Comparison of thromboelastometry by ROTEM^® Delta and ROTEM^® Sigma in women with postpartum haemorrhage

Haemostatic treatment in women experiencing postpartum haemorrhage is increasingly based on point-of-care devices such as ROTEM^® thromboelastometry. Recently, a fully automated successor of the ROTEM^® Delta device, the ROTEM^® Sigma was introduced. To determine whether these devices provide similar results, we compared ROTEM^® parameters using the ROTEM^® Delta and Sigma devices in women experiencing postpartum haemorrhage. Prospective observational cohort study of 23 women experiencing postpartum haemorrhage. ROTEM^® INTEM, EXTEM, FIBTEM and APTEM measurements handled by the ROTEM^® Delta and Sigma devices were compared. ROTEM^® FIBTEM values were also related to Clauss fibrinogen values. A correlation of Spearman's r (r_s) varying between 0.76 and 0.95 was displayed between clot firmness measured in millimeters at 5 (A5), 10 (A10) and 20 (A20) minutes after start of clot formation measured by EXTEM, INTEM and APTEM assays executed on both devices; A5, A10 and A20 of FIBTEM correlated less well (r_S between 0.71 and 0.74), especially after five and ten minutes. Correlation between both devices regarding clotting time (CT) was poor. The observed correlation between levels of Clauss fibrinogen and FIBTEM A5 was r_s = 0.70, (95% confidence interval (CI): 0.38 to 0.87) for Delta and r_s = 0.85, (CI 0.65 to 0.94) for Sigma. A5, A10 and A20 measured in EXTEM, INTEM and APTEM obtained from ROTEM^® Delta and Sigma devices were similar. EXTEM, FIBTEM and APTEM CT values from both devices showed no correlation. Substantial variation was found between FIBTEM assays of the devices. Consequently, results of FIBTEM assays should always be interpreted in the context of device-specific reference values. Correlation with Clauss fibrinogen was better in the ROTEM^® Sigma device.