Drug dosing during continuous arteriovenous hemofiltration.
An overview of continuous arteriovenous hemofiltration (CAVH), which is an alternative to hemodialysis and peritoneal dialysis in the management of acute renal failure, is provided, and literature concerning drug clearance via hemofiltration is reviewed. CAVH is a slow, continuous process that removes, by convective mass transport, non-protein-bound solutes smaller than 10,000 daltons from blood diverted through an extracorporeal filter. The system provides a creatinine clearance of approximately 10 mL/min. The sieving coefficient of a particular compound reflects its ability to permeate the filter membrane and is primarily influenced by protein binding. Clearance of a compound depends on its sieving coefficient and the ultrafiltration rate. Methods for estimating drug clearance, the amount of drug removed per time interval, and appropriate drug dosages are discussed. Many drugs commonly used in an intensive-care setting, including aminoglycosides, cephalosporins, acyclovir, vancomycin, phenobarbital, ranitidine, and theophylline, can be expected to have a limited but clinically important clearance during CAVH. CAVH substantially enhances the current treatment of acute renal failure; although limited data for specific drugs are available in the literature, drug dosages may be adjusted based on the methods outlined in this review.