Oxygen therapy for cluster headache. A mask comparison trial. A single-blinded, placebo-controlled, crossover study.

Purpose The purpose of this article is to investigate possible differences in effect between three types of masks in the acute treatment of cluster headache (CH). Patients and methods Fifty-seven CH patients according to ICHD-II-criteria participated in a single-blinded, semi-randomized, placebo-controlled, crossover inpatient study, and 102 CH attacks were treated with 100% oxygen delivered by demand valve oxygen (DVO), Optimask or simple mask (15 liters/min) or placebo delivered by DVO for 15 minutes. Primary endpoint: Two-point decrease of pain on a five-point rating scale within 15 minutes. Results Only 10 CH patients had multiple attacks and reached the point of placebo. There were no significant differences between masks in the primary endpoints ( p = 0.412). After 15 minutes 48% had a two-point decrease using the DVO compared to 45% with placebo ( p = 0.867). After 30 minutes 68% were pain free or had pain relief using DVO and 45% by placebo ( p = 0.061). The DVO was preferred by 62% compared to 5% and 33% for simple mask ( p < 0.0001) and Optimask ( p = 0.061). In the first attack the DVO was significantly better at achieving pain relief at 15 minutes ( p = 0.018). Treatment with DVO or Optimask reduced the need for rescue medication compared to the simple mask (23%, 19%, 50%, respectively). No treatment-related adverse events were observed. Conclusion The primary endpoint with pain relief at 15 minutes was non-significant; however, a post hoc analysis of the first attack significantly favored DVO. Further, therapy by Optimask and DVO resulted in a decreased need for rescue medication. We recommend that CH patients be offered DVO or Optimask before oxygen therapy is abandoned.