title: Unestablished indications for hyperbaric oxygen therapy.
abstract: Unestablished indications are conditions in which systematic clinical use of hyperbaric oxygen treatment (HBOT) is not supported by adequate proof of benefit. HBOT is vulnerable to use in many such conditions for various reasons, perhaps the most important being that a placebo or participation effect may create an impression of efficacy. The systematic use of HBOT in unestablished indications raises ethical concerns about provision of misleading information, giving false hope, and taking payment for therapy of doubtful benefit. Any practice perceived as unethical or unscientific has the potential to draw the wider field into disrepute. Of substantial contemporary relevance is the use of HBOT in treatment of various forms of chronic brain injury; in particular, cerebral palsy in children and the sequelae of mild traumatic brain injury in adults. There are now multiple, randomised, blinded, sham-controlled trials of HBOT in both indications. None of these studies showed benefit of HBOT when compared to sham control, though the sham and HBOT groups often both improved, indicating that a placebo or participation effect influenced outcomes. These results almost certainly explain those of open-label trials (lacking sham controls) in which HBOT frequently seems beneficial. Advocates for HBOT in chronic brain injury claim that the sham treatments (usually 1.3 ATA pressure exposure whilst air breathing) in the blinded trials are actually active treatments; however, the same dose of oxygen can be achieved at 1 ATA breathing 27% oxygen. To counter this argument, advocates also claim that the extra 0.3 ATA of pressure is somehow independently beneficial, but this notion has limited biological plausibility and there is little supporting evidence. Chronic brain injuries remain unestablished indications at this time and, in our opinion, should not be systematically treated with HBOT.
authors.affiliation: Consultant anaesthetist and hyperbaric physician at Auckland City Hospital. He is the Head of the Department of Anaesthesiology at the University of Auckland, Department of Anaesthesiology, School of Medicine, University of Auckland Private Bag 92019, Auckland, New Zealand, E-mail: sj.mitchell@auckland.ac.nz.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Mitchell
authors.affiliation: Consultant anaesthetist and hyperbaric physician at Prince of Wales Hospital, Sydney, Australia.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Bennett
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000628:therapy*; D002547:Cerebral Palsy / Q000628:therapy*; D002648:Child; D006801:Humans; D006931:Hyperbaric Oxygenation; D056687:Off-Label Use
keywords: Hyperbaric oxygen therapy; central nervous system; children; ethics; evidence; hyperbaric research; review article; trauma and stress