Studies on Ventilatory Mechanics in Cardiacs and in Patients with Pulmonary Diseases

Abstract

Effective compliance, average flow resistance and mechanical work were measured by intraesophageal pressure technic in following subjects: 14 normals, 14 cardiacs, 11 emphysematous and 6 patients with pulmonary fibrosis. The influence of respiratory rate on these values and gradient of alveolar N2 fraction by single breath analysis were also studied, and results were as follows. (1) In cardiacs, compliances were significantly decreased, and flow resistances and viscous work were moderately increased, while total work was markedly increased. In changing respiratory rate, compliances and mechanical works remained stable. Gradients of alveolar N2 fraction were in normal range. (2) In emphysematous patients, compliances were widely scattered and the difference from normal subjects was not significant, though markedly decreased in tachypnea. Flow resistances and mechanical works were markedly elevated. In changing respiratory rate from resting state, marked elevation of mechanical works was noted. Gradients of alveolar N2 fraction were markedly elevated. (3) In patients with pulmonary fibrosis, decrease in resting compliance and moderately increased flow resistance and mechanical workswere noted. Effect of changing respiratory rate on mechanical values was not marked. Gradients of alveolar N2 fraction were moderately elevated. (4) These results indicated that the mechanical behavior in cardiacs and patients with pulmonary fibrosis made sharp contrast with that in the patients with emphysema.