**1. Introduction**

Anticoagulation during extracorporeal membrane oxygenation (ECMO) is necessary to prevent catastrophic circuit clotting, but it contributes to significant morbidity and mortality. The Extracorporeal Life Support Organization (ELSO) international registry shows a 24% increase in the number of patients placed on ECMO and a 55% growth of centers utilizing ECMO from 2009 to 2015 [1]. Although there has been rapid growth in ECMO around the world, pediatric mortality rates have remained static or even increased depending on the reason for cannulation [1]. In a multicenter study, Dalton et al. showed that 19–70% of patients had a bleeding event and 12–43% of pediatric patients had a thrombotic event while anticoagulated on ECMO [2]. With the increase in centers utilizing ECMO, anticoagulation has become an important area of research.
