Does a balanced transfusion ratio of plasma to packed red blood cells improve outcomes in both trauma and surgical patients? A meta-analysis of randomized controlled trials and observational studies

Background: The effect of high transfusion ratios of fresh frozen plasma (FFP): packed red blood cell (RBC) on mortality is still controversial. Observational evidence contradicts a recent randomized controlled trial regarding mortality benefit. This is an updated meta-analysis, including a non-trauma cohort. Methods: Patients were grouped into high vs. low based on FFP:RBC ratio. Primary outcomes were 24-h and 30-day/in-hospital mortality. Secondary outcomes were acute respiratory distress syndrome and acute lung injury rates. Random model and leave-one-out-analyses were used. Results: In 36 studies, lower ratio showed poorer 24-h and 30-day survival (p < 0.001). In trauma and non-trauma settings, a lower ratio was associated with worse 24-h and 30-day mortality (P < 0.001). A ratio of 1:1.5 provided the largest 24-h and 30-day survival benefit (p < 0.001). The ratio was not associated with ARDS or ALI. Conclusions: High FFP:RBC ratio confers survival benefits in trauma and non-trauma settings, with the highest survival benefit at 1:1.5.