Post-Stroke Prophylactic Oxygen Does Not Improve Outcomes

Routine low-dose prophylactic oxygen does not improve outcomes among patients without hypoxia who experienced an acute stroke, according to the findings of a recent study.

The single-blind randomized clinical trial included 8003 adults who experienced an acute stroke. Participants were enrolled in the study within 24 hours after hospital admission if there were no clear indications for or contraindications to oxygen therapy. The researchers randomly assigned 2668 patients to continuous oxygen therapy for 72 hours, 2667 patients to nocturnal oxygen therapy for 3 nights, and 2668 patients to receive oxygen only if clinically indicated (control group). Oxygen was administered using nasal tubes at 3 L/min if a patient’s baseline oxygen saturation was 93% or less and was administered at 2 L/min if their baseline oxygen saturation was over 93%. 
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Patients completed the modified Rankin Scale Score after 90 days. Logistic regression was used to calculate the odds ratio (OR) for changes from 1 disability level to the next, with OR over 1 indicating improvements. The minimum clinically important difference in Rankin Scale scores was 1 point.

Overall, the primary outcome was available for 7677 patients (96%).

The researchers were unable to identify a subgroup that benefited from oxygen therapy. The unadjusted OR for a better outcome was 0.97 for oxygen compared with controls and was 1.03 for continuous compared with nocturnal oxygen.

While no significant harms were identified, at least 1 serious adverse event occurred in 348 patients (13%) in the continuous oxygen group, 294 patients (11%) in the nocturnal oxygen group, and 322 patients (12.1%) in the control group.

“Among nonhypoxic patients with acute stroke, the prophylactic use of low-dose oxygen supplementation did not reduce death or disability at 3 months,” the researchers concluded. “These findings do not support low-dose oxygen in this setting.”

—Melissa Weiss

Reference:

Roffe C, Nevatte T, Sim J, et al. Effect of routine low-dose oxygen supplementation on death and disability in adults with acute stroke the Stroke Oxygen Study randomized clinical trial [published online September 26, 2017]. JAMA. doi:10.1001/jama.2017.11463.