Continuous or Nocturnal Oxygen Therapy in Hypoxemic Chronic Obstructive Lung Disease

TLDR

The two groups were initially well matched physiologically and neuropsychologically, yet the reason for the observed mortality difference remains unclear. A multicenter randomized trial enrolled 203 hypoxemic COPD patients, assigning them to continuous O₂ therapy or 12‑hour nocturnal O₂ therapy and followed them for a mean of 19.3 months. Compliance was good, but mortality was 1.94 times higher with nocturnal O₂, particularly in patients with CO₂ retention, poor lung function, low nocturnal saturation, severe brain dysfunction, or mood disturbances, whereas continuous O₂ improved outcomes in those with low pulmonary artery pressure, low vascular resistance, and preserved exercise capacity, concluding that continuous O₂ lowers mortality versus nocturnal O₂.

Abstract

At six centers, 203 patients with hypoxemic chronic obstructive lung disease were randomly allocated to either continuous oxygen (O2) therapy or 12-hour nocturnal O2 therapy and followed for at least 12 months (mean, 19.3 months). The two groups were initially well matched in terms of physiological and neuropsychological function. Compliance with each oxygen regimen was good. Overall mortality in the nocturnal O2 therapy group was 1.94 times that in the continuous O2 therapy group (P = 0.01). This trend was striking in patients with carbon dioxide retention and also present in patients with relatively poor lung function, low mean nocturnal oxygen saturation, more severe brain dysfunction, and prominent mood disturbances. Continuous O2 therapy also appeared to benefit patients with low mean pulmonary artery pressure and pulmonary vascular resistance and those with relatively well-preserved exercise capacity. We conclude that in hypoxemic chronic obstructive lung disease, continuous O2 therapy is associated with a lower mortality than is nocturnal O2 therapy. The reason for this difference is not clear.