Hyperbaric oxygen for experimental intracerebral haemorrhage: Systematic review and stratified meta-analysis

Objective: Hyperbaric oxygen (HBO) is widely used in treating various neurological diseases. However, HBO for treatment of intracerebral haemorrhage (ICH) remains controversial, in either animal or clinical studies. Therefore, we conducted this systematic review and meta-analysis on studies describing the efficacy of HBO in animal models of ICH.Methods: Studies were identified by searching mainstream databases through November 2015. The efficacy of HBO in animal models of ICH was assessed by changes in the brain water content (BWC), neurobehavioural outcome (NO) or both. Subgroup analyses were performed according to different design characteristics.Results: In total 15 studies met our inclusion criteria. HBO can reduce the BWC (−0.982, 95% CI, −1.148 to −0.817; P < 0.01; 57 comparisons), and improve NO (−0.767, 95% CI, −1.376 to −0.159; P < 0.01; eight comparisons). HBO was most effective in reducing BWC when given 72 h after ICH for a 4- to 5-day consecutive treatment at the chamber pressure of 3.0 atmosphere absolute. Efficacy was higher with phenobarbital anaesthesia, the blood infusion model and in rabbits.Conclusion: Although HBO was found to be effective in experimental ICH, additional confirmation is needed due to possible publication bias, poor study quality and the limited number of studies conducting clinical trials.