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Biomedical subjects

N W Levin

Publications and source records attributed to N W Levin.

At least 55 records · Page 3Linked to original sources
PubMed2000

The acute-phase response varies with time and predicts serum albumin levels in hemodialysis patients. The HEMO Study Group.

BACKGROUND: Cross sectional studies have established that the serum albumin level is dependent on serum levels of acute-phase proteins (APPs) or cytokine levels in hemodialysis patients. While the acute-phase response is generally associated with acute inflammatory events, a cross sectional analysis relating laboratory values to outcomes assumes these values to be unchanging. The longitudinal relationship among laboratory measurements and how they vary over time in a population of patients are unknown. METHODS: Patients who were enrolled in the HEMO Study were recruited into an ancillary longitudinal study to establish the predictive effect of temporal variation in the levels of APPs and of temporal variation in normalized protein catabolic rate (nPCR) on the serum albumin concentration. nPCR was measured monthly using a double-pool method. The positive APPs-C-reactive protein (CRP), alpha1 acid glycoprotein (alpha1-AG), and ceruloplasmin-and the negative APP-transferrin (Trf)-were measured in serum obtained before each dialysis session for six weeks and then monthly in 37 hemodialysis patients. A random coefficient regression analysis was used to assess the association of serum albumin with other measured parameters at each time point, as well as fixed patient characteristics. RESULTS: The within-subject coefficients of variation of albumin (median, range of 25th to 75th percentiles; median, 0.0614; range, 0.0485 to 0.0690) were significantly less than that of APPs (CRP, median, 0.878; range, 0.595 to 1.314, P < 0. 05; and alpha1 AG, median, 0.173; range, 0.116 to 0.247, P < 0.05). The levels of APPs and albumin varied considerably over time. The primary predictor of current albumin was the current CRP level (P = 0.0014). nPCR also was a significant predictor for albumin levels (P = 0.0440) after controlling for the effect of APPs, suggesting an effect of nPCR on serum albumin concentration irrespective of the acute-phase response. Age and the presence of an arteriovenous graft were significant predictors that were associated with reduced albumin. CONCLUSIONS: The acute-phase response is intermittent and is not a continuous feature in individual dialysis patients. Levels of APPs are the most powerful predictors for the levels of albumin concentration in hemodialysis in a longitudinal setting. Since variations in albumin are small, measurement of variations in APPs may provide greater insight into the dynamics of clinically relevant processes.

Acute-Phase Reaction↗
PubMed2000

Effects of a reduced inner diameter of hollow fibers in hemodialyzers.

BACKGROUND: The clearance of middle molecules in high-flux hemodialyzers is due to the higher contribution of convection in the overall solute transport. Although net filtration can be maintained low by the machine control, internal filtration in the proximal part of the dialyzer remains high. The final fluid balance is achieved by significant amounts of backfiltration in the distal part of the dialyzer. To increase further middle molecule clearance (MMK), hemodiafiltration has been used. This technique, however, requires complex machines and large amounts of substitution fluid. We present a novel solution to increase the convective transport of middle molecules in high flux dialyzers without the need for substitution fluids. In particular, high-flux dialyzers with a reduced hollow fiber diameter are compared with standard dialyzers in terms of internal filtration and solute clearances. METHODS: Hemodialyzers with 175 micro inner diameter polysulfone fibers were compared with standard 200 micro polysulfone hollow fiber dialyzers. The study was carried out in vitro using a previously published method to measure internal filtration and backfiltration rates. The method is based on the detection by a gamma camera of segmental variations in concentration along the length of the dialyzer of a nondiffusable Tc99-labeled marker molecule injected in the blood in vitro circuit. At the same time, pressures were detected in the blood and dialysate compartment. The system was operated at zero net filtration maintaining volumetrically constant both dialysate and blood circuits. In vivo clearances were also measured for solutes with different molecular weight. RESULTS: The pressure drop in the blood compartment at 300 mL/min of blood flow passed from 112 to 159 mm Hg. At the same blood flow, the internal filtration-backfiltration rates increased from 23. 1 to 48.2 mL/min. This resulted in a significant increase of in vivo in clearances of vitamin B12 and inulin of more than 30%. Urea, creatinine, and phosphate clearance did not display any change. CONCLUSIONS: A reduction of the inner diameter of the hollow fibers in high-flux dialyzers may result in a significant increase of the blood compartment resistance. In turn, this results in increased rates of internal filtration and backfiltration. The practical effect in clinical dialysis is demonstrated on middle molecules. While, in fact, the clearances for small solutes such as urea and creatinine are not affected, the clearances of larger solutes such as vitamin B12 or inulin increase significantly (P < 0.01).

