阅读说明：本技术 一种基于呼吸装置的肺弹性系数测量方法及系统 (Lung elasticity coefficient measuring method and system based on breathing device ) 是由 张玉欣 金江春植 白晶 于 2019-11-18 设计创作，主要内容包括：本发明公开一种基于呼吸装置的肺弹性系数测量方法及系统。肺弹性系数为肺内部压力与肺体积的商。该测量方法包括：获取呼吸装置检测到的一个呼吸周期内的管道末端压力、肺内气体体积和管道气体流量；根据管道末端压力和肺内气体体积利用基于广义回归神经网络计算肺弹性变量系数；建立表达管道末端压力、肺内气体体积、管道气体流量、肺弹性常数系数和肺弹性变量系数之间关系的呼吸方程；将管道末端压力、肺内气体体积、管道气体流量和肺弹性变量系数代入呼吸方程,利用最小二乘法求呼吸方程的解,得到肺弹性常数系数；将肺弹性常数系数乘以肺弹性变量系数得到肺弹性系数。本发明能够适用于呼吸装置的实时调节和自动调节。(The invention discloses a lung elasticity coefficient measuring method and system based on a breathing device. The lung elastic coefficient is the quotient of the pressure inside the lung and the lung volume. The measuring method comprises the following steps: acquiring the pressure at the tail end of the pipeline, the volume of air in the lung and the flow of the pipeline air in a respiratory cycle detected by a breathing device; calculating a lung elastic variable coefficient by utilizing a neural network based on generalized regression according to the pressure at the tail end of the pipeline and the volume of the gas in the lung; establishing a respiratory equation expressing the relationship among the pipeline terminal pressure, the volume of gas in the lung, the pipeline gas flow, the lung elastic constant coefficient and the lung elastic variable coefficient; substituting the pressure at the tail end of the pipeline, the volume of gas in the lung, the gas flow of the pipeline and the lung elastic variable coefficient into a respiratory equation, solving the solution of the respiratory equation by using a least square method to obtain a lung elastic constant coefficient; and multiplying the lung elasticity constant coefficient by the lung elasticity variable coefficient to obtain the lung elasticity coefficient. The invention can be applied to real-time adjustment and automatic adjustment of the breathing apparatus.)

1. A lung elasticity coefficient measuring method based on a breathing device is disclosed, wherein the lung elasticity coefficient is the quotient of the internal pressure of a lung and the volume of the lung; the lung elasticity coefficient is the product of the multiplication of a lung elasticity constant coefficient and a lung elasticity variable coefficient, and the measuring method is characterized by comprising the following steps:

acquiring the pressure at the tail end of the pipeline, the volume of air in the lung and the flow of the pipeline air in a respiratory cycle detected by a breathing device;

calculating the lung elastic variable coefficient according to the pipeline end pressure and the volume of the gas in the lung by utilizing a neural network based on generalized regression;

establishing a respiratory equation expressing the relationship among the pipeline terminal pressure, the volume of gas in the lung, the pipeline gas flow, the lung elastic constant coefficient and the lung elastic variable coefficient;

substituting the pipeline tail end pressure, the volume of the gas in the lung, the pipeline gas flow and the lung elastic variable coefficient into the respiratory equation, and solving the respiratory equation by using a least square method to obtain the lung elastic constant coefficient;

multiplying the lung elasticity constant coefficient by the lung elasticity variable coefficient to obtain the lung elasticity coefficient; the lung elastic coefficient is used to adjust the ventilation and/or ventilation pressure of the breathing apparatus.

