Blood Transfusion for Severe Hemorrhage: Indications and Rationale

In massive hemorrhage, blood transfusion is lifesaving. It addresses the lethal triad: hypovolemia, coagulopathy, and tissue hypoxia.

Critical Indications

1. Volume restoration: Replaces lost intravascular volume → maintains preload, cardiac output, blood pressure.
2. Oxygen delivery: Packed red blood cells (PRBCs) carry O₂; target Hb >7–8 g/dL (higher if cardiac disease).
3. Coagulation support: Fresh frozen plasma (FFP) replaces clotting factors; platelets for thrombocytopenia; cryoprecipitate for fibrinogen. Goal: INR <1.5, fibrinogen >1.5 g/L, platelets >50–100k.
4. Acidosis correction: Stored blood has citrate (metabolized to bicarbonate) and improves perfusion/lactate clearance.
5. Electrolyte/protein replacement: Plasma provides albumin, electrolytes.

Massive Transfusion Protocol (MTP)

• Fixed-ratio transfusion (e.g., 1:1:1 PRBC:FFP:Platelets) or goal-directed (TEG/ROTEM).
• Early activation reduces mortality.
• Calcium replacement (citrate chelates Ca²⁺).
• Tranexamic acid (TXA) within 3 hours of trauma (CRASH-2 trial).

Risks

• Transfusion reactions (fever, allergy, TRALI, TACO, hemolysis).
• Infection (extremely rare with screening).
• Immunomodulation (possible increased infection/recurrence).
• Volume overload.

Decision Making

Based on clinical assessment (vitals, lactate, base deficit), lab values (Hb, coagulation), and response to initial resuscitation. Balanced resuscitation with crystalloids, blood products, and surgical/endovascular bleeding control is standard.