Ultrafiltration/Hemofiltration Overview: Where Does CAVH Fit?

Abstract

Hemofiltration was initiated as a test strategy to evaluate the pathophysiologic significance of “middle molecules” for the uremic patient (1,2). As such, the system was devised for use in the patient with stable end stage renal failure. As originally applied it was recognized to be at a disadvantage in the removal of low molecular weight solutes (< 350 daltons) when compared with hemodialysis. Many changes in how convective mass transport is applied have occurred since then. Postdilution versus predilution (3), hemodiafiltration (4–6) combining the best of both diffusion and convection, and continuous low efficiency hemofiltration for the treatment of acute renal failure (7) are some of the creative applications to which this ultrafiltration methodology has been put. In placing this spectrum of techniques into the perspective of “where does CAVH fit,” I would wish to take a brief backward look in order to extrapolate the future.