Proof Ronco C (ed): Acute Kidney Injury in the Critically Ill. Contrib Nephrol. Basel, Karger, 2007, vol 156, pp 287–296 Dialysate and Replacement Fluid Composition for CRRT Filippo Aucella, Salvatore Di Paolo, Loreto Gesualdo Department of Nephrology, Dialysis and Transplantation, University of Foggia, Foggia, Italy Abstract Continuous renal replacement therapies (CRRTs) are increasingly used in order to maintain normal or near-normal acid-base balance in intensive care unit (ICU) patients. Acid-base balance is greatly influenced by the type of dialysis employed and by the adminis- tration route of replacement fluids. In continuous veno-venous hemofiltration, buffer balance depends on losses with ultrafiltrate and gain with replacement fluid, while in techniques such as continuous veno-venous hemodiafiltration, clinicians should balance the role of the dialysate. The type of buffer greatly influences not only acid-base correction, but also clini- cal outcome. Lactate or bicarbonate fluids are currently used, but recent studies suggest that bicarbonate-buffered replacement fluids can improve acid-base status and reduce cardiovas- cular events better than lactate fluids. The buffer concentration should exert a buffer load that may compensate for deficits, for losses in the buffer process, and for extracorporeal losses and should therefore usually be supraphysiological. However, the dialysate buffer or elec- trolyte concentration need always to be balanced with that of the replacement fluids employed. Both fluids should contain electrolytes in concentrations aiming for a physiologic level and taking into account preexisting deficits or excess and all input and losses. Clinicians should be aware that in CRRTs the quality control for sterility, physical properties, individualized prescription and balance control are vitally important. Copyright © 2007 S. Karger AG, Basel Major changes have occurred in the medical management of intensive care unit (ICU) patients over the past two decades, and the role of extracorporeal blood treatments has broadened from conventional renal function replacement to a series of non-renal conditions. Continuous renal replacement therapies (CRRTs) have found widespread use and acceptance because they incorporate several advantages, such as improved hemodynamic stability, gradual urea removal without fluctuations, CNP156287.qxd 7/03/07 2:48 PM Page 287