Massive Transfusion Protocol

MTP Basics - Code Red Start!

• Massive Transfusion (MT): Defined as:

  • 10 units PRBCs in 24h

  • 4 units PRBCs in 1h

  • Replacement of > 50% blood volume in 3h
  • Bleeding > 150 mL/min

• Triggers/Activation Criteria:

  • Clinical signs: Hemorrhagic shock (SBP < 90 mmHg, HR > 120 bpm)
  • Scoring systems: ABC Score (Assessment of Blood Consumption)
  • Specific injuries: Penetrating torso trauma, pelvic fractures, major vascular injury.

⭐ A common definition of MTP is the replacement of one entire blood volume in 24 hours, or the transfusion of >10 units of PRBCs in 24 hours.

Blood Buffet - The Perfect Mix

• MTP Goals: Restore volume, ↑ O₂ capacity, correct coagulopathy, prevent lethal triad (acidosis, hypothermia, coagulopathy).
• Blood Products & Typical Volumes/Contents:
  • PRBCs: ~250-350 mL; ↑ Hb by ~1 g/dL, ↑ O₂ capacity.
  • FFP: ~200-250 mL; all clotting factors, fibrinogen.
  • Platelets (apheresis unit): ~200-300 mL; ~3 x $10^{11}$ platelets.
  • Cryoprecipitate: ~10-20 mL/unit; concentrated fibrinogen (≥150mg), FVIII, FXIII, vWF.
• Target Ratio: 1:1:1 (PRBC:FFP:Platelets).
  • Rationale: Mimics whole blood, prevents dilutional coagulopathy, improves survival.

⭐ Early administration of FFP and platelets in a balanced ratio (typically 1:1:1) with PRBCs is crucial to prevent dilutional coagulopathy and improve outcomes in massively bleeding trauma patients.

MTP Mayhem - Dodging Dangers

📌 Lethal Triad: AHC (Acidosis, Hypothermia, Coagulopathy)

• Hypothermia (Target >35°C)
  • Cause: Cold blood.
  • Mgmt: Blood warmers, warming.
• Acidosis (Metabolic) (pH <7.35)
  • Cause: Stored blood, hypoperfusion.
  • Mgmt: Correct shock, judicious $HCO_3^{-}$.
• Hypocalcemia (Citrate Toxicity) (Ionized Ca <1.1 mmol/L)
  • Cause: Citrate in PRBCs chelates Ca.
  • Mgmt: 1g CaCl2 or 3g Ca gluconate / 4U PRBC.

  ⭐ Hypocalcemia due to citrate anticoagulation in blood products is a common and rapidly developing complication of MTP, requiring empirical or guided calcium replacement to prevent myocardial depression and coagulopathy.

• Hyperkalemia (K+ >5.5 mEq/L)
  • Cause: K+ from old PRBCs.
  • Mgmt: Monitor, fresh blood, temporize.
• Dilutional Coagulopathy
  • Cause: Factor/platelet dilution.
  • Mgmt: 1:1:1 ratio, TEG/ROTEM.
• TRALI (Transfusion-Related Acute Lung Injury)
  • Cause: Donor Abs vs. recipient WBCs.
  • Mgmt: Supportive ventilation.
• TACO (Transfusion-Associated Circulatory Overload)
  • Cause: Fluid overload.
  • Mgmt: Diuretics, slow rate, monitor.

Vital Vigilance - Tracking & Tweaking

• Lab Monitoring (Serial):
  • Hb, Hct, Platelet count.
  • Coagulation: PT/INR, aPTT, Fibrinogen (target >1.5-2.0 g/L).
  • ABG: pH, lactate, base deficit, K+, Ca++ (ionized).
• Viscoelastic Hemostatic Assays (VHA):
  • TEG/ROTEM: Guide goal-directed therapy, identify specific coagulopathy.
• Key Adjuncts & Targets:
  • Tranexamic Acid (TXA): 1g IV over 10 min within 3h injury, then 1g IV over 8h.
  • Calcium: Replace (esp. with citrate); monitor ionized Ca++.
  • Blood Warmers: Maintain normothermia (prevents worsening coagulopathy).
  • Permissive Hypotension: Target SBP 80-90 mmHg (if no TBI) until definitive hemorrhage control.

⭐ Tranexamic acid (TXA) administered within 3 hours of injury in bleeding trauma patients significantly reduces mortality from hemorrhage, primarily by inhibiting fibrinolysis.

High‑Yield Points - ⚡ Biggest Takeaways

• MTP triggered by anticipated need for >10 units PRBCs/24h or >4 units/1h.
• Aim for 1:1:1 ratio of PRBC:FFP:Platelets to mimic whole blood.
• Tranexamic acid (TXA) crucial; administer within 3 hours of injury.
• Monitor for and manage "Lethal Triad": hypothermia, acidosis, coagulopathy.
• Watch for complications: hypocalcemia (citrate toxicity), hyperkalemia, TRALI, TACO.
• Thromboelastography (TEG/ROTEM) guides component therapy.
• Part of Damage Control Resuscitation (DCR) strategy.