High Flow Oxygen as a Treatment for Cluster Headache

In a recent randomized, double-blind crossover study out of the United Kingdom, the treatment of cluster headaches with high-flow oxygen vs. a placebo was evaluated. Between 2002 and 2007 a total of 76 patients completed the study by self administering canisters of either 100% oxygen or air for 15 minutes during the beginning of an attack. Patients were unaware of the contents of their canisters and were allowed to use different means of treatment if pain relief was not felt within 15 minutes of administering a canister. Patients self reported their results 15, 30, 45, and 60 minutes after treatment, with the primary outcome measure being absence of pain or adequate relief from attack at 15 minutes. Of the participating patients, 78% of those receiving 100% oxygen had symptom resolution or adequate pain relief after 15 minutes, while only 20% of those receiving air experienced resolution or relief at 15 minutes. These results demonstrate with a high degree of certainty that 100% oxygen for 15 minutes is a better than high-flow air to treat the symptoms of cluster headache when applied at symptom onset. Although this study was relatively small and it was subject to recall bias and Hawthorne effect, the results were very impressive and both statistically and clinically significant. The remaining question which deserves further study is the mechanism by which the 100% oxygen treatment alleviates the symptoms of cluster headaches.