Abstract: Objective To evaluate the efficacy of high ( ≥ 1 ∶ 2) and low (<1 ∶ 2) plasma: red blood cell (RBC) ratio resuscitation in
patients with severe trauma requiring massive blood transfusion. Methods The databases including the Cochrane Library,
Pubmed, Web of Science, and EMBASE were systemically searched for relevant studies published between January, 2009 and
April, 2016. The selection of studies, assessment of methodological quality and data extraction were performed by two
researchers independently according to the inclusion and exclusion criteria. The main endpoint was 24-h mortality, 30-day
mortality and 24-h survival rate. Results Five observational studies reporting outcomes of 1024 patients were included in this
meta-analysis. Four studies documented civilian cases and one study had a military setting. No significant differences were
found in the Injury Severity Score (ISS) between patient groups receiving high and low plasma: RBC ratio resuscitation.
Compared with the low-ratio group, the patients with high-ratio resuscitation showed a significant reduction in the 24-h
mortality rate (OR=0.35, 95%CI [0.25, 0.48], P <0.00001) and the 30-day mortality rate (OR=0.55, 95%CI [0.41, 0.75], P =0.0001). An
increased survival rate was observed in patients receiving high plasma: RBC ratio resuscitation within the initial 24 h following
the trauma (HR=2.34, 95%CI [1.46, 3.73], P =0.00001). Conclusion Raising the plasma: RBC ratio to 0.5 or higher may decrease
the mortality rate of the patients with severe trauma who need massive blood transfusion.