Point-of-care testing of coagulation and fibrinolytic status during postpartum haemorrhage: Developing a thrombelastography®-guided transfusion algorithm

Abstract

Thrombelastography® is a monitor of coagulation and fibrinolytic status, with point-of-care applications in managing haemorrhaging patients. Advocates have suggested a possible role in managing obstetric haemorrhage. This study aims to develop a pregnancy-specific thrombelastography-guided transfusion algorithm, which could be integrated into the management of postpartum haemorrhage. In this prospective observational study, 57 healthy, term-parturients provided pre-caesarean whole blood specimens for thrombelastography analyses. Specimens were processed according to a standardised protocol involving simultaneous analyses using three assays: native (non-activated); kaolin-activated; and kaolin and tissue factor-activated (RapidTEG®). For each assay, the following thrombelastography parameters were measured: reaction time (minutes); clot formation kinetics time (minutes); maximum amplitude (mm); and α angle (degree). Subsequent reference values were used to establish assay-specific reference intervals. For all thrombelastography parameters studied, reference values obtained using a non-activated assay differed from the corresponding values obtained using activated assays, and also demonstrated greater inter-sample variability. From the assay-specific reference intervals obtained, it was possible to establish a pregnancy-specific thrombelastography-guided transfusion algorithm. Specific features of this transfusion algorithm included the preferential use of activated assays, the need for duplicates and a recommendation that an initial baseline thrombelastography measurement is established for subsequent serial comparisons. This transfusion algorithm has been developed to assist with assessment of coagulation and fibrinolytic status during postpartum haemorrhage.