MASSIVE BLOOD TRANSFUSION 

1. DEFINITION

Classical Definitions

Massive transfusion is defined as any of the following:

Definition

Criteria

Classic

≥ 10 units PRBC in 24 hours

Half-massive

≥ 5 units PRBC in 4 hours

Critical bleeding (preferred)

≥ 3 units PRBC in 1 hour with ongoing bleeding

Blood volume–based

Replacement of one blood volume in 24 h or 50% blood volume in 3 h

Pediatric

≥ 40 mL/kg PRBC within 24 h

👉 Modern guidelines prefer “critical bleeding requiring MTP” rather than waiting for 10 units.


2. INDICATIONS FOR ACTIVATING MTP

Trauma

  • Penetrating trauma
  • Blunt trauma with hypotension
  • Pelvic fracture with shock
  • FAST positive with hypotension
  • Severe polytrauma

Non-trauma

  • Massive GI bleed
  • Post-partum hemorrhage
  • Ruptured AAA
  • Liver transplantation
  • Cardiac surgery catastrophe
  • Major vascular surgery
  • ECMO bleeding


3. PREDICTION SCORES FOR MASSIVE TRANSFUSION

A. ABC Score (Assessment of Blood Consumption)

Parameter

Score

Penetrating mechanism

1

SBP ≤ 90 mmHg

1

HR ≥ 120/min

1

FAST positive

1

Score ≥ 2 → Activate MTP


B. Shock Index

  • HR / SBP > 1
  • Associated with high transfusion requirement


C. Laboratory Predictors

  • INR > 1.5
  • Platelets < 100,000
  • Base deficit > 6
  • Lactate > 4 mmol/L


4. GOALS OF MASSIVE TRANSFUSION

  1. Restore oxygen-carrying capacity
  2. Correct coagulopathy
  3. Prevent dilutional thrombocytopenia
  4. Maintain normothermia
  5. Prevent metabolic complications
  6. Achieve rapid surgical hemostasis


5. COMPONENT THERAPY IN MBT

CORE PRINCIPLE: Balanced Transfusion

Recommended Ratio (Damage Control Resuscitation)

Component

Ratio

PRBC : Plasma : Platelets

1 : 1 : 1

Alternative acceptable

2 : 1 : 1

📌 Based on PROPPR trial – improved hemostasis and early survival.


6. COMPONENT DETAILS

A. Packed Red Blood Cells (PRBC)

  • Restores oxygen delivery
  • Hb target:
    • Trauma/active bleed: ≥ 7–9 g/dL
    • TBI, ischemic heart disease: ≥ 9–10 g/dL

Issues

  • No platelets or clotting factors
  • Citrate load
  • Potassium accumulation
  • Storage lesion → ↓ 2,3-DPG


B. Fresh Frozen Plasma (FFP)

Property

Value

Contains

All clotting factors

Dose

15–20 mL/kg

INR correction

Best if INR > 1.5

Used early, not as rescue.


C. Platelets

Parameter

Target

Platelet count

> 50,000/mm³

Neurotrauma

> 100,000/mm³
  • 1 adult apheresis platelet ≈ 6 pooled units
  • Dilutional thrombocytopenia develops early


D. Cryoprecipitate

Component

Content

Fibrinogen

Highest concentration

Also contains

Factor VIII, XIII, vWF

Indication

  • Fibrinogen < 150–200 mg/dL

Dose

  • 10 units → raises fibrinogen ~50 mg/dL

👉 Early fibrinogen replacement is critical


7. FIBRINOGEN – THE FIRST FACTOR TO FALL

Stage

Fibrinogen

Early hemorrhage

↓↓↓

Before INR prolongs

Yes

Replacement Options

  • Cryoprecipitate
  • Fibrinogen concentrate (where available)


8. ADJUNCTIVE THERAPIES

A. Tranexamic Acid (TXA)

CRASH-2 Trial

Parameter

Recommendation

Indication

Suspected major hemorrhage

Dose

1 g IV over 10 min → 1 g over 8 h

Time

Within 3 hours ONLY

After 3 h

Harmful


B. Calcium Replacement

Why hypocalcemia occurs

  • Citrate in blood binds calcium

Effects

  • ↓ Myocardial contractility
  • Hypotension
  • Coagulopathy

Targets

  • Ionized Ca > 1.1 mmol/L

Treatment

  • Calcium gluconate or calcium chloride


C. Warming

  • Hypothermia worsens coagulopathy
  • Use:
    • Blood warmers
    • Forced air warming
    • Warm IV fluids


9. LETHAL TRIAD OF TRAUMA

Component

Effect

Hypothermia

Platelet dysfunction

Acidosis

↓ Enzyme activity

Coagulopathy

Ongoing bleeding

👉 Massive transfusion aims to break this triad


10. DILUTIONAL & CONSUMPTIVE COAGULOPATHY

Mechanisms

  • Loss of clotting factors
  • Dilution from crystalloids
  • Platelet consumption
  • Hyperfibrinolysis


11. TRANSFUSION-RELATED COMPLICATIONS IN MBT

A. Metabolic

Complication

Cause

Hypocalcemia

Citrate

Hyperkalemia

Stored RBCs

Metabolic alkalosis

Citrate metabolism

Hypomagnesemia

Citrate


B. Hematologic

Complication

Explanation

Dilutional thrombocytopenia

Platelet loss

DIC

Ongoing shock

Coagulopathy

Factor depletion


C. Pulmonary

Condition

Mechanism

TRALI

Anti-HLA antibodies

TACO

Volume overload

ARDS

Inflammatory response


D. Immunologic & Infectious

  • Febrile reactions
  • Hemolytic reactions
  • Transfusion-transmitted infections (rare)


12. LABORATORY & VISCOELASTIC MONITORING

Standard Labs

  • Hb
  • Platelets
  • INR/PT
  • aPTT
  • Fibrinogen
  • ABG, lactate
  • Ionized calcium


Viscoelastic Tests (Preferred)

Test

Role

TEG / ROTEM

Goal-directed transfusion

Advantages

Rapid, functional clot assessment

Guides

  • Fibrinogen replacement
  • Platelets
  • Plasma
  • Antifibrinolytics


13. DAMAGE CONTROL RESUSCITATION (DCR)

Core Principles

  1. Permissive hypotension (SBP 80–90)
    ❌ Contraindicated in TBI
  2. Early MTP activation
  3. Minimal crystalloids
  4. Rapid hemorrhage control
  5. Early TXA
  6. Correction of hypothermia, acidosis


14. TERMINATION OF MTP

Criteria

  • Surgical hemostasis achieved
  • Hemodynamics stabilized
  • Lactate improving
  • Reduced transfusion need
  • Labs normalized


15. SPECIAL POPULATIONS

A. Traumatic Brain Injury

  • Avoid hypotension
  • Platelets > 100,000
  • Higher Hb targets


B. Obstetric Hemorrhage

  • Early fibrinogen replacement
  • TXA early
  • Uterine source control


C. Liver Disease

  • Baseline coagulopathy
  • Viscoelastic testing preferred



17. KEY EXAM PEARLS (VERY HIGH-YIELD)

  • Fibrinogen is first factor to fall
  • 1:1:1 transfusion improves early hemostasis
  • TXA only within 3 hours
  • Hypocalcemia is common and lethal
  • Avoid crystalloids
  • Use TEG/ROTEM if available
  • Stop MTP as soon as bleeding controlled