2. The respiratory device-based lung elastic coefficient measurement method according to claim 1, wherein the calculating the lung elastic variable coefficient by using a generalized regression-based neural network according to the duct end pressure and the intra-pulmonary gas volume specifically comprises:

selecting N data center points from the sample data in the expiration stage and N data center points from the sample data in the inspiration stage by taking the data of the pressure at the tail end of the pipeline and the volume of the gas in the lung as the sample data;

according to the formula

3. The method for measuring the lung elastic coefficient based on the breathing device according to claim 1, wherein the establishing of the breathing equation expressing the relationship among the duct end pressure, the volume of the gas in the lung, the duct gas flow, the lung elastic constant coefficient and the lung elastic variable coefficient specifically comprises:

establishing a basic respiration equation:

wherein P is_ao(t) is the pressure at the end of the pipeline,is P_aoFirst derivative of (t), P_l(t) is the pressure inside the lungs, P_r(t) is the pressure loss in the breathing apparatus conduit, V (t) is the volume of gas in the lungs,

and carrying out relation conversion on the basic breathing equation to obtain a converted breathing equation:

wherein cf_gConstituting the lung elastic coefficient, c is a lung elastic constant coefficient, f_gIs the coefficient of the lung elastic variable,

converting the converted breathing equation into a matrix form to obtain a matrix expression:

wherein the content of the first and second substances,

4. the respiratory device-based lung elastic coefficient measurement method according to claim 3, wherein the obtaining the lung elastic constant coefficient by substituting the conduit end pressure, the intra-pulmonary gas volume, the conduit gas flow and the lung elastic variable coefficient into the respiratory equation and solving the respiratory equation with a least square method comprises:

performing integral operation on two sides of the matrix expression to obtain an integral expression;

substituting the pipeline tail end pressure, the volume of the gas in the lung, the pipeline gas flow and the lung elastic variable coefficient into the integral expression, and solving by using a least square method to obtain the value of each element in the quantity matrix to be solved.

5. A lung elasticity coefficient measuring system based on a breathing device is disclosed, wherein the lung elasticity coefficient is the quotient of the internal pressure of a lung and the volume of the lung; the lung elastic coefficient is a product of multiplication of a lung elastic constant coefficient and a lung elastic variable coefficient, and the measuring system is characterized by comprising:

the acquisition module is used for acquiring the pipeline tail end pressure, the intra-pulmonary gas volume and the pipeline gas flow in one respiratory cycle detected by the breathing device;

the lung elastic variable coefficient calculating module is used for calculating the lung elastic variable coefficient by utilizing a generalized regression-based neural network according to the pipeline tail end pressure and the volume of the gas in the lung;

the respiratory equation establishing module is used for establishing a respiratory equation expressing the relationship among the pressure at the tail end of the pipeline, the volume of gas in the lung, the flow of the pipeline gas, the lung elastic constant coefficient and the lung elastic variable coefficient;

the least square solving module is used for substituting the pipeline tail end pressure, the volume of the gas in the lung, the pipeline gas flow and the lung elastic variable coefficient into the respiratory equation, and solving the respiratory equation by using a least square method to obtain the lung elastic constant coefficient;

a lung elasticity coefficient determining module, configured to multiply the lung elasticity constant coefficient by the lung elasticity variable coefficient to obtain the lung elasticity coefficient; the lung elastic coefficient is used to adjust the ventilation and/or ventilation pressure of the breathing apparatus.

6. The respiratory device-based lung elastic coefficient measurement system according to claim 5, wherein the lung elastic variable coefficient calculation module comprises:

the central point selection unit is used for selecting N data central points from the sample data in the expiration stage and selecting N data central points from the sample data in the inspiration stage by taking the pressure at the tail end of the pipeline and the volume data of the gas in the lung as the sample data;

lung elasticity variable coefficient calculating unitFor according to the formula

7. The respiratory device-based lung elastic coefficient measurement system of claim 5, wherein the respiratory equation establishment module comprises:

a basic respiration equation establishing unit for establishing a basic respiration equation:

wherein P is_ao(t) is the pressure at the end of the pipeline,

the relation conversion unit is used for carrying out relation conversion on the basic breathing equation to obtain a converted breathing equation:

wherein cf_gConstituting the lung elastic coefficient, c is a lung elastic constant coefficient, f_gIs the coefficient of the lung elastic variable,is the first derivative of V (t), F (t) is the pipeline gas flow,

a matrix conversion unit, configured to convert the converted breathing equation into a matrix form, so as to obtain a matrix expression:

wherein the content of the first and second substances,

8. the respiratory device-based pulmonary elasticity coefficient measurement system of claim 7, wherein the least squares solution module comprises:

the integral unit is used for carrying out integral operation on two sides of the matrix expression to obtain an integral expression;

and the least square solving unit is used for substituting the pipeline tail end pressure, the volume of the gas in the lung, the pipeline gas flow and the lung elastic variable coefficient into the integral expression, and solving by using a least square method to obtain the value of each element in the quantity matrix to be solved.

