(1399) A Case of Refractory Hypoxemia Requiring Dual Venovenous ECMO Circuits in Parallel

Introduction: Veno-venous extracorporeal membrane oxygenation (V-V ECMO) is used for refractory Acute Respiratory Distress Syndrome (ARDS). There is no consensus on the preferred management of ongoing hypoxemia despite V-V ECMO. We describe a case of a 48-year-old healthy male who despite full support on V-V ECMO had refractory hypoxemia requiring the initiation of dual V-V ECMO circuits in parallel.

Description: A 48-year-old male Body Mass Index 36.1 presented as a transfer for V-V ECMO due to refractory ARDS secondary to an unknown etiology. He initially presented with 7 days of fever, shortness of breath, and cough. He underwent intubation, neuromuscular blockade, and proning following admission due to hypoxic respiratory failure. Despite broad spectrum antimicrobials, maximal ventilator support, steroids and inhaled pulmonary vasodilators he had ongoing hypoxemia requiring transfer for V-V ECMO on ICU day 6. On arrival, his PaO2 was 52mmhg on APRV 30/0 and 100% FiO2. After initiation on V-V ECMO flow 5L FiO2 100%, the PaO2 transiently improved to 92mmhg. Over the next 48 hours, the patient clinically worsened and on ECMO day 3, he had a pulse oximetry of 74% and a PaO2 of 53mmhg despite 7L of flow and 100% FiO2. Echocardiography showed no pathology and normal biventricular function. ECMO gases were not consistent with recirculation or failure of oxygenation. The patient was transitioned to dual V-V ECMO circuits via Internal Jugular-Femoral, and Subclavian-Femoral cannulation. This provided a combined 9-10L of flow and the PaO2 improved from 51 to 168mmhg. Our patient was maintained on dual circuit support for 58 days as he underwent lung transplant workup. He developed intra-peritoneal hemorrhage unrelated to ECMO cannulation that was refractory to surgical management. The patient’s family transitioned to comfort care and upon removal of mechanical support the patient died.

Discussion: Ongoing hypoxemia despite full support on V-V ECMO is an uncommon issue. It is important to address common mechanical complications of the ECMO circuit which may contribute to the problem; however, one additional consideration is a mismatch between native cardiac output and ECMO flows. Dual parallel circuits allow for increased flows and are a salvage intervention for refractory hypoxemia on V-V ECMO.