Quality of hemodialysis water in a resource‐poor country: The Nigerian example

Hemodialysis (HD) patients are exposed to large volumes of water, separated from patients' blood by semipermeable membrane of dialyzers. Chemical contaminants in poorly treated water impact negatively on quality of life of these patients. This survey was carried out to assess the HD water quality in Lagos, Nigeria. Ten milliliters of feed and treated water from all six HD centers in Lagos were tested for aluminum, copper, zinc, magnesium, calcium using atomic absorption spectrometry; sodium and potassium were tested using flame photometry, fluoride with molecular photoluminescence method; sulfate using turbidimetry, nitrates measured by cadmium column reduction method, chloramines and free chlorine were measured using N, N‐diethyl‐1‐P‐phenylenediamine colorimetric method. Information on sources of feed water, frequency of testing of HD water, methods of water treatment, type of water purification system and maintenance was also obtained. All centers used borehole as main source of water supply. None of the centers met Association for the Advancement of Medical Instrumentation (AAMI) guidelines for most chemical contaminants. Only chlorine (0.48 ± 0.07 mg/L) and potassium (3.9 ± 0.95 mg/L) levels met AAMI standards after treatment. Mean levels of chemical contaminants in treated water were as follows: aluminum 0.04 ± 0.01 mg/L, zinc 0.27 ± 0.08 mg/L, chloramines 0.16 ± 0.03 mg/L, fluoride 1.83 ± 0.40 mg/L, sulfate 117 ± 86.1 mg/L which were mildly elevated; calcium 126.00 ± 22.7 mg/L, sodium 179 ± 25.6 mg/L, and nitrate 70.5 ± 50.8 mg/L, which were markedly elevated; and magnesium 8.3 ± 3.38 mg/L, which was moderately elevated above AAMI recommended levels. HD water quality is poor in our environment. Concerted efforts are required to ensure good quality water for HD.     

Does the presence of an arteriovenous fistula alter changes in body water following hemodialysis as determined by multifrequency bioelectrical impedance assessment?

Multifrequency bioelectrical impedance assessments (MFBIAs) aid clinical assessment of hydration status for hemodialysis (HD) patients. Many MFBIA devices are restricted to whole body measurements and as many patients dialyze using arteriovenous fistulas (AVFs), we wished to determine whether AVFs affected body water measurements. We reviewed pre‐ and post‐HD segmental MFBIA measurements in 229 patients attending for midweek HD sessions. Up to 144 were dialyzed with a left arm AVF (L‐AVF), 42 with a right arm AVF (R‐AVF), and 43 by central venous access catheter (CVC). Water content and lean tissue were greater in the left compared to right arm in those patients with L‐AVFs both pre and post dialysis (pre 2.1 ± 0.7 vs. 2.0 ± 0.7 L, and post 1.9 ± 0.6 vs. 1.8 ± 0.6 L and pre 2.65 ± 0.9 vs. 2.56 ± 0.8 kg, and post 2.34 ± 0.8 vs. 2.48 ± 0.8 vs. 2.34 ± 0.8 kg, respectively) and were also greater in the right compared to left arm for those patients dialyzing with R‐AVFs (pre‐HD 1.92 ± 0.5 vs. 1.86 ± 0.6 L and post‐HD 1.79 ± 0.5 vs. 1.7 ± 0.5 L, and pre‐HD 2.47 ± 0.6 vs. 2.38 ± 0.7 kg and post‐HD 2.3 ± 0.74 vs. 1.28 ± 0.7 kg, respectively), all Ps < 0.05. There were no significant differences in arm volumes or composition pre or post dialysis in those dialyzing with CVCs. Segmental MFBIA detects differences in arm water and lean mass in patients with AVFs. The presence on an AVF increases the water content in the ipsilateral arm both pre and post HD. This increased water content of the fistula arm will not be detected by whole body bioimpedance devices.     

Quality of water in hemodialysis centers in Baghdad,Iraq

Dialysis water quality is one of the important parameters all over the world because of its direct influence on the health of kidney patients. In Iraq, there are more than 20 dialysis centers; most of them contain identical units for the production of dialysis water. In this work, the quality of water used for dialysis in six dialysis centers located within Baghdad hospitals was evaluated. Samples of product water from each of the six dialysis centers were examined for total heterotrophic bacteria, endotoxin, and chemical contaminants. Endotoxin was measured on‐site using a portable instrument. Bacteriological and chemical examinations were done in the laboratory after collecting samples from each dialysis center. The results showed a fluctuation in the produced water quality that makes the produced water unaccepted when compared with international standards. Bacterial counts for 60% of the analyzed samples were above the action level (50 colony‐forming units[CFU]/mL), while five out of the six dialysis centers showed values higher than the maximum value (100 CFU/mL). Chemical analysis showed that the dialysis water quality suffers from elevated aluminum concentration for all dialysis centers. All hemodialysis centers need thorough monitoring and preventive maintenance to ensure good water quality. In addition, it is important to revise the design of the water treatment units according to the feed and product water quality.     

