[Low-concentration nitrous oxide inhalation in the treatment of high-altitude pulmonary edema].

Objective: To investigate the therapeutic effect of low-concentration of nitroic oxide (NO) inhalation in high-altitude pulmonary edema.
Method: Sixty-five male patients with high-altitude pulmonary edema were randomized into three groups. Patients in the conventional therapy group received oxygen, intravenous furosemide, aminophylline and dexamethasone; patients in the nifedipine group received oral nifedipine (10 mg, tid) in addition to conventional therapy; and patients in the NO group received NO (10 ppm) inhalation for 30 min, in addition to oral nifedipine. The time for which pulmonary rales on auscultation and shadows on chest radiograph lasted, and the course of disease, were compared.
Result: In the NO group, pulmonary rales disappeared in 0.4 +/- 0.3 d, shadows on chest radiograph disappeared in 0.6 +/- 0.2 d, and the course of disease was 1.8 +/- 0.7 d, all of which were significantly different from those of the nifedipine group (2.4 +/- 1.4 d, 4.1 +/- 1.7 d, 6.8 +/- 1.8 d, respectively) and the conventional therapy group (3.7 +/- 1.2 d, 5.5 +/- 1.8 d, 9.6 +/- 3.1 d, respectively).
Conclusion: Low-concentration NO inhalation on the basis of conventional and nifedipine therapies was very effective in the treatment of high-altitude pulmonary edema, which deserves further and larger scale investigation.