Statistical Analysis And Modeling Of Tidal Volume By Initial Exhalation Pressure In Trilevel PAP

Chronic obstructive pulmonary disease(COPD)is a common preventable and treatable disease which is persistent,progressive,incomplete reversible,airflow limited,and has many complications.It has been proved clinically that non-invasive positive pressure ventilation is an effective method for treating chronic obstructive pulmonary disease without artificial airway implantation.Non-invasive ventilators on the market mainly use continuous positive airway pressure,bilevel positive airway pressure ventilation,trilevel positive airway pressure ventilation and so on.Existing studies have shown that in non-invasive ventilation,the human body relies on the elastic retraction force of the lungs during expiration,and the expiratory pressure has no supporting effect on the expiratory process.This is contrary to some clinical results.So far,no specific experimental data have been provided to verify this.Aiming at the influence of initial expiratory pressure on human tidal volume during non-invasive positive pressure ventilation,this paper simulated expiration of healthy people and two typical COPD patients under different ventilation modes by using Testchest simulation lung,classified and analyzed tidal volume data collected.Then,using a variety of analysis methods to calculate the contribution of draught pressure difference of initial and terminal expiratory on tidal volume;Finally,based on circuit theory,the aerodynamic model of respiratory process was established and validated.The main research contents of this paper are as follows:(1)Design and implement a reasonable tidal volume collection experiment,using the Testchest simulation lung to simulate namely healthy people,patients with COPD characterized by emphysema as the main phenotype,and patients with COPD characterized by bronchitis as the main phenotype.After collecting the tidal volume changes of the three groups with using Trilevel PAP ventilation,it was concluded that the change of initial expiratory pressure had a significant impact on the tidal volume changes.(2)Through correlation analysis and multivariate linear regression analysis,the relationship between initial expiratory pressure difference,terminal expiratory pressure difference and human tidal volume was analyzed linearly.It was verified that the initial and terminal expiratory pressure differences contribute to tidal volume using non-invasive positive pressure ventilation,without considering that excessive airway resistance made the body slowly respond to the change of air pressure,and the former contributes significantly greater than the latter.(3)A human body breathing simulation model based on electricity was designed for the clinical research of noninvasive ventilation.The characteristics of power supply,resistance and capacitance were used to simplify the respiratory pressure,elastic resistance and inelastic resistance during breathing.The simulation model was constructed by using MATLAB.By matching the respiratory waveforms collected in the experiment,the most suitable additional air pressure value and the descending edge coefficient of expiratory phase airflow were screened out,which verified the conjecture put forward in this paper.In summary,when using trilevel positive pressure ventilation,the initial pressure of the expiratory phase can cause the body to generate additional respiratory muscle pressure against the airflow,and the force of the active exhalation will be converted into a force that helps to inhale,thereby increasing the tidal volume.The airflow rate of the gas process slows down and plays the role of ventilation support.