PURPOSE:

• Thromboelastography (TEG) can determine whether a patient has impaired coagulation  
• A thin wire is placed in a blood sample and clot formation rate, strength, stability, retraction and lysis can be measured using computational modeling
• Point-of-care TEG analyzers are available that can readily measure clot changes in strength and elasticity and are used by anesthesiology and surgery services when coagulation status is urgently required
• Rigouzzo et al. (Anesthesia & Analgesia, 2020) assessed the accuracy of TEG vs standard coagulopathy lab testing during postpartum hemorrhage

METHODS:

• Retrospective observational cohort study
• Participants
  • Women with PPH >500 mL who were bleeding sufficiently to require coagulation assessment
• Coagulopathy definition (‘Gold Standard’)
  • Hypofibrinogenemia ≤2 g/L
  • Thrombocytopenia ≤80,000/mm3
  • Prothrombin ratio (PR) ≤50% or aPTT ratio ≥1.5)
• TEG parameters
  • Kaolin assays: Kaolin-maximum amplitude (K-MA) | Kaolin-maximum rate of thrombus generation using G (K-MRTGG)
  • Functional fibrinogen assays: Functional fibrinogen -maximum amplitude (FF-MA) | Functional fibrinogen-maximum rate of thrombus generation using G (FF-MRTGG)
• Primary outcome
  • To Compare predictive accuracy of TEG parameters vs standard lab parameters
• Secondary outcomes
  • To compare the time delay between TEG amplitude parameters vs velocity curve-derived parameters
  • To evaluate the accuracy of TEG parameters to predict severe hemorrhage based on blood loss

RESULTS:

• 98 patients were included
  • All parameters had excellent predictive performance
• Kaolin assay
  • No significant difference between the amplitude assay (K-MA) vs velocity assay for prediction of hypofibrinogenemia and/or thrombocytopenia (AUC, 0.970 vs 0.981)
• Functional fibrinogen assay
  • No significant difference between amplitude assay (FF-MA) vs velocity assay (FF-MRTGG) for the prediction of hypofibrinogenemia (AUC, 0.988 vs 0.974)
• Time to obtain results were shorter with the velocity vs the amplitude assays
  • K-MRTGG: 7.7 minutes vs K-MA: 24.7 minutes (P < .001)
  • FF-MRTGG: 2.7 minutes versus FF-MA: 14.0 minutes (P < .001)
• PPH prediction: TEG parameters were significantly predictive for severe PPH >2500 mL, transfusion of >4 RBC units, and transfusion of FFP
• TEG did not perform as well for the prediction of PR / aPTT (AUC 0.651)

CONCLUSION:

• TEG can reliably detect hypofibrinogenemia and/or thrombocytopenia during PPH
• Using velocity-based parameters, results can be obtained in minutes, vs lab testing which may require transport, analysis and reporting back to the OR
• The authors state

…when coagulation assessment is indicated, TEG parameters rapidly predict hypofibrinogenemia and/or thrombocytopenia during PPH

This approach may help physicians achieve rapid diagnosis and treatment of clotting disorders during evolving PPH 

Learn More – Primary Sources:

Assessment of Coagulation by Thromboelastography During Ongoing Postpartum Hemorrhage: A Retrospective Cohort Analysis

Related ObG Topics:

Postpartum Hemorrhage – Medications to Treat Uterine Atony 

Postpartum Hemorrhage Prophylaxis – Is IM or IV Route Better?

What are the Possible Causes of a PPH that is Unresponsive to First Line Uterotonics?

Latest Cochrane Review: What is the Most Effective Prophylactic Treatment for Postpartum Hemorrhage?