Biocompatible Materials↗
PubMed2000

Estimation of body fluid changes during peritoneal dialysis by segmental bioimpedance analysis.

UNLABELLED: Estimation of body fluid changes during peritoneal dialysis by segmental bioimpedance analysis. BACKGROUND: Commonly used bioimpedance analysis (BIA) is insensitive to changes in peritoneal fluid volume. The purpose of this study was to show, to our knowledge for the first time, that a new segmental approach accurately measures extracellular fluid changes during peritoneal dialysis (PD). METHODS: Fourteen stable PD patients were studied during a standard exchange with fluids of known conductivity. Bioimpedance was continuously measured in the arm, trunk, and leg and from wrist to ankle. Volume changes were calculated using both a newly developed sum of segmental BIA (SBIA) and current wrist-to-ankle BIA (WBIA) and were compared with actual volume changes measured gravimetrically. RESULTS: When 2.19 +/- 0.48 L were removed from the peritoneal cavity during draining, 95.2 +/- 13.8% of this volume was detected by SBIA compared with only 12.5 +/- 24. 3% detected by WBIA. When 2.11 +/- 0.20 L of fresh dialysate was infused into the peritoneal cavity during filling, 91.1 +/- 19.6% of this volume was detected by SBIA compared with only 8.8 +/- 21.1% detected by WBIA. CONCLUSION: The good agreement between measured and calculated data using SBIA was due to: (a) improved placement of electrodes, (b) estimation of trunk extracellular volume based on a new algorithm, and (c) consideration of changes in dialysate conductivity. Correct estimation of fluid volume in the trunk is a prerequisite for applications in which direct analysis of fluid changes cannot be performed such as with peritoneal equilibration tests and continuous flow PD.

Adult↗
PubMed2000

US nephrologists' recommendation of dialysis modality: results of a national survey.

Selection of a dialysis modality for persons with end-stage renal disease (ESRD) has important lifestyle and occupational implications. The factors affecting modality choice remain unclear, resulting in a low rate of peritoneal dialysis (PD) in the United States compared with other countries. A national survey of 271 US nephrologists was conducted from June 1997 to June 1998 to assess the relative importance of nonclinical and clinical factors related to dialysis modality selection for patients with ESRD. Hypothetical patient scenarios were randomly assigned to nephrologists to determine their recommendation for dialytic therapy based on patient demographic, clinical, and social factors. US nephrologists were more likely to recommend PD for men with ESRD compared with women (39% versus 33%; P: < 0.05; adjusted odds ratio, 1.44; 95% confidence interval, 1.15 to 1.80), as well as for patients with good compliance (adjusted odds ratio, 11.80; 95% confidence interval, 9.29 to 15.01), weight less than 200 lb (adjusted odds ratio, 2.3; 95% confidence interval, 1.8 to 2.9), residual renal function (adjusted odds ratio, 2.14; 95% confidence interval, 1.71 to 2.70), absence of diabetes (adjusted odds ratio, 2.0; 95% confidence interval, 1.6 to 2.5), and living with family (adjusted odds ratio, 1.7; 95% confidence interval, 1.4 to 2.1). Nephrologists in practice for 11 or more years were less likely to recommend PD. The association of male sex with PD therapy suggests a potential bias or sensitivity to women's perception of body image. Race was not associated with PD recommendations after controlling for other demographic and clinical characteristics. Because the incident US ESRD population is increasingly characterized by factors associated with not selecting PD (diabetes, obesity, malnourishment, living alone, and substance abuse problems), our results suggest that PD use may decrease over time.

Adult↗
PubMed2000

Methods used to evaluate the quality of evidence underlying the National Kidney Foundation-Dialysis Outcomes Quality Initiative Clinical Practice Guidelines: description, findings, and implications.

