In critically ill children, acute renal failure (ARF) is associated with a high mortality. To assess the outcome and complications of pump-assisted hemofiltration (PAHF) using a standard volumetric pump to regulate blood flow, we retrospectively reviewed our experience in 52 patients with ARF treated with PAHF from 1989 to 1995. These patients ranged in age from < 1 month to 19 years and in weight from 2 to 125 kg. The most common underlying diagnoses were congenital heart disease and infection. The duration of PAHF averaged 9 +/- 8 days (range 24 h to 43 days). Hemodiafiltration for solute control was required in 40 patients. Total fluid intake while on PAHF was 136 +/- 95 ml/kg per day, while urine output and ultrafiltration averaged 15 +/- 24 ml/kg per day and 89 +/- 58 ml/kg per day, respectively. Management of laboratory abnormalities was efficient with only 4 patients requiring 1 or 2 additional treatments of hemodialysis for control of uremia. Complications included hyponatremia in 13 patients, hypokalemia in 14 patients, hypovolemia in 8 patients, hyperglycemia in 6 patients, and bleeding in 9 patients. No complications specifically related to use of the volumetric infusion pump for PAHF were noted. PAHF using a volumetric infusion pump for blood flow regulation in critically ill children with ARF is a practical and efficient therapy.