Clinical use of high-efficiency hemodialysis treatments: long-term assessment.

Significant technological changes in blood flow rate, dialyzer membrane permeability, bicarbonate dialysate, and ultrafiltration-controlled delivery systems permitted the implementation of 3 modifications to conventional hemodialysis as follows: high-efficiency hemodialysis (HEHD), high-flux hemodialysis (HFHD), and double-high-flux hemodiafiltration (HDF). The impact of these techniques on the quantity of the treatment administered and treatment time were assessed. One hundred and eighty-three patients were enrolled over 6 years. Monthly Kt/Vurea and dialysis treatment time were compared among the treatment techniques. In vivo extracorporeal clearances were measured for the dialyzers used. In vivo kinetically derived effective dialyzer clearances were calculated from Kt/V. Patient survival and standardized mortality ratio (SMR) were determined for each treatment modality. Treatment time averaged 192+/-28, 176+/-29, and 159+/-32 min, Kt/Vurea averaged 1.33+/-.34, 1.29+/-.30, 1.41+/-.32, and in vivo delivered urea clearance averaged 222+/-51, 272+/-34, and 333+/-43 mL/min for HEHD, HFHD, and HDF, respectively. These results were achieved even in patients with body weights in excess of 80 kgs. Net ultrafiltration rate during the treatment reached 20-30 mL/min, without clinical untoward effects. Blood flow rate ranged between 450-650 mL/min in all patients. Kaplan-Meier Survival analysis yielded a significant difference when high-efficiency treatments were compared with USRDS outcomes. Standardized mortality ratio analysis showed significance for only HDF vs. USRDS. High-efficiency treatments can provide the same quantity of treatment in a shorter period of time without affecting mortality. The increased spectrum of solutes removal provided by HFHD and HDF may be a further advantage of these treatments.

In vitro performance of hemodialysis membranes after repeated processing.

BACKGROUND: Dialyzers reprocessed with chlorine-based solutions have been associated with increases in ultrafiltration coefficient and middle-molecule removal. Increased pore size has been hypothesized as the mechanism for the latter phenomenon. Dialyzers exposed to Amukin-D (Amuchina Int Inc, Gaithersburg, MD), a chlorine-based reprocessing agent, were evaluated for changes in molecular weight (MW) cutoff and ultrafiltration properties. METHODS: In vitro MW cutoff studies were performed on Fresenius F-80A (Fresenius, Lexington, MA) and Gambro Polyflux 17 (Gambro, Lakewood, CO) hemodialyzers that were reprocessed 20 times using Amukin-D. Permeability (Uf-A), defined as the area from the ultrafiltered compartment (Uf) compared with the area from the equivalent arterial compartment (A), for dextran across the hemodialyzer membrane was determined after the initial use and after reuses 1, 5, 10, 15, and 20 by using size-exclusion chromatography. RESULTS: Uf-A for dextran increased approximately 10-fold between hemodialyzer reuses 1 and 5. Thereafter, additional reprocessing did not increase the Uf-A ratio further. MW cutoff increased during these 5 washes and did not change thereafter. CONCLUSION: Reprocessing with Amukin-D increased the MW cutoff and permeability of both hemodialyzers between reuses 1 and 5, resulting in a greater ultrafiltration rate and greater middle-molecule removal. After reuse 5, there were no further increases in MW cutoff with additional reprocessing in either hemodialyzer. This suggests that reprocessing and storage of each hemodialyzer with Amukin-D affects the permeability of dextran in a nonlinear fashion and to a finite level, such that subsequent reprocessing has no further effect on the MW cutoff of the membrane.