STATIC VOLUME-PRESSURE CHARACTERISTICS OF THE RESPIRATORY SYSTEM DURING MAXIMAL EFFORTS.

Abstract

Maximal expiratory and inspiratory static airway pressures at different lung volumes were measured in 56 normal subjects of both sexes ranging in age from 6 to 64 years. A new method was used requiring a special mouthpiece, a series of containers of different volumes (allowing volume combinations from 1.5 to 200 liters), and a manometer. The subjects breathed into or out of the containers as forcibly as possible; the lung volumes corresponding to the maximal pressures developed were calculated by Boyle's law. The results are compared with those obtained by other authors. The maximal pressures developed by our subjects, particularly on expiration, were considerably higher than most published values. This was probably the result of using a special mouthpiece which provided an adequate seal even at high pressures. One experienced subject obtained pressures as high as 300 cm H2O on expiration and 200 cm H2O on inspiration. strength; muscles; pressures; chest Submitted on November 29, 1963