CN106730208B

CN106730208B - Method and ventilator for adaptively adjusting air leakage

Info

Publication number: CN106730208B
Application number: CN201710036325.9A
Authority: CN
Inventors: 戴征; 丁锦; 刘炜; 徐勤鹏; 黄皓轩
Original assignee: Hunan Micomme Zhongjin Medical Technology Development Co Ltd
Current assignee: Hunan Mingkang Zhongjin Medical Technology Co ltd
Priority date: 2017-01-18
Filing date: 2017-01-18
Publication date: 2020-05-15
Anticipated expiration: 2037-01-18
Also published as: CN106730208A

Abstract

The present invention relates to a method for adaptively adjusting air leakage and a ventilator. The method for adaptively adjusting air leakage includes: collecting the total gas flow Qt of the ventilator in this breathing cycle, and based on the total flow Qt and use preset rules to calculate the air leakage Q1 of the ventilator in this breathing cycle, and store it; obtain the pre-stored air leakage Q2 corresponding to the previous breathing cycle, if the difference between the air leakage Q1 and the air leakage Q2 If the difference is greater than the first preset threshold, the air leakage of the ventilator is adjusted to be the air leakage Q1. The present invention enables the ventilator to adjust the air leakage in an adaptive and timely manner, adapt to the current breathing state of the user, and better supply air to the user.

Description

Method for adaptively adjusting air leakage and breathing machine

Technical Field

The invention relates to the technical field of medical instruments, in particular to a method for adaptively adjusting air leakage and a breathing machine.

Background

The breathing machine has the advantages that the types of the face masks of the breathing machine are various, the sizes of the leakage holes are not uniform, in addition, the breathing mode method of each user is generally different, and in addition, the finally obtained flow data and pressure data of the breathing machine are greatly different due to the influence of factors such as wearing or body position and the like. Most ventilators on the market currently can be adaptive, such as the baseline drift technique of Vietnam, which calculates an air leakage baseline during each breath, and performs trigger judgment when the flow exceeds the baseline based on the baseline during the next breath.

The air leakage baseline in the prior art is updated every time of breathing, but when a user breathes unstably (for example, sudden large mouth breathing or the breathing frequency changes suddenly) or leaks air greatly (for example, the user wears the mask after taking off the mask or separates the part where the mask is attached to the face after the body position of the user changes to cause a large amount of air leakage), the air leakage baseline cannot be adapted in time so as to be adjusted.

Disclosure of Invention

The invention aims to provide a method for adaptively adjusting air leakage and a respirator, aiming at enabling the respirator to adaptively adjust the air leakage in time, adapting to the current breathing state of a user and better supplying air to the user.

In order to achieve the above object, the present invention provides a method for adaptively adjusting air leakage, including:

step S1, collecting the total flow Qt of the gas of the respirator in the current breathing cycle, calculating the air leakage Q1 of the respirator in the current breathing cycle based on the total flow Qt and a preset rule, and storing the air leakage Q1;

and step S2, acquiring a pre-stored air leakage Q2 corresponding to the previous respiratory cycle, and if the difference value between the air leakage Q1 and the air leakage Q2 is greater than a first preset threshold value, adjusting the air leakage of the respirator to be the air leakage Q1.

Preferably, the step S1 includes:

step S11, collecting the total flow Qt of gas of the respirator in the current breathing cycle, and calculating the first air leakage Qa in the current breathing cycle based on the total flow Qt;

step S12, when the total flow Qt is greater than the first air leakage Qa, determining an inspiration inflection point of the present breathing cycle, and determining an inspiration flow Qp corresponding to the inspiration inflection point;

step S13, when the difference between the inspiratory flow Qp and the first air leakage amount Qa is greater than a second preset threshold, calculating first air leakage amounts Qc1, Qc2, a..... and Qcn and differences δ 1, δ 2, a... and δ n of corresponding inspiratory flow Qp1, Qp2, a... and Qpn in a preset number of consecutive respiratory cycles before the present respiratory cycle, and calculating a sum M of the differences, where n represents a preset number and is an integer greater than 1;

and step S14, if the sum M is greater than a third preset threshold, reading a reference air leakage Q of the mask prestored by the respirator, calculating a second air leakage Qb in the current breathing cycle based on the total flow Qt, the sum M of the difference values and the reference air leakage Q, and storing the second air leakage Qb as the air leakage Q1.

