Continuous venovenous hemodialysis in a neonate model: a two-pump system

Abstract

Objective: To evaluate the efficiency and tolerance of venovenous hemofiltration, hemodiafiltration, and hemodialysis with a two-pump system in a neonatal animal model of acute renal failure.

Design: Prospective trial.

Setting: Animal laboratory at a large university-affiliated medical center.

Subjects: New Zealand white rabbits, weighing 3325 +/- 380 g.

Interventions: Venovenous hemofiltration, hemodiafiltration, and hemodialysis were performed in anesthetized rabbits with previous bilateral ureteral ligation.

Measurements and main results: At a blood flow rate of 19 +/- 0.5 mL/min, we determined hematocrit, urea, creatinine, and electrolyte values in blood, at the inlet and outlet of the hemofilter, and in ultrafiltrate at the start and after 15, 30, 60, 90, 120, and 180 mins of hemofiltration (ultrafiltrate flow rate of 1.9 +/- 0.2 mL/min), hemodiafiltration (dialysate plus ultrafiltrate flow rate of 16.9 +/- 0.8 mL/min), and hemodialysis (dialysate flow rate of 15.7 +/- 1.1 mL/min). Arterial blood pressure, heart rate, and body temperature were monitored during the procedures. Urea and creatinine instantaneous clearances were higher with hemodiafiltration (8.0 +/- 0.7 and 6.2 +/- 0.7, respectively, n = 29) and hemodialysis (6.8 +/- 1.1 and 4.8 +/- 0.9, respectively, n = 31) than with hemofiltration (1.8 +/- 0.6 and 1.9 +/- 0.4, respectively, n = 16). Initial and final weights, temperatures, and hematocrit, sodium, and protein blood concentrations of each 180-min procedure were similar.

Conclusions: Hemodiafiltration had a higher urea removal rate than hemodialysis but the management of hemodiafiltration was more cumbersome and time consuming in the absence of a flow equalizer device. As a result, we recommend continuous venovenous hemodialysis as the therapy of choice.