123: Parallel Dual-Circuit Configuration for Management of Refractory Hypoxemia on Veno-Venous ECMO

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is an effective treatment for severe hypoxemic respiratory failure. On VV-ECMO, arterial oxygenation (PaO2) depends on ECMO blood flow and oxygenator performance in relation to native cardiac output and pulmonary shunt fraction. With near-total pulmonary shunt and elevated cardiac output, even a maximally efficient single VV-ECMO circuit may not result in adequate PaO2. Previous case series have reported the addition of a second circuit in parallel in this situation. Here we report a retrospective review of our experience with parallel circuits for refractory hypoxemia in thirteen patients treated with VV-ECMO from January 1, 2021 to June 1, 2023. All initial cannulations were percutaneous femoral-internal jugular. For severe hypoxemia despite maximal ECMO flow, red cell transfusion, and neuromuscular blockade, a second VV-ECMO circuit was added contralaterally. Patients were mostly male (12/13), average age 35.2 years (standard deviation 28.7-41.7) and body mass index of 45.3 (25-65.6). Nine had COVID-19 and four had other causes of respiratory failure. After addition of the second circuit, total flow increased from 5.9L/min (5.5-6.4) to 7.3L/min (6.0-8.0) [p<0.001], and PaO2 improved from 45.4mmHg (35.6-61.1) to 76.2mmHg (55.8-96.5) [p<0.0001]. Eleven patients survived to decannulation after an average of 19.8 days (7-32.6) on parallel circuits and 52.4 (18.8-86) total ECMO days. There was one accidental decannulation, four patients developed deep vein thromboses, and five developed bacteremia. Nine patients survived to discharge (61.5%), either to home or inpatient rehabilitation. Parallel, dual VV-ECMO circuit configuration appears to correct refractory hypoxemia with good survival and functional status.