Thromboelastography (TEG) predicts bleeding in pediatric patients undergoing cardiac surgery. We hypothesize that TEG parameters at rewarming correlate with post-protamine values and that rewarming TEG is associated with surrogate endpoints for postoperative bleeding in pediatric patients undergoing complex cardiac surgery.

In a retrospective study of pediatric (≤18yrs) patients (N=703) undergoing complex cardiac surgery procedures, TEG obtained during rewarming and following protamine administration were compared using linear regression. A composite endpoint of extended blood product transfusion or surgical re-exploration for bleeding was utilized as a surrogate for post-operative bleeding.

By multivariable analysis, longer cardiopulmonary bypass time and lower TEG maximal amplitude (MA) during rewarming were independently associated with risk of composite endpoint in the operating room or intensive care unit (p<0.05). Among patients with MA<45mm during rewarming, those who received platelet transfusion compared to those who did not in the operating room were less likely to reach composite endpoint within the subsequent 24 hours (8%vs.32% respectively; p<0.01). Good correlation was observed between TEG parameters at rewarming vs. after protamine administration (Pearson r≥0.7). The relationship between platelet transfusion volume (ml/kg) and percent change in MA was determined using linear regression and a platelet transfusion calculator was generated.

Lower MA during rewarming is associated with increased risk of perioperative bleeding. In patients with rewarming MA<45mm, intraoperative platelet transfusion may reduce the risk of subsequent bleeding. Individualized platelet transfusion therapy based on rewarming TEG may reduce the risk of bleeding while minimizing unnecessary platelet transfusion.