Relationship of air flow to pressure during maximal respiratory effort in man.

Abstract

The relationship between esophageal pressure and rate of change of lung volume during maximal effort was studied at various degrees of thoracic inflation in 4 normal subjects. An inverse relationship was obtained. Relating these findings to measurements of maximal respiratory flow of air indicated that, in a given subject, inspiratory flow at all volumes and expiratory flow at near-total lung capacity are potentially limited by the muscular apparatus. Maximal expiratory flow at lesser lung inflations is much less dependent on subject effort and is limited basically by the mechanical properties of the lung.