What is Massive Transfusion Protocol (MTP)
A massive transfusion protocol is a standardized, pre-defined system for rapidly delivering blood products in fixed ratios to patients with life-threatening hemorrhage, typically activated when a patient requires ≥10 units of packed red blood cells within 24 hours or ≥4 units within 1 hour. 1, 2
Core Definition and Activation Criteria
MTP should be activated based on anticipated need rather than retrospective volume, using clinical parameters including systolic blood pressure <100 mmHg, lactate ≥5 mmol/L, base excess ≤-6, or hemoglobin ≤9 g/dL. 1 The traditional definition of massive transfusion is >10 units of PRBCs in 24 hours, though the more acute definition of ≥4 units in 1 hour better identifies patients at highest mortality risk. 1, 2
Hemodynamic instability triggering MTP activation includes: 3
- Admission systolic blood pressure <90 mmHg with evidence of skin vasoconstriction (cool, clammy skin, decreased capillary refill)
- Altered level of consciousness and/or shortness of breath
- Heart rate >120 bpm
- Requirement for bolus infusions/transfusions and/or vasopressor drugs
- Base excess >-5 mmol/L and/or shock index >1
- Transfusion requirement of at least 4-6 units of PRBCs within first 24 hours
Blood Product Ratios and Components
Current MTPs should utilize balanced transfusion ratios between 1:1:1 and 1:1:2 of plasma:platelets:red blood cells. 2 This high-ratio transfusion strategy (at least 1:2 FFP:PRBC) is supported for trauma patients with massive bleeding. 1
Standard MTP delivery includes: 3
- First and second packs: 3 PRBCs, 3 plasma units, 1 platelet unit (or whole blood alternatives being studied)
- Subsequent rounds: Continue balanced ratio delivery
- Early platelet transfusion within 4 hours is associated with lower rates of multiorgan failure and 30-day mortality 1
Obstetric-Specific Considerations
Hospitals with obstetric-specific MTPs (50% of surveyed institutions) include at least one pool of cryoprecipitate or fibrinogen concentrate in the first MTP round, compared to only 14% of general MTPs. 4 This reflects the importance of fibrinogen replacement in postpartum hemorrhage.
Implementation Requirements
Successful MTP implementation requires multispecialty coordination involving Trauma, Critical Care, Anesthesiology, Transfusion Medicine, and Emergency Medicine departments. 5 The protocol must delineate: 6
- How blood products are ordered, prepared, and delivered
- Laboratory algorithms to guide transfusion
- Communication pathways between personnel
- Duties and responsibilities of each team member
Critical Timing Elements
Blood products must be immediately available in the trauma bay when the patient arrives—the shorter the time to blood product delivery, the better the outcomes. 2 Each transfusion unit must be completed within 4 hours of removal from temperature-controlled storage to prevent bacterial proliferation and hemolysis. 7
Clinical Applications Beyond Trauma
The majority of MTP activations (58% in adults, 65% in pediatrics) are for non-trauma indications, including postpartum hemorrhage, surgical bleeding, and gastrointestinal hemorrhage. 4 Most hospitals (74%) utilize a single MTP for all adult bleeding emergencies, though 20 hospitals in one survey provided obstetric-specific protocols. 4
Adjunctive Therapies
Tranexamic acid decreases mortality in trauma patients requiring massive transfusion and should be administered early in resuscitation. 6 Ongoing trials are evaluating: 3
- Prothrombin complex concentrate (PCC) as alternative to FFP
- Fibrinogen concentrate for early coagulopathy correction
- Thromboelastography-guided transfusion strategies
- Whole blood for initial resuscitation packs
Monitoring and Correction
Throughout resuscitation, metabolic and coagulation abnormalities must be continuously corrected, including: 6
- Hypothermia prevention/correction
- Acidosis reversal
- Hypocalcemia correction
- Coagulopathy management guided by laboratory testing
The application of massive transfusion protocols is of paramount importance in managing trauma-induced coagulopathy, which is frequently associated with aggressive resuscitation and activation/deactivation of multiple procoagulant and anticoagulant factors. 3
Quality Improvement
A robust performance improvement process is essential to monitor MTP implementation, identify problems in real-time, and deliver feedback to optimize the protocol. 5 This ongoing evaluation helps improve clinical outcomes and decrease overall blood utilization with minimal wastage of blood products. 5