This report describes the approach the National Kidney Foundation-Dialysis Outcomes Quality Initiative (NKF-DOQI) used to assess the strength of published evidence pertinent to individual NKF-DOQI Clinical Practice Guidelines, as well as the relationship between that approach and methods used by the US Preventive Services Task Force, the Cochrane Collaboration, and the Agency for Health Care Policy and Research to rate the quality and/or strength of evidence. We also present the results of an analysis of the strength of evidence underlying the NKF-DOQI Guidelines showing that one cannot infer the quality of evidence reported in a study (rated either on a 0-to-1 scale or categorically as excellent, very good, good, fair, or poor) simply by knowing the type of study design used (randomized trial, nonrandomized trial, natural experiment, cohort study, cross-sectional study, case-control study, case report). Issues related to assessment of the strength of evidence underlying a practice guideline opposed to that reported in an individual study are highlighted.

Evidence-Based Medicine↗
PubMed2000

Isothermic hemodialysis and ultrafiltration.

The increase in patient temperature during hemodialysis is explained by hemodynamic compensation during ultrafiltration and hypovolemia that leads to peripheral vasoconstriction and reduced heat losses. We analyzed 51 stable high-efficiency hemodialysis treatments in 27 patients during isothermic dialysis in which body temperature was maintained at a constant level (+/-0.1 degrees C) using the temperature-control option of the Blood Temperature Monitor (BTM; Fresenius Medical Care, Bad Homburg, Germany). Hemodialysis was delivered using ultrapure water (limulus amebocyte lysate test < 0. 06 endotoxin units/mL) at mean blood flows of 410 +/- 40 mL/min. During treatments lasting 178 +/- 23 minutes, 4.8% +/- 1.4% of postdialysis body weight (W%) and 9.5% +/- 2.5% of postdialysis body water were removed using mean ultrafiltration rates of 1.1 +/- 0.3 L/h. Dialysate temperatures significantly decreased from 35.9 degrees C +/- 0.3 degrees C to 35.6 degrees C +/- 0.6 degrees C during hemodialysis. During these treatments, 187 +/- 69 kJ of thermal energy were removed from the patients through the extracorporeal circulation using cool dialysate. Extracorporeal heat flow was 17 +/- 6 W. Energy expenditure (H) estimated from anthropometric data was 65 +/- 12 W. Thus, 28% +/- 10% of estimated energy expenditure (H%) was removed during isothermic dialysis. A highly significant correlation was observed between H% and W% (H% = -5.6 * W%; r(2) = 0.91; P < 0.0001). This result is in support of the volume hypothesis of intradialytic heat accumulation and provides a rule of thumb to estimate extracorporeal cooling requirements for isothermic dialysis. Approximately 6% of H must be removed through the extracorporeal circulation for each percent of ultrafiltration-induced body-weight change. The importance of body temperature control during hemodialysis increases with increased ultrafiltration requirements.

Body Temperature↗
PubMed2000

Sensitivity and specificity of the thermodilution technique in detection of access recirculation.

BACKGROUND/AIM: Recirculation measured by thermodilution includes effects caused by access and cardiopulmonary recirculation. The aims of this study were to illustrate the accuracy of thermodilution in measurement of hemodialysis recirculation and also to identify a sensitive and specific threshold to detect access recirculation. METHODS: 110 studies were performed in 19 patients. Recirculation obtained directly by the blood temperature monitor (BTM) was compared to that calculated from access blood flow, pump blood flow, and cardiac output determined by ultrasound dilution using the hemodialysis monitor (HDM). RESULTS: A highly significant linear correlation was obtained between repeated BTM recirculation measurements (R(BTM, 2) = 0.99.R(BTM, 1) - 0.22%, r(2) = 0.99). There were no significant differences between repeated BTM recirculation measurements with correct placement (11.4+/-7.1 vs. 10.9+/-7.4%, p = NS) or reversed placement (30.0+/-15.6 vs. 30.2 +/-15.9%, p = NS) of blood lines. A strong linear relationship was obtained between the recirculation determined by thermodilution and the recirculation calculated from HDM measurements (R(calc) = 0.98. R(BTM) - 1.49%, r(2) = 0.95). The mean recirculation obtained by BTM was not significantly different from the recirculation calculated by HDM with correct placement (9.5+/- 2.2 vs. 8.6+/-2.5%, p = NS) or with reversed placement (25.4+/-7.8 vs. 23.8+/-7.7%, p = NS) of blood lines. When a recirculation greater than 15% measured by the BTM was considered as the threshold at which true access recirculation occurred, sensitivity and specificity of the thermodilution method to detect access recirculation were 93 and 98%, respectively. CONCLUSIONS: Recirculation measurements made by the BTM are accurate and precise. Even though BTM thermodilution includes effects of cardiopulmonary recirculation, so that low levels of access recirculation might not be detected, a BTM recirculation >15% represents a highly significant access recirculation.

