Acute Pulmonary Edema of Altitude

Abstract

Three separate episodes of acute pulmonary edema are described that developed in two otherwise healthy individuals during heavy exertion at high altitudes. Detailed physical examination and laboratory studies failed to demonstrate pulmonary infection or cardiac disease. Data obtained by cardiac catheterization during one of these episodes revealed elevation of the pulmonary artery pressure and a normal left atrial pressure. This syndrome appears to be the consequence of pulmonary vascular obstruction distal to the capillary bed, presumably in the pulmonary veins. It is brought about by exposure of susceptible individuals to high altitudes, and is completely reversed by oxygen administration.

Altitude and the Human Pulmonary Circulation

“…However, others have shown conclusively that high altitude pulmonary oedema is by no means rare in lowlanders exposed for the first time to altitude (Houston, 1960;Fred, Schmidt, Bates & Hecht, 1962;Singh et al, 1965). Identified risk factors are: (i) the rapidity of ascent; (ii) the altitude above 3500 m, although high altitude pulmonary oedema may occur at lower altitudes (Fred et al, 1962;Frates, Harrison & Edwards, 1977); (iii) heavy physical exercise shortly after arrival at altitude; (iv) individual susceptibility as shown by the occurrence of familial cases in parents or siblings (Hultgren et al, 1961;Fred et al, 1962;Scoggin et al, 1977) and by recurrence of high altitude pulmonary oedema on successive reentries to altitude (Vega, 1955;1961;Fred et al, 1962;Hultgren, Lopez, Lundberg & Miller, 1964;Roy, Guleria, Khanna, Manchada, Pande & Subba, 1969;Lakshminarayan & Pierson, 1975;Frates et al, 1977).…”

“…Catheterization studies (Fred et al, 1962;Hultgren et al, 1964;Penaloza & Sime, 1969;Roy et al, 1969) have been performed in 13 cases of high altitude pulmonary oedema from a few hours to 4 days after the onset of respiratory symptoms. Patients were still quite ill, although most of them had been treated before the study and five had already been moved to a lower altitude.…”

“…Pulmonary arterial hypertension is more severe in native highlanders than in native lowlanders. Oxygen breathing causes a marked fall in pulmonary arterial pressure within minutes (Fred et al, 1962;Hultgren et al, 1964).…”

“…Thus structural changes and vasoconstriction of pulmonary veins whose outer diameter is 150 pm or less (Wagenvoort & Wagenvoort, 1976;Dingenmans & Wagenvoort, 1978) might be responsible for high pressure in the pulmonary microcirculation in chronic alveolar hypoxia that would not be detectable by conventional methods; however, the role of hypoxic pulmonary venoconstriction as a causative factor of high altitude pulmonary oedema is as conjectural nowadays as it was in the early sixties (Hultgren et al, 1961;Fred et al, 1962;Nayak et al, 1964;Singh et al, 1965). In 1961, Hultgren et al suggested that acute left ventricular failure was the most likely immediate cause of high altitude pulmonary oedema.…”

The Measurement of Pulmonary Extravascular Water Volume during Exposure to Simulated High Altitude,

“…The pathogenesis of high altitude pulmonary edema has not been elucidated despite clinical (5,6), hemodynamic (5,7,8), and post mortem (9, 10) studies in a largi number of patients with this condition. Research has been impeded by the fact that high altitude pulmonary edema appears .-oradically in hum..n subjects and by the logistics of conducting complex cardiorespiratory measurements at high terrestial elevations.…”