Measurement of the delivery of dialysis in acute renal failure

Background Recent studies in patients with acute renal failure (ARF) have s hown a relationship between the delivered dose of dialysis and patient surv ival. However, there is currently no consensus on the appropriate method to measure the dose of dialysis in ARF patients. In this study, the dose of d ialysis was measured by blood- and dialysate-based kinetic methods in a gro up of ARF patients who required intermittent hemodialysis. Methods. Treatments were performed using a Fresenius 2008E volumetric hemod ialysis machine with the ability to fractionally collect the spent dialysat e. Single-, double-pool, and equilibrated Kt/V were determined from the pre -, immediate post-, and 30-minute post-blood urea nitrogen (BUN) measuremen ts. The solute reduction index was determined from the collected dialysate, as well as the single- and double-pool Kt/V. Results. Forty-six treatments in 28 consecutive patients were analyzed. The mean prescribed Kt/V (1.11 +/-. 0.32) was significantly greater than the d elivered dose estimated by single-pool (0.96 +/- 0.33), equilibrated (0.84 +/- 0.28), and double-pool (0.84 +/- 0.30) Kt/V (compared with prescribed, each P < 0.001). There was no statistical difference between the equilibrat ed and double-pool Kt/V (P = NS). The solute removal index, as determined f rom the dialysate, corresponded to a Kt/V of 0.56 +/- 0.27 and was signific antly lower than the single-pool and double-pool Kt/V (each P < 0.001). Conclusion. Blood-based kinetics used to estimate the dose of dialysis in A RF patients on intermittent hemodialysis provide internally consistent resu lts. However, when compared with dialysate-side kinetics, blood-based kinet ics substantially overestimated the amount of solute (urea) removal.