Preferably, the step S1 further includes:

step S15, if the sum M is less than or equal to a third preset threshold, or the difference between the intake flow Qp and the first air leakage amount Qa is less than or equal to a second preset threshold, the first air leakage amount Qa is used as the air leakage amount Q1 and stored.

Preferably, the step S11 includes:

acquiring total flow Qt of gas of a breathing machine in a current breathing cycle, acquiring a gas leakage curve Q (t) based on the total flow Qt, and calculating a first gas leakage amount Qa based on the gas leakage curve Q (t):

Qa＝∫Q(t)dt。

preferably, the calculating the second air leakage Qb in the present respiratory cycle based on the total flow Qt, the sum M of the difference values, and the reference air leakage q includes:

to achieve the above object, the present invention also provides a ventilator comprising:

the calculation module is used for acquiring the total flow Qt of gas of the breathing machine in the breathing cycle, calculating the air leakage Q1 of the breathing machine in the breathing cycle based on the total flow Qt and a preset rule, and storing the air leakage Q1;

and the adjusting module is used for acquiring a pre-stored air leakage Q2 corresponding to the previous breathing cycle, and if the difference value between the air leakage Q1 and the air leakage Q2 is greater than a first preset threshold value, adjusting the air leakage of the breathing machine to be the air leakage Q1.

Preferably, the calculation module comprises:

the first calculation unit is used for acquiring the total flow Qt of gas of the breathing machine in the current breathing cycle and calculating the first air leakage Qa in the current breathing cycle based on the total flow Qt;

the determining unit is used for determining an inspiration inflection point of the respiratory cycle when the total flow Qt is greater than the first air leakage Qa, and determining an inspiration flow Qp corresponding to the inspiration inflection point;

a second calculating unit, configured to, when a difference between the inspiratory flow rate Qp and the first air leakage amount Qa is greater than a second preset threshold, calculate first air leakage amounts Qc1, Qc2, a.... and Qcn and differences δ 1, δ 2, a.... and δ n between corresponding inspiratory flow rates Qp1, Qp2, a.. and Qpn in a preset number of consecutive respiratory cycles before the current respiratory cycle, and calculate a sum M of the differences, where n represents a preset number and is an integer greater than 1;

and a third calculating unit, configured to, if the sum M is greater than a third preset threshold, read a reference air leakage Q of a mask prestored by a ventilator, calculate a second air leakage Qb in the current breathing cycle based on the total flow Qt, the sum M of the differences, and the reference air leakage Q, and use the second air leakage Qb as the air leakage Q1 to store.

Preferably, the calculation module further comprises:

and the processing unit is configured to, if the sum M is less than or equal to a third preset threshold, or a difference between the inspiration flow Qp and the first air leakage Qa is less than or equal to a second preset threshold, use the first air leakage Qa as the air leakage Q1 and store the air leakage Q1.

Preferably, the first calculating unit is specifically configured to acquire a total flow Qt of gas of the ventilator in the current breathing cycle, obtain an air leakage curve q (t) based on the total flow Qt, and calculate a first air leakage amount Qa based on the air leakage curve q (t):

Qa＝∫Q(t)dt。

preferably, the third calculating unit is specifically configured to calculate a second air leakage Qb in the current respiratory cycle based on the total flow Qt, the sum M of the difference values, and the reference air leakage q, and includes:

the invention has the beneficial effects that: when a user uses the breathing machine, if the breathing of the user is stable, the air leakage is basically unchanged, if the air leakage is suddenly increased or decreased due to an unexpected situation in the using process, the breathing machine can be adjusted accordingly, generally speaking, the adjustment of the air leakage can be completed within 2-3 breathing cycles, so that the breathing machine can adaptively and timely adjust the air leakage, adapt to the current breathing state of the user, better supply air to the user, provide better use comfort for the user and achieve the best curative effect.

Drawings

FIG. 1 is a schematic flow chart illustrating a method for adaptively adjusting an air leakage amount according to an embodiment of the present invention;

FIG. 2 is a detailed flowchart of step S1 shown in FIG. 1;

FIG. 3 is a graph of total flow Qt collected by a ventilator over time;

FIG. 4 is a schematic structural diagram of a ventilator according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of the calculation module shown in fig. 4.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.

