STATIC AND DYNAMIC REGIONAL DISTRIBUTION OF GAS WITHIN THE NORMAL HUMAN LUNG

Abstract

This chapter discusses static and dynamic regional distribution of gas within the normal human lung. A study was carried out suggesting that in man, under normal conditions, the dynamic changes in pleural surface pressure (Ppl) are essentially uniform throughout the lung. In this study, the changes in mouth pressure were compared with those measured with a balloon placed at different levels of the esophagus during dynamic respiratory efforts made by normal subjects against a closed tap (glottis open). In both sitting and supine position, independent of lung volume, it was found that the changes in mouth and esophageal pressure were identical (or nearly so), independent of the frequency with which the respiratory efforts were performed. The changes in mouth pressure can be taken as reflecting the overall change in pressure over the whole surface of the lung, the concordance between the local (esophageal) Δ P s, and the overall (mouth) Δ P 's strongly suggests that the changes in pleural pressure were uniform over the whole lung surface.