Impact of bleach cleaning on the performance of dialyzers with polysulfone membranes processed for reuse using peracetic Acid

Dialyzer performance may change with reuse depending on whether or not the dialyzer is cleaned with bleach. Bleach is usually used in conjunction with formaldehyde as the germicide. Because few data are available for dialyzers cleaned with bleach and disinfected with peracetic acid, we examined dialyzer performance in a cross-over study of dialyzers containing polysulfone membranes reprocessed using bleach and peracetic acid or peracetic acid alone. Each dialyzer was used for a total of 16 treatments, or until it failed standard criteria for continued use. Urea, beta2-microglobulin, and albumin removal were determined during the first, second, seventh, and 16th use of each dialyzer. Urea removal did not differ between the two reprocessing methods and did not change with reuse. Overall, beta2-microglobulin removal remained unchanged in dialyzers reprocessed with peracetic acid alone, but tended to increase after the seventh use in dialyzers reprocessed with bleach and peracetic acid. Approximately 60% of beta2-microglobulin removal resulted from trapping of beta2-microglobulin at the dialyzer membrane. Albumin loss into the dialysate was clinically insignificant throughout the study with both reprocessing methods. These data show that the clearance of both small and large molecules by dialyzers containing polysulfone membranes is well maintained by reprocessing with peracetic acid and that additional cleaning with bleach has limited impact on performance.     

Dialyzer Reuse Following Manual Reprocessing with a New Sterilant, RenNew-D

Dialysis patients are at risk for toxicity from formaldehyde used in the reprocessing of dialyzers for reuse; therefore, replacing formaldehyde as a dialyzer sterilant would be advantageous. The potential for RenNew-D as a sterilizing agent was investigated in seven stable in-center hemodialysis patients over 20 consecutive dialyses with cuprammonium cellulose hollow-fiber dialyzers. Treatment with RenNew-D showed no toxicity to patients or dialyzers except for two blood leaks occurring in one patient. The mean number of dialyzer uses was 4.9. In all the dialyzers that passed functional testing small solute clearances were maintained with reuse. The ability of RenNew-D to improve the biocompatibility of reused dialyzers was documented with mean neutrophil counts falling to only 78% of initial values during first reuse of dialyzers processed with RenNew-D compared with a decrease in neutrophil count to 2% of initial values during first use of the same dialyzers. Our results suggest that RenNew-D may be a useful alternative to formaldehyde for the purpose of dialyzer reuse. A reuse procedure that includes processing with RenNew-D is associated with improved biocompatibility, possibly because of maintenance of the blood-derived membrane coating established during prior dialysis.     

Dialyzer reuse-Part I: Historical perspective

The first apparatus for hemodialysis in animals, made painstakingly by Abel et al. in their laboratory at the beginning of 20th century, was cleaned with acid-pepsin to digest blood, disinfected with thymol, and reused for up to 30 experiments for as long as 8 months. The obvious incentive was saving time. In the early years of hemodialysis in patients, dialyzers and lines were assembled and sterilized immediately before dialysis. Various methods of dry and moist heat sterilization and miscellaneous chemical agents were employed for disinfection. Significant time was required to assemble the dialyzers, so there was an incentive to reuse previously assembled dialyzers to save time, especially for home hemodialysis. Bleach to clean and formaldehyde to disinfect the membranes and lines was used for this purpose. Preassembled dialyzers, commercially introduced in the 1950s, were the most expensive components of hemodialysis systems, therefore reprocessing of these dialyzers was the most effective way to save money. Refrigeration of coil dialyzers with blood, introduced in the mid-1960s, was associated with frequent febrile reactions and was soon abandoned. Preassembled coil and plate dialyzers permitted almost complete return of blood after dialysis and led to the introduction of chemical disinfection for dialyzer reprocessing. A variety of disinfectants have been used. Formaldehyde was the most common disinfectant until the end of the 1970s. Sodium hypochlorite was used to clean the majority of dialyzers and to sterilize dialyzers with polyacrylonitrile membranes. In the early 1980s, peracetic acid and glutaraldehyde started to compete with formaldehyde. By the 1990s, formaldehyde had become less popular than peracetic acid. In the mid-1990s, disinfection and membrane cleaning with acetic acid and heat was introduced. Manual reprocessing was replaced by early reuse machines in the mid-1970s and a more sophisticated second generation of automated hemodialyzer reprocessing machines followed in the late 1970s. Recently disinfection of dialyzers with moist heat has resumed. Saving both time for the patient and money for the provider were the main motivations for designing a new machine for daily home hemodialysis. The machine, developed in the 1990s, cleans and moist-heat disinfects the dialyzer and lines in situ so they do not need to be changed for a month. In contrast, the reuse of dialyzers in home hemodialysis patients treated with other hemodialysis machines has become less popular and is almost extinct.     

