Mean pulmonary artery pressure and alveolar oxygen tension in man at different altitudes.

Abstract

Measurements of mean pulmonary artery pressure (MPAP) and alveolar oxygen tension (pA02) in normal man at 8 altitudes between sea level and 17,100 ft and predicted values for similar altitudes were compared in a computer program which calculated linear regression slopes and intercepts and plotted the regression line as well as the constants of linear regression equations. pAO2 predictions were derived from the linear regression slope of actual pAO2 and altitude; and MPAP predictions were based on an empirical formula using inspired oxygen tension (pAO2), the ratios of ambient and sea-level barometric pressure, and predicted pA02. There was highly significant positive linear correlation between predicted MPAP and altitude, predicted and measured MPAP, and predicted and measured pA02, and highly significant negative linear correlation between actual pA02 and altitude. Measured mean pAO2 and MPAP of newcomers were within 2 SE of those for natives of the same altitude.