Impact of Hemolysis on Acute Kidney Injury and Mortality in Children Supported with Cardiac Extracorporeal Membrane Oxygenation

Intravascular hemolysis with elevated plasma-free hemoglobin (PFH) complicates extracorporeal membrane oxygenation (ECMO). In 50 consecutive pediatric cardiac patients requiring ECMO, we sought to describe the relationship between PFH and clinical outcomes; primary outcomes were acute kidney injury (AKI) and prolonged (>14 days) renal replacement therapy (RRT). Median age was 35 days, median weight 3.9 kg, and median ECMO duration 4.2 days. Seventy-eight percent (39/50) weaned off ECMO; survival to discharge was 50% (25/50). Seventy percent (35/50) had AKI on ECMO. Seventy-seven percent (30/39) required RRT post-ECMO; median duration was 5.2 days (0, 14.2). Prolonged RRT was associated with higher daily PFH (67.5 mg/dL [54.1, 102.5] vs. 46.7 mg/dL [40, 72.6], = .025) and higher peak PFH (120 mg/dL [90, 200] vs. 60 mg/dL [40, 135], = .016). After adjusting for ECMO duration and oliguria/elevated creatinine on ECMO day 0, peak PFH >90 mg/dL was associated with prolonged RRT (operating room [OR] = 18, confidence interval [CI] 1.9-167.8). Patients who died had higher daily PFH (65 mg/dL [51.6, 111.7] vs. 42.5 mg/dL [37.5, 60], = .0040). Adjusting for ECMO duration and blood product administration, daily PFH >53 mg/dL was associated with mortality (OR 4.8, CI 1.01-23.3). Elevated PFH during pediatric cardiac ECMO is associated with prolonged RRT and non-survival to discharge. Initiatives to decrease PFH burden may improve clinical outcomes.