Technical Field

The invention relates to the field of breathing devices, in particular to a lung elastic coefficient measuring method and system based on a breathing device.

Background

Breathing devices are often required when working in special circumstances (e.g. rescue of drowning persons in water) or to provide oxygen to clinical patients. Most of the existing breathing apparatuses have the function of automatically adjusting the ventilation volume and/or the ventilation pressure.

Current approaches to automatically adjust ventilation are generally estimated as tidal volume per minute x ventilation frequency. Wherein the tidal volume of the adult is estimated according to the weight of 6-8 ml/kg, the tidal volume of the child is estimated according to the weight of 15-23 ml/kg, the ventilation frequency of the adult is 14-20 times/min, and the ventilation frequency of the child is 18-40 times/min.

The mode of automatically adjusting the ventilation pressure is generally to set the upper and lower pressure limits for ensuring the ventilation safety. The upper limit of adult pressure is generally 50-60 cmH₂O, the upper limit of the child pressure is generally 20 to 40cmH₂O。

The dual regulation of ventilation and ventilation pressure is generally performed by constant pressure ventilation, and when the ventilation is insufficient, the ventilation is supplemented by a ventilation of a constant volume. This mode of regulation requires monitoring of lung function indicators for automatic regulation. However, the monitored function index is limited to the measurement of tidal volume, and any error in the measurement of tidal volume can lead to errors in the automatic regulation of the breathing apparatus.

For the automatic adjustment of the breathing apparatus, it is desirable to perform adaptive adjustment according to the difference of the human body. This difference is reflected in characteristics such as lung elastic coefficient. Although the lung elastic coefficient can be well suitable for the automatic adjustment of the breathing device, the measurement of the lung elastic coefficient needs to temporarily block the respiratory airflow of a person, brings certain pain to the person, and is not suitable for the real-time adjustment and the automatic adjustment of the breathing device.

Disclosure of Invention

The invention aims to provide a lung elasticity coefficient measuring method and system based on a breathing device, which are suitable for real-time adjustment and automatic adjustment of the breathing device.

In order to achieve the purpose, the invention provides the following scheme:

a lung elasticity coefficient measuring method based on a breathing device is disclosed, wherein the lung elasticity coefficient is the quotient of the internal pressure of a lung and the volume of the lung; the lung elasticity coefficient is the product of the multiplication of a lung elasticity constant coefficient and a lung elasticity variable coefficient, and the measuring method comprises the following steps:

acquiring the pressure at the tail end of the pipeline, the volume of air in the lung and the flow of the pipeline air in a respiratory cycle detected by a breathing device;

calculating the lung elastic variable coefficient according to the pipeline end pressure and the volume of the gas in the lung by utilizing a neural network based on generalized regression;

establishing a respiratory equation expressing the relationship among the pipeline terminal pressure, the volume of gas in the lung, the pipeline gas flow, the lung elastic constant coefficient and the lung elastic variable coefficient;

substituting the pipeline tail end pressure, the volume of the gas in the lung, the pipeline gas flow and the lung elastic variable coefficient into the respiratory equation, and solving the respiratory equation by using a least square method to obtain the lung elastic constant coefficient;

multiplying the lung elasticity constant coefficient by the lung elasticity variable coefficient to obtain the lung elasticity coefficient; the lung elastic coefficient is used to adjust the ventilation and/or ventilation pressure of the breathing apparatus.

