Elevated Plasma Atrial Natriuretic Factor and Vasopressin in High-Altitude Pulmonary Edema

Abstract

A diagnosis of acute high-altitude pulmonary edema was made in five male skiers (age, 35.0 ± 1.8 years) by history and physical examination and was confirmed by a characteristic chest radiogram showing alveolar infiltrates associated with a normal cardiac silhouette. Five healthy age- and sex-matched subjects with similar physical activity at the same altitude served as controls. Plasma sodium was 135.0 ± 1.5 mmol/L in the acutely ill patients compared with 144.0 ± 3.3 mmol/L in the controls (P < 0.025). Mean plasma atrial natriuretic factor immunoreactivity averaged 17.6 ± 5.6 pmol/L in patients with high-altitude pulmonary edema compared with 6.8 ± 0.7 pmol/L in the controls at the same altitude (P < 0.05). Elevated atrial natriuretic factor levels normalized to 7.5 ± 1.9 pmol/L (P < 0.05) during recovery in Denver (altitude, 1600 meters) 24 hours later. Plasma arginine vasopressin levels were 1.8 ± 0.37 pmol/L in patients with high-altitude pulmonary edema at diagnosis compared with 0.92 ± 0.28 pmol/L in controls (P = 0.07). The inappropriately elevated arginine vasopressin levels decreased to 1.29 ± 0.37 pmol/L during recovery (P < 0.025), but the lowered plasma sodium concentration had not normalized by discharge within 24-hours of transfer to Denver and averaged 135.8 ± 1.2 mmol/L. The pathophysiologic implications of these findings are discussed.