Pulmonary circulation in acclimatized man at high altitude

Abstract

Cardiac catheterization studies have been carried out in 30 acclimatized adults at an altitude of 12,3000 ft in the Peruvian Andes. Mean pulmonary artery pressure was 22 mm. Hg (range 14-31 mm Hg) compared to 15 mm Hg (range 11-17 mm Hg) observed in sea-level subjects. The pulmonary artery wedge pressure was normal and calculated pulmonary arteriolar resistance was increased by 180% over sea-level values. The arteriovenous oxygen content difference and oxygen consumption were slightly greater at high altitude, but the cardiac output was normal. There was no relationship between hematocrit and pulmonary artery pressure or resistance, suggesting that in the high-altitude resident, blood viscosity in a hematocrit range of 40-78% does not significantly affect resistance to blood flow. Nine subjects studied at 14,200 ft had the same mean pulmonary artery pressure (22 mm Hg, range 17-32 mm Hg) as the larger group at 12,300 ft. pulmonary artery pressure Submitted on May 8, 1964