Hyperventilation therapy for acute traumatic brain injury (Cochrane Review)

A substantive amendment to this systematic review was last made on 14 July 1997. Cochrane reviews are regularly checked and updated if necessary.

Background: Because hyperventilation is often associated with a rapid fall in intracranial pressure, it has been assumed to be effective in the treatment of severe head injury. Hyperventilation reduces raised intracranial pressure by causing cerebral vasoconstriction and a reduction in cerebral blood flow. Whether reduced cerebral blood flow improves neurological outcome is, however, unclear.

Objectives: To quantify the effect of hyperventilation on death and neurological disability following head injury.

Search strategy: The search strategy drew on that of the Injuries Group as a whole. The reference lists of all relevant articles identified were checked and the first author of reports was contacted to ask for assistance in identifying any further trials. The most recent search was done in November 2002.

Selection criteria: All randomised trials of hyperventilation, in which study participants had a clinically defined acute traumatic head injury of any severity. There were no language restrictions.

Data collection and analysis: We collected data on the participants, the timing and duration of the intervention, duration of follow-up, neurological disability and death. Relative risks (RR) and 95% confidence intervals (95%CI) were calculated for each trial on an intention-to-treat basis. Timing, degree and duration of hyperventilation were identified a-priori as potential sources of heterogeneity between trials.

Main results: One trial of 113 participants was identified. Hyperventilation alone, as well as in conjunction with a buffer (THAM [tris-hydroxy-methyl-amino methane]), showed a beneficial effect on mortality at one year after injury, although the effect measure was imprecise (RR = 0.73; 95%CI 0.36, 1.49, and RR = 0.89; 95%CI 0.47, 1.72 respectively). This improvement in outcome was not supported by an improvement in neurological recovery. For hyperventilation alone, the RR for death or severe disability was 1.14 (95%CI 0.82, 1.58). The RR for death or severe disability in the hyperventilation-plus-THAM group, was 0.87 (95%CI 0.58, 1.28).

Reviewers' conclusions: The data available are inadequate to assess any potential benefit or harm that might result from hyperventilation in severe head injury. Randomised controlled trials to assess the effectiveness of hyperventilation therapy following severe head injury are needed.

Citation: Roberts I, Schierhout G. Hyperventilation therapy for acute traumatic brain injury (Cochrane Review). In: The Cochrane Library, Issue 3, 2003. Oxford: Update Software.

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This is an abstract of a regularly updated, systematic review prepared and maintained by the Cochrane Collaboration. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).

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