What is the optimal ratio of red blood cells (RBCs) to fresh frozen plasma (FFP) to platelets for massive transfusion to minimize complications?

Optimal Ratio of Components for Massive Transfusion

For trauma patients requiring massive transfusion, a ratio of 1:1:1 to 1:1:2 (plasma:platelets:RBCs) should be used to minimize complications and reduce mortality. 1

Rationale for High-Ratio Transfusion in Trauma

• 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 1
• 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
• Higher transfusion ratios may result in better clinical hemostasis, reducing probability of death by exsanguination (RR 0.7,95% CI 0.51–0.96) 1
• 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 1

Benefits of High-Ratio Transfusion

• Improved survival rates, particularly within the first 6 hours after admission, suggesting that early administration of FFP and platelets is critical 2
• Decreased overall PRBC transfusion requirements 2
• Reduced probability of death from exsanguination 1
• Better clinical hemostasis in severely bleeding patients 1
• Decreased truncal hemorrhage and increased ICU, ventilator, and hospital-free days 3

Evidence from Clinical Studies

• The PROPPR randomized controlled trial confirmed the benefits of a balanced transfusion ratio 4
• A large multicenter study showed that higher 6-hour ratios of FFP:PRBCs and PLTs:PRBCs led to improved 6-hour mortality (from 37.3% to 15.7% to 2.0% in the highest ratio group) and improved in-hospital mortality 2
• A study of 466 massively transfused civilian trauma patients found that 30-day survival was increased in patients with high plasma:RBC ratio (≥1:2) relative to those with low plasma:RBC ratio (<1:2) (59.6% vs. 40.4%) 3
• Recent evidence suggests that even patients requiring submassive transfusion (>3 units but <10 units of PRBCs) benefit from combined resuscitation with plasma and platelets 5

Implementation Considerations

• 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 1
• Statistical modeling indicates that a clinical guideline with mean plasma:RBC ratio equal to 1:1 would encompass 98% of patients within the optimal 1:2 ratio 3
• Massive transfusion protocols (MTPs) should be in place at hospitals to ensure rapid delivery of blood products in appropriate ratios 4
• The faster the replacement of blood products, the better the outcomes 4

Special Considerations for Non-Trauma Patients

• For non-traumatic massive bleeding, there is insufficient evidence to make a firm recommendation regarding fixed high-ratio transfusion strategies 1
• 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 1
• 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 1

Potential Pitfalls and Caveats

• 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 1
• Time bias may affect interpretation of observational studies, as patients who die early may not have time to receive plasma products 1
• Individual patient factors and institutional capabilities should be considered when implementing massive transfusion protocols 4
• 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 1