As shown in fig. 1, fig. 1 is a schematic flow chart of an embodiment of a method for adaptively adjusting air leakage, where the method for adaptively adjusting air leakage includes the following steps:

step S1, collecting the total flow Qt of the gas of the respirator in the current breathing cycle, and calculating and storing the air leakage Q1 of the respirator in the current breathing cycle by adopting a preset rule based on the total flow Qt;

in this embodiment, the ventilator has a flow sensor at the position of the air outlet to collect flow data, and the sampling frequency is 200 HZ. The flow data directly acquired by the sensor is often contaminated with noise, and therefore a low pass filter is required to remove the noise. After the noise of the flow data is removed, a smooth curve is obtained, so that errors in judgment caused by errors caused by the noise can be avoided.

One way to calculate the air leakage Q1 of the ventilator during the present breathing cycle based on the total flow Qt and using preset rules may be: acquiring the air leakage of a user in an inspiration phase and the air leakage of the user in an expiration phase, wherein the sum of the air leakage of the inspiration phase and the air leakage of the expiration phase is the air leakage Q1 of the breathing machine in the breathing cycle; or acquiring a variation curve of the air leakage Q1 in the current breathing cycle according to the variation curve of the total flow Qt, and integrating the variation curve of the air leakage Q1 to obtain the air leakage Q1 of the respirator in the current breathing cycle, and the like.

During the inspiration phase, a part of the total flow rate Qt enters the lungs of the user for gas exchange, and another part of the gas leaks into the air through the holes in the mask. During the exhalation phase, a part of the gas in the total flow rate Qt is the gas exhaled by the user, and another part of the gas leaks into the air through the holes on the mask.

And step S2, acquiring a pre-stored air leakage Q2 corresponding to the previous breathing cycle, and if the difference value between the air leakage Q1 and the air leakage Q2 is greater than a first preset threshold value, adjusting the air leakage of the respirator to be the air leakage Ql.

In this embodiment, before the respirator is used after being turned on, the respirator first reads the air leakage data stored therein to determine the basic air leakage of the currently used mask corresponding to the set pressure. Generally, the respirator stores the basic air leakage of several masks, for example, for mask 1, the basic air leakage is 20LPM when worn correctly under 4cmH2O pressure, and 50LPM when worn correctly under 8cmH2O pressure. Generally, the basic air leakage represents the lowest air leakage, because the user may have the situations of inaccurate wearing, damaged mask or jack-up mask when the pressure is increased during the use process, which results in the situation of increased air leakage.

When the pre-stored air leakage Q2 corresponding to the previous respiratory cycle is obtained for the first time, the basic air leakage can be used as the air leakage Q2. And then comparing the air leakage Q2 corresponding to the previous breathing cycle with the calculated air leakage Q1 in the current breathing cycle, if the difference between the air leakage Q1 and the air leakage Q2 is greater than a first preset threshold, for example, the difference is greater than 2LPM, adjusting the air leakage of the ventilator to be the air leakage Ql, and if the difference between the air leakage Q1 and the air leakage Q2 is not greater than the first preset threshold, maintaining the current air leakage unchanged, that is, still using the air leakage Q2 as the air leakage of the ventilator.

It can be seen from the above description that, in the process of using the breathing machine by the user, if the breathing of the user is stable, the air leakage is basically unchanged, and if the air leakage suddenly increases or decreases due to an unexpected situation in the using process, the breathing machine can be adjusted accordingly, generally speaking, the adjustment of the air leakage can be completed within 2-3 breathing cycles, so that the breathing machine can adaptively and timely adjust the air leakage, adapt to the current breathing state of the user, better supply air to the user, provide better use comfort for the user, and achieve the best curative effect.

In a preferred embodiment, as shown in fig. 2, on the basis of the embodiment of fig. 1, the step S1 includes:

step S14, if the sum M is larger than a third preset threshold, reading a reference air leakage Q of a mask prestored by a respirator, calculating a second air leakage Qb in the current breathing cycle based on the total flow Qt, the sum M of the difference values and the reference air leakage Q, and storing the second air leakage Qb as the air leakage Q1;

step S15, if the sum is less than or equal to a third preset threshold or the difference between the intake flow Qp and the first air leakage Qa is less than or equal to a second preset threshold, the first air leakage Qa is used as the air leakage Q1 and stored.

