, the work required for exhalation increases, causing difficulty in exhaling, which may lead to increased risk of suffocation and increased work of breathing. At present, the mechanical positive end-expiratory pressure control method used by the ventilator cannot accurately control the end-expiratory pressure and the positive end-expiratory pressure cannot be continuously adjusted. The safety factor is insufficient and the gas consumption is high.

The working principle of the PEEP valve is to control the opening pressure of the diaphragm by adjusting the magnitude of the current. The advantage of this valve is better linearity. The current usual method is to first calibrate the opening pressure of the diaphragm corresponding to each current point through testing, and obtain a corresponding table of pressure and current. Then, according to the desired pressure, look up the table to find the corresponding current value, and obtain the desired PEEP pressure through a given current. At the same time, the existing ventilator is controlled according to the collected airway pressure data, but basically does not process the collected data, resulting in high delay, slow response, inaccurate pressure collection, and poor adaptability in the pressure control of the ventilator. And the shortcomings of low stability, so that the PEEP valve can not achieve high working accuracy. Because in order to obtain high working accuracy, a relatively fine correspondence table of pressure and current must be obtained, which requires a lot of tedious tests. And to store this fine table value also requires a lot of storage space. At the same time, referring to this fine table value for calculation also requires a lot of system time and resources.

Contents of the invention

In view of the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is to provide a method for controlling the airway pressure of a ventilator that can monitor the pressure of the patient's breathing circuit in real time and control the PEEP valve with higher precision.

In order to achieve the above object, the present invention provides a method for controlling the airway pressure of a ventilator, which is controlled by a ventilator airway control system. The ventilator airway control system includes: a processing unit, an air circuit system, The PEEP valve of the unit and its driving unit; the air circuit system includes a breathing circuit, and the breathing circuit is respectively connected to the inspiratory valve and the PEEP valve through the air circuit pipeline; the PEEP valve is used to discharge the driving gas into the atmosphere; The breathing circuit is also connected with an inspiratory branch and an expiratory branch; the expiratory branch is provided with an airway pressure sensor; the airway pressure sensor is used to collect the pressure value in the airway at the end of the expiratory cycle; the The signal output end of the airway pressure sensor is connected to the signal input end of the processing unit, the first control signal output end of the processing unit is connected to the driving unit of the PEEP valve, and the processing unit drives the The on-off of the PEEP valve; the second control signal output end of the processing unit is connected to the control signal input end of the suction valve; proceed as follows:

Step 1: Input the set pressure value P1 into the processing unit, the processing unit obtains the corresponding current value I1 according to the stored comparison table and uses the current value I1 to control the opening of the PEEP valve;

Step 2. At the end of the expiratory cycle, the pressure sensor detects the airway pressure in the expiratory branch and compensates the detected airway pressure value Qt, and then sends the compensated _airway pressure value _Zc to said processing unit;

Step ₃ , calculating the deviation value ΔP=Zc-P1 by the processing unit, and judging whether the deviation value ΔP is within the expected control range;

When ΔP is not within the desired control range, the adjustment value P1' is obtained according to P1'=P1+ΔP×K; the processing unit uses the adjustment value P1' as the set pressure value, and performs the above steps 1 to 3 in a loop, Until the deviation value is within the desired control range; the K is a proportional factor for control adjustment, 0.4<K<0.9;

When ΔP is within the desired control range, the processing unit judges whether a stop command is received, and ends when the processing unit receives the stop command; returns to step 2 when the processing unit does not receive the stop command;

Compensation for the detected airway pressure value Q _t in step 2 is performed in the following steps:

S1. Set the collected airway pressure value to Qt, where _t is a positive integer;

S2. Acquiring the effective pressure sequence;

Set the effective judgment value to P _a , set the judgment threshold to R; calculate P _a =Q _a -Q _a-1 to get P _a ; judge whether P _a ≥ R, and delete Q _a when P _a ≥ R; When P _a < R, store Q _a in the effective pressure array; 2≤a≤t and a is an integer; the R>0; set the effective pressure array as {M _b }, and b is positive integer;

S3. Calculating pressure compensation parameters;

Set the pressure compensation parameter as N _c , calculate Obtain pressure compensation parameter N _c ; said M _c ∈ {M _b } and c≥3, c is an integer;

S4. Compensating M _c ;

Set the compensated airway pressure value Z _c , calculate

The compensated airway pressure value Z _c is obtained.

