A drop in blood oxygen levels is common in the first few days after an acute stroke. One imagines that this oxygen deficit would be harmful in someone whose brain cells were already under attack. It is known that the area where cells have died in a stroke is surrounded by an area (penumbra) where cells are damaged, but may recover.
But plausible hypotheses are often not confirmed when put to a scientific test. So a randomised trial was conducted in over 8000 stroke patients to get better information on this point. The resulting paper, published in JAMA, showed almost identical results when patients were treated with or without prophylactic oxygen supplementation. The primary outcome was a score of disability assessed at 90 days after the original insult.
Outcomes were measured within narrow confidence limits and the therapy was unhelpful across various subgroups and irrespective of baseline oxygen levels. So here is another example of a superficially appealing treatment, which confers no benefit when put to the test. Administering supplemental oxygen is intrusive and I do not recommend this therapy.
— Richard Lilford, CLAHRC WM Director
- 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. JAMA. 2017; 318(12):1125-35.