The Relationship Among Thromboelastography, Hemostatic Variables, and Bleeding After Cardiopulmonary Bypass Surgery in Children

BACKGROUND: Mediastinal bleeding is common after pediatric cardiopulmonary bypass (CPB) surgery. Thromboelastography (TEG (R)) may predict bleeding and provide insight into likely mechanisms. We aimed to (a) compare perioperative temporal profiles of TEG (R) and laboratory hemostatic variables between patients with significant hemorrhage (BLEED) and those without (CONTROL), (b) investigate the relationship between TEG (R) variables and routine hemostatic variables, and (c) develop a model for prediction of bleeding.

METHODS: TEG and laboratory hemostatic variables were measured prospectively at 8 predefined times for 50 children weighing

RESULTS: Patients who bled demonstrated different TEG (R) profiles than those who did not. This was most apparent after protamine administration and was partly attributable to inadequate heparin reversal, but was also associated with a significantly lower nadir in mean (so) fibrinogen for the BLEED group compared with CONTROL group: 0.44 (0.18) and 0.71 (0.40) g/L, respectively (P = 0.01). Significant nonlinear relationships were found between the majority of TEG (R) and laboratory hemostatic variables. The strongest relationship was between the maximal amplitude and the platelet-fibrinogen product (logarithmic r(2) = 0.71). Clot strength decreased rapidly when (a) fibrinogen concentration was

CONCLUSIONS: Hypofibrinogenemia and inadequate heparin reversal are 2 important factors contributing to clot strength and perioperative hemorrhage after pediatric CPB. TEG (R) may be a useful tool for predicting and guiding early treatment of mediastinal bleeding in this group.