No evidence that hyperbaric oxygen improves neurological state or infarct size following stroke.

Clinical Bottom Line:
1.No evidence of improved neurological function in the oxygen-treated group at four months.
2.No evidence for reduced infarction size at four months.

Appraised by: Mike Bennett
Dept of Diving and Hyperbaric Medicine
Prince of Wales Hospital
Sydney; Monday, 15 February, 1999

Clinical Scenario: A 75 year old man with a cerebral ischaemic stroke presented for treatment and we wondered if hyperbaric oxygen would improve outcome.
Three-part Question: In patients presenting acutely with ischaemic cerebral infarction, does the administration of hyperbaric oxygen in addition to standard therapy, result in any improvement in functional ability in the long-term?
Search Terms: Brain infarction, central nervous system diseases, stroke

The Study:
Double-blinded concealed randomised controlled trial with intention-to-treat.
Non-pregnant patients aged 20 to 90 years with onset of neurological deficit secondary to cerebral ischaemia in the carotid artery territory on one side within the preceding two weeks. Minor deficits excluded along with those rapidly resolving.
Control group (N =19;14 analysed): Standard physical and occupational therapy in a neurological intensive care plus sham hyperbaric oxygen exposures breathing air and at the times and pressures outlined for the active group. Patients received sedation as required and Vitamin E.
Experimental group (N =20;17 analysed): As above plus hyperbaric oxygen at 1.5ATA for 1 hour every 8 hours for a total of 15 treatments.

Non-Event Outcomes Time to outcome Air group HBO group P-value
Mean neurological
examination scores
0(best)-100(worst) 4 months 25.6 34.5 0.33

Infarct volumes
(mls) 4 months 29.0 49.2 0.25

1. All trends were in the direction of improvement in the air group.
2. The trial was stopped prematurely (by an external monitoring committee) because of the above and poor compliance.
3. There was also a trend to larger infarct size on admission in the oxygen group which may explain the findings.
4. The staff and patients found compliance with the regime difficult.
5. Mean interval from stroke to compression was 51.8 hours.

Expiry date: July 2022
1. Anderson DC, Bottini AG, Jagiella WM, Westphal B, Ford S, Rockswold GL, Loewenson RB. A pilot study of hyperbaric oxygen in the treatment of human stroke. Stroke 1991; 22:1137-1142.