Hyperbaric oxygen therapy for the adjunctive treatment of traumatic brain injury
Abstract
Background
Traumatic brain injury is a common health problem with significant effect on quality of life. Hyperbaric oxygen therapy (HBOT) has been suggested to improve oxygen supply to the injured brain and reduce the volume of brain that will ultimately perish. It is postulated that adding HBOT to the standard intensive care regimen may reduce patient death and disability.
Objectives
To assess the benefits and harms of adjunctive HBOT for traumatic brain injury.
Search methods
We searched CENTRAL, MEDLINE, EMBASE, CINAHL and DORCTHIM databases; the searches were last updated in January 2009. We searched reference lists of eligible articles, handsearched relevant journals and contacted researchers.
Selection criteria
Randomised studies comparing the effect of therapeutic regimens which included HBOT with those that did not, on patients with traumatic brain injury.
Data collection and analysis
Three authors independently evaluated trial quality and extracted data.
Main results
Five trials were included in this review (229 participants receiving HBOT and 213 in the control group). There was no significantly altered risk of unfavourable outcome with HBOT (relative risk (RR) for unfavourable outcome with HBOT 0.51, 95% CI 0.25 to 1.08, P = 0.08). Pooled data show a significant reduction in the risk of dying when HBOT was added to the treatment regimen (RR 0.69, 95% CI 0.54 to 0.88, P = 0.003) and suggests we would have to treat seven patients to avoid one extra death (number‐needed‐to‐treat (NNT) 7, 95% CI 4 to 22). One trial suggested favourably lower intracranial pressure in patients receiving HBOT in whom myringotomies had been performed (weighted mean difference (WMD) with myringotomy ‐8.2 mmHg, 95% CI ‐14.7 mmHg to ‐1.7 mmHg, P = 0.01); another trial reported a significantly better GCS in patients treated with HBOT. There was a reported incidence of 13% for significant pulmonary impairment in the HBOT group versus 0% in the non‐HBOT group (P = 0.007).
Authors' conclusions
In people with traumatic brain injury, while the addition of HBOT may reduce the risk of death, there is little evidence that the survivors have a good outcome. The routine application of HBOT to these patients cannot be justified from this review. Given the modest number of patients, methodological shortcomings of included trials and poor reporting, the result should be interpreted cautiously. An appropriately powered trial of high methodological rigour is required to define which patients, if any, can be expected to benefit most from HBOT.
PICOs
Plain language summary
Does hyperbaric oxygen therapy improve the survival and quality of life in patients with traumatic brain injury?
Traumatic brain injury is a major cause of death and disability. Not all damage to the brain occurs at the moment of injury; reduction of the blood flow and oxygen supply to the brain can occur afterwards and cause further secondary brain damage, which is itself an important cause of avoidable death and disability. In the early stages after injury it is therefore important that efforts are made to minimise secondary brain damage to provide the best chances of recovery.
Hyperbaric oxygen therapy (HBOT) has been proposed as a treatment for minimising secondary brain damage by improving the oxygen supply to the brain. Patients undergoing HBOT are placed inside a specially designed chamber in which 100% oxygen is delivered at a greater than normal atmospheric pressure. It is sometimes used as a treatment to increase the supply of oxygen to the injured brain, in an attempt to reduce the area of brain that will die.
The effectiveness of HBOT on the recovery of brain‐injured patients is uncertain. There is also concern regarding potential adverse effects of the therapy, including damage to the ears, sinuses and lungs from the effects of pressure, temporary worsening of short‐sightedness, claustrophobia and oxygen poisoning.
In an attempt to address the uncertainty surrounding the use of HBOT, the authors of this review identified all high quality trials investigating the effectiveness of HBOT in traumatically brain‐injured patients of all ages.
The authors found five eligible studies involving 442 patients. The combined results suggest that HBOT reduces the risk of death; however, there is no good evidence that these survivors have improved outcome in terms of quality of life. It is possible, therefore, that the overall effect of hyperbaric oxygen is to make it more likely that people will survive with severe disability after such injuries. The authors conclude that the routine use of HBOT in brain‐injured patients cannot be justified by the findings of this review.
Due to the small number of trials with a limited number of participants, it is not possible to be confident in the findings; further large, high quality trials are required to define the true extent of benefit from HBOT.
