Arterial lactate for predicting mortality in children requiring extracorporeal membrane oxygenation

Background. Dynamic arterial lactate indices predict mortality more accurately than static arterial lactate measurements in children with septic shock or congenital cardiac defects. The current study evaluates whether this also applies to children with primary respiratory disease requiring extracorporeal membrane oxygenation (ECMO). Methods. Static arterial lactate levels (LACabs) were prospectively collected before and during ECMO support for this single center, observational cohort study. Also, time-weighted arterial lactate (LAC(tw)) and lactate change over time (LACdelta) were calculated as dynamic indices for, respectively, the duration and the trend over time of lactate derangement. Intensive care mortality was the primary endpoint. Analyses were performed for neonatal and pediatric patients separately. Results. Fifty-six neonatal and 39 pediatric patients were included. Eighteen (32%) neonatal and 12 (31%) pediatric patients died. The evolution of LACabs and LACdelta differed between the pediatric survivors and the pediatric non-survivors (P <0.001, P=0.025). The hazard ratio was 1.23 (CI95=1.06-1.43, P=0.007) for LACabs and 20.64 (CI95=1.99-214.20, P=0.011) for LACdelta, indicating that higher lactate levels increase the risk for mortality. The predictive value for LACabs was 0.75 (CI95=0.57-0.93) and for LACdelta 0.69 (CI95=0.51-0.87), respectively. There were neither consistent differences for LACtw in the pediatric patients, nor for any of the static or dynamic lactate indices in the neonatal patients. Conclusion. Static arterial lactate measurements and, to a lesser extent, dynamic arterial lactate indices predict mortality in pediatric, but not neonatal ECMO patients. The magnitude and trend over time rather than the duration of lactate derangement are associated with mortality