In this embodiment, after acquiring the total flow Qt of gas in the current breathing cycle of the ventilator, the first air leakage amount Qa is calculated based on the total flow Qt, and specifically, the air leakage curve q (t) is obtained based on the total flow Qt:

as shown in fig. 3, fig. 3 is a graph of total flow Qt collected by a ventilator as a function of time. The hatched portion of the vertical line is the volume of inhaled air of the lungs of the user Vinsp, and the hatched portion of the horizontal line is the volume of exhaled air Vexp of the user, and generally speaking, the volume of inhaled air of the user is consistent with the volume of exhaled air of the user, that is, Vinsp ═ Vexp. If the area of vissp is supplemented to Vexp in fig. 3, the area enclosed by the dotted line part and the abscissa axis in fig. 3 is the total air leakage (i.e., the first air leakage Qa) in the whole respiratory cycle, the dotted line is the air leakage curve q (t), and the air leakage curve q (t) is integrated to obtain the first air leakage Qa:

Qa＝∫Q(t)dt。

preferably, the integration time period t is 10S. However, other values of the time duration t are possible, as long as the integrated time duration includes a complete respiration cycle.

When the total flow rate Qt is greater than the first air leakage Qa (i.e., the user is in the inspiration phase), determining an inspiration inflection point of the present breathing cycle, for example, by analyzing the flow data (i.e., the total flow rate Qt curve) and the pressure data of the ventilator in combination to determine the inspiration inflection point of the present breathing cycle:

calculating a second derivative of the flow data, if the second derivative is in a range taking 0 as a midpoint in a first time period, taking the time before the first time period in the same period as a second time period, taking the time after the first time period in the same period as a third time period, calculating a first derivative of the flow data in the second time period and the third time period, and if the first derivatives corresponding to the second time period in a continuous preset period are all smaller than the first derivatives corresponding to the third time period, acquiring a first derivative of the pressure data in the third time period; and if the first derivative of the pressure data in the third time period is less than 0, taking the corresponding time point when the second derivative of the flow data is 0 as the time point of the trigger inflection point of the respirator, wherein the time point is the time point corresponding to the inspiration inflection point, and thus determining the inspiration flow Qp corresponding to the inspiration inflection point.

In addition, in this embodiment, the inspiration inflection point of the current breathing cycle may also be determined by analyzing the flow data alone, for example, calculating a first derivative of the flow data, and determining the inspiration inflection point of the current breathing cycle by analyzing the first derivative of the flow data, which is not described herein again.

When the difference between the inspiratory flow Qp and the first air leakage Qa is greater than a second preset threshold, for example, the difference is greater than 3LPM, the first air leakage Qa needs to be adjusted, and the adjusted second air leakage Qb is used as the air leakage Q1 of the ventilator.

Specifically, the difference values δ 1, δ 2,.. and δ n of the first air leakage quantities Qc1, Qc2, Qp, Qcn and the corresponding inspiratory flow rates Qp1, Qp2, Qp.. and Qpn in a preset number of consecutive respiratory cycles prior to the present respiratory cycle are calculated, for example, the differences δ 1, δ 2, · δ 6 between the first air leakage quantities Qc1, Qc2, Qc3, Qc4, Qc5, Qc6 and the corresponding inspiratory flow rates Qp1, Qp2, Qp3, Qp4, Qp5, Qp6 of the consecutive 6 respiratory cycles before the present respiratory cycle are calculated, the differences δ 1, δ 2,..... δ 6 of the 6 respiratory cycles are added to obtain a sum M of the differences, and if the sum M is greater than a third preset threshold, e.g. | M | >3LPM, then the second air leakage Qb is calculated based on the total flow Qt, the sum M of the differences and the reference air leakage q according to the new formula:

in a preferred embodiment, on the basis of the above embodiment of fig. 2, if the sum M of the differences δ 1, δ 2, and δ n between the first air leakage quantities Qc1, Qc2, and the corresponding inspiratory flow rates Qp1, Qp2, and the corresponding inspiratory flow rates Qp, Qpn is less than or equal to a third preset threshold, the first air leakage quantity Qa is not required to be adjusted, and the first air leakage quantity Qa is directly used as the air leakage quantity Q1 of the ventilator and is stored for subsequent use.

In addition, if the difference between the inspiration flow rate Qp and the first air leakage amount Qa is less than or equal to the second preset threshold, the first air leakage amount Qa is directly used as the air leakage amount Q1 of the ventilator and is stored for subsequent use.

