The effects of peracetic acid-hydrogen peroxide reprocessing on dialyzer solute and water permeability

Evaluation and control of microbial and chemical contamination in dialysis water plants of Italian nephrology wards

BACKGROUND

Patients receiving haemodialysis are exposed to a large volume of dialysis fluid. The Italian Society of Nephrology (ISN) has published guidelines and microbial quality standards on dialysis water (DW) and solutions to ensure patient safety.

AIM

To identify microbial and chemical hazards, and evaluate the quality of disinfection treatment in DW plants.

METHODS

In 2015 and 2016, water networks and DW plants (closed loop and online monitors) of nine dialysis wards of Italian hospitals, hosting 162 dialysis beds overall, were sampled on a monthly basis to determine the parameters provided by ISN guidelines. Chlorinated drinking water was desalinated by reverse osmosis and distributed to the closed loop which feeds all online monitors. Disinfection with peracetic acid was performed in all DW plants on a monthly basis.

FINDINGS

Over the 24-month study period, seven out of nine DW plants (78%) recorded negative results for all investigated parameters. Closed loop contamination with Burkholderia cepacia was detected in a DW plant from January 2015 to March 2015. Pseudomonas aeruginosa was isolated from March 2016 to May 2016 in the closed loop of another DW plant. These microbial contaminations were eradicated by shock disinfection with sodium hypochlorite and peracetic acid, followed by water flushing.

CONCLUSION

These results highlight the importance of chemical and physical methods of DW disinfection. The maintenance of control measures in water plants hosted in dialysis wards ensures a microbial risk reduction for all dialysis patients.

Status of Hemodialysis of Drugs in 2002

Hemodialysis is a life-sustaining chronic therapy for individuals with end stage renal disease (ESRD). It is also frequently used for days to weeks for patients with acute renal failure who are awaiting the recovery of their kidneys from the acute toxic or traumatic event. Both populations of patients often require complex pharmacotherapeutic regimens, and it is not uncommon for them to be receiving 10 or more concomitant medications. Optimization of care for these patients is dependent on the selection of the most appropriate drug as well as dosage regimen design, which accounts for the influence of hemodialysis therapy on drug disposition. During the last 10 to 15 years there have been several significant changes in the prescribed dose of dialysis and the composition and size of dialyzers available for use. Furthermore, reuse of dialyzers, which was rare in the early 1980s, is now common; it is employed with over 70% of patients with ESRD. The new synthetic dialyzers, which are now used for over 60% of ESRD patients in the United States, are uniformly associated with dramatic improvements in drug removal; dialysis clearance increases of 3 to 10 fold were common for the few drugs evaluated. The influence of these changes in hemodialysis therapy on drug disposition are discussed in a quantitative fashion, and a conceptual framework for drug therapy regimen decision making is presented. For the majority of the drugs reviewed, however, there were no data in the literature regarding dialyzability with currently available dialyzers. The generation of dialyzability data for old and new pharmacotherapeutic agents with state of the art dialysis procedures is clearly needed.

Effect of uremia and hemodialysis on proteome profile of blood platelets and plasma

The aim of the present research was to assess the differences in blood platelet and plasma proteome profiles of patients with uremia in comparison with healthy participants. It was found that 23 peptides in the platelet proteome profiles of hemodialyzed patients and only 6 peptides in nondialyzed patients were upregulated. On the other hand, 18 peptides with reduced expression in nondialyzed patients and only 1 peptide in hemodialyzed patients were found. For serum, only 6 upregulated peptides in patients undergoing hemodialysis and 15 peptides in nondialyzed patients were found, most of these were about 10 kDa. A decrease in serum peptide expression was not observed. In conclusion, it should be noted that the process of hemodialysis modifies the platelet proteome to a greater extent than uremia alone, however the sera of nondialyzed patients have much larger amounts of low-molecular-weight peptides than those of hemodialyzed patients.

Abandoning peracetic acid-based dialyzer reuse is associated with improved survival

BACKGROUND AND OBJECTIVES

Higher mortality risk reported with reuse versus single use of dialyzers is potentially related to reuse reagents that modify membrane surface characteristics and the blood-membrane interface. A key mechanism may involve stimulation of an inflammatory response.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a prospective crossover design, laboratory markers and mortality from 23 hemodialysis facilities abandoning reuse with peracetic acid mixture were tracked. C-reactive protein (CRP), white blood cell (WBC) count, albumin, and prealbumin were measured for 2 consecutive months before abandoning reuse and subsequently within 3 and 6 months on single use. Survival models were utilized to compare the 6-month period before abandoning reuse (baseline) and the 6-month period on single use of dialyzers after a 3-month "washout period."

