Increases in pulmonary artery pressure and pulmonary vascular resistance are present. Increasing proteinaceous interstitial exudate, sometimes resembling bronchopneumonia, develops as pulmonary edema worsens. The exudate contans vasoactive eicosanoids and complement proteins. Autopsy frequently shows thrombi, pulmonary hemorrhage, and infarcts. However, left-sided cardiac function is maintained.
Hyperbaric treatment can substitute for low-flow oxygen.
Oxygen rapidly reduces pulmonary artery pressure, respiratory rate, and other symptoms. In severe cases, if immediate descent is not possible, request an airdrop of oxygen rather than wait for rescue teams or helicopter evacuation. Hospitalization is indicated until functionally recovered, but hypocapnic alkalosis and some hypoxemia persist for days. Oxygen saturation of 90 percent or higher is satisfactory for discharge, usually in several days. Subsequent ascents should be more gradual, but are not contraindicated.