Time-Varying Pulmonary Resistance and Compliance III Human

Abstract

The objective of the present study was to compute the continuous changes of the pulmonary resistance and lung compliance in a respiratory cycle in human. A time-varying system analysis and the inverse relations of the pulmonary resistance and compliance against the lung volume were used to compute continuous changes of the resistance and compliance, as compared with the conventional discrete measurements in time-invariant model. In two patients, the measured mouth-to-esophageal pressure, the respiratory flow, and the volume data were used as the input data for the estimation by a combination of two least-square-error algorithms. The first algorithm is for estimation of the resistance parameters for various compliance parameters, and the second algorithm is for computing the optimal values of compliance parameters with the minimal standard error between the measured and the computed pressure. The results show that the computed values of the present method were comparable to other results obtained with more complicated conventional forced oscillation method. Also, the curve fitting in the time-varying model could be accomplished with smaller standard errors, compared with time-invariant analysis.