What is the recommended approach to blood product administration in a patient with significant bleeding or at high risk of bleeding, as guided by thrombelastograph (TEG) readings and laboratory values such as prothrombin time (PT) and partial thromboplastin time (PTT)?

TEG-Guided Blood Product Administration in Massive Hemorrhage

In patients with significant bleeding or high bleeding risk, use thromboelastography (TEG) or rotational thromboelastometry (ROTEM) to guide targeted blood product administration rather than relying solely on conventional coagulation tests (PT/PTT), as this approach reduces unnecessary transfusions while maintaining or improving hemostatic outcomes. 1, 2

Initial Assessment and Blood Product Strategy

Immediate Resuscitation Protocol

• Initiate massive transfusion protocol with 1:1:1 ratio of packed red blood cells (RBCs), fresh frozen plasma (FFP), and platelets as the starting point in massive hemorrhage 1
• Do not delay blood product administration while awaiting laboratory results in the setting of massive hemorrhage 1
• After initial resuscitation, modify the 1:1:1 ratio based on TEG/ROTEM parameters and laboratory values 1

TEG/ROTEM-Guided Transfusion Thresholds

Fresh Frozen Plasma (FFP):

• Administer FFP when TEG reaction time (r) is >40 minutes 3
• Alternative indication: PT or aPTT >1.5 times control 1
• Recommended dose: 10-15 mL/kg initially, with additional doses as needed 1

Platelet Transfusion:

• Administer platelets when TEG maximum amplitude (MA) is <30 mm 3
• Alternative thresholds based on clinical scenario:
  • Maintain platelet count >50 × 10⁹/L for general massive bleeding 1
  • Maintain platelet count >100 × 10⁹/L for traumatic brain injury or severe multiple trauma 1
• Initial dose: 4-8 platelet concentrates or one apheresis pack 1

Cryoprecipitate:

• Administer when hyperfibrinolysis is identified on TEG/ROTEM 1
• Consider antifibrinolytics (tranexamic acid or epsilon aminocaproic acid) when TEG demonstrates hyperfibrinolysis 1

Advantages of TEG/ROTEM Over Conventional Testing

Clinical Evidence Supporting TEG/ROTEM Use

• TEG-guided transfusion reduces blood product utilization by 83% compared to standard care (16.7% vs 100% transfusion rate) without increasing bleeding complications 3
• TEG/ROTEM-guided therapy reduces mortality in trauma patients, decreases need for additional hemostatic interventions in surgical patients, and reduces overall blood product use across all populations 2, 4
• In emergency settings, TEG guidance reduces mortality (p=0.049), decreases platelet and plasma transfusion requirements, and increases ventilator-free days 4

Limitations of Conventional Coagulation Tests

• PT/INR and aPTT do not correlate with or predict bleeding risk in many clinical scenarios 1
• These tests are time-consuming and may not reflect the global hemostatic picture 1, 3
• TEG provides real-time, comprehensive assessment of the entire coagulation process including clot formation, strength, and fibrinolysis 1, 3

Specific TEG Parameters and Interpretation

Key TEG Values:

• Reaction time (r): Reflects clotting factor activity; prolonged r-time (>40 min) indicates need for FFP 3
• Maximum amplitude (MA): Reflects platelet function and fibrinogen; MA <30 mm indicates need for platelets 3
• Alpha angle: Reflects fibrinogen function and clot formation rate 1
• Lysis parameters: Identify hyperfibrinolysis requiring antifibrinolytic therapy 1

Critical Caveats and Pitfalls

When TEG/ROTEM May Not Be Sufficient

• In patients with traumatic brain injury requiring emergency neurosurgery, maintain higher platelet thresholds (>100 × 10⁹/L) and PT/aPTT <1.5 times control regardless of TEG values 1
• For ICP probe insertion, optimize coagulation parameters beyond standard TEG thresholds 1

Complementary Laboratory Monitoring

• Continue monitoring conventional coagulation tests (PT, aPTT, platelet count, fibrinogen) alongside TEG/ROTEM 1
• TEG parameters do not directly correlate with achieving hemostasis in all clinical contexts; use clinical assessment of bleeding as the primary endpoint 1

Blood Product Quality Considerations

• Whole blood leukoreduced with platelet-sparing filters maintains superior hemostatic properties on TEG compared to non-platelet-sparing filters (mean MA 54.9 mm vs 13.9 mm, p<0.001) 5
• Cold-stored whole blood with platelet-sparing filtration yields essentially normal TEG tracings over 14-day storage 5

Implementation Algorithm

1. Activate massive transfusion protocol with 1:1:1 ratio (RBC:FFP:PLT) immediately 1
2. Obtain baseline TEG/ROTEM and conventional coagulation tests (PT, aPTT, fibrinogen, platelet count) 1
3. Transition to TEG-guided therapy after initial resuscitation:
   • FFP if r-time >40 min or PT/aPTT >1.5× control 1, 3
   • Platelets if MA <30 mm or platelet count <50 × 10⁹/L (or <100 × 10⁹/L for TBI) 1, 3
   • Cryoprecipitate/antifibrinolytics if hyperfibrinolysis detected 1
4. Reassess TEG/ROTEM every 30-60 minutes during ongoing hemorrhage 1
5. Achieve surgical/interventional hemorrhage control as definitive therapy; blood products are temporizing measures 1