Moderate hypothermia treatment in adult patients with severe traumatic brain injury: a meta-analysis.

Objectives: To evaluate the effect of moderate hypothermia treatment (MHT) in severe traumatic brain injury (sTBI) compared to normothermia management. Methods: PubMed, Medline, Springer, Elsevier Science Direct, Cochrane Library and Google scholar were searched up to December 2012. Pooled risk ratios (RRs) and 95% confidence intervals (CIs) for the mortality and clinical neurological outcome of the adult patients with sTBI were collected and calculated in a fixed-effects model or a random-effects model. Summary effect estimates were stratified by study design and ethnicity. Egger's regression asymmetry tests were utilized for detecting the publication bias. Results: The overall estimates showed that MHT could reduce the mortality (hypothermia vs. normothermia, RR = 0.86, 95% CI = 0.73-1.01, p = 0.06) and unfavourable clinical neurological outcomes (RR = 1.21, 95% CI = 0.95-1.53, p = 0.12) for traumatic brain injured patients without statistical significance. Moreover, the further stratification sub-group analysis indicated that MHT presented a significant reduction (RR = 0.60, 95% CI = 0.44-0.83, p = 0.002) of mortality compared to the normothermia management in an Asian population. Surprisingly, American patients treated with moderate hypothermia showed an increasing mortality (RR = 1.07, 95% CI = 0.83-1.39, p = 0.61). Conclusions: MHT may be effective in reducing death and unfavourable clinical neurological outcomes, but this finding is not statistically significant, except for decreasing the mortality in Asian patients.