Method and system for detecting pulmonary function parameters by integrating four-subdivisions impedance information

Pulmonary function parameter testing is the principal medical method for the early diagnosis and postoperative monitoring of diseases with impaired pulmonary ventilation. Bioimpedance measurement, known for its noninvasive nature and absence of respiratory resistance, has garnered widespread attention over traditional flow-rate methods for assessing pulmonary function. However, relying solely on integral thoracic impedance to characterize changes in pulmonary air volume overlooks the potential errors introduced by alterations in nonpulmonary tissues. This article proposes a method for assessing lung ventilation parameters based on regional information that integrates impedance data from four distinct lung subdivisions, constructing a multivariate nonlinear mathematical model of the impedance variation of the four lung branches in relation to lung volume, thereby minimizing the impact of non-pulmonary factors on calculations. The 2-D thoracic equivalent model simulations revealed the ability to achieve regional impedance measurement focusing with a specific drive measurement pattern and four zonal focusing measurement electrode configurations were obtained for the lungs. The precision of the four-zone electrode configurations was confirmed through 3-D lung model simulations, revealing a generalized mathematical relationship between zonal impedance changes and air volume transformations in corresponding lung zones. Optimize and determine the integral calculation equation by selecting the parameters with the highest individual difference correlation through 500 clinical trials. The clinical trial results showed that the maximum relative errors of forced ventilation volume (FVC) and forced expiratory volume in one second (FEV1) were 1.02 % and 1.31 %, respectively, with differences within +/- 1.96 SD.