Optionally, the calculating the lung elastic variable coefficient according to the pipeline end pressure and the volume of the gas in the lung by using a neural network based on a generalized regression specifically includes:

selecting N data center points from the sample data in the expiration stage and N data center points from the sample data in the inspiration stage by taking the data of the pressure at the tail end of the pipeline and the volume of the gas in the lung as the sample data;

according to the formula

Calculating the lung elastic variable coefficient, wherein_g(V) is the lung elastic variable coefficient, i represents the center point of each datum, P_iThe pressure at the end of the pipeline at the center point of the ith data, and V in the division dataVolume of gas in the lungs, V, of sample data other than the heart point_iThe volume of the gas in the lung, which is the central point of the ith data, σ is the smoothing factor.

Optionally, the establishing a respiratory equation expressing a relationship among the pressure at the end of the duct, the volume of gas in the lung, the flow rate of the duct gas, the lung elastic constant coefficient, and the lung elastic variable coefficient specifically includes:

establishing a basic respiration equation:

wherein P is_ao(t) is the pressure at the end of the pipeline,

is P_aoFirst derivative of (t), P_l(t) is the pressure inside the lungs, P_r(t) is the pressure loss in the breathing apparatus conduit, V (t) is the volume of gas in the lungs,

is the second derivative of V (t), P_eeaRespiratory end alveolar pressure, e (t) is an error value;

and carrying out relation conversion on the basic breathing equation to obtain a converted breathing equation:

wherein cf_gConstituting the lung elastic coefficient, c is a lung elastic constant coefficient, f_gIs the coefficient of the lung elastic variable,is the first derivative of V (t), F (t) is the pipeline gas flow,is the first derivative of F (t), a, c, f_g、r₁、r₂And b are coefficients;

converting the converted breathing equation into a matrix form to obtain a matrix expression:

wherein the content of the first and second substances,

in the form of a matrix of known quantities,

θ_gin order to be able to obtain a matrix of quantities,

optionally, substituting the pressure at the end of the conduit, the volume of the gas in the lung, the flow of the conduit and the lung elastic variable coefficient into the respiratory equation, and solving the solution of the respiratory equation by using a least square method to obtain the lung elastic constant coefficient specifically includes:

performing integral operation on two sides of the matrix expression to obtain an integral expression;

substituting the pipeline tail end pressure, the volume of the gas in the lung, the pipeline gas flow and the lung elastic variable coefficient into the integral expression, and solving by using a least square method to obtain the value of each element in the quantity matrix to be solved.

A lung elasticity coefficient measuring system based on a breathing device is disclosed, wherein the lung elasticity coefficient is the quotient of the internal pressure of a lung and the volume of the lung; the lung elastic coefficient is the product of the multiplication of a lung elastic constant coefficient and a lung elastic variable coefficient, and the measuring system comprises:

the acquisition module is used for acquiring the pipeline tail end pressure, the intra-pulmonary gas volume and the pipeline gas flow in one respiratory cycle detected by the breathing device;

the lung elastic variable coefficient calculating module is used for calculating the lung elastic variable coefficient by utilizing a generalized regression-based neural network according to the pipeline tail end pressure and the volume of the gas in the lung;

the respiratory equation establishing module is used for establishing a respiratory equation expressing the relationship among the pressure at the tail end of the pipeline, the volume of gas in the lung, the flow of the pipeline gas, the lung elastic constant coefficient and the lung elastic variable coefficient;

the least square solving module is used for substituting the pipeline tail end pressure, the volume of the gas in the lung, the pipeline gas flow and the lung elastic variable coefficient into the respiratory equation, and solving the respiratory equation by using a least square method to obtain the lung elastic constant coefficient;

a lung elasticity coefficient determining module, configured to multiply the lung elasticity constant coefficient by the lung elasticity variable coefficient to obtain the lung elasticity coefficient; the lung elastic coefficient is used to adjust the ventilation and/or ventilation pressure of the breathing apparatus.

