Thromboelastography versus Standard Coagulation Assays in Patients with Postpartum Hemorrhage

Abstract

Key words: postpartum hemorrhage, thromboelastography, coagulopathy, fibrinogen, massive transfusion. Objective: Thromboelastography, a point-of-care test that measures blood’s dynamic viscoelastic properties, is routinely used to guide resuscitation in surgical specialties with high hemorrhage risk. Patients with ongoing postpartum hemorrhage often develop coagulopathy and hypofibrinogenemia. Timely assessment of fibrinogen is crucial because cryoprecipitate for repletion requires thawing prior to administration. Thromboelastography may provide rapid assessment of coagulopathy in ongoing hemorrhage but this has not been thoroughly studied. Our objective was to determine if thromboelastography accurately reflects coagulopathy in ongoing postpartum hemorrhage when compared to standard assays. Study Design: This was a retrospective cohort study of people with ongoing postpartum hemorrhage (quantified blood loss >1000 mL), from 1/1/16-12/31/19. Thromboelastography variables and standard coagulation parameters were compared in patients who had both assays drawn simultaneously. As a secondary analysis, patients who had thromboelastography were compared to those who did not. Mann-Whitney, Fisher’s Exact, Kruskal-Wallis, Spearman’s Rho, and logistic regression tests were used for analysis. Significance was set at p < 0.05. Results: A total of 680 patients were included. 69 had thromboelastography and coagulation parameters drawn simultaneously and were included in the primary analysis. The remainder were included in the secondary analysis. Thromboelastography variables and coagulation assays correlated significantly - prolonged R with increased PTT (rho 0.25, p=0.04), prolonged K and decreased alpha angle with decreased fibrinogen (rho -0.61, p<0.001; rho 0.24, p<0.001), and decreased maximum amplitude with decreased platelets (rho 0.62, p<0.001). Those who had thromboelastographic assays had higher blood loss and need for interventions to manage hemorrhage than those who did not. Conclusion: Thromboelastography correlated significantly with standard laboratory assays in ongoing postpartum hemorrhage, including for patients with hypofibrinogenemia Given the point-of-care nature and rapid turnaround time, thromboelastography should be considered for timely hemorrhage evaluation and directed resuscitation of coagulopathy.

Comparison of Two Viscoelastic Testing Devices in a Parturient Population

“…For comparative studies between devices, it is important to interpret the results in the context of a measurement range, because the generalization of results over a broad range of measurements could lead to equalizing existing differences. VHAs are shown to facilitate coagulation therapy due to their faster turnover times and higher sensitivity for early signs of coagulopathy [7,34,35]. An improved mortality rate has been shown thanks to the use of VHAs compared to standard laboratory tests [36].…”

“…The use of viscoelastic hemostatic assays (VHAs) for diagnostic use and for the guidance of hemostatic therapy is increasing worldwide, and new technologies continue to emerge [1][2][3][4][5]. Currently, VHAs complete or even replace standard laboratory testing and, therefore, represent a cornerstone of modern hemostatic resuscitation [6][7][8]. Viscoelastic hemostatic assays provide more detailed insights into the complex pathophysiology of bleeding than standard coagulation tests [9].…”