Treatment of Acute Mountain Sickness: Hyperbaric Versus Oxygen Therapy

Study objectives: To compare the benefits of simulated descent in a hy perbaric chamber with those of supplementary oxygen for the treatment of acute mountain sickness. Design: A prospective study. Setting: The Snake River Health Clinic in Keystone, Colorado, which has an altitude of 2,850 m (9,300 it). Type of participants: Twenty-four patients who presented with acute mountain sickness. Interventions: A simulated descent of 1,432 m (4,600 it) was attained by placing the patients in a fabric hyperbaric chamber and pressurizing the chamber to 120 mm Hg (2.3 PSI) above ambient pressure. Patients were randomly assigned to either the hyperbaric treatment or treatment with 4 L of oxygen given by facemask; both treatments lasted for two hours. Measurements and main results: Mean arterial oxygen saturation (Sao2) increased 7% (84 +- 2% to 91 +_ 1%) with pressurization and 14% (83 +_ 4% to 96 ± 1%) with oxygen during treatment over pretreatment levels. Symptoms of acute mountain sickness decreased as rapidly with pressur ization as with oxygen treatment, despite significantly higher Sao 2 in the oxygen-treated group during treatment, Symptomatic improvement was retained in both groups at least one hour after treatment. Conclusion: Simulated descent in a fabric hyperbaric chamber is as ef fective as oxygen therapy for the immediate relief of acute mountain sick ness. [Kasic JF, Yaron M, Nicholas RA, Lickteig JA, Roach R: Treatment of acute mountain sickness: Hyperbaric versus oxygen therapy. Ann Emerg Med October 1991;20:1109-1112.]