Optionally, the lung elastic variable coefficient calculating module includes:

the central point selection unit is used for selecting N data central points from the sample data in the expiration stage and selecting N data central points from the sample data in the inspiration stage by taking the pressure at the tail end of the pipeline and the volume data of the gas in the lung as the sample data;

a lung elastic variable coefficient calculating unit for calculating the lung elastic variable coefficient according to the formula

Calculating the lung elastic variable coefficient, wherein_g(V) is the lung elastic variable coefficient, i represents the center point of each datum, P_iPressure at the end of the pipeline at the ith data center point, V is the volume of gas in the lung of other sample data except the data center point, V_iThe volume of the gas in the lung, which is the central point of the ith data, σ is the smoothing factor.

Optionally, the breathing equation establishing module includes:

a basic respiration equation establishing unit for establishing a basic respiration equation:

wherein P is_ao(t) is the pressure at the end of the pipeline,

is P_aoFirst derivative of (t), P_l(t) is the pressure inside the lungs, P_r(t) is the pressure loss in the breathing apparatus conduit, V (t) is the volume of gas in the lungs,

is the second derivative of V (t), P_eeaRespiratory end alveolar pressure, e (t) is an error value;

the relation conversion unit is used for carrying out relation conversion on the basic breathing equation to obtain a converted breathing equation:

wherein cf_gConstituting the lung elastic coefficient, c is a lung elastic constant coefficient, f_gIs the coefficient of the lung elastic variable,

is the first derivative of V (t), F (t) is the pipeline gas flow,is the first derivative of F (t), a, c, f_g、r₁、r₂And b are coefficients;

a matrix conversion unit, configured to convert the converted breathing equation into a matrix form, so as to obtain a matrix expression:

wherein the content of the first and second substances,

in the form of a matrix of known quantities,θ_gin order to be able to obtain a matrix of quantities,

optionally, the least squares solving module includes:

the integral unit is used for carrying out integral operation on two sides of the matrix expression to obtain an integral expression;

and the least square solving unit is used for substituting the pipeline tail end pressure, the volume of the gas in the lung, the pipeline gas flow and the lung elastic variable coefficient into the integral expression, and solving by using a least square method to obtain the value of each element in the quantity matrix to be solved.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects: according to the lung elasticity coefficient measuring method and system based on the breathing device, the lung elasticity variable coefficient is calculated by using the generalized regression neural network on the basis of acquiring data directly acquired by the breathing device, and the breathing equation is solved by using the data directly acquired by the breathing device on the basis of acquiring the lung elasticity variable coefficient, so that the lung elasticity coefficient is measured. The invention calculates the lung elasticity variable coefficient by relying on the generalized regression neural network, thereby directly obtaining the lung elasticity variable coefficient, establishing a foundation for the calculation of the lung elasticity constant coefficient, realizing the measurement of the lung elasticity coefficient by directly utilizing the data acquired by the breathing device, avoiding blocking the respiratory airflow of people, and being suitable for the real-time regulation and the automatic regulation of the breathing device.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

Fig. 1 is a flowchart of a method for measuring lung elastic coefficient based on a breathing apparatus according to embodiment 1 of the present invention;

FIG. 2 is a graph of the end of the tubing pressure collected by the breathing apparatus when the breathing apparatus is in use by an infant;

FIG. 3 is a graph of the volume of air in the lungs collected by the respirator as the respirator was used by an infant;

FIG. 4 is a graph of the flow of gases through a conduit collected by a respiratory device while an infant is using the respiratory device;

FIG. 5 is a graph of the pressure at the end of the tube as a function of the volume of air in the lungs during inhalation by an infant;

FIG. 6 is a graph of the pressure at the end of the conduit as a function of the volume of gas in the lungs during exhalation by an infant;

FIG. 7 is a graph of the results of comparing the actual values of the static pressure inside the lungs during inspiration with the estimated values of the present invention;

FIG. 8 is a graph of the results of comparing the actual values of the static pressure inside the lungs during exhalation with the estimated values of the present invention;

fig. 9 is a system configuration diagram of a lung elastic coefficient measurement system based on a breathing apparatus according to embodiment 2 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.