The effectiveness of on-line hemodiafiltration on beta-2 microglobulin clearance in end stage renal disease.

OBJECTIVE: To compare beta2-microglobulin (beta2M) clearance between on-line hemodiafiltration (HDF) and high flux hemodialysis (HFHD). MATERIAL AND METHOD: The total, convection/diffusion, and membrane adsorption components of beta2M clearance in 10 hemodialysis patients treated with on-line HDF at the replacement fluid rates of 75 (HDF75) and 125 (HDF125) mL/min, were determined and compared with HFHD. RESULTS: The total beta2M clearance in the HDF 125 group was significantly higher than the HDF75 group (124.5 +/- 4.4 vs 101.3 +/- 4.1 mL/min; p < 0.05); both values were much greater than the HFHD group (p < 0.01). The convection/diffusion was the major portion of total beta2M clearance in all three groups. The values of convection/diffusion and membrane adsorption in both HDF groups were about 2 and 3 times, respectively, of the HFHD group (p < 0.01). Both components of beta2M clearance in the HDF125 group did not statistically differ from the HDF75 group, however; the value of convection/diffusion clearance in HDF125 was more than in the HDF75 group. Regarding Kt/Vurea and phosphate clearance, there were no significant differences among the study groups. CONCLUSION: On-line HDF could provide more beta2M clearance than HFHD by increasing both the convection/ diffusion, and membrane adsorption clearances. HDF125 provided more total beta2M clearance than HDF75 from the convection/diffusion mechanism while the adsorptive mechanisms were equal.

Target quantity for twice-a-week hemodialysis: the EKR (equivalent renal urea clearance) approach.

OBJECTIVE: The targets of dialysis per session, in terms of Kt/V and URR are well established for thrice-a-week hemodialysis (HD). The target values of these parameters could not be applied for the patients undergoing twice-a-week HD, which is performed in several developing countries. The equivalent renal urea clearance EKR (EKR [mL/min) = G (mg/min)/TAC (mg/mL)], which measures urea clearance in a continuous fashion, has been used in comparing amount of dialysis among the different modalities. For any chronic dialysis regimens the target EKRc, which was normalized to urea volume of distribution of 40 L, would be above 13 mL/min. Therefore, there is no data available regarding Kt/V, URR, and EKRc for twice-a-week HD. MATERIAL AND METHOD: The EKRc of 26 Thai patients treated with twice-a-week high flux HD were measured monthly for 12 months. The Kt/V, URR, and serum albumin were also measured monthly. RESULTS: Overall, the mean EKRc of 294 patient-month analysis was 11.68 +/- 0.16 mL/min. Monthly EKRc had a high correlation to Kt/V (r = 0.80) and URR (r = 0.82). When serum albumin was employed as a surrogate marker for treatment failure, ROC analysis revealed that EKRc above 13 mL/min had 90% and 100% probabilities to maintain monthly and 12-month serum albumin levels above 4 gm/dL, respectively. To obtain the target EKRc above 13 mL/min at 90 and 95% confidence, the values of Kt/V per session were 2.11 and 2.25, respectively while those of URR were 82.89 and 84.52%, respectively. CONCLUSION: For twice-a-week HD, to have the EKRc level above 13 mL/min, at 95% confidence, the Kt/V should exceed 2.2 and the URR should exceed 85% per session.

Comparison of different culture methods on bacterial recovery in hemodialysis fluids.

To examine the culture method that could provide the highest bacterial recovery, 143 reverse osmosis water samples used in hemodialysis were collected for comparison of the media (Tryptic Soy Agar, TSA vs Reasoner's 2A Agar, R2A), the temperature (20 degrees C vs 37 degrees C), the duration of incubation (48-hour vs 7-day), and the culture technique (membrane filtration vs spread plate methods). The European Best Practice Guideline method, R2A at 20 degrees Cfor 7-day incubation provided higher bacterial recovery than the Association for the Advancement of Medical Instrumentation (AAMI) method, TSA at 37 degrees C for 48-hour incubation. The membrane filtration method gave better yield than the spread plate method. As such, the European Best Practice Guideline method in combination with the membrane filtration technique would be the culture method of choice for hemodialysis fluids.