Changes in biochemical,hemodynamic, and dialysis adherence parameters in hemodialysis patients during Ramadan

This paper aimed to study the effect of Ramadan fasting on biochemical and clinical parameters and compliance for dialysis. A prospective multicenter observational cross‐sectional study comparing fasting with a non‐fasting stable adult hemodialysis patients for demographic and biochemical parameters, compliance with dialysis, inter‐dialytic weight gain, pre‐ and post‐blood pressure, and frequency of intradialytic hypotensive episodes was carried out. Six hundred thirty‐five patients, of whom 64.1% fasted, were studied. The fasters were younger (53.3 ± 16.2 vs. 58.4 ± 16.1 years; P = 0.001) but had similar duration on dialysis (P = 0.35). More fasters worked (22.0% vs. 14.6%; P = 0.001) and missed dialysis sessions during Ramadan. No differences were noted between groups in sex, diabetic status, or dialysis shift or day. There were no differences in the pre‐ and post‐dialysis blood pressure; serum potassium, albumin or weight gain; diabetic status; sex; and dialysis shift time or days. However, serum phosphorous was significantly higher in the fasting group (2.78 ± 1.8 vs. 2.45 ± 1.6 mmol/L; P = 0.045). There were no intragroup differences in any of the parameters studied when comparing the findings during Ramadan with those in the month before Ramadan. Fasters were significantly younger and more likely to be working, to miss dialysis sessions, and to have higher serum phosphorous levels. No other differences were observed.     

Necrotizing fasciitis of thigh associated with Escherichia Coli bacteremia in a patient on chronic hemodialysis

Necrotizing fasciitis is a lethal soft tissue infection for its rapid progression to septic shock. We present a 59‐year‐old male on chronic hemodialysis (HD). We made the diagnosis of necrotizing fasciitis of the right thigh due to the crepitus from physical examination and subcutaneous emphysema from an X film. He was successfully treated with antibiotics and surgical debridement. The blood and surgical drainage cultures showed Escherichia coli, which is less commonly seen in cutaneous infection. The colonoscopic finding revealed adenomatous polyps. Necrotizing fasciitis in patients on HD requires early diagnosis and aggressive treatment to ensure the favorable clinical outcomes.     

Parathyroidectomized patients have impaired capacity of peripheral vascular constriction during hemodialysis

Parathyroidectomy (PTx) seems to improve cardiovascular outcomes and reduce blood pressure levels. However, the effect of PTx on hemodynamic changes during hemodialysis (HD) is still overlooked. This was a prospective cohort design. Patients with end‐stage renal disease on maintenance HD were included. Diabetes and nonsinusal rhythm were exclusion criteria. History of PTx was recorded. Finometer monitor was used to access parameters immediately pre‐ and post‐HD sessions. Cardiac index (CI) variation (ΔCI) and peripheral arterial resistance variation (ΔPAR) were the variables of interest. Biochemical and echocardiographic data were also obtained. PTx patients (n = 11) were matched to non‐PTx patients (n = 20). ΔPAR was lower in PTx group in comparison with non‐PTx group (P = 0.039), which was independent of parathyroid hormone (PTH) levels. Multiple regression analysis showed that PTx, ΔCI, and dialysate calcium remained independently associated with PAR variation and even adjusted for ultrafiltration rate (adjusted r² = 0.64). In conclusion, parathyroidectomized patients have impaired capacity of vasoconstriction in response to ultrafiltration, an effect independent of serum PTH levels. Further studies are needed to elucidate mechanisms explaining the interaction between PTx and systemic vascular tonus.     

Role of T‐regulatory cells in the response to hepatitis B vaccine in hemodialysis patients

Human disease elicits a complex array of biological processes that results in long‐term protective immunological memory to infectious agents. Chronic kidney disease is known to impair induction of sustained immunological memory to hepatitis B vaccine (HBVax) antigens. We asked the question: Does end‐stage renal disease promote changes in subtypes of regulatory T (Treg) cells that correlate with diminished amnestic response to HBVax antigen compared to healthy controls? The study design and setting was a prospective observational cohort at a veterans affairs medical center. End‐stage renal disease patients on hemodialysis (HD) were compared with individuals with self‐reported normal kidney function. All subjects received HBVax. Peripheral blood was sampled for assessment for Treg cells pre and post vaccination. CD4+ FOXP3 Treg numbers were similar between HD and healthy subjects during a 14‐day time period post vaccination. HD subjcts had lower anti‐HBSag antibody than CON (control) subjects (330 ± 108.7 vs. 663.1 ± 129.7 IU/mL; P = 0.063). Hemodialysis subjects with resting Tregs higher than the median value in our cohort demonstrated a significantly lower change in HBsAB at 30 days post booster vaccination (P = 0.030). No such relationship was found for the activated Treg subset among HD subjects, or either subset among CON subsets. In our limited comparison study of 11 HD and 8 CON subjects, Treg subsets did not differ between the two groups; but differences in the suppressive Treg numbers in the HD group could explain the altered antibody response to HBVax and is worthy of further study.     

