Hyperbaric oxygen did not improve outcome in head injury patients with coma.

Clinical Bottom Line:
1. No evidence for improvement in mortality or wakefulness in head injured patients treated with hyperbaric oxygen
2. Some weak evidence of effect in young, initially unresponsive patients with brain stem contusion on sub-group analysis.
Appraised by: Mike Bennett, Dept of Diving and Hyperbaric Medicine
Prince of Wales Hospital, Sydney; Thursday, 21 January, 1999

Clinical Scenario: A 30 year old male with a traumatic head injury resulting in coma and with global cerebral oedema.

Three-part Question: In comatose patients following head injury, does the administration of hyperbaric oxygen in addition to all usual care, result in any improvement in recovery from brain injury?
Search Terms: Hyperbaric oxygenation, head injury, brain injuries.

The Study:
Non-blinded randomised controlled trial with intention-to-treat.
Patients with history of head injury leading to coma and admitted to a neurological intensive care unit.
Control group (N = 29; 29 analysed): Usual management including intubation, mechanical ventilation and frusemide administration in the majority. Operative neurosurgery where indicated.
Experimental group (N = 31; 31 analysed): As above plus oxygen at 2.5 ATA for 60 minutes (90 minute cycle) for 10 days with 4 days break and repetition of the cycle until return of consciousness or death. Average 10.5 sessions.

The Evidence:

Time to Outcome
Control rate
HBO rate
Relative risk reduction
Absolute risk reduction
1 year
95% CI:

-33% to 58%
-0.18 to 0.32
NNT = 3 to INF NNH = 5 to INF

Non-Event Outcomes Control group HBO group P-value

Duration of coma
(days) 32.7 28.2 >0.05

1. 60 patients out of 185 recruited due to chamber availability- selection bias may reduce validity of this study.
2. Subgroup analysis of patients <30 years with brain stem contusion and initially unresponsive to painful stimuli suggest there may be a benefit in this group.
3. Due to complications and logistic difficulties, only 17 of 31 HBO patients received 4 or more HBO sessions, reducing any treatment effect.
4. Somewhat inconclusive study.

Expiry date: November 2021
1. Artru F, Chacornac R, Deleuze R. Hyperbaric oxygenation for severe head injuries. Preliminary results of a controlled study. European Neurology 1976; 14:310-318.