What is the protocol for transfusing blood in hemorrhagic shock?

Protocol for Transfusing Blood in Hemorrhagic Shock

RBC transfusion is indicated immediately for patients with evidence of hemorrhagic shock, and the decision to transfuse should be based on the patient's physiologic state, evidence of blood loss, and potential for ongoing hemorrhage—not on hemoglobin levels alone. 1

Initial Resuscitation Approach

Begin with isotonic crystalloid solutions and rapid hemorrhage control as the foundation of treatment. 1

• Administer 2 liters of crystalloid fluid resuscitation initially while simultaneously controlling the source of bleeding through direct pressure, tourniquets, or hemostatic dressings 1, 2
• Secure large-bore IV access (including central access if needed) and administer high FiO2 to ensure adequate oxygenation 2
• If hemorrhagic shock persists after 2 liters of crystalloid (following ATLS guidelines), proceed immediately to RBC transfusion 1
• Use warmed blood products, starting with O-negative blood if cross-matched blood is unavailable, to prevent hypothermia 2

Blood Product Transfusion Strategy

For massive hemorrhage, administer blood products in a 1:1:1 ratio of RBC:FFP:platelets. 2, 3

• Begin early FFP administration at 10-15 ml/kg to prevent dilutional coagulopathy 2
• Maintain platelet count ≥75 × 10⁹/L throughout resuscitation 2
• For established coagulopathy (fibrinogen <1 g/L or PT/aPTT >1.5× normal), administer >15 ml/kg of FFP 2
• Target fibrinogen levels >1 g/L using fibrinogen concentrate or cryoprecipitate 2

Hemoglobin Targets

Target a hemoglobin of 70-90 g/L (7-9 g/dL) during active resuscitation. 1, 4

• This restrictive threshold (70-80 g/L) shows no evidence of harm compared to liberal thresholds (90-100 g/L) in critically ill patients 1
• However, in actively bleeding patients, maintaining hemoglobin around 100 g/dL may be reasonable until hemorrhage is controlled, particularly in elderly patients or those at risk for myocardial infarction 5
• Critical caveat: Do not wait for hemoglobin measurements to initiate transfusion in obvious hemorrhagic shock—the decision must be based on clinical assessment of shock severity, ongoing blood loss, and hemodynamic instability 1, 2

Monitoring and Assessment

Use blood lactate and base deficit measurements as sensitive indicators of hypoperfusion and shock severity. 1

• Obtain baseline laboratory tests including FBC, PT, aPTT, Clauss fibrinogen, and cross-match 2
• Monitor continuously for signs of ongoing bleeding (visible blood loss, hemodynamic instability) 2
• Perform early imaging (ultrasound, CT) or proceed to surgery for definitive hemorrhage control 2
• Assess intravascular volume status, evidence of shock, duration and extent of anemia, and cardiopulmonary parameters—not just hemoglobin—when making transfusion decisions 1

Coagulopathy Management

Prevent and treat the lethal triad: hypothermia, acidosis, and coagulopathy. 3

• Maintain normothermia, pH >7.2, and normocalcemia throughout resuscitation 2, 4
• Administer tranexamic acid early if no contraindications exist 2
• Consider thromboelastography when available to guide blood product and hemostatic adjunct administration 3

Permissive Hypotension Strategy

Apply permissive hypotension (systolic BP 80-90 mmHg) until definitive hemorrhage control is achieved, unless contraindicated. 2, 4

• This strategy limits ongoing bleeding while maintaining minimal organ perfusion 4
• Exception: Avoid permissive hypotension in traumatic brain injury patients, where cerebral perfusion pressure must be maintained 1

Massive Transfusion Protocol Activation

Activate the massive transfusion protocol early when massive hemorrhage is anticipated—do not delay. 2

• Delaying activation increases mortality 2
• Waiting for laboratory results before administering blood products in obvious massive hemorrhage increases mortality 2

Post-Resuscitation Management

Once bleeding is controlled, normalize blood pressure, acid-base status, and temperature. 2

• Admit to critical care for ongoing monitoring 2
• Initiate venous thromboprophylaxis as soon as hemostasis is secured, as patients rapidly develop a prothrombotic state 2
• In trauma patients requiring damage control surgery, proceed before complete physiologic normalization if necessary 2

Common Pitfalls to Avoid

• Never use hemoglobin level as the sole "trigger" for transfusion—this approach fails to account for the dynamic nature of hemorrhagic shock and individual patient physiology 1
• Do not administer excessive crystalloid—this causes dilutional coagulopathy and worsens outcomes; transition to blood products early 1, 3
• Avoid hypothermia—use warmed fluids and blood products, as hypothermia exacerbates coagulopathy 2, 3