Background: Providing renal support for small children is very challenging using the machinery currently available in the United States. As the extracorporeal volume (ECV) relative to blood volume increases and the state of critical illness worsens, the chance for instability during continuous renal replacement therapy (CRRT) initiation also increases. CRRT machines with smaller ECV could reduce the risks and improve outcomes. Methods: We present a case series of small children (n = 12) who received continuous venovenous hemofiltration (CVVH) via an Aquadex™ machine (ECV = 33 ml) with 30 ml/kg/h of prereplacement fluids at Children’s of Alabama between December 2013 and April 2015. We assessed in vitro fluid precision using the adapted continuous veno-venous hemofiltration (CVVH) system. Results: We used 101 circuits over 261 days to provide CVVH for 12 children (median age 30 days; median weight 3.4 kg). Median CVVH duration was 14.5 days [interquartile range (IQR) = 10; 22.8 days]. Most circuits were routinely changed after 72 h. Five of 101 (5 %) initiations were associated with mild transient change in vital signs. Complications were infrequent (three transient cases of hypothermia, three puncture-site bleedings, one systemic bleed, and one right atrial thrombus). Most patients (7/12, 58 %) were discharged from the intensive care unit; six of them (50 %) were discharged home. Conclusions: CRRT machines with low ECV can enable clinicians to provide adequate, timely, safe, and efficient renal support to small, critically ill infants.