Reduction of platelet/fibrin deposition in haemodialysers by aspirin administration.

Aspirin, a drug known to inhibit the platelet release reaction, was evaluated for its potential in reducing platelet/fibrin deposition in hollow fibre dialysers. Twelve patients with endstage renal failure were given the drug under controlled conditions while being treated by regular maintenance haemodialysis. After base-line data were collected during a mean number of 11.7 dialysers per study, observations were repeated for a mean of 9.3 dialysers, during which time each patient took 600 mg of aspirin by mouth every morning. Thrombus deposition, measured by volume loss of the blood compartment of the dialyser fibre bundle, was significantly reduced (P less than 0.05) during aspirin administration in six of the 12 studies. The mean volume loss of the fibre bundle in these six studies (responders) was 25% per dialysis during the control period, and 13% with aspirin; in the other six studies (non-responders), the mean values were 8% and 6% respectively. Aspirin prolonged the bleeding time in all patients, and significantly (p less than 0.05) impaired platelet aggregation in both responders and non-responders.

Hemodialyzer performance: an assessment of currently available units.

The performance characteristics of nine currently available disposable parallel-flow dialyzers were assessed, both before and immediately following dialysis, by measuring: (i) in vitro clearances of C14 labeled urea, creatinine, and sucrose and H3 labeled vitamin B12 at standard conditions, (ii) ultrafiltration rates in saline at 37C, and (iii) loss in the mass transfer coefficient-membrane area product (hoA), following a single dialysis. Parallel-plate dialyzers underwent considerable membrane stretching during dialysis and exhibited greater variability, particularly regarding vitamin B12 clearance and ultrafiltration ability, than did capillary dialyzers. The variability in plate units was greater for large-area dialyzers where there were 25 to 26 blood channels. However, despite considerable differences in performance characteristics, all dialyzers were judged to be clinically acceptable in terms of both solute clearance and ultrafiltration characteristics.

Long-term continuous ambulatory peritoneal dialysis. Mass transfer and nutritional and metabolic stability.

Long-term mass transfer and nutritional and metabolic stability of end-stage renal disease patients maintained on continuous ambulatory peritoneal dialysis (CAPD) continue to be of concern. This study longitudinally monitored 43 Japanese CAPD patients (29 males, 14 females) from three centres within the Tokyo Metropolitan Area for an average period of 15 +/- (SD) 8 months. The mean time for patients on CAPD at study initiation was 18 +/- 15 months. Monitored parameters included urea and creatinine mass transfer coefficients, clearances and blood levels, ultrafiltration, lipid levels, dietary protein intake, and weight. Lipid data were also gathered retrospectively from patient records from the time of CAPD initiation. The results were analyzed using regression growth curve analysis and analysis of variance. Statistically significant linear rises with time were apparent only for the creatinine mass transfer coefficients, although this was not considered clinically significant in terms of changes either in peritoneal creatinine clearances or ultrafiltration. Serum cholesterol levels were found to rise significantly above pre-dialysis levels 11 months after CAPD onset, thereafter returning to levels not significantly above baseline levels. In summary, CAPD provided stable, acceptable treatment over the study period.

Sorbent membrane dialysis in uremia.

The inclusion of activated charcoal within hemodialysis membranes offers potentially improved plasma clearance of creatinine and middle molecules. However, the carbon becomes saturated with continued use and beyond 1 h removal of solutes is by dialysis alone. Two independently conducted crossover studies, to assess the efficacy of sorbent membrane dialysis (SMD) in the treatment of uremia, found predialysis urea levels increased by approximately 15%, creatinine by 10-15%, and inorganic phosphate levels by 10-18% on SMD compared to conventional hemodialysis. One study also observed "middle molecule' (peak "b') levels elevated. No differences were observable in the clinical status of patients. The results suggest that the charcoal content of the SMD device is too small to effect any advantages over conventional dialysis.