Hyperbaric oxygen is no better than a sham procedure for treating persistent postconcussion symptoms in military personnel, according to results from the randomized HOPPS trial .

Both hyperbaric oxygen (HBO) and a sham treatment were associated with significant improvements in postconcussion symptoms and secondary outcomes, including posttraumatic stress disorder, depression, and sleep quality compared to routine post-concussion care, reported Dr. R. Scott Miller of the Uniformed Services University of the Health Sciences, Bethesda, Md., and his associates. The results suggested that improvements in the chamber intervention groups were tied to placebo effects or the potential benefit of daily interactions with medical staff, the researchers said in the paper published Nov. 17 (JAMA Intern. Med. 2014; [ doi:10.1001/jamainternmed.2014.5479 ]).

The Hyperbaric Oxygen Therapy for Persistent Postconcussive Symptoms After Mild Traumatic Brain Injury (HOPPS) double-blind study randomized 72 military service members who had persistent postconcussion symptoms for more than 4 months to 40 hyperbaric oxygen treatments, 40 sham treatments in an air-filled chamber, or routine postconcussion care.

No differences were seen between the groups for improvement of at least two points (defined as clinically significant) on the Rivermead Post Concussion Symptoms Questionnaire ( RPQ ) symptoms subscale ( RPQ-3 ) (25% in the no intervention group, 52% in the HBO group, and 33% in the sham group; P = .24). Compared with the no intervention group (average change score, 0.5; P = .91), the HBO and sham groups showed improvement in symptoms on the RPQ total score (average change score, 5.4; P = .008 in the HBO group and 7.0; P = .02 in the sham group).

The results suggest that the improvements seen in the HBO and sham groups were not oxygen mediated but may reflect “nonspecific improvements related to placebo effects.

“Taken with results from other concurrent investigations our study does not support phase III trials of HBO for the treatment of PCS at this time,” the researchers concluded.

Hyperbaric oxygen 100% was administered at a dose of 1.5 atmospheres absolute for 60 minutes at a time. The sham treatment followed the same procedures but the chamber was pressurized to 1.2 atmospheres absolute.

The study sponsor is the U.S. Army Office of the Surgeon General who holds the investigational new drug application for hyperbaric oxygen to treat traumatic brain injury.