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.