Prevention of severe nocturnal hypoxemia in COPD patients at high altitude. (Results of a randomized controlled trial)

Objective. To assess the efficacy of acetazolamide in preventing severe nocturnal hypoxemia in patients with chronic obstructive pulmonary disease (COPD) during a short-term stay at an altitude of 3100 m. Material and methods. In a randomized, double-blind, placebo-controlled trial, 176 patients with COPD (FEV1 40—80% of predicted, SpO2≥92%, PaCO2<5.5 kPa at 750 m), residing in lowlands (<800 m), were included. Participants received acetazolamide (125 mg in the morning and 250 mg in the evening) or placebo during a two-day stay at 3100 m. The primary outcome was the incidence of severe nocturnal hypoxemia (SpO2<80% for >30 min). Secondary outcomes included nocturnal oxygen saturation (SpO2) and desaturation index (DI). Monitoring was performed using respiratory polygraphy, spirometry, and clinical examination. Results. Severe nocturnal hypoxemia occurred in 12% of patients in the acetazolamide group (10/86) versus 48% in the placebo group (43/90; p<0.001). Mean nocturnal SpO2 at 3100 m was 86±2% (acetazolamide) versus 84±2% (placebo; p<0.001), with a DI of 13.8±14.4 versus 26.3±26.6 per hour (p<0.001). Adverse effects were minimal, with no serious adverse events reported. Conclusion. Prophylactic use of acetazolamide significantly reduces the incidence of severe nocturnal hypoxemia in COPD patients at 3100 m, improving oxygenation and reducing the desaturation index. Acetazolamide can be recommended as an effective and safe measure for COPD patients traveling to high altitudes.