Continuous renal replacement therapy with a pulsatile tubular pump: parameters must be adjusted in each case.

A three-valve, pulsatile tubular pump was used in 24 pigs weighing 10.2 +/- 3.2 kg; the pump was connected to a neonatal hemofiltration circuit. Ninety-two periods of 30 min were studied to analyze the efficacy of the system with variations in the percentage time in diastole, the diastolic speed, the systolic speed, and the percentage time in systole during which the postfilter valve was closed. System efficacy was determined by the blood flow through the filter, the ultrafiltrate volume, the vascular overload measured by the inlet aspiration pressure, and the filter overload measured by the cross-filter pressure drop and the transmembrane pressure. The variations in the pump parameters did not lead to significant differences in the efficacy of the system or in the vascular or filter overload. The parameters must be adjusted in each case to obtain the best yield with the lowest vascular and filter overload.