Arteriovenous Shunt, Surgical↗
PubMed2000

Challenges for chronic dialysis in the new millennium.

Although significant technical advances have occurred in the dialysis industry in the last 20 to 30 years, their collective impact on clinical outcomes has been less well-documented than their commercial successes. This article delineates the technical, administrative, and socioeconomic challenges which must be overcome in the next millennium in order to incorporate predicted technological advances into substantive improvements in quality of life, patient satisfaction, and adequacy of renal replacement therapy in the end-stage renal disease population. Technological advances envisioned include new athrombogenic materials for dialyzers and blood lines; membranes with absorptive properties; more efficient dialyzers; biofeedback sensor systems for physiological control of dialysis, on-line screening, and trend analysis; increased utilization of frequent dialysis; new vascular access techniques; increasing use of practice guidelines; global capitation; and attention to patients' views on standards of care, quality of life, and operation of dialysis facilities. Whereas many new technologies will be available, their application will largely depend on both fundamental research and socioeconomic factors.

Humans↗
PubMed2000

Blood flow distribution in sorbent beds: analysis of a new sorbent device for hemoperfusion.

A new polymer-based sorbent cartridge has been recently developed for enhancing middle molecule removal during hemodialysis. The cartridge (Betasorb, Renaltech, New York, USA) has been designed to be placed in series with the dialyzer in the blood circuit. It is therefore important to evaluate the distribution of flow into the blood compartment of the device in order to assess if the surface of the sorbent is utilized to the best. For this purpose, a special imaging technique was utilized. Cartridges were analyzed during a simulated in vitro circulation at 250 and 350 ml/min of blood flow and 25% and 40% hematocrit. Cartridges were placed in vertical position and a cross longitudinal section 1 cm thick was analyzed in sequence by a helical scanner. Dye was injected into the arterial inlet and the progressive distribution was evaluated by sequential densitometrical measures carried out automatically by the machine. The sequential images analyzed by the scanner demonstrated excellent distribution of the flow in the blood compartment with minimal difference between the central and the peripheral regions of the compartment. In particular the following flow velocity pattern could be observed under the different experimental conditions tested. We may conclude that the cartridge design is adequate and no channelling effects could be detected in the blood compartment. The flow distribution is slightly affected by changes in flow rate and hematocrit showing an optimal utilization of the available surface for molecule adsorption.

Adsorption↗
PubMed2000

Predictive value of access blood flow and stenosis in detection of graft failure.

AIMS: Low access flow and the diagnosis of high degrees of venous stenosis have been recommended as indications for prophylactic angioplasty. However, recent studies have shown that prophylactic angioplasty for > 50% stenosis did not prolong graft patency, and that a single flow measurement may not accurately predict graft failure. In this study we compared the value of monthly measurement of access flow and of the maximal degree of stenosis in the detection of graft failure over a three-month period. METHODS: Thirty-nine hemodialysis patients with polytetrafluoroethylene (PTFE) grafts were evaluated by Doppler ultrasound at monthly intervals for three months. Graft failures were defined as thrombosis, or surgical and angioplastic revisions required because of the presence of access recirculation, and patients with graft failure were followed within the subsequent one-month periods of observation. RESULTS: Twelve graft failures occurred during the three-month period of observation. The risk for subsequent graft failure significantly increased at flows < 300 ml/min. Nine (20%) graft failures occurred with stenoses of 30 to 50%, and three (13%) with stenoses of> 50%. The grafts that failed in the second and the third study months had a 25.8% (380 +/- 62 vs. 287 +/- 190 ml/min, p < 0.05) and a 36.5% (393 +/- 142 vs. 226 +/- 41 ml/min, p < 0.05) decrease in access flow, respectively. There was no significant change in access flow for the grafts patent throughout the study (911 +/- 333, 794 +/- 302, and 919 +/383 ml/min, p = ns). No significant increases in maximal stenosis were found for the grafts that failed in the second month (44 +/- 6.1 vs. 48 +/- 15%, p = ns) and the third month (48 +/- 9 vs. 51 +/- 16%, p = ns). There were no significant changes in the maximum stenosis for the grafts patent throughout the three-month study periods (37 +/- 15,43 +/- 11, and 44 +/- 15%, p = ns). CONCLUSIONS: Access flow is a more sensitive predictor of graft failure than stenosis. Examination of trend in decline of access flow is a more powerful indicator to detect graft dysfunction than an individual single flow value.

