Continuous venovenous renal replacement therapy using a conventional infusion pump

To evaluate continuous venovenous hemofiltration and hemodiafiltration with a conventional infusion pump in a pediatric sized animal model. Fourteen Maryland pigs weighing 8 to 13 kg were used. A conventional infusion pump (IVAC 571), with a flow of 900 ml/h and a pediatric hemofilter of 0.22 m2 were used. Ringer's solution was used for both the dialysate and the replacement fluid. Each experiment included 1 hour of hemofiltration and 1 hour of hemodiafiltration. Heart rate, arterial blood pressure, pH, Na, K, Cl, and hematocrit were measured every 30 minutes. Mean ultrafiltrate flow was 249.7 +/- 100.3 ml/hr, 240.5 +/- 109.5 ml/hr with hemofiltration and 271 +/- 101.1 ml/hr with hemodiafiltration, the differences not being significant. No significant changes were seen in heart rate, blood pressure, hematocrit, electrolytes, or pH. Pressure in the circuit rose from 107.7 +/- 70.3 mm Hg at the beginning of the experiment to 234.2 +/- 118.1 mm Hg after 2 hours (p < 0.05). The technique was well tolerated by all the pigs. Continuous venovenous hemofiltration and hemodiafiltration with a conventional infusion pump is a possible alternative to conventional methods of extrarenal replacement therapy in neonates and infants.