Tiny Patients, Big Challenges: Aquadex in Low-Birth-Weight Neonates: A Case Series

Introduction: Acute kidney injury (AKI) and fluid overload are associated with higher morbidity and mortality in hospitalized neonates. Due to their small size, limited options exist for kidney support therapy. The Aquadex™ machine with its circuit extracorporeal volume of 33mL allows for better hemodynamic tolerance. We present a case series of 9 neonates who received modified continuous venovenous hemofiltration (mCVVH) via Aquadex™ at Orlando Health Winnie Palmer Hospital NICU between February 2024 and February 2025. Case Description: Initiation of mCVVH was based on weight, hemodynamic instability, and inability to use peritoneal dialysis. Access consisted of double lumen catheters, 6 internal jugular and 3 subclavian. Prescription consisted of blood flows 10-40 mL/min with prefilter solution of 30 mL/kg. Initial ultrafiltration (UF) targeted at 5% of body weight in 24 hours. Daily UF adjusted based on percent fluid overload (PFO) and clinical assessment of tolerance (blood pressures, q12h weight and basic metabolic panels). Mean age at initiation: 5.66 days. Mean birth weight: 2.25 kg; 4 with low birth weight (LBW) and 1 extremely LBW. Mean weight at initiation: 2.60 kg. All patients had underlying renal disease; 3 ARPKD, 2 MCDK, 2 renal dysplasia, and 2 bilateral renal agenesis. Comorbidities included 3 pulmonary hypertension, 7 prematurity, 1 ECMO therapy. All patients had oliguria, 2 in anuric state. 8 of 9 were anticoagulated with heparin. Mean PFO at initiation: 19%, at end: 9.9%. Serum creatinine (mg/dL) at start of treatment: 2.91, 72 hours: 1.22, and 5 days: 0.975. Mean duration of treatment: 22.6 days. Complications included thrombocytopenia in all patients, 2 had hypothermia prior to tubing insulation, 3 had circuit clots requiring replacements, and 1 experienced catheter bleeding. None of these complications required discontinuation of therapy. 5 of 9 did not survive due to unrelated complications including 2 pulmonary hypertension, 1 DIC/sepsis, and 1 necrotizing enterocolitis. Discussion: mCVVH via Aquadex™ is a safe and effective tool in treating LBW and critically ill neonates with AKI and fluid overload providing adequate clearance and UF. Despite high overall mortality due to underlying comorbidities, the therapy itself was well tolerated, expanding the possibilities of extracorporeal support even in the smallest patients.