Aged↗
PubMed1999

Association of acidosis and nutritional parameters in hemodialysis patients.

There is extensive literature supporting an important role for acidosis in inducing net protein breakdown, both in experimental animals and humans. However, the clinical importance of the moderate intermittent metabolic acidosis frequently observed in hemodialysis patients has not been determined. We performed a cross-sectional analysis of the baseline laboratory data in the first 1,000 patients recruited to the Hemodialysis Study, looking for correlations between predialysis serum total carbon dioxide levels and parameters related to dietary intake and nutritional status. We found the mean predialysis serum total carbon dioxide level was moderately low (21.6 +/- 3.4 mmol/L; mean +/- SD) despite the use of bicarbonate dialysate and an average single-pool Kt/V of 1.54. Predialysis serum total carbon dioxide level correlated negatively with normalized protein catabolic rate (P < 0.001), suggesting patients with lower serum total carbon dioxide levels have a greater protein intake. The degree of acidosis observed in our patients does not seem to have a deleterious effect on the nutritional status of these patients because correlation of serum total carbon dioxide level with nutritional parameters, such as serum creatinine and serum albumin levels, was either negative or not statistically significant. Further investigation of the effect of modifying serum bicarbonate concentration on nutritional markers is needed to test these hypotheses.

Acidosis↗
PubMed1999

An overview of the National Kidney Foundation-Dialysis Outcomes Quality Initiative Implementation.

Rigorously developed clinical practice guidelines have the potential to improve outcomes and favorably alter practice patterns. Because of widespread community concerns over the quality of dialysis care, the National Kidney Foundation initiated a Dialysis Outcomes Quality Initiative (NKF-DOQI) in March 1995 in an effort to create evidence-based best-practice clinical guidelines. Independent interdisciplinary Work Groups reviewed the available body of scientific literature on four selected topics: hemodialysis adequacy, peritoneal dialysis adequacy, vascular access, and anemia. More than 11,000 publications were identified, of which 1,500 were considered relevant and were subjected to structured review. Draft guidelines, with supporting rationales of their evidentiary basis, were subjected to a three-stage public and organizational review process. The final guidelines were issued in the fall of 1997. Because the potential benefit of guidelines depends on their implementation, planning for the implementation of NKF-DOQI was begun simultaneously with its review process. A 3-year implementation plan, with specific priorities and estimated costs, was developed and set into action by the end of 1997. The main objectives of the rather diverse and multifaceted plan of action are translating the NKF-DOQI Guidelines into clinical practice, building on what has been accomplished, and continued evaluation and review of the Guidelines.

Evidence-Based Medicine↗
PubMed1999

Sum of segmental bioimpedance analysis during ultrafiltration and hemodialysis reduces sensitivity to changes in body position.

BACKGROUND: Bioimpedance, a noninvasive technique to analyze body composition, has attracted interest in determining body hydration in hemodialysis patients. However, the so-called whole-body (wrist-to-ankle) bioimpedance analysis (WBIA) is sensitive to changes in regional fluid distribution and tends to underestimate fluid changes during ultrafiltration in hemodialysis patients. The aim of this study was to show that volume changes calculated from a new approach, that is, segmental bioimpedance analysis (SBIA), are not affected by changes in body position. METHODS: Ten male patients (age 44 +/- 8 years, target weight 70.8 +/- 10 kg) were studied during their regular hemodialysis treatment while maintaining either a sitting or a supine body position throughout the study. Extracellular volume was calculated from extracellular resistance obtained from bioimpedance data measured for a range of frequencies (5 to 500 kHz) using the Xitron BIS4000B analyzer. Wrist-to-ankle measurements were compared with segmental arm, trunk, and leg measurements. RESULTS: Changes in extracellular volume estimated from wrist-to-ankle measurements only reached 80 +/- 13% and 65 +/- 17% of the actual change in body mass during sitting and supine dialysis treatments, respectively. However, when segmental measurements were analyzed, the calculated change in extracellular volume was 101 +/- 6% and 100 +/- 3% of the actual change in body mass during the sitting and supine treatments, respectively. CONCLUSIONS: SBIA properly identifies regional fluid changes and provides an appropriate measure of fluid changes caused by ultrafiltration and hemodialysis. The volume estimation based on the sum of segmental bioimpedance measurements is independent of body position, which is a prerequisite for applications in everyday practice.

