Sustained low-efficiency dialysis for critically ill patients requiring renal replacement therapy

Background. The replacement of renal function for critically ill patients i s procedurally complex and expensive, and none of the available techniques have proven superiority in terms of benefit to patient mortality. In hemody namically unstable or severely catabolic patients, however, the continuous therapies have practical and theoretical advantages when compared with conv entional intermittent hemodialysis (IHD). Methods. We present a single center experience accumulated over 18 months s ince July 1998 with a hybrid technique named sustained low-efficiency dialy sis (SLED), in which standard IHD equipment was used with reduced dialysate and blood flow rates. Twelve-hour treatments were performed nocturnally, a llowing unrestricted access to the patient for daytime procedures and tests . Results. One hundred forty-five SLED treatments were performed in 37 critic ally ill patients in whom IHD had failed or been withheld. The overall mean SLED treatment duration was 10.4 hours because 51 SLED treatments were pre maturely discontinued. Of these discontinuations, 11 were for intractable h ypotension, and the majority of the remainder was for extracorporeal blood circuit clotting. Hemodynamic stability was maintained during most SLED tre atments, allowing the achievement of prescribed ultrafiltration goals in mo st cases with an overall mean shortfall of only 240 mt per treatment. Direc t dialysis quantification in nine patients showed a mean delivered double-p ool Kt/V of 1.36 per (completed) treatment, Mean phosphate removal was 1.5 g per treatment. Mild hypophosphatemia and/or hypokalemia requiring supplem entation were observed in 25 treatments. Observed hospital mortality was 62 .2%, which was not significantly different from the expected mortality as d etermined from the APACHE II illness severity scoring system. Conclusions. SLED is a viable alternative to traditional continuous renal r eplacement therapies for critically ill patients in whom IHD has failed or been withheld, although prospective studies directly comparing two modaliti es are required to define the exact role for SLED in this setting.