Platelet‐to‐red blood cell ratio and mortality in bleeding trauma patients: A systematic review and meta‐analysis

BACKGROUND: In traumatic bleeding, transfusion practice has shifted toward higher doses of platelets and plasma transfusion. The aim of this systematic review was to investigate whether a higher platelet‐to‐red blood cell (RBC) transfusion ratio improves mortality without worsening organ failure when compared with a lower ratio of platelet‐to‐RBC. METHODS: Pubmed, Medline, and Embase were screened for randomized controlled trials (RCTs) in bleeding trauma patients (age ≥16 years) receiving platelet transfusion between 1946 until October 2020. High platelet:RBC ratio was defined as being the highest ratio within an included study. Primary outcome was 24 hour mortality. Secondary outcomes were 30‐day mortality, thromboembolic events, organ failure, and correction of coagulopathy. RESULTS: In total five RCTs (n = 1757 patients) were included. A high platelet:RBC compared with a low platelet:RBC ratio significantly improved 24 hour mortality (odds ratio [OR] 0.69 [0.53–0.89]) and 30‐ day mortality (OR 0.78 [0.63–0.98]). There was no difference between platelet:RBC ratio groups in thromboembolic events and organ failure. Correction of coagulopathy was reported in five studies, in which platelet dose had no impact on trauma‐induced coagulopathy. CONCLUSIONS: In traumatic bleeding, a high platelet:RBC improves mortality as compared to low platelet:RBC ratio. The high platelet:RBC ratio does not influence thromboembolic or organ failure event rates.