A PRIMER ON CONTINUOUS RENAL REPLACEMENT THERAPY FOR CRITICALLY ILL PATIENTS

OBJECTIVE: TO characterize the multiple continuous renal replacement t herapy (CRRT) techniques available for the management of critically il l adults, and to review the indications for and complications of use, principles of drug removal during CRRT, drug dosage individualization guidelines, and the influence of CRRT on patient outcomes. DATA SOURCE S: MEDLINE (January 1981-December 1996) was searched for appropriate p ublications by using terms such as hemofiltration, ultrafiltration, he modialysis, hemodiafiltration, medications, and pharmacokinetics; sele cted articles were cross-referenced, STUDY SELECTION: References selec ted were those considered to enhance the reader's knowledge of the pri nciples of CRRT, and to provide adequate therapies on drug disposition . DATA SYNTHESIS: CRRTs use filtration/convection and in some cases di ffusion to treat hemodynamically unstable patients with fluid overload and/or acute renal failure. Recent data suggest that positive outcome s may also be attained in patients with other medical conditions such as septic shock, multiple organ dysfunction syndrome, and hepatic fail ure. Age, ventilator support, inotropic support, reduced urine volume, and elevated serum bilirubin concentrations have been associated with poor outcomes. Complications associated with CRRT include bleeding du e to excessive anticoagulation and Line disconnections, fluid and elec trolyte imbalance, and filter and venous clotting, CRRT can complicate the medication regimens of patients for whom it is important to maint ain drug plasma concentrations within a narrow therapeutic range, Sinc e the physicochemical characteristics of a drug and procedure-specific factors can alter drug removal, a thorough assessment of all factors needs to be considered before dosage regimens are revised. In addition , an algorithm for drug dosing considerations based on drug and CRRT c haracteristics, as well as standard pharmacokinetic equations, is prop osed. CONCLUSIONS: The use of CRRT has expanded to encompass the treat ment of disease states other than just acute renal failure, Since ther e is great variability among treatment centers, it is premature to con clude that there is enhanced survival in CRRT-treated patients compare d with those who received conventional hemodialysis, This primer may h elp clinicians understand the need to individualize these therapies an d to prospectively optimize the pharmacotherapy of their patients rece iving CRRT.