Sonoclot® predicts operation time and blood loss after cardiopulmonary bypass in children

Background: As the circulating blood volume is relatively small in pediatric patients, blood components are quickly lost when bleeding, which make it more difficult to stop the bleeding. Particularly in pediatric cardiac surgery, loss of clotting factors associated with cardiopulmonary bypass (CPB) would likely to be prominent. As a result, bleeding is further promoted and the operation time is extended. In order to search for the relation between clotting factors and the amount of bleeding, we used a viscoelastic point of care test. Objectives: We used Sonoclot® as viscoelastic point of care test to evaluate coagulation function before CPB and before weaning from CPB in pediatric cardiac surgery. Design: Retrospective. Setting: Single-institutional. Participants: We included 55 pediatric patients (median age 13 months [IQR 5–32]) who underwent cardiac surgery under CPB from December 2015 to November 2016. Interventions: None. Measurements and main results: Sonoclot® analysis was performed after induction of anesthesia (pre-data, or baseline data) and before any heparinized saline was given, and right after modified ultrafiltration after weaning from CPB (post-data). Post-data was compared with post-CPB operation time and post-CPB blood loss by multiple regression analysis. Furthermore, effects of fresh frozen plasma (FFP) added on CPB on coagulation function and post-platelet function (describe as PF_SC) was assessed. Activated coagulation time (describe as ACT_SC) and clot rate (describe as CR_SC) showed no significant change between baseline data and post-data. Post-PF_SC was worsened by prolonged CPB time (p < 0.05) and correlated to bleeding amount and operation time after CPB (p < 0.05). Total amount of platelet concentrate (PC) transfused was higher in patients with smaller PF_SC (p < 0.05). Total amount of FFP and PC transfused correlated with bleeding amount and operation time after CPB (p < 0.05). In the subgroup analysis, PF_SC declined in the FFP-included group, whereas there was no significant difference in coagulation function. Addition of FFP to CPB did not significantly affect CR, whereas PF_SC deteriorated as CPB time was prolonged (CPB time = 1/(0.0021∗PF_SC + 0.0055)). Conclusion: Sonoclot® is useful to evaluate coagulation function in pediatric patients who undergo CPB. Preventive administration of FFP or PC in CPB circuit could reduce bleeding after CPB.