Using the above technical solutions to filter the collected airway pressure values can effectively overcome the fluctuation interference caused by accidental factors, and provide accurate airway pressure acquisition unit values for subsequent data processing. Then, the collected pressure value is compensated by calculating the pressure compensation parameters. Due to the large pressure deviation and poor dynamic response collected by the traditional ventilator, the trend of pressure change is not considered, so the pressure must be compensated. This technical solution is adopted The obtained pressure compensation parameters and compensation methods can dynamically compensate the collected airway pressure according to the collected airway pressure value and the change trend of airway pressure, so that the ventilator can accurately predict the amount of airway pressure adjustment to The air pressure of the patient's breathing circuit is adjusted adaptively, which improves the stability of the air pressure control of the patient's breathing circuit and ensures the adaptability of the airway pressure control method in different use environments. The present invention improves precision through closed-loop control, monitors the end-expiratory airway pressure value controlled by the PEEP valve in real time during control, and uses it as feedback to continuously calculate and adjust the PEEP valve, so that the output of the PEEP valve can achieve higher precision . At the same time, because the simple corresponding table of pressure and current is still used, the calibration process of the PEEP valve is simplified, the storage space of the table value is reduced, and the calculation time is also reduced.

The beneficial effects of the present invention are: the present invention can accurately predict the amount of airway pressure adjustment, so as to adjust the air pressure of the patient's breathing circuit adaptively, improve the stability of the air pressure control of the patient's breathing circuit, and ensure the airway pressure. The adaptability of the control method in different usage environments. At the same time, the invention simplifies the calibration process of the PEEP valve, reduces the storage space of the table value, and also reduces the calculation time.

Description of drawings

FIG. 1 is a schematic diagram of the principle of an airway control system for a ventilator according to a specific embodiment of the present invention.

Fig. 2 is a schematic flow chart of a specific embodiment of the present invention.

detailed description

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

As shown in Figure 1, a ventilator airway control system includes: a processing unit 1, an air circuit system 2, a PEEP valve 3 controlled by the processing unit 1 and its drive unit 4; the air circuit system includes a breathing circuit 2, The breathing circuit 2 communicates with the inspiratory valve 6 and the PEEP valve 3 through an air pipeline respectively; the PEEP valve 3 is used to discharge the driving gas into the atmosphere; the breathing circuit 2 is also connected with an inspiratory branch and a Expiratory branch; the expiratory branch is provided with an airway pressure sensor 5; the airway pressure sensor 5 is used to collect the pressure value in the airway at the end of the expiratory cycle; the signal output of the airway pressure sensor 5 terminal is connected to the signal input terminal of the processing unit 1, the first control signal output terminal of the processing unit 1 is connected to the driving unit 4 of the PEEP valve 3, and the processing unit 1 drives the PEEP through the driving unit 4. On and off of the valve 3 ; the second control signal output end of the processing unit 1 is connected to the control signal input end of the suction valve 6 . The gas enters the outer cavity of the bellows in the breathing circuit through the inhalation valve, and the airbag in the compressed bellows moves downward, so that the gas in the bag flows into the patient side through the inhalation branch, so that the patient can inhale the gas. The gas is returned from the patient side through the exhalation branch to the inside of the folded airbag of the bellows in the breathing circuit, and the airbag is pushed up so that the driving gas outside the bellows is discharged into the atmosphere through the PEEP valve.

As shown in Figure 2, a ventilator airway pressure control method is carried out by using the ventilator airway control system according to the following steps:

Step 1: Input the set pressure value P1 into the processing unit 1, the processing unit 1 obtains the corresponding current value I1 according to the stored comparison table and uses the current value I1 to control the PEEP valve 3 to open to the opening corresponding to the current value I1.

Step 2. At the end of the expiratory cycle, the airway pressure sensor 5 detects the airway pressure in the exhalation branch and compensates the detected airway pressure value Qt, and then _sends the compensated airway pressure value Z _c is delivered to the processing unit 1 .

Step 3: The processing unit 1 calculates the deviation value ΔP=Z _c −P1, and judges whether the deviation value ΔP is within the desired control range.

When ΔP is not within the desired control range, the adjustment value P1' is obtained according to P1'=P1+ΔP×K; the processing unit 1 uses the adjustment value P1' as the set pressure value, and performs the above steps 1 to 3 in a loop , until the deviation value is within the expected control range; the K is a proportional factor for control adjustment, 0.4<K<0.9.

When ΔP is within the desired control range, the processing unit 1 judges whether a stop command is received, and ends when the processing unit 1 receives the stop command; returns to step 2 when the processing unit 1 does not receive the stop command.

Compensation for the detected airway pressure value Q _t in step 2 is performed in the following steps:

S1. Set the collected airway pressure value to Qt, where _t is a positive integer;

S2. Acquiring the effective pressure series;

Set the effective judgment value to P _a , set the judgment threshold to R; calculate P _a =Q _a -Q _a-1 to get P _a ; judge whether P _a ≥ R, and delete Q _a when P _a ≥ R; When P _a < R, store Q _a in the effective pressure array; 2≤a≤t and a is an integer; the R>0; set the effective pressure array as {M _b }, and b is positive integer. At least 4 effective pressure values are collected in the effective pressure series; the pressure values in the effective pressure series are arranged in the order of collection, the first collected effective pressure value is M ₁ , and the second collected effective pressure value is is M ₂ , ... the bth collected effective pressure value is M _b . This program starts from the second collection pressure Q ₂ to eliminate the sudden pressure data caused by the interference signal, filter out the influence of the environment, and ensure the accuracy and validity of the collected data;

S3. Calculating pressure compensation parameters;

Set the pressure compensation parameter as N _c , calculate Obtain pressure compensation parameter N _c ; said M _c ∈ {M _b } and c≥3, c is an integer;

S4. Compensating M _c ;

Set the compensated airway pressure value Z _c , calculate

The compensated airway pressure value Z _c is obtained.

