C. Giorni, C. Garisto, E. Iannace, U. Schloderer, C. Varano, M. Averardi, P. Cogo

Dept of Pediatric Cardiac Surgery, Bambino Gesù Hospital, Rome, Italy

Background and aims: Extracorporeal life support (ECLS) is widely used in children with low cardiac output, hypoxemia or as a bridge to cardiac transplant. Continuous heparin infusion is used to prevent thromboembolic events. Bedside point of care assays to monitor anticoagulation include activated partial thromboplastin time (aPTT) and thromboelastography (TEG). Our aim was to assess the role of aPTT and TEG reaction time (r) on anticoagulation monitoring

Methods: Simultaneous aPTT and r levels in patients undergoing ECLS were retrospectively retrieved. APTT was performed by Hemocron® (ITC,NJ,USA) whole blood coagulation system.
TEG was performed by Thrombo Elastometer Automated® (Framar Biomedica, Rome,Italy). By institutional protocol, heparin dose was adjusted to obtain a aPTT value of 50 seconds. Associations were assessed by Pearson correlation.

Results: Fifty-nine aPTT/r couples from 15 children undergoing ECLS were analyzed. Median (interquartile range) patients age was 63 (10-339) days, and their weight was 5.5 (3-8) kg. Median administered heparin dose was 17 (10-27) i.u./kg/h, median aPTT value was 52.5 (45-58) seconds and median r value was 108 (45-200) seconds. We found no correlation between heparin dose and aPTT value (p:0.9, r2:0.0002) and a significant correlation between r and heparin dose (p:0.0001, r2:0.25). Mean heparin infusion time, at samples analysis, was 8 (5-14) days. The significant correlation between r and heparin dose was independent from the heparin infusion time.

Conclusion: R is more sensitive than aPTT to detect heparin dose modifications. We recommend the implementation of a daily TEG exam to aPTT tests when ECLS is delivered to pediatric