Optimal Ratio of Components for Massive Transfusion in Trauma Patients

Rationale for High-Ratio Transfusion

The American College of Emergency Physicians recommends using a fresh frozen plasma (FFP):platelet:packed red blood cells (PRBC) ratio from 1:1:1 to 1:1:1.5 to reduce 24-hour mortality without increasing morbidity 1
High-ratio transfusion strategies (at least one unit plasma per two units of packed red blood cells) are recommended for critically ill patients with massive bleeding due to trauma 2
Higher transfusion ratios may result in better clinical hemostasis, reducing probability of death by exsanguination (RR 0.7, 95% CI 0.51–0.96) 2
Observational trauma evidence suggests high transfusion ratios ranging from 1:1 to 1:2 FFP:RBC result in mortality benefit both early on and at 30 days 3

If a fixed high-ratio transfusion approach is used, the 1:1:1 ratio is the most reasonable approach to initiate empiric transfusion when massive hemorrhage is suspected 4

For non-traumatic massive bleeding, there is insufficient evidence to make a firm recommendation regarding fixed high-ratio transfusion strategies 2
In obstetric hemorrhage, such as placenta accreta spectrum, data from other surgical disciplines support the use of a 1:1:1 to 1:2:4 strategy of packed red blood cells:fresh frozen plasma:platelets 5
The European Society of Intensive Care Medicine makes no recommendation regarding the use of fixed high-ratio transfusion strategies in critically ill patients with non-traumatic massive bleeding due to very low certainty evidence 2

Increased FFP and platelet ratios may create new needs and stress on the existing limited blood product supply 1
The evidence for optimal ratios is stronger for trauma patients than for non-trauma patients 2, 4
Time bias may affect interpretation of observational studies, as patients who die early may not have time to receive plasma products 6
While high-ratio transfusion is beneficial, there is a point of diminishing returns - a prospective cohort study observed maximal hemostatic effect with a plasma:RBC ratio ranging between 1:2 and 3:4, with higher ratios sometimes causing deterioration in hemostatic function 6