Safety and feasibility of conversion from venoarterial to venovenous extracorporeal membrane oxygenation in pediatric patients: A case series

IntroductionIn children requiring venoarterial (VA) extracorporeal membrane oxygenation (ECMO) for long durations, conversion to venovenous (VV) support may be advantageous. The purpose of this study was to evaluate the feasibility and safety of conversion from VA to VV ECMO.MethodsThis is a retrospective review of all children who underwent conversion from VA to VV ECMO at a single institution, from 2015 to 2022. Indications for and methods of conversion were examined as well as adverse events including re-operation, ischemic complications, renal failure, and mortality.ResultsOf 422 pediatric patients on initial VA ECMO, 4 children (0.9%) underwent conversion from VA to VV support. The indications for cannulation were: respiratory failure due to COVID19, respiratory failure due to congenital diaphragmatic hernia, cardiac dysfunction following heart transplant, and sepsis with associated left ventricular dysfunction. The indications for conversion were bleeding from the arterial cannula and ongoing respiratory failure. The median time to conversion was 6.5 days (range 4-54 days) and the median length of ECMO run was 34.5 days. Three patients required renal replacement therapy with two progressing to long-term dialysis. There were no ischemic limb complications although one patient developed a femoral artery pseudoaneurysm that required re-operation. Three patients survived to discharge. One patient was unable to be decannulated after conversion and mechanical support was withdrawn.ConclusionsConversion to VV ECMO from initial VA ECMO cannulation is feasible but a rare event. For patients with cardiac stability but continued need for respiratory support, conversion to VV ECMO can be considered.