Dialyzer reuse--part II: advantages and disadvantages

Although single dialyzer use and reuse by chemical reprocessing are both associated with some complications, there is no definitive advantage to either in this respect. Some complications occur mainly at the first use of a dialyzer: a new cellophane or cuprophane membrane may activate the complement system, or a noxious agent may be introduced to the dialyzer during production or generated during storage. These agents may not be completely removed during the routine rinsing procedure. The reuse of dialyzers is associated with environmental contamination, allergic reactions, residual chemical infusion (rebound release), inadequate concentration of disinfectants, and pyrogen reactions. Bleach used during reprocessing causes a progressive increase in dialyzer permeability to larger molecules, including albumin. Reprocessing methods without the use of bleach are associated with progressive decreases in membrane permeability, particularly to larger molecules. Most comparative studies have not shown differences in mortality between centers reusing and those not reusing dialyzers, however, the largest cluster of dialysis-related deaths occurred with single-use dialyzers due to the presence of perfluorohydrocarbon introduced during the manufacturing process and not completely removed during preparation of the dialyzers before the dialysis procedure. The cost savings associated with reuse is substantial, especially with more expensive, high-flux synthetic membrane dialyzers. With reuse, some dialysis centers can afford to utilize more efficient dialyzers that are more expensive; consequently they provide a higher dose of dialysis and reduce mortality. Some studies have shown minimally higher morbidity with chemical reuse, depending on the method. Waste disposal is definitely decreased with the reuse of dialyzers, thus environmental impacts are lessened, particularly if reprocessing is done by heat disinfection. It is safe to predict that dialyzer reuse in dialysis centers will continue because it also saves money for the providers. Saving both time for the patient and money for the provider were the main motivations to design a new machine for daily home hemodialysis. The machine, developed in the 1990s, cleans and heat disinfects the dialyzer and lines in situ so they do not need to be changed for a month. In contrast, reuse of dialyzers in home hemodialysis patients treated with other hemodialysis machines is becoming less popular and is almost extinct.     

Effect of Dialyzer Reprocessing Methods on Complement Activation and Hemodialyzer-Related Symptoms

The effects of different dialyzer processing methods and of reuse on complement activation and dialyzer-related symptoms were studied in 96 maintenance hemodialysis patients. New dialyzers were either unprocessed (Group 1) or machine-washed with bleach and stored in formaldehyde (Group 2). Reused dialyzers were manually cleansed using the combination of bleach and formaldehyde (Group 3), or machine-washed in formaldehyde (Group 4) or peracetic acid (Group 5). Prewashed new dialyzers (Group 2) were associated with greater complement activation during dialysis when compared with unprocessed, new dialyzers (Group 1) (p less than 0.05). Reused, unbleached but formaldehyde-treated or peracetic acid-treated dialyzers (Groups 4 and 5) were associated with reduced complement activation (p less than 0.05). Complement activation was not reduced when bleach was used for reprocessing (Group 3). The percentage of patients without symptoms during dialysis was significantly greater with reused dialyzers than with new dialyzers (Groups 3 through 5 versus Groups 1 and 2; 39 versus 25%; p = 0.035). The severity of total symptoms correlated significantly (p = 0.0004) with complement activation. Our results suggest that total symptoms during dialysis are correlated with the degree of complement activation. However, trends in the data pertaining to chest pain suggest that factors other than complement activation may be important in the pathogenesis of some dialyzer-related symptoms.     

