What is balanced transfusion?

Balanced Transfusion in Trauma and Critical Care

Balanced transfusion refers to the administration of blood components (red blood cells, plasma, and platelets) in fixed ratios that approximate their proportions in whole blood, typically in a 1:1:1 or 1:1:2 ratio, to prevent and treat coagulopathy in massively bleeding patients.

Definition and Rationale

Balanced transfusion strategies have evolved from the recognition that massive hemorrhage leads to consumption of coagulation factors and platelets, requiring replacement of these components alongside red blood cells to maintain hemostasis.

Key components of balanced transfusion include:

• Red Blood Cells (RBCs): Restore oxygen-carrying capacity
• Fresh Frozen Plasma (FFP): Provides coagulation factors
• Platelets: Essential for clot formation

Evidence-Based Transfusion Ratios

The optimal ratio for balanced transfusion has been established primarily in trauma settings:

• 1:1:1 ratio (RBC:plasma:platelets) is recommended in trauma patients with massive bleeding 1
• This approach has been shown to reduce death from exsanguination compared to lower ratios 1
• The PROPPR trial demonstrated better clinical hemostasis with 1:1:1 ratio compared to 1:1:2 1

While observational studies showed dramatic mortality benefits with balanced transfusion, randomized controlled trials show more modest but still important benefits, particularly in reducing early deaths from exsanguination 1.

Implementation in Clinical Practice

Trauma Patients

For trauma patients with massive bleeding:

1. Initiate balanced transfusion with a 1:1:1 ratio of RBC:plasma:platelets 1
2. Continue until hemorrhage control is achieved
3. Once bleeding is controlled, transition to targeted transfusion based on laboratory parameters

Non-Trauma Patients

For non-trauma patients with massive bleeding:

• Evidence is less robust than for trauma patients
• No specific recommendation can be made for or against fixed high-ratio transfusion 1
• Consider individual patient factors and cause of bleeding

Practical Considerations

Timing and Availability

• The average time between dispensing RBCs and plasma is approximately 26 minutes due to thawing requirements 2
• This delay can result in patients receiving multiple units of RBCs before plasma is available
• Some centers maintain thawed plasma inventory to address this issue 2

Monitoring During Transfusion

• Monitor vital signs at baseline, 15 minutes after starting each unit, and within 60 minutes of completion 3
• Pay particular attention to respiratory rate, as dyspnea and tachypnea are early symptoms of serious transfusion reactions
• Watch for signs of transfusion-associated circulatory overload (TACO), especially in high-risk patients 3

Transfusion Thresholds

When implementing balanced transfusion, consider appropriate hemoglobin thresholds:

• Hemodynamically stable patients: Transfuse at Hb ≤7 g/dL 1
• Patients with cardiovascular disease: Consider transfusion at Hb ≤8 g/dL 1
• Patients with acute coronary syndrome: Insufficient evidence to recommend liberal or restrictive strategy 1

Complications and Mitigation Strategies

Transfusion-Associated Circulatory Overload (TACO)

• High-risk patients include elderly, those with cardiac dysfunction, renal impairment 3
• For high-risk patients, consider slower transfusion rates (1 unit over 4+ hours) 3
• Standard rate for stable patients: 1-2 mL/kg/hour initially 3

Other Complications

• Febrile non-hemolytic transfusion reactions
• Allergic reactions
• Transfusion-related acute lung injury (TRALI)
• Infectious complications (now rare due to improved screening)

Special Considerations

Calcium Replacement

• Monitor ionized calcium levels during massive transfusion 1
• Administer calcium chloride to correct hypocalcemia 1
• Citrate in stored blood products can bind calcium and cause hypocalcemia

Platelet Transfusion Thresholds

• For patients undergoing invasive procedures: maintain platelet count >50 × 10^9/L 1
• For patients with CNS bleeding or severe trauma: consider higher platelet thresholds

Conclusion

Balanced transfusion with fixed ratios of blood components has become standard practice in managing massive hemorrhage, particularly in trauma. The evidence most strongly supports a 1:1:1 ratio of RBC:plasma:platelets for trauma patients with massive bleeding. Implementation requires institutional protocols to ensure rapid availability of blood components and careful monitoring for complications.