Urea removal by hemofiltration and hemodiafiltration.

Abstract

Continuous hemofiltration is usually regarded as a safe method for controlling fluid overload in neonates presenting acute renal failure. We considered that continuous hemodiafiltration with a hemofilter type especially designed for use in the neonatal period could improve urea removal as compared with hemofiltration. Continuous arteriovenous hemofiltration (CAVH) and hemodiafiltration (CAVHD) were consecutively performed on 7 anesthetized adult rabbits which were given an urea infusion. The hemofilter was a 800-cm2 polysulfone model (Amicon Minifilter Plus). Mean values for physiological and operational parameters were comparable during CAVH and CAVHD, i.e., mean blood pressure (69.6 +/- 14.9 and 70 +/- 13.1 mm Hg, respectively), arterial oncotic pressure (16.0 +/- 2.4 and 16.0 +/- 1.7 mm Hg), hematocrit (36.2 +/- 5.8 and 36.7 +/- 4.4%), protein plasma level (38.9 +/- 7.0 and 39.0 +/- 6.4 g/l), urea plasma level (20.6 +/- 6.5 and 19.9 +/- 7.0 mmol/l), plasma flow in the hemofilter (7.89 +/- 8.48 and 7.12 +/- 3.08 ml/min), and ultrafiltrate rate (1.17 +/- 0.49 and 1.73 +/- 0.78 ml/min). CAVHD allowed a significant increase in urea clearance (4.74 +/- 4.51 ml/min) as compared with CAVH (1.23 +/- 0.81 ml/min). These experimental results suggest that CAVHD usefulness should be assessed in neonates presenting acute renal failure.