Effect of RenNew-D as a sterilant on the performance of reused dialyzers

RenNew-D (Alcide), a novel demand-release sporocidal agent, was employed instead of formaldehyde in the reprocessing for reuse of cuprophan hollow fiber dialyzers (Gambro) and the performance of these dialyzers was evaluated over 40 consecutive dialyses in six patients on maintenance hemodialysis. When RenNew-D was part of automated reprocessing performed with 4.3% bleach as specified by the manufacturer (Lixivitron), dialyzer survival was prolonged (16.7 +/- 7.2 uses) and hemodialysis neutropenia was unchanged with reuse. When RenNew-D was part of manual reprocessing conducted in the absence of bleach, marked improvement in dialyzer biocompatibility was observed but with a decreased survival (4.8 +/- 3.0). The majority of dialyzer failures were due to a fall in fiber bundle volume below a 85% set limit. Small solute clearances were maintained with both types of reprocessing. Dialyses were well tolerated throughout. Our data suggest that RenNew-D is a safe and efficacious product which can serve as a valuable alternative to formaldehyde for the purpose of dialyzer reuse.     

Relationship between dialyzer reuse and the presence of anti-N-like antibodies in chronic hemodialysis patients.

One hundred eleven chronic hemodialysis patients from five dialysis units were tested for the presence of antibodies reactive with red blood cell N substance; 77 patients were available for follow-up study after 18 to 24 months. Initially, 18 patients (16%) had serum anti-N-like antibodies. Thirteen of these patients were in a home dialysis program and were reusing hollow fiber dialyzers. The other five had practiced hollow fiber dialyzer reuse in the past. None of 37 patients using coil dialyzers had anti-N-like antibody. On follow-up testing, anti-N-like antibody persisted in all patients restudied except for one who had a successful renal transplant. Anti-N-like antibodies developed in four additional patients: three were reusing hollow fiber dialyzers at the time, but one had not reused dialyzers for 24 months. Statistical analyses indicated that dialyzer reuse, hollow fiber dialyzers, and home dialysis were significantly related to the presence of anti-N-like antibodies. We interpret the clinical and statistical data to indicate that dialyzer reuse is the major clinical factor in the development of anti-N-like antibody. The likely mechanism involves the prolonged exposure of red cells trapped in the dialyzer to formaldehyde used in preparing dialyzers for reuse. No adverse clinical effects of anti-N-like antibodies were evident in our patients, but hemolysis and acute transplant failure have been reported by others.     

Water permeability of high-flux dialyzer membranes after Renalin reprocessing

Dialysis with high-flux membranes is widely used, in part, because they are thought to increase the removal of middle molecules when compared with low-flux membranes. Dialyzer reprocessing; however, is thought to alter middle molecule clearance. Renalin, a mixture of germicidal agents, has widespread use in dialyzer reprocessing. We determined the effect of Renalin reprocessing on the water permeability of three different dialyzers of Fresenius (F80A and 200A) and Gambro (17R) manufacture using the dead-end filtration method. Two hundred and seventeen, predominantly used but some new, dialyzers were evaluated. Water permeability of the used, but not the new, dialyzers fell abruptly and dramatically with reprocessing. The permeability fell almost 70% in the F80A dialyzer after three reprocessing procedures with similar, but somewhat slower declines, seen in the other two dialyzers. We conclude that there is a decline in water permeability seen in Renalin reprocessed dialyzers. This factor and the associated change in solute clearance and ultrafiltration characteristics should be considered in assessing the effectiveness of dialyzer reprocessing.     

Effect of dialyzer reprocessing with Renalin on serum beta-2-microglobulin and complement activation in hemodialysis patients.

