What is a massive transfusion protocol in cases of severe bleeding?

Massive Transfusion Protocol: Definition and Implementation

A massive transfusion protocol (MTP) is a standardized, pre-established institutional algorithm that enables rapid delivery of blood products in fixed ratios—specifically 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

Core Definition and Activation Criteria

Every hospital must have an MTP in place that includes clinical, laboratory, and logistic responses. 2, 1 The protocol is typically activated when 1-1.5 blood volumes may need to be infused acutely or within a 24-hour period, though the traditional definition involves transfusion of ≥10 units of packed red blood cells within 24 hours. 1 Critically, the nature of the injury alerts clinicians to probable massive hemorrhage before formal thresholds are met—do not wait for laboratory confirmation or formal criteria to activate the protocol. 1, 3

Immediate Critical Actions Upon Activation

Control obvious bleeding immediately through direct pressure, tourniquets for extremity hemorrhage, or hemostatic dressings—this is the paramount priority. 2, 3, 4 Simultaneously:

• Secure large-bore IV access with two large-bore peripheral cannulae, considering 8-Fr central access in adults or intraosseous access if peripheral fails. 3
• Administer high FiO₂ to ensure adequate oxygenation during hemorrhagic shock. 3, 4
• Obtain baseline laboratory samples immediately: FBC, PT, aPTT, Clauss fibrinogen, blood bank sample, biochemical profile, and blood gases. 3, 4

Blood Product Resuscitation Strategy

The cornerstone of modern MTPs is balanced transfusion using a 1:1:1 ratio of RBC:FFP:platelets, based on military experience and the PROPPR trial showing improved survival and hemostasis. 1, 3 This recommendation is strongest for trauma patients with massive bleeding, though the European Society of Intensive Care Medicine notes no recommendation can be made for or against fixed high-ratio transfusion outside trauma settings due to potential differences in pathophysiology. 2, 3

Blood Product Administration Sequence

• Start with O-negative blood only if blood is needed immediately, limiting to 2 units maximum, then transition to group-specific blood without antibody screening. 3 For male patients, O RhD positive red cells are acceptable to preserve O-negative stock. 3
• Begin early FFP administration at 10-15 ml/kg to prevent dilutional coagulopathy before it develops. 2, 1, 4
• Maintain platelet count ≥75 × 10⁹/L throughout resuscitation, as thrombocytopenia below 50 × 10⁹/L is strongly associated with hemostatic compromise and microvascular bleeding. 2, 1, 3
• Use warmed blood products via a blood component administration set incorporating a 170-200 μm filter, with adequate warming devices available in all emergency rooms and theatre suites. 3

Coagulopathy Management Targets

Target fibrinogen levels >1 g/L, as levels below this threshold represent established hemostatic failure and predict microvascular bleeding. 2, 1, 3, 4 The most effective rapid fibrinogen replacement is achieved with fibrinogen concentrate at 30-60 mg/kg (requires no thawing) or cryoprecipitate if concentrate is unavailable. 1, 3

Keep PT and aPTT <1.5 times normal, as values exceeding this indicate established coagulopathy requiring aggressive correction. 2, 3 For established coagulopathy, more than 15 ml/kg of FFP is required to correct. 2, 4

Organizational Structure and Team Roles

The MTP requires designated team roles: 1

• Team leader (usually the most senior physician) who declares the massive hemorrhage situation and coordinates management 1
• Communications lead to facilitate rapid information exchange 1
• Dedicated personnel for IV access and blood product administration 1

Laboratory Monitoring During Resuscitation

Repeat coagulation studies every 4 hours or after 1/3 blood volume replacement, as coagulopathy can develop rapidly in massive hemorrhage. 3 Continuously monitor hemoglobin, blood gases, and wound drains. 3

Definitive Hemorrhage Control

Pursue early surgical or obstetric intervention to arrest bleeding at the source, as damage control surgery may be necessary to control bleeding before complete physiologic normalization. 3, 4 The use of cell salvage is encouraged in all cases of massive hemorrhage to reduce need for donor blood. 3

Post-Resuscitation Management

Once bleeding is controlled, aggressively normalize blood pressure, acid-base status, and temperature, then admit to critical care for ongoing monitoring. 1, 3, 4

Initiate standard venous thromboprophylaxis as soon as hemostasis is secured, as patients rapidly develop a prothrombotic state following massive hemorrhage. 2, 1, 3, 4 This is critical—the prothrombotic shift occurs quickly after hemorrhage control.

Critical Pitfalls to Avoid

• Delaying activation of the MTP increases mortality—activate early when massive hemorrhage is anticipated, not after formal criteria are met. 4
• Waiting for laboratory results before administering blood products in obvious massive hemorrhage increases mortality. 4
• Avoid overdependence on group O RhD negative red cells, as this may adversely impact local and national blood stock management. 3
• Monitor for and correct electrolyte abnormalities, particularly hypocalcemia from citrate toxicity, to prevent cardiac dysfunction. 4

Special Population Considerations

Anticipate consumptive coagulopathy in obstetric hemorrhage, cardiopulmonary bypass, massive trauma with head injury, and sepsis, with hyperfibrinolysis particularly associated with obstetric hemorrhage, CPB, and liver surgery. 3 In obstetric practice specifically, actual usage of blood components often differs from standardized protocols—when rapid laboratory evaluation is available, careful modification of the initial fixed transfusion ratio based on etiology and individual patient response may be appropriate. 5

For pediatric patients, apply the same principles: minimize and stop blood loss, minimize donor exposure, and use pediatric components where readily available. 3

Evidence Quality and Ongoing Research

The 2021 European Society of Intensive Care Medicine guidelines note widespread practice of incorporating high-ratio transfusion into hospital massive transfusion protocols, though there is an urgent need for high-quality evidence to guide clinicians, particularly in non-trauma populations. 2 Multiple ongoing trials are evaluating whole blood, prothrombin complex concentrate, fibrinogen replacement strategies, and thromboelastography-guided transfusion. 2