Adult↗
PubMed1999

Development of a new approach to vascular access.

Three modes of access for hemodialysis (HD) have been available for over 20 years, the native arterial to venous (A-V) fistula, the polytetrafluorethylene (PTFE) graft fistula, and the central venous catheter. Overall, vascular access remains the single most costly source of morbidity and hospitalization in HD patients, indicating a severe need for improvement in this area. A significant contributor to access morbidity is the HD catheter, which protrudes through the skin and is subject to frequent infection. Subcutaneous ports have been developed to overcome this problem with catheters, but their application to HD has been elusive for 2 reasons, the use of a degradable septum that becomes vulnerable to infection with the use of large bore needles and the presence of a nonlinear flow path which produces damage to blood cells and stimulates thrombus formation at the required high flow rates. A new device, the Dialock, overcomes these objections by its use of a mechanical valve that maintains a linear flow path without directly contacting the blood. Results of a pilot study with 23 patients demonstrated a 78% cumulative survival rate after 1 year with a reduced rate of infection compared to catheters and sustained blood flow of 330 ml/min. The device represents a most promising advance in vascular access.

Arteriovenous Shunt, Surgical↗
PubMed1999

Validation of haemodialysis recirculation and access blood flow measured by thermodilution.

BACKGROUND: Recirculation (R) and access blood flow (Qac) measurements are considered useful indicators of adequate delivery of haemodialysis. It was the purpose of this study to compare measurements of R and Qac obtained by two different techniques which are based on the same principle of indicator dilution, but which differ because of the characteristics of the injection and detection of the different indicators used. METHODS: Recirculation measured by a thermal dilution technique using temperature sensors (BTM, Fresenius Medical Care) was compared with recirculation measured by a validated saline dilution technique using ultrasonic transducers placed on arterial and venous segments of the extracorporeal circulation (HDM, Transonic Systems, Inc.). Calculated access flows were compared by Bland Altman analysis. Data are given as mean +/- SD. RESULTS: A total of 104 measurements obtained in 52 treatments (17 patients, 18 accesses) were compared. Recirculation measured with correct placement of blood lines and corrected for the effect of cardiopulmonary recirculation using the 'double recirculation technique' was -0.02 +/- 0.14% by the BTM technique and not different from the 0% measured by the HDM technique. Recirculation measured with reversed placement of blood lines and corrected for the effect of cardiopulmonary recirculation was 19.66 +/- 10.77% measured by the BTM technique compared with 20.87 +/- 11.64% measured by the HDM technique. The difference between techniques was small (-1.21 +/- 2.44%) albeit significant. Access flow calculated from BTM recirculation was 1328 +/- 627 ml/min compared with 1390 +/- 657 ml/min calculated by the HDM technique. There was no bias between techniques. CONCLUSION: BTM thermodilution yields results which are consistent with the HDM ultrasound dilution technique with regard to both recirculation and access flow measurement.

Blood Circulation↗
PubMed1999

Effects of hemodialyzer reuse on clearances of urea and beta2-microglobulin. The Hemodialysis (HEMO) Study Group.

Although dialyzer reuse in chronic hemodialysis patients is commonly practiced in the United States, performance of reused dialyzers has not been extensively and critically evaluated. The present study analyzes data extracted from a multicenter clinical trial (the HEMO Study) and examines the effect of reuse on urea and beta2-microglobulin (beta2M) clearance by low-flux and high-flux dialyzers reprocessed with various germicides. The dialyzers evaluated contained either modified cellulosic or polysulfone membranes, whereas the germicides examined included peroxyacetic acid/acetic acid/hydrogen peroxide combination (Renalin), bleach in conjunction with formaldehyde, glutaraldehyde or Renalin, and heated citric acid. Clearance of beta2M decreased, remained unchanged, or increased substantially with reuse, depending on both the membrane material and the reprocessing technique. In contrast, urea clearance decreased only slightly (approximately 1 to 2% per 10 reuses), albeit statistically significantly with reuse, regardless of the porosity of the membrane and reprocessing method. Inasmuch as patient survival in the chronic hemodialysis population is influenced by clearances of small solutes and middle molecules, precise knowledge of the membrane material and reprocessing technique is important for the prescription of hemodialysis in centers practicing reuse.

Acetic Acid↗