The peracetic acid-based sterilant Renalin is increasingly being used for reprocessing hemodialyzers. In order to evaluate the effects of reprocessing on beta 2-microglobulin (beta 2M) kinetics and complement activation in chronic hemodialysis patients, we compared 4 dialyzer membranes on 1st, 2nd and 4th use of the membrane. Dialysis with new cuprammonium rayon dialyzers (0.8 m2) for 4 h resulted in a nonsignificant increase in serum beta 2M concentrations of 10.7% (corrected for changes in extracellular volume) and significant generation of the complement component C3a des Arg. On reuse, minimal changes in serum beta 2M levels were noted and complement activation was absent. Dialysis with new cellulose acetate (CA, 1.5 m2), polyacrylonitrile (AN69 HF, 1.6 m2) or polymethylmethacrylate (PMMA, 1.6 m2) membranes resulted in significant decreases in serum beta 2M levels (19.5, 31.7 and 50.8%, respectively). Reprocessing had negligible effects on the removal of beta 2M by CA and AN69, but by the 4th use halved the effectiveness of PMMA. Reprocessing reduced the significant generation of C3a des Arg observed with new CA and PMMA membranes. We conclude that, except for PMMA, Renalin reprocessing has minor effects on the ability of the membranes to remove beta 2M and improves the biocompatibility of all membranes studied.     

UNRESOLVED ISSUES IN DIALYSIS: Dialyzer Best Practice: Single Use or Reuse?

Outcome studies have shown either no additional risk or a small additional risk for hospitalization and mortality associated with reprocessing dialyzers. Although the risks from reprocessing dialyzers have yet to be fully elucidated, reuse can be done safely if it is performed in full compliance with the standards of Association for the Advancement of Medical Instrumentation (AAMI). Like most industrial processes, however, complete control of the reuse process in a clinical environment and full compliance with regulations at all times is difficult. Potential errors and breakdowns in the reuse process are continuing concerns. The quality controls for reprocessing of dialyzers are not equal to the rigor of the manufacturing process under the purview of the U.S. Food and Drug Administration (FDA). Therefore, if one were to determine "best practice," single use is preferable to reuse of dialyzers based on medical criteria and risk assessment. The long-term and cumulative effects of exposure to reuse reagents are unknown and there is no compelling medical indication for reprocessing of dialyzers. The major impediment when deciding to convert from reuse to single use of dialyzers is economic. The experience in Fresenius Medical Care-North America (FMCNA) facilities demonstrates that converting from a practice of reuse to single use is achievable. However, the overall economic impact of conversion to single use is provider specific. The dominance of reuse has been negated of late by a major shift in practice toward single use. Physicians and patients should be well informed in making decisions regarding the practice of single use versus reuse of dialyzers.     

Dialyzer Reuse: Interaction Between Dialyzer Membrane, Disinfectant (Formalin), and Blood During Dialyzer Reprocessing

Abstract: The growing practice of dialyzer reuse in recent years is mainly based on medical and economic considerations. However, adverse reactions such as immunohemolytic anemia due to anti-N_from antibody associated with dialyzer reuse have been reported. In this study, scanning electron microscopy and cytologic staining were used to evaluate the interaction between blood components and the reprocessed synthetic dialyzer membrane (polysulfone) after disinfectant (formaldehyde) treatment. The results showed that various blood components such as fibrin and blood cells still adhered to the dialyzer membrane after reprocessing. The study also demonstrated that the adhered denatured blood components could be detached by sonication andlor simulated hemodialysis and then gain access into the circulation. The re-entry of the denatured blood components to the patients exposed to reused dialyzers may result in an enhanced imrnunological response which may contribute to antibody formation (such as anti-N_from antibody) with a reused hemodialyzer.     

