Roles of thrombelastography and thromboelastometry for patient blood management in cardiac surgery.

The value of thrombelastography (TEG) and thromboelastometry (ROTEM) to improve perioperative hemostasis is under debate. We aimed to assess the effects of TEG- or ROTEM-guided therapy in patients undergoing cardiac surgery on the use of allogeneic blood products. We analyzed 12 trials including 6835 patients, 749 of them included in 7 randomized controlled trials (RCTs). We collected data on the amount of transfused allogeneic blood products and on the proportion of patients who received allogeneic blood products or coagulation factor concentrates. Including all trials, the odds ratios (ORs) for transfusion of red blood cell (RBC) concentrates, fresh-frozen plasma (FFP), and platelets were 0.62 (95% confidence interval [CI], 0.56-0.69; P<.001), 0.28 (95% CI, 0.24-0.33; P<.001), and 0.55 (95% CI, 0.49-0.62; P<.001), respectively. However, more than 50% of the patients in this analysis were derived from one retrospective study. Including RCTs only, the ORs for transfusion of RBC, FFP, and platelets were 0.54 (95% CI, 0.38-0.77; P<.001), 0.36 (95% CI, 0.25-0.53; P<.001), and 0.57 (95% CI, 0.39-0.81; P=.002), respectively. The use of coagulation factor concentrates was reported in 6 studies, 2 of them were RCTs. The ORs for the infusion of fibrinogen and prothrombin complex concentrate were 1.56 (95% CI, 1.29-1.87; P<.001) and 1.74 (95% CI, 1.40-2.18; P<.001), respectively. However, frequencies and amounts were similar in the intervention and control group in the 2 RCTs. It is presumed that TEG- or ROTEM-guided hemostatic management reduces the proportion of patients undergoing cardiac surgery transfused with RBC, FFP, and platelets. This presumption is strongly supported by similar ORs found in the analysis including RCTs only. Patient blood management based on the transfusion triggers by TEG or ROTEM appears to be more restrictive than the one based on conventional laboratory testing. However, evidence for improved clinical outcome is limited at this time.