Development of a Clinical Pulmonary Function Analyzer Suitable for Screening Tests.

摘要

The pulmonary function analyzer (PFA) which is the subject of this report operates on a nondispersive infrared (NDIR) principle and provides -from a single breath of sample gas - a continuous profile of the measured gas concentrations. The PFA,therefore,allows determinations of pulmonary diffusing capacity and pulmonary perfusion as well as lung volume with a time response consistent with normal respiration. Carbon Monoxide (CO) is utilized for diffusion and Acetylene (C2H2) for perfusion measurements. Methane (CH4) is used as an insoluble reference gas,based on a combination of technical and physiological criteria,providing dilution normalization for both measurements. Earlier evolutionary models of the PFA (CO/He and CO/SF6) are also described. Laboratory evaluation of the prototype CO/C2H2/CH4 3-gas PFA confirmed design goals with noise levels of 0.3% in all channels and a transient response of less than 65msec. Linearity was also improved relative to earlier prototypes. Results of clinical evaluation support the applicability of this technique to detection of obstructive pulmonary disease.