Influence of Reuse and of Reuse Sterilants on the First-Use Syndrome

Over a 4 year period, five of 98 patients at our dialysis unit developed signs and symptoms consistent with first-use syndrome (FUS). Marked improvement was noted after subjecting new dialyzers to automated processing using either formaldehyde or peracetic acid. No episodes of FUS occurred in patients being treated with reused dialyzers. Use of formaldehyde sterilization was associated with development of anti-N-like antibodies in the blood of four (8%) of 50 patients over a follow-up period of 14 months. In two patients on the reuse program, itching during dialysis resolved after changing from formaldehyde-sterilization to a method using peracetic acid. Our results confirm the beneficial effects of reuse with regard to first-use syndrome. However, our data also suggest that use of formaldehyde, the most common reuse sterilant, continues to be associated with undesirable clinical and laboratory side effects.     

Anaphylactoid reactions associated with reuse of hollow-fiber hemodialyzers and ACE inhibitors.

From July 18 through November 27, 1989, 12 anaphylactoid reactions (ARs) occurred in 10 patients at a hemodialysis center in Virginia. One patient required hospitalization; no patients died. ARs occurred within minutes of initiating dialysis and were characterized by peripheral numbness and tingling, laryngeal edema or angioedema, facial or generalized sensation of warmth, and/or nausea or vomiting. All 12 ARs occurred with dialyzers that had been reprocessed with an automated reprocessing system. A cohort study, including all patients undergoing dialysis sessions on the six days when an AR occurred, showed that the patients who experienced ARs were significantly more likely than patients who did not to be treated with angiotensin-converting enzyme (ACE) inhibitors (7/10 vs. 3/33; relative risk = 7.9; 95% confidence interval = 2.5 to 25.2) and to have been exposed to reused dialyzers rather than to new dialyzers (12/70 sessions vs. 0/31; P = 0.016). In those sessions using a reused dialyzer, the mean number of dialyzer uses in case-sessions was significantly higher than for noncase-sessions (10.3 vs. 6.2; P = 0.016). After reuse of dialyzers was discontinued at the center, no further ARs occurred, despite the continued administration of ACE inhibitors. This is the first report of an outbreak of ARs associated exclusively with reused dialyzers. We hypothesize that interactions between a dialyzer that has been repeatedly reprocessed and reused, blood, and additional factors, such as ACE inhibitors, increased the risk of developing ARs.     

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 200 ml/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 +/- 4 ml/min fell progressively to 112 +/- 18 (P less than 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.     

Dialyzer-dependent changes in solute and water permeability with bleach reprocessing

The effects of bleach reprocessing on the performance of high-flux dialyzers have not been comprehensively characterized. We compared the effects of automated bleach/formaldehyde reprocessing on solute and hydraulic permeability for cellulose triacetate (CT190) and polysulfone (F80B) dialyzers using an in vitro model. Dialyzers were studied after initial blood exposure (R0) and after 1 (R1), 5 (R5), 10 (R10), and 15 (R15) reuse cycles. Ultrafiltration coefficient (K(uf)), serial clearances, and/or sieving coefficients (SCs) of urea, creatinine, vancomycin, inulin, myoglobin, and albumin were determined. Urea, creatinine, and vancomycin clearances and SCs did not significantly differ from R0 to R15 with either dialyzer. Inulin clearances and SC also did not significantly change from R0 to R15 for the CT190. However, these same values for the F80B significantly increased (P < 0.05). The inulin clearance and SC values for the CT190 dialyzer were significantly higher than those for the F80B at all stages except R15. Myoglobin clearances significantly increased over 15 reuses for both dialyzers (P < 0.01). However, CT190 myoglobin clearances were significantly higher at all stages (R0 = 37.7 +/- 9.7; R15 = 52.5 +/- 8.8 mL/min) than the F80B (R0 = negligible; R15 = 41.3 +/- 16.5 mL/min; P < 0.01). Albumin pre- and postdialysis SCs significantly increased for both dialyzers (P < 0.01). K(uf) for R0 and R15 were 52.3 +/- 3.3 and 52.6 +/- 7.6 mL/h/mm Hg for CT190 (P = not significant) and 48.8 +/- 4.4 and 87.3 +/- 7.0 mL/h/mm Hg for F80B (P < 0.0001). We conclude that bleach reprocessing significantly increases larger solute and hydraulic permeability of high-flux cellulosic and polysulfone dialyzers. This effect is more pronounced for the polysulfone membrane. Until 10 reuses or greater, the removal of solutes greater than 1,500 d is significantly compromised with the polysulfone dialyzer used in this study.     

