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

Abstract

BACKGROUND: Rapid assessment of hemostasis during postpartum hemorrhage (PPH) is essential to allow characterization of coagulopathy, to estimate bleeding severity, and to improve outcome. Point of care (POC) coagulation monitors could be of great interest for early diagnosis and treatment of coagulation disorders in PPH. METHODS: Women with ongoing PPH >500 mL who clinically required an assessment of coagulation with thromboelastography (TEG) were included. The primary aim of this retrospective observational cohort study was to assess the predictive accuracy of TEG parameters for the diagnosis of coagulation disorders (hypofibrinogenemia ≤2 g/L, thrombocytopenia ≤80,000/mm3, prothrombin ratio ≤50%, or activated partial thromboplastin time ratio ≥1.5) during PPH. The analyzed TEG parameters were Kaolin-maximum amplitude (K-MA), Kaolin-maximum rate of thrombus generation using G (K-MRTGG), functional fibrinogen-maximum amplitude (FF-MA), and functional fibrinogen-maximum rate of thrombus generation using G (FF-MRTGG). Secondary aims of this study were (1) comparison of the time delay between classical parameters and velocity curve–derived parameters (K-MA versus K-MRTGG and FF-MA versus FF-MRTGG) and (2) evaluation of the accuracy of TEG parameters to predict severe hemorrhage estimated by calculated blood losses. RESULTS: Ninety-eight patients were included with 98 simultaneous TEG analyses and laboratory assays. All parameters had an excellent predictive performance. For the Kaolin assay, no significant difference was evidenced between K-MA and K-MRTGG for the predictive performance for hypofibrinogenemia ≤2 g/L and/or thrombocytopenia ≤80,000/mm3 (respective area under the curve [AUC], 0.970 vs 0.981). For the functional fibrinogen assay, no significant difference was evidenced between FF-MA and FF-MRTGG for the predictive performance for hypofibrinogenemia ≤2 g/L (respective AUC, 0.988 vs 0.974). For both assays, the time to obtain results was shorter for the velocity parameters (K-MRTGG: 7.7 minutes [2.4 minutes] versus K-MA: 24.7 minutes [4.2 minutes], P < .001; FF-MRTGG: 2.7 minutes [2.7 minutes] versus FF-MA: 14.0 minutes [4.3 minutes], P < .001). All TEG parameters derived from the Kaolin and functional fibrinogen assays and Clauss fibrinogen were significantly predictive of severe PPH >2500 mL. CONCLUSIONS: During PPH, when coagulation assessment is indicated, TEG provides a rapid and reliable detection of hypofibrinogenemia ≤2 g/L and/or thrombocytopenia ≤80,000/mm3. No difference in performance was evidenced between the velocity-derived parameters (K-MRTGG and FF-MRTGG) and the classical parameters (K-MA and FF-MA). However, velocity-derived parameters offer the advantage of a shorter time to obtain results: FF-MRTGG parameter is available within ≤5 minutes. POC assessment of hemostasis during PPH management may help physicians to diagnose clotting disorders and to provide appropriate hemostatic support.

Viscoelastic Hemostatic Assays for Postpartum Hemorrhage

“…The use of TEG and ROTEM in the identification of hypocoagulopathy and guiding BCT/HAT in PPH is rising in popularity. Only recently have TEG and ROTEM been increasingly studied within the context of PPH [2,3,21,25,[52][53][54][55]58,59,[74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92]. BCT/HAT can be tailored to this patient population's specific needs using TEG or ROTEM parameters.…”

“…Physiologic postpartum hemostasis of placental blood flow depends greatly upon adequate myometrial contraction and mechanical compression of the spiral arteries. Uterine atony is the failure of this physiologic myometrial contraction in the immediate postpartum period and is the most common cause of PPH [2,3,9,15,25,70,74,134,135]. Risk factors for uterine atony include multiparity, multiple gestation, history of PPH, prolonged labor, and placenta previa [70,102].…”

“…Much as occurred in trauma, there is a now growing demand for a POC test that can equip obstetricians with rapid results on developing coagulopathic states [2,3,8,12,16,17,19]. Much as occurred in trauma, there is a now growing demand for a POC test that can equip obstetricians with rapid results on developing coagulopathic states [2,3,8,12,16,17,19].…”

“…Postpartum hemorrhage (PPH) is the leading cause of maternal morbidity and mortality throughout the world [1][2][3]. Its prevalence has risen around the globe despite advancements in obstetric protocols for preventing and treating massive hemorrhage [4,5].…”

The role of viscoelastic testing in the management of the parturient

“…18,19 In postpartum hemorrhage, TEG variables have been compared to traditional laboratory assays. Rigouzzo et al 20 found that the TEG provided rapid detection of hypofibrinogenemia and thrombocytopenia. Algorithms for obstetric care with viscoelastic testing have also been described.…”