Bedside Assessment of Coagulation Disorders in Post-Partum Hemorrhage by Thrombelastography: A Pilot Study

Nicolas LOUVET, M.D., Agnès Rigouzzo, M.D., Laure Girault, M.D., Federica Piana, M.D., Rémi Favier, M.D., Isabelle Constant, Ph.D.Hopital A. Trousseau, Paris, France

Introduction: Early identification and treatment of post-partum hemorrhages are major matters of concern to improve maternal outcome. A low fibrinogen concentration (< 2g/L) is an early indicator of hemorrhage severity. Point of care coagulation monitors have already been evaluated in traumatic and obstetric hemorrhages: they provide an early detection of coagulation disorders allowing adapted treatment which could lead to an improved prognosis. The aim of this study was to compare the Thrombelastography (TEG®, Haemonetics) parameters to standard coagulation tests during post-partum hemorrhage.

Methods: Prospective observational study, after IRC approval, including women developing a post-partum hemorrhage requiring iv sulprostone. Blood samples were collected at discretion of the anesthesiologist in charge. Each blood sample was simultaneously collected and analyzed by standard coagulation tests (PT, aPTT, fibrinogen concentration with Clauss method (FibC)) and by a TEG assay : Kaolin (K) and Functional Fibrinogen(FF). The recorded parameters for TEG were: the maximal amplitude (MA-K), the maximum rate of thrombus generation (MRTGG-K and MRTGG-FF) and functional fibrinogen level (FLEV). The aim of the study was to assess the relationship between FLEV and FibC using a Bland-Altman analysis. The secondary aim was to evaluate the performance of TEG parameters using ROC curves: 1/ MA-K or MRTGG-K for the diagnosis of a hypofibrinogenemia < 2g/L and/or a thrombocytopenia < 80.000/mm3; 2/ FLEV or MRTGG-FF for the diagnosis of a hypofibrinogenemia < 2g/L. The time to obtain the results was compared between MA-K and MRTGG-K and between FLEV and MRTGG-FF.

Results: 133 blood samples were collected in 95 women. FLEV was linearly correlated with FibC (R²=0.6; p<0.001). The bias between FLEV and FibC was -0.2 (CI95%: -0.4 - 0). The 95% limits of agreement were: -2.3 - 1.8. For the Kaolin assay, the AUC were not statistically different between MA-K and MRTGG-K (0.955 vs 0.973 p=0.1). The time to obtain results was shorter for MRTGG-K compared to MA-K (8±3 min vs 26±5 min, p<0.001). For the Functional fibrinogen assay, the AUC were not statistically different between FLEV and MRTGG-FF (0.948 vs 0.915 p=0.06) but the time to obtain results was shorter for MRTGG-FF compared to FLEV (3±3 min vs 13±6 min, p<0.001). Performances parameters of TEG assays are summarized in table 1 (estimations, CI95%; sensibility, specificity, positive predictive value, negative predictive value).

Conclusion: During post-partum hemorrhage, thrombelastography derived parameters (MRTGG-K and MRTGG-FF) provide an early and reliable detection of coagulation disorders: hypofibrinogenemia <2g/L and/or thrombocytopenia < 80.000/mm3. 

Figure 1 

http://www.glowm.com/resource_type/resource/textbook/title/a-comprehensive-textbook-of-postpartum-hemorrhage-2%3Csup%3End%3C-sup%3E-edition/resource_doc/1275