Peri-partum reference ranges for ROTEM(R) thromboelastometry.

Background: Post-partum haemorrhage (PPH) causes rapidly developing deficiencies in clotting factors and contributes to substantial maternal morbidity and mortality. Rotational thromboelastometry (ROTEM(®)) is increasingly used as a point of care coagulation monitoring device in patients with massive haemorrhage; however, there are limited data on reference ranges in the peri-partum period. These are required due to the haemostatic changes in pregnancy.
Methods: In a Dutch multi-centre trial, 161 subjects were included; blood samples were obtained during labour (T1) and within 1 h of delivery (T2). Reference ranges of ROTEM(®) INTEM, EXTEM, FIBTEM, and APTEM were set and correlation with laboratory results was investigated using the guidelines of the International Federation of Clinical Chemistry.
Results: Reference ranges were obtained for clotting time (CT), clot formation time (CFT), α-angle, clot firmness at 10 and 20 min (A10, A20), maximum clot firmness (MCF), and maximum lysis (ML). These were comparable from centre to centre, and between T1 and T2. Reference ranges T1: EXTEM: CT 31-63 s, CFT 41-120 s, and MCF 42-78 mm.
Intem: CT 109-225 s, CFT 40-103, and MCF 63-78 mm.
Fibtem: CT 31-79 s and MCF 13-45 mm.
Aptem: CT 33-62 s, CFT 42-118, and MCF 61-79 mm.
Conclusions: Reference values for ROTEM(®) parameters are reported. The previously published correlation between FIBTEM parameters and plasma fibrinogen levels by the Clauss method is confirmed. Further research is needed to define threshold values for haemostatic therapy in the course of PPH. Clinical trial registration NTR 2515 (http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2515).