RESULTS

Patients from baseline and single-use periods had a mean age of approximately 63 years; 44% were female, 54% were diabetic, 60% were white, and the mean vintage was approximately 3.2 years. The unadjusted hazard ratio for death was 0.70 and after case-mix adjustment was 0.74 for single use compared with reuse. Patients with CRP≥5 mg/L during reuse (mean CRP=26.6 mg/ml in April) declined on single use to 20.2 mg/L by August and 20.4 mg/L by November. WBC count declined slightly during single use, but nutritional markers were unchanged.

CONCLUSIONS

Abandonment of peracetic-acid-based reuse was associated with improved survival and lower levels of inflammatory but not nutritional markers. Further study is needed to evaluate a potential link between dialyzer reuse, inflammation, and mortality.

Antibiotic pharmacokinetic and pharmacodynamic considerations in patients with kidney disease

Although pharmacokinetic changes occurring in kidney disease are well described, pharmacodynamics in kidney disease is rarely considered. Knowledge of pharmacodynamic principles can allow a clinician to maximize an antibiotic's effectiveness while minimizing adverse effects and antibacterial resistance. An antibiotic's pharmacokinetic and pharmacodynamic profiles should drive dose adjustment decisions in patients with kidney disease. For example, although the half-lives of beta-lactams and aminoglycosides are both prolonged in these patients, beta-lactams exhibit time-dependent antibacterial activity; consequently, maintenance doses should be smaller but given at the same interval. In contrast, aminoglycosides are concentration-dependent antibiotics; hence prolongation of the dosing interval while using larger doses may be advantageous. The timing of drug administration in relation to hemodialysis may be used to achieve specific pharmacodynamic goals. Aminoglycosides given before hemodialysis generate high peaks, whereas subsequent dialytic drug removal minimizes the area under the serum concentration-time curve, potentially decreasing the risk of developing toxicity. Furthermore, new dialysis prescribing patterns (eg, automated peritoneal dialysis, nocturnal dialysis) affect pharmacokinetic and pharmacodynamic parameters in ways not appreciated by clinicians. Studies quantifying the often considerable drug removal with these therapies, as well as efforts to identify pharmacodynamic targets in patients with kidney disease are essential. This paper reviews pharmacodynamic as well as pharmacokinetic issues that should be considered when prescribing antibiotics to treat infections in this population.

Adsorption of oxacalcitriol by polysulphone haemodialyser in patients with secondary hyperparathyroidism

AIMS

This study was undertaken to evaluate removal of 22-oxacalcitriol (OCT), an active and intravenously used vitamin D3 analogue with less calcaemic activity, by polysulphone haemodialyser in vivo and in vitro. We further compared the pharmacodynamic efficacy [suppression of intact parathyroid hormone (iPTH)] when given intravenously either during or at the end of the haemodialysis.

METHODS

(i) Drug clearance by the polysulphone dialyser was measured during a single continuous infusion (5 microg) for 30 min into the arterial side of the dialyser in end-stage renal failure patients with secondary hyperparathyroidism (n = 7). (ii) The drug adsorption by the hollowfibre membrane during incubation for 30 min was measured in vitro. (iii) To evaluate efficacy, the drug was given (i.v. bolus) during or at the end of haemodialysis for 4 weeks in a cross-over fashion with a washout period of 8 weeks (n = 9). Serum Ca(2+), phosphate (P) and iPTH concentrations just before the initiation of the dialysis were monitored every week.

RESULTS

(i) OCT was significantly cleared by the polysulphone haemodialyser, but the clearance declined in a time-dependent manner to approach zero at 30 min. Arterial (at the place between the drug infusion site and the haemodialyser column) drug concentrations did not change during the infusion (mean = 2064 +/- 233 pg ml(-1)). Venous (just after the dialyser) drug concentrations at 10 min after the infusion were significantly lower than those of the arterial side (mean = 784 +/- 84 pg ml(-1)); however, they increased with time and reached those of the arterial side at 30 min. (ii) In vitro, OCT was adsorbed by the membrane. The amount of adsorption was concentration-dependent and was lower in the presence of human serum (55 +/- 4% without and 23 +/- 4% with serum at 600 pg ml(-1) of OCT). (iii) Although serum Ca(2+) and P increased and iPTH decreased by both treatment regimens (i.e. OCT administered either during or at the end of haemodialysis), these changes did not significantly differ. Mean differences (and 95% confidence interval) of Ca(2+), P, and iPTH at the end of the trial were 0.03 (-0.04, 0.09) mm, 0.41 (-0.43, 1.26) mg dl(-1) and 38 (-42, 88) pg ml(-1), respectively.

CONCLUSION

OCT is adsorbed by polysulphone dialyser in vitro and in vivo. However, the pharmacodynamic effectiveness was largely independent of the administration regimen of OCT given either during or at the end of haemodialysis.

