One trial of 113 participants, not all of whom had raised intracranial pressure, was identified by a Cochrane review [Abstract] 1. Hyperventilation alone, as well as in conjunction with the buffer THAM showed a beneficial effect on mortality at one year after injury, although the effect was not statistically significant (RR 0.73, 95% CI 0.36 to 1.49 and RR 0.89, 95% CI 0.47 to 1.72). 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 to 1.58). The RR for death or severe disability in the hyperventilation plus THAM group was 0.87 (95% CI 0.58 to 1.28).
Another systematic review 2 including 1 RCT (n=113), 6 quasi-experimental studies (n=245), and 5 descriptive case studies (n=235) was abstracted in DARE. The findings suggest that head-injured patients in the pre-hospital and early phases of care are at increased risk of suffering hyperventilantion-induced secondary brain injury and that cautious, highly monitored and selective approach to hyperventilation be adopted.
Comment: The quality of evidence is downgraded by sparse data, inconsistency of results, and study limitations. The review may have missed earlier studies, and there are inadequacies in the reporting of some studies.
Primary/Secondary Keywords