What is a massive transfusion protocol (MTP)?

What is a Massive Transfusion Protocol?

A massive transfusion protocol (MTP) is a standardized, pre-established institutional algorithm that enables rapid delivery of blood products in fixed ratios (typically 1:1:1 of red blood cells:fresh frozen plasma:platelets) to patients experiencing life-threatening hemorrhage, activated immediately when massive bleeding is anticipated or confirmed. 1, 2

Core Definition and Activation

Hospitals must have an MTP in place that includes clinical, laboratory, and logistic responses. 1 The protocol is typically activated when:

• 1-1.5 blood volumes may need to be infused acutely or within a 24-hour period 1
• The traditional definition involves transfusion of ≥10 units of packed red blood cells within 24 hours, though this occurs in less than 2% of civilian trauma patients 1, 3
• The nature of injury alerts clinicians to probable massive hemorrhage before formal thresholds are met 1

A critical pitfall: Delaying MTP activation increases mortality—activate immediately when massive hemorrhage is declared or anticipated, rather than waiting for laboratory confirmation. 2, 4

Organizational Structure

The MTP requires designated team roles: 1

• Team leader (usually the most senior physician) who declares the massive hemorrhage situation and coordinates management
• Communications lead whose sole role is liaising with laboratories and other departments
• Dedicated personnel to transport blood samples and products between laboratory and clinical areas
• IV access specialist to secure large-bore (8-Fr central) or intraosseous access

Blood Product Delivery Strategy

The cornerstone of modern MTPs is early administration of blood products in balanced ratios, specifically 1:1:1 of RBC:FFP:platelets, based on military experience showing improved survival. 1, 2, 5

Key transfusion principles:

• Begin early FFP administration at 10-15 ml/kg to prevent dilutional coagulopathy before it develops 1, 2, 4
• Maintain platelet count ≥75 × 10⁹/L throughout resuscitation 2, 4
• Use warmed blood products—start with O-negative blood if needed immediately, then transition to group-specific or cross-matched blood 2, 4
• For established coagulopathy (fibrinogen <1 g/L or PT/APTT >1.5× normal), administer >15 ml/kg of FFP 2, 4

The evidence base evolved significantly: Seven retrospective studies showed better outcomes with high FFP:RBC ratios (approaching 1:1), with casualties receiving 1:4 ratios having three-fold higher mortality than those receiving 2:3 ratios. 1 This military data, though retrospective and involving young males with penetrating injuries, fundamentally changed civilian practice. 1

Critical Protocol Components

MTPs must address both clinical management and logistics to deliver blood products rapidly to the patient while organizing definitive hemorrhage control (surgical or radiological). 1

Essential elements include:

• Immediate control of obvious bleeding through direct pressure, tourniquets, or hemostatic dressings 2, 4
• High FiO₂ administration and securing large-bore IV access 2, 4
• Baseline laboratory tests (FBC, PT, aPTT, Clauss fibrinogen, cross-match) 2, 4
• Active warming of patient and all transfused fluids to prevent hypothermia 2, 4
• Consideration of cell salvage autotransfusion when appropriate 2, 4

Coagulopathy Management

Target fibrinogen levels >1 g/L using fibrinogen concentrate or cryoprecipitate, as fibrinogen <1 g/L represents established hemostatic failure and predicts microvascular bleeding. 2, 4

The most effective rapid fibrinogen replacement is achieved with fibrinogen concentrate or cryoprecipitate. 2, 4

Common Pitfalls

Several critical errors undermine MTP effectiveness:

• Do not wait for laboratory results before administering blood products in obvious massive hemorrhage—this increases mortality 2, 4
• Do not administer excessive crystalloid, as this causes dilutional coagulopathy and worsens outcomes; transition to blood products early 4, 6
• Do not use hemoglobin level as the sole trigger for transfusion, as this fails to account for the dynamic nature of hemorrhagic shock 4, 6

Post-Resuscitation Care

Once bleeding is controlled, aggressively normalize blood pressure, acid-base status, and temperature, then admit to critical care for ongoing monitoring. 2, 4

Initiate standard venous thromboprophylaxis as soon as hemostasis is secured, as patients rapidly develop a prothrombotic state following massive hemorrhage. 1, 2, 4

Effectiveness and Outcomes

MTPs are effective in decreasing mortality, with better outcomes when blood products are readily available in the trauma bay upon patient arrival. 5 However, massive transfusion carries significant mortality (approximately 15% for trauma patients, up to 40-53% overall), which increases with the number of products transfused. 7, 8, 3

The strongest predictors of mortality include the number of PRBC transfusions at 4 and 24 hours, age, mechanism of injury, and initial Glasgow Coma Scale. 3