Mannitol cannot reduce the mortality on acute severe traumatic brain injury (TBI) patients: a meta–analyses and systematic review

BACKGROUND: We aimed to systematically review the efficacy of mannitol (MTL) on patients with acute severe traumatic brain injury (TBI). METHODS: Databases such as PubMed (US National Library of Medicine), CENTRAL (The Cochrane Library 2014, Issue 3), ISI (Web of Science: Science Citation Index Expanded), Chinese Biomedicine Database (CBM), and China Knowledge Resource Integrated Database (CNKI) have been searched for relevant studies published between 1 January 2003 and 1 October 2014. We have established inclusion and exclusion criteria to identify RCTs, which were suitable to be enrolled in the systematic review. The comparison group could be hypertonic saline (HS), hydroxyethyl starch, or others. The quality assessment was based on the Cochrane Handbook for Systematic Reviews of Interventions Version 5.0.1 and modified Jadad score scale. The major outcome was mortality, followed by the secondary outcomes such as neurological outcome, days on intensive care unit (ICU), and ventilator day. In addition, intracranial pressure (ICP), cerebral perfusion pressure (CPP), and mean arterial pressure (MAP) were used as the surrogate endpoints. Data synthesis and meta-analysis was conducted by using R (version 3.7-0.). RESULTS: When 176 potential relevant literatures and abstracts have been screened, four RCTs met all the inclusion criteria and were enrolled for the meta-analysis. Amongst all the enrolled studies, two trials have provided the primary outcome data. There was no heterogeneity between two studies (I(2) = 0 %) and a fixed model was used for meta-analysis (n = 53), pooled result indicated that the mortality was similar in mannitol intervention and control treatment, OR = 0.80, 95 % CI [0.27, 2.37], P = 0.38. We found that both mannitol and HS were efficient in decreasing the ICP. Furthermore, the effect of the HS on the ICP appeared to be more effective in the patients with diffuse brain injuries than mannitol did. CONCLUSIONS: As a conclusion, the mannitol therapy cannot reduce the mortality risk of acute severe traumatic brain injury. Current evidence does not support the mannitol as an effective treatment of acute severe traumatic brain injury. The well-designed randomized controlled trials are in urgent need to demonstrate the adoption of mannitol to acute severe traumatic brain injury.