The safety and efficacy of oxygen treatment for cluster headache attacks with oxygen delivered at a flow rate of 7 L/min and 12 L/min may be comparable, with a preference by patients for the higher flow rate, according to a study published in the Journal of Headache and Pain.
In this study, 70 oxygen-naive patients with cluster headaches were enrolled and their attacks were treated with oxygen at 7 and 12 L/min. The primary outcome was the percentage of participants reporting being pain-free 15 minutes after oxygen therapy for ≥2 attacks/day during the first 2 days of the study. Secondary outcomes were the percentage of successfully treated attacks, percentage of attacks after which participants were pain-free, drop in Visual Analog Scale score, and participant preference in all treatment periods.
Of 98 enrolled participants, 70 provided valid data and 56 used both flow rates (total of 604 attacks recorded). The primary analysis only included 5 participants who treated a total of 27 attacks during the first 2 days of the study. In these patients, the percentage of attacks after which participants were pain-free was comparable with oxygen flow rates of 12 L/min and 7 L/min (P =.180). Participants reported preferring the 12 L/min vs the 7 L/min oxygen flow rate (P =.005), but a greater percentage of participants reported being pain-free after using 7 L/min compared with 12 L/min oxygen (P =.039).
Comparable side effects were reported by participants after using each oxygen flow rate.
The odds ratio of being pain-free when using 12 L/min oxygen compared with 7 L/min was 0.73 (P=.061).
“These results suggest that although more patients were pain-free using 7 L/min, this is insufficient to state that 7 L/min is the more effective treatment. We suggest there is a sub- group of patients, who benefit from using the higher flow rate,” the researchers wrote.
Dirkx THT, Haane DYP, Koehler PJ, et al. Oxygen treatment for cluster headache attacks at different flow rates: a double-blind, randomized, crossover study. [published online October 10, 2018]. J Headache Pain. doi:10.1186/s10194-018-0917-4