An assessment of clinical interchangeability of TEG and RoTEM thromboelastographic variables in cardiac surgical patients.

BACKGROUND: Bedside thromboelastography is increasingly used, but an assessment of the clinical interchangeability of the 2 major systems, TEG ® (Hemoscope) and RoTEM ® (Pentapharm), has not been performed. METHODS: We measured blood samples from 46 cardiac surgical patients after induction of anesthesia with kaolin TEG ® (kaoTEG), native TEG ® (natTEG ® ), intrinsic RoTEM ® (inTEM), and extrinsic RoTEM (exTEM). Each measurement consisted of reaction time (R), coagulation time (K), maximum amplitude (MA), and angle (). Bland–Altman plots and mixed-model analysis were used. To assess repeatability, we made 7 replicated measurements in rapid succession in 2 volunteers. RESULTS: One hundred sixty-six measurements were available for analysis. The R time of the kaoTEG ® (345 102 seconds, mean SD) was longer than that of the inTEM (179 74 seconds, P 0.001) and the exTEM (55 28 seconds, P 0.001). The K time of the kaoTEG ® (78 18s) was not different from that of the inTEM (75 52 seconds, P 0.60) but was longer than the K time of the exTEM (61 24 seconds, P 0.003). The MA of the kaoTEG ® (71 6.5 mm) was larger than the MA of the inTEM (67 5.2 mm, P 0.02) and almost similar to that of the exTEM (69 6.3 mm). The of the kaoTEG ® (72° 4.1°) was not significantly different from that of both the inTEM (76° 7°) and the exTEM (79° 4.5°). The variability for MA and was 10%. The repeatability of the R and K times was poor in both devices, whereas the repeatability of the MA and was sufficient for clinical purposes. CONCLUSIONS: The TEG ® and RoTEM ® measurements demonstrated a close correlation for the MA, but the did not for the R and K variables. The kaoTEG ® had the best agreement with the exTEM measurement. Therefore TEG ® and RoTEM ® measurements are not completely interchangeable, and the clinical interpretation of thromboelastograhic data should be used with caution. (Anesth Analg 2010;111:339–44)