Analysis of high frequency chest compression devices and modeling.

摘要

High frequency chest compression (HFCC) systems were developed as one of airway clearance techniques for the patients having chronic obstructive pulmonary disease. The effectiveness and safety of HFCC has been proven from clinical studies. But the mechanism of HFCC is still unclear. As a transitional work, this thesis analyzes all HFCC systems with electrical engineering and physiological background information. These six HFCC systems were compared and the mathematical modeling of HFCC and respiration system was suggested.;The first part of the thesis is about the analysis of HFCC systems. Jacket pressure pulses to the chest wall oscillation in the lung trace mouth and nose. The assumption is that the effectiveness of the treatment can be measured in the mouth airflow which is believed to be the indicator of the efficacy of HFCC therapy.;We found that all the HFCC systems have different jacket pressure characteristics for their frequency and pressure variables. This thesis compares the six HFCC systems in three ways: First, with jacket pressure produced by all possible change of frequency and pressure dials. Second, instruction of frequency and pressure dial selections built by clinical observation is analyzed with jacket pressure data (the Minnesota Table). Third, how the jacket circumference alters the transfer of pulse energy to the chest.;In second part, the respiratory pattern during all frequency and pressure settings of 103(TM) HFCC sessions is analyzed. The change of respiratory pattern and the delivery of HFCC pulses deal with the lung mechanics and the computational lung model.;The last part of the thesis is about the identification of HFCC system model. This system model contains jacket and chest function model. The transfer function model and the amplitude modulation model are selected for each model. It reveals that the breathing pattern can be estimated from the jacket pressure during HFCC running. The chest function model predicts HFCC induced airflow at the mouth. The model parameters are estimated with the prediction error method. The estimated models can be used to improve HFCC systems and to suggest how to increase the delivery of the pulses.