Fig. 4 is a schematic structural diagram of a ventilator according to an embodiment of the present invention, and the ventilator includes:

the calculation module 101 is configured to acquire a total flow Qt of gas of the ventilator in the current breathing cycle, calculate an air leakage Q1 of the ventilator in the current breathing cycle based on the total flow Qt and a preset rule, and store the air leakage Q1;

The adjusting module 102 is configured to obtain a pre-stored air leakage Q2 corresponding to a previous respiratory cycle, and adjust the air leakage of the ventilator to be the air leakage Q1 if a difference between the air leakage Q1 and the air leakage Q2 is greater than a first preset threshold.

In a preferred embodiment, as shown in fig. 5, on the basis of the embodiment of fig. 4, the computing module 101 comprises:

the first calculating unit 1011 is used for acquiring the total flow rate Qt of the gas of the breathing machine in the current breathing cycle, and calculating the first air leakage Qa in the current breathing cycle based on the total flow rate Qt;

a determining unit 1012, configured to determine an inspiration inflection point of the current breathing cycle and determine an inspiration flow Qp corresponding to the inspiration inflection point when the total flow Qt is greater than the first air leakage Qa;

a second calculating unit 1013, configured to calculate, when a difference between the inspiratory flow Qp and the first air leakage Qa is greater than a second preset threshold, first air leakage quantities Qc1, Qc2, a.

And a third calculating unit 1014, configured to, if the sum M is greater than a third preset threshold, read a reference air leakage Q of a mask prestored by a ventilator, calculate a second air leakage Qb in the current breathing cycle based on the total flow Qt, the sum M of the differences, and the reference air leakage Q, and use the second air leakage Qb as the air leakage Q1 to store.

Qa＝∫Q(t)dt。

in a preferred embodiment, based on the embodiment of fig. 5, the computing module 101 further includes: and the processing unit is used for directly taking the first air leakage quantity Qa as the air leakage quantity Q1 of the respirator without adjusting the first air leakage quantity Qa if the sum M of the differences delta 1, delta 2, delta.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. a ventilator, it is characterised in that the ventilator comprises a calculation module and an adjustment module:

The calculation module is used to collect the total flow Qt of the gas of the ventilator in this breathing cycle, calculate the air leakage Q1 of the ventilator in this breathing cycle based on the total flow Qt and adopt a preset rule, and to store;

The adjustment module is used to obtain the pre-stored air leakage Q2 corresponding to the previous breathing cycle. If the difference between the air leakage Q1 and the air leakage Q2 is greater than the first preset threshold, the air leakage of the ventilator is adjusted to be: Air leakage Q1;

The calculation module includes a first calculation unit, a determination unit, a second calculation unit and a third calculation unit:

The first calculation unit is used to collect the total flow Qt of the gas of the ventilator in this breathing cycle, and calculate the first air leakage Qa in this breathing cycle based on the total flow Qt;

The determining unit is configured to determine the inspiratory inflection point of this breathing cycle when the total flow Qt is greater than the first air leakage volume Qa, and determine the inspiratory flow Qp corresponding to the inspiratory inflection point;

The second calculation unit is configured to calculate the continuous preset number of breathing cycles before this breathing cycle when the difference between the inspiratory flow Qp and the first air leakage volume Qa is greater than a second preset threshold The difference δ1, δ2, ...... , δn, and calculate the sum M of the differences, M=δ1+δ2+...+δn, where n represents a preset number, which is an integer greater than 1;

The third calculation unit is configured to read the reference air leakage volume q of the mask pre-stored by the ventilator if the sum M is greater than a third preset threshold, based on the total flow Qt and the sum of the differences M and the reference air leak volume q to calculate the second air leak volume Qb in this breathing cycle, and use the second air leak volume Qb as the air leak volume Q1 and store it.

2. The ventilator according to claim 1, wherein the computing module further comprises:

The processing unit is configured to, if the sum M is less than or equal to a third preset threshold, or the difference between the inspiratory flow Qp and the first leakage volume Qa is less than or equal to a second preset threshold, use the The first air leakage amount Qa is stored as the air leakage amount Q1.

3 . The ventilator according to claim 1 , wherein the first calculation unit is specifically used to collect the total flow Qt of the gas of the ventilator in this breathing cycle, and obtain air leakage based on the total flow Qt. 4 . Curve Q(t), based on the gas leakage curve Q(t) to calculate the first leakage amount Qa:

Qa=∫Q(t)dt.