Severe dialyzer dysfunction undetectable by standard reprocessing validation tests

Severe dialyzer dysfunction undetectable by standard reprocessing validation tests. It is generally accepted that careful monitoring of total cell volume and ultrafiltration rates will ensure adequate function of reprocessed dialyzers. During routine urea kinetic measurements we noted that the percent of patients with clearances less than 200ml/min increased from 5% to 48% despite adherence to these validation tests. As these patients did not have evidence of recirculation in the vascular access, possible causes of dialyzer dysfunction were investigated. Injection of methylene blue into the dialysate port revealed non-uniform flow of dialysate in dialyzers from patients with markedly reduced clearances. In vitro studies of dialyzers subjected to sequential daily reprocessing, without patient exposure, demonstrated that in vitro clearances declined in one lot but not another. The initial clearances of 218 ± 4ml/min fell progressively to 112 ± 18 (P < 0.001) after 15 reuses. No effects of reprocessing were found in a different lot (230 ± 2 vs. 226 ± 4 ml/min). Soaking the dialyzers from the affected lot in either the disinfectant or dialysate solution caused a decline in the clearances which was less than that of serial reuse. Although the magnitude of the problem of dialyzer malfunction with reuse is unknown, careful attention to dialyzer function is warranted in patients treated with reprocessed dialyzers

Relationship between volume status and blood pressure during chronic hemodialysis

Relationship between volume status and blood pressure during chronic hemodialysis.BackgroundThe relationship between volume status and blood pressure (BP) in chronic hemodialysis (HD) patients remains incompletely understood. Specifically, the effect of interdialytic fluid accumulation (or intradialytic fluid removal) on BP is controversial.MethodsWe determined the association of the intradialytic decrease in body weight (as an indicator of interdialytic fluid gain) and the intradialytic decrease in plasma volume (as an indicator of postdialysis volume status) with predialysis and postdialysis BP in a cross-sectional analysis of a subset of patients (N = 468) from the Hemodialysis (HEMO) Study. Fifty-five percent of patients were female, 62% were black, 43% were diabetic and 72% were prescribed antihypertensive medications. Dry weight was defined as the postdialysis body weight below which the patient developed symptomatic hypotension or muscle cramps in the absence of edema. The intradialytic decrease in plasma volume was calculated from predialysis and postdialysis total plasma protein concentrations and was expressed as a percentage of the plasma volume at the beginning of HD.ResultsPredialysis systolic and diastolic BP values were 153.1 ± 24.7 (mean ± SD) and 81.7 ± 14.8mm Hg, respectively; postdialysis systolic and diastolic BP values were 136.6 ± 22.7 and 73.9 ± 13.6mm Hg, respectively. As a result of HD, body weight was reduced by 3.1 ± 1.3kg and plasma volume was contracted by 10.1 ± 9.5%. Multiple linear regression analyses showed that eachkg reduction in body weight during HD was associated with a 2.95mm Hg (P = 0.004) and a 1.65mm Hg (P = NS) higher predialysis and postdialysis systolic BP, respectively. In contrast, each 5% greater contraction of plasma volume during HD was associated with a 1.50mm Hg (P = 0.026) and a 2.56mm Hg (P < 0.001) lower predialysis and postdialysis systolic BP, respectively. The effects of intradialytic decreases in body weight and plasma volume were greater on systolic BP than on diastolic BP.ConclusionsHD treatment generally reduces BP, and these reductions in BP are associated with intradialytic decreases in both body weight and plasma volume. The absolute predialysis and postdialysis BP levels are influenced differently by acute intradialytic decreases in body weight and acute intradialytic decreases in plasma volume; these parameters provide different information regarding volume status and may be dissociated from each other. Therefore, evaluation of volume status in chronic HD patients requires, at minimum, assessments of both interdialytic fluid accumulation (or the intradialytic decrease in body weight) and postdialysis volume overload

Continuous ambulatory peritoneal dialysis and bone

Continuous ambulatory peritoneal dialysis and bone. We studied the effects of continuous ambulatory peritoneal dialysis (CAPD) on the histological manifestations of uremic bone disease. Twelve patients underwent bone biopsy immediately prior to and after one year of such treatment. Those with larger quantities of non-mineralized bone matrix (osteoid) experienced a reduction in relative osteoid volume, mean osteoid seam width, and total osteoid surface. Moreover, the use of time–spaced kinetic markers of mineralization (tetracycline) enabled us to demonstrate that CAPD usually decreased the amount of non-mineralized bone matrix by shortening mineralization lag time (that is, the interval from organic matrix deposition to its mineralization). The changes in the histomorphology appeared to occur independently of bone aluminum. These data indicate that CAPD generally enhances the mineralizing capacity of individual osteoblasts and suggests that such therapy is beneficial to the uremic skeleton