The effects of reprocessing cuprophane and polysulfone dialyzers on beta 2-microglobulin removal from hemodialysis patients

To further define the relationship between dialyzer reuse and the removal of beta 2-microglobulin (beta 2M) during dialysis, 26 patients who received hemodialysis were studied. Thirteen patients were dialyzed with conventional cuprophane dialyzers, and thirteen patients were dialyzed with high-flux polysulfone dialyzers. Patients in each group were dialyzed with only new dialyzers during the primary-use phase of the study, and reprocessed dialyzers during the reuse phase. Dialyzers were used six times during the reuse phase. Serum beta 2M levels were measured both predialysis and postdialysis, and adjusted for fluid loss. Dialysis with conventional cuprophane new dialyzers during the primary-use phase of the study resulted in a 3.3% increase in serum beta 2M levels, and a 2.4% increase in serum beta 2M levels during the reuse phase. The difference in the change of the concentration of beta 2M between primary-use and reuse phases was not statistically significant. Dialysis with high-flux polysulfone new dialyzers during the primary-use phase was associated with a decrease of 59.5% in the mean postdialysis concentration of serum beta 2M compared with the predialysis level. A corresponding decrease of 62.6% in serum beta 2M levels was observed after dialysis with high-flux polysulfone reprocessed dialyzers during the reuse phase. These data show no evidence of an adverse effect on the clearance of beta 2M during dialysis from the reuse of dialyzers up to six times. The results confirm previous studies that have reported that high-flux dialysis with polysulfone dialyzers removes substantial amounts of beta 2M, and dialysis with conventional cuprophane dialyzers does not.     

Beta 2-microglobulin kinetics in maintenance hemodialysis: a comparison of conventional and high-flux dialyzers and the effects of dialyzer reuse

beta 2-Microglobulin (beta 2M) forms synovial and bony amyloid deposits in long-term hemodialysis patients. To define the kinetics of beta 2M during hemodialysis and the effects of dialyzer reprocessing, we measured serum beta 2M, plasma C3a, and neutrophil counts immediately predialysis; 15, 90, and 180 minutes after beginning dialysis; and 15 minutes postdialysis in ten chronic hemodialysis patients. The studies were performed during first and third uses of cuprammonium rayon and polysulfone dialyzers processed by rinsing with water, then bleach, in an automated system (Seratronics DRS 4) and then packed in 1.5% formaldehyde. Mean serum beta 2M (corrected for ultrafiltration) decreased by 16.6% +/- 18.1% with new cuprammonium dialyzers and 57.1% +/- 12.8% with new polysulfone dialyzers. Dialyzer reprocessing had no significant effect on this decline. Predialysis serum beta 2M decreased by 30.4% +/- 15.5% 1 month after switching from cuprammonium to polysulfone dialyzers; these levels remained stable after 3 months of dialysis with polysulfone. Complement activation and neutropenia during dialysis were significantly more marked with cuprammonium, but were not affected by reprocessing of either dialyzer. In vitro adsorption of 124I-beta 2M to polysulfone fibers was greater than to cuprammonium; adsorption was not influenced by dialyzer reprocessing.     