Levofloxacin pharmacokinetics in ESRD and removal by the cellulose acetate high performance-210 hemodialyzer

BACKGROUND

No published data are available describing the pharmacokinetics of intravenous levofloxacin in patients with end-stage renal disease (ESRD). Objectives of this study are to determine the pharmacokinetics and dialytic clearance of levofloxacin and develop dosing strategies in these patients.

METHODS

Eight noninfected subjects receiving long-term thrice-weekly hemodialysis, with no measurable residual renal function, were administered intravenous levofloxacin, 250 mg, over 1 hour after a scheduled hemodialysis session. Blood samples were collected serially during the interdialytic period, during the next intradialytic period, and immediately after the next hemodialysis session. Serum concentrations of levofloxacin were determined by high-performance liquid chromatography. Differential equations describing a 2-compartment open-infusion pharmacokinetic model were fit to each individual subject's serum concentration-time data by iterative nonlinear weighted least-squares regression analysis using Adapt II (Biomedical Simulations Resource, University of Southern California, Los Angeles, CA). Ratios of maximum serum concentration (C(max)) to minimum inhibitory concentration (MIC) were calculated for common respiratory pathogens by using MIC for 90% of isolates (MIC90) data from published studies.

RESULTS

All subjects completed the study, and no adverse events were reported. Median systemic clearance, volume of distribution at steady state, elimination half-life, and C(max) were 37.0 mL/min (range, 12.8 to 42.7 mL/min), 103.3 L (range, 39.8 to 139.3 L), 34.4 hours (range, 28.4 to 39.3 hours), and 5.2 microg/mL (range, 4.1 to 11.3 microg/mL), respectively. Median dialytic clearance and levofloxacin reduction ratios were 84.4 mL/min (range, 61.8 to 107.6 mL/min) and 0.244 (range, 0.181 to 0.412), respectively. Median C(max)-MIC90 ratios were 10 or greater for Haemophilus influenzae, Moraxella catarrhalis, Enterobacter cloacae, and Klebsiella pneumoniae, approximately 5 for Streptococcus pneumoniae, and less than 1 for Pseudomonas aeruginosa.

CONCLUSION

The administration of levofloxacin to patients with ESRD as 500 mg initially, followed by 250 mg every 48 hours, will provide adequate C(max)-MIC ratios after the first and subsequent doses for most patients with respiratory tract infections caused by organisms with levofloxacin MICs of 1 microg/mL or less.

Rapid microtiter plate assay for determination of inulin in human plasma and dialysate

A rapid, sensitive, and reproducible microtiter plate assay for the determination of inulin in human plasma, dialysate, and phosphate-buffered saline (PBS) was developed. Plasma or PBS samples (100 microl aliquots) were prepared by the addition of indole-3-acetic acid (150 microl) and HCl (3 ml) and then briefly vortex-mixed. Samples were then incubated in a 60 degrees C water bath for 20 min, cooled in a room temperature water bath for 40 min, then diluted with deionized, distilled water (DDW; 3 ml) and again vortex-mixed. Finally, an aliquot (200 microl) of each sample was transferred to a 96-well microtiter plate and read spectrophotometrically at 490 nm. Dialysate samples were processed in a similar manner, but required an initial enzymatic step in order to remove dextrose and minimize assay interference. Samples (100 microl aliquots) were prepared by the addition of glucose oxidase/catalase solution (100 microl), briefly vortex mixed, and then incubated in a 37 degrees C water bath for 60 min, samples were then reacted with indole-3-acetic acid as before. Calibration curves were linear over the concentration range of 0.5-4 mg/ml or 0.025-0.4 mg/ml for plasma or PBS and dialysate, respectively; correlation coefficients (r(2)) were >0.99. The intra- and inter-day coefficients of variation in plasma, PBS, and dialysate were <15%. This method is well suited for the rapid analysis of large numbers of samples and is currently being used for in vitro investigations of solute removal by hemodialysis.

Determination of albumin and myoglobin in dialysate and ultrafiltrate samples by high-performance size-exclusion chromatography

A high-performance size-exclusion chromatographic method was developed, validated and implemented for simultaneous and quantitative determination of albumin and myoglobin along with inulin, vancomycin and creatinine in dialysate and ultrafiltrate samples from in vitro hemodialysis experiments. The experimental parameters including mobile phase pH, ionic strength, detection wavelength, flow-rate, injection volume were first optimized for the determination of albumin, myoglobin, inulin, vancomycin and creatinine. The peak height ratio and detection limits of the proteins were then comparatively studied at 210, 254 and 280 nm by UV and diode array detection. The method was further validated by evaluating the linearity, precision and accuracy of the proteins. The assay was finally implemented to the simultaneous and quantitative determination of the proteins in dialysate and ultrafiltrate samples.