Predilution versus postdilution continuous venovenous hemofiltration: no effect on filter life and azotemic control in critically ill patients on heparin.

In continuous venovenous hemofiltration (CVVH), the delivery of replacement fluid in pre- or postdilution mode remains the subject of controversy. We compared both modes in terms of filter life, dose, and azotemic control. All patients admitted to the intensive care units of a university hospital between November 2004 and December 2006 receiving CVVH and systemic anticoagulation with heparin were retrospectively studied. Thirty-six patients treated by CVVH in predilution and 27 in postdilution mode were studied, with 132 filters in the former and 111 in the latter. The filter life [median ± interquartile range (IQR)] was 24 ± 38 hours and 29 ± 46 hours (p = 0.58) in the pre- and postdilution modes, respectively. Although the fall in creatinine and urea depended on the dose, 19% greater delivered dose in the post- than predilution mode did not impact on azotemic control. In critically ill, heparinized patients on CVVH, filter life and azotemic control are similar in pre- and postdilution modes and underscore the clinical applicability of the predilution mode.