In the above scheme, when M _C-1 -M _c-2 >0 and M _C -M _c-1 >0, the airway pressure is in a continuous rising period; when M _C-1 -M _c-2 >0 and M _C -M _c-1 <0, the airway pressure is affected by the drop, when M _C-1 -M _c-2 <0 and M _C -M _c-1 <0, the airway pressure is a continuous decline period, when M _C-1 -M _c-2 <0 and M _C -M _c-1 >0, the airway pressure will be affected and rise, when M _C-1 -M _c-2 =0 or M _C -M _c-1 = 0, the airway pressure is in a stable period. According to the different trends of the airway pressure, the above scheme adopts the corresponding compensation method, avoids the wrong pressure compensation, improves the stability of the airway pressure, and can dynamically regulate the pressure during the use of the ventilator.

The present invention can accurately predict the airway pressure adjustment amount, and compensate the airway pressure according to the change trend of the airway pressure, thereby improving the stability of the airway pressure control, and at the same time greatly eliminating the influence of interference data, ensuring The adaptability of the airway pressure control method in different environments.

The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make many modifications and changes according to the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall be within the scope of protection defined by the claims.

Claims (1)

1. A ventilator airway pressure control method is controlled by a ventilator airway control system, and the ventilator airway control system includes: a processing unit (1), a breathing circuit (2), controlled by a processing unit ( 1) the PEEP valve (3) and its drive unit (4); the breathing circuit (2) communicates with the inspiratory valve (6) and the PEEP valve (3) through an air pipeline respectively; the PEEP valve (3) ) is used to discharge the driving gas into the atmosphere; the breathing circuit (2) is also connected with an inspiratory branch and an expiratory branch; the expiratory branch is provided with an airway pressure sensor (5); the gas The airway pressure sensor (5) is used to collect the pressure value in the airway at the end of the expiratory cycle; the signal output end of the airway pressure sensor (5) is connected to the signal input end of the processing unit (1), and the processing unit The first control signal output end of (1) is connected to the driving unit (4) of the PEEP valve (3), and the processing unit (1) drives the channel of the PEEP valve (3) through the driving unit (4). off; the second control signal output end of the processing unit (1) is connected to the control signal input end of the suction valve (6); it is characterized in that the following steps are carried out: Step 1: Input the set pressure value P1 into the processing unit (1), the processing unit (1) obtains the corresponding current value I1 according to the stored comparison table and uses the current value I1 to control the PEEP valve (3) open; Step 2. At the end of the expiratory cycle, the airway pressure sensor (5) detects the airway pressure in the expiratory branch and compensates the detected airway pressure value _Qt , and then sends the compensated airway pressure The value _Zc is delivered to said processing unit (1); Step ₃ , calculating the deviation value ΔP=Zc-P1 by the processing unit (1), and judging whether the deviation value ΔP is within the desired control range; When ΔP is not within the desired control range, the adjustment value P1' is obtained according to P1'=P1+ΔP×K; the processing unit (1) uses the adjustment value P1' as the set pressure value, and performs the above steps 1 to cyclically Step 3, until the deviation value is within the desired control range; the K is a proportional factor for control adjustment, 0.4<K<0.9; When ΔP is within the desired control range, the processing unit (1) judges whether a stop command is received, and ends when the processing unit (1) receives the stop command; when the processing unit (1) does not receive the stop command Go back to step 2; Compensation for the detected airway pressure value Q _t in step 2 is performed in the following steps: S1. Set the collected airway pressure value to Qt, where _t is a positive integer; S2. Acquiring the effective pressure series; Set the effective judgment value to P _a , set the judgment threshold to R; calculate P _a =Q _a -Q _a-1 to get P _a ; judge whether P _a ≥ R, and delete Q _a when P _a ≥ R; When P _a < R, store Q _a in the effective pressure array; 2≤a≤t and a is an integer; the R>0; set the effective pressure array as {M _b }, and b is positive integer; S3. Calculating pressure compensation parameters; Set the pressure compensation parameter as N _c , calculate Obtain pressure compensation parameter N _c ; said M _c ∈ {M _b } and c≥3, c is an integer; S4. Compensating M _c ; Set the compensated airway pressure value Z _c , calculate The compensated airway pressure value Z _c is obtained.