The Adequacy of Fragmin as a Single Bolus Dose with Reused Dialyzers

Abstract: Thirty-four hemodialysis patients were studied in a crossover fashion to compare the effectiveness of bolus-dose Fragmin (a low molecular weight heparin) with regular heparin usage in hemodialysis. For each anticoagulant, 3 dialyzes were studied for each patient; the first sessions involved a new dialyzer, and the subsequent sessions involved dialyzers reprocessed with peracetic acid. To assess the effectiveness of the anticoagulation regimens, the following were measured: the dialyzer fiber bundle volume and the instantaneous dialyzer clearances for urea (1 h into the second session). In addition, factor Xa levels were measured in 5 patients during the first and second sessions at 0 min, 30 min, and 4 h. Fiber bundle volumes were (in ml) 75.4 ± 8.8, 73.0 ± 8.9, and 73.5 ± 7.6 on first, second, and third uses with Fragmin (p = ns); and 77.8 ± 9.0, 73.4 ± 8.1, and 73.8 ± 8.1 with heparin (p < 0.001 second and third vs. first). Thus, there were no significant differences between Fragmin and heparin. Instantaneous dialyzer clearances were 165.8 ± 12.6ml/min with Fragmin and 163.8 ± 9.8 with heparin (p = ns). Factor Xa levels were 0 predialysis, 0.81 ± 0.17 U/ml at 30 min on first use, and 0.92 ± 0.09 U/ml on second use (p = ns); they were 0.51 ± 0.21 U/ml at 4 h on first use and 0.61 ± 0.16 U/ml on second use (p = ns). Thus, bolus-dose Fragmin provided similar results to constant infusion heparin and is not deleteriously influenced by reprocessing dialyzers with peracetic acid.     

Risk factors for hip fracture among patients with end-stage renal disease

BACKGROUND: Although bone disease is well described among end-stage renal disease (ESRD) patients, little attention has been paid to the occurrence of fracture. We sought to identify factors that are associated with hip fracture among ESRD patients. METHODS: Data from patients who participated in the United States Renal Data System Dialysis Morbidity and Mortality Study Wave 1 were used for this study. Hip fractures occurring among these patients between 1993 and 1996 were identified from Medicare claims data available from the United States Renal Data System. Cox proportional hazards models were used to estimate the risk of hip fracture associated with demographic and medical variables. RESULTS: Of the 4952 patients included in this analysis, 103 sustained a hip fracture. In the multivariate analysis, age (per increasing decade, RR = 1.40, 95% CI 1.20, 1.64), female gender (RR = 2.26, 95% CI 1.48, 3.44), race (blacks compared with whites, RR = 0.58, 95% CI 0.37, 0.91), body mass index (per 1 unit increase, RR 0.89, 95% CI 0.86, 0.93), and the presence of peripheral vascular disease (RR 1.94, 95% CI 1.29, 2.92) were independently associated with hip fracture. Serum intact parathyroid hormone (iPTH), aluminum, diabetes, and bicarbonate levels did not appreciably influence the risk of hip fracture. CONCLUSIONS: Demographic and other characteristics that predict risk of hip fracture in the population at large also do so in ESRD patients. However, we could identify no characteristics of ESRD or its treatment that were independently related to hip fracture incidence.     

Outbreak of gram-negative bacteremia and pyrogenic reactions in a hemodialysis center

During the period from April 4, 1988, to April 20, 1988, nine pyrogenic reactions and five gram-negative bacteremias occurred in 11 patients undergoing dialysis. All pyrogenic reactions and gram-negative bacteremias occurred among patients in whom a reprocessed dialyzer was used. The rate of pyrogenic reactions or bacteremias per 100 sessions using a reprocessed dialyzer was higher than in sessions during which a new dialyzer was used (4.5 vs. 0; p = 0.03). Dialyzers were manually reprocessed with 2.5% Renalin germicide. The Renalin concentrations varied widely in 12 dialyzers stored after manual reprocessing during the epidemic period (0.9-4.2%); the median endotoxin concentrations varied from 0 to 246 ng/ml and were higher in dialyzers with Renalin concentrations less than or equal to 1.0% than in dialyzers with higher concentrations (p = 0.01). Experiments using a dilution technique described by a technician resulted in Renalin concentrations ranging from 1.4% at the surface to 3.5% at the bottom of the preparation container. These findings suggest that failure to adequately admix Renalin during dilution may be associated with low levels of disinfectant, high levels of bacteria and endotoxins in dialyzers, and outbreaks of pyrogenic reactions and gram-negative bacteremias in dialysis patients.