Risk factors associated with elevated serum pancreatic amylase levels during hemodialysis

Elevated levels of serum pancreatic enzymes are frequently observed in hemodialysis (HD) patients. The complex hemodynamic, biochemical, and physiological alterations in uremia were speculated to cause excessive release of pancreatic enzymes beyond decreased renal clearance. However, hemodynamic factors are seldom explored in this aspect. We performed the study to evaluate the association between intradialytic hemodynamic change and elevated serum pancreatic amylase (SPA). Eighty‐three prevalent HD patients without any clinical evidence of acute pancreatitis underwent pre‐HD and post‐HD blood sampling for serum pancreatic enzyme levels. Demographic, biochemical, and hematological data were collected from patient record review. Hemodialysis information including intradialytic blood pressure changes and ultrafiltration (UF) amount were collected and averaged for 1 month before the blood sampling day. Patients with elevated SPA during the HD session had greater mean systolic blood pressure and mean arterial pressure reduction, greater UF volume, greater pre‐HD blood urea nitrogen and serum creatinine, higher serum phosphorus, lower pre‐HD serum total CO₂, and lower left ventricle ejection fraction (LVEF). Using multivariate linear and logistic regression analysis, the independent predictors of elevated SPA were determined to be mean arterial pressure reduction during HD, mean UF amount, pre‐HD serum total CO₂, and LVEF. Greater blood pressure reduction during HD, greater UF volume, lower pre‐HD serum total CO₂, and lower LVEF were significantly associated with elevated SPA during HD. This suggests that hemodynamic factors contribute to elevated serum pancreatic enzymes in HD patients.     

Serum coenzyme Q10 levels are associated with coronary flow reserve in hemodialysis patients

Accelerated atherosclerosis is the major cause of mortality in patients on chronic hemodialysis (HD). The aim of this study was to evaluate the relation between coenzyme Q10 (CoQ10) levels and coronary flow reserve (CFR) in HD patients as an indicator of atherosclerosis. Seventy‐one chronic HD patients and 65 age‐ and sex‐matched healthy individuals were included in the study. Plasma CoQ10 levels were performed by high‐performance liquid chromatography measurements. CFR was assessed by transthoracic Doppler echocardiography. Serum CoQ10 levels (1.36 ± 0.43 vs. 2.53 ± 0.55, P < 0.001) and CFR values (1.73 ± 0.11 vs. 2.32 ± 0.28, P < 0.001) were significantly lower in HD patients compared with controls. There was a significant positive correlation between CFR and serum levels of CoQ10 (r = 0.669, P < 0.001). A linear regression analysis showed that serum levels of CoQ10 were still significantly and positively correlated with CFR (regression coefficient = 0.235, P < 0.001). Our data have demonstrated that HD patients exhibit decreased plasma CoQ10 levels and CFR values. The study also showed for the first time that serum CoQ10 levels independently predict CFR in HD patients.     

Dialysate saving by automated control of flow rates: comparison between individualized online hemodiafiltration and standard hemodialysis

Cost reduction and quality improvement seem to be conflicting issues. However, online hemodiafiltration (oHDF) with new automatic functions offers a cost‐efficient therapy compared to hemodialysis (HD). Seven dialysis centers conducted a randomized clinical trial with cross‐over design: high‐flux HD vs. postdilutional oHDF with functions coupling both dialysate and substitution flow rates to blood flow rates. During the 6 weeks of the study, all treatment parameters remained unchanged for HD and oHDF, apart from dialysate and substitution flow rate. Treatment data were recorded during each treatment, and predialytic and postdialytic concentrations of urea were recorded at the end of each study phase. The analysis involved 956 treatments of 54 patients. The mean dialysate consumption was 123.2 ± 6.4 l for HD and 113.4 ± 14.9 l for oHDF (p < 0.0001), the mean dialysis dose was 1.42 ± 0.23 for HD and 1.47 ± 0.26 for oHDF (p < 0.0001); oHDF resulted in a lower dialysate consumption (8.0% less) and a slightly increased dialysis dose (Kt/V 3.5% higher) compared to HD. oHDF with the investigated automatic functions offers substantial savings in dialysate consumption without decreasing dialysis dose.     

Enhanced solute removal with intermittent, in-center, 8-hour nocturnal hemodialysis

Advances in the dialysis technique and increasing urea Kt/V have not improved outcomes for end‐stage renal disease patients maintained on hemodialysis (HD) therapy. Attention has, thus, focused on enhancing solute removal via prolonged HD sessions. A reduction in the serum levels of phosphorus and β‐2‐microglobulin (B2M) with longer HD treatments has been linked to improved patient outcomes. We have shown that serum phosphorus levels are significantly lowered in patients maintained on thrice‐weekly, in‐center, 8‐hour nocturnal HD performed at a blood flow rate of 400 mL/min. The kinetics of this modality were examined. A total of 8 patients participated in the study (age 45±7 years). Serum creatinine levels decreased from 9.2±1.9 to 3.0±1.0 mg/dL at 8 hours while serum phosphorus decreased from 5.7±1.9 to 2.5±0.7 mg/dL at 8 hours. The initial decrease from predialysis values to 1 hour after the start of HD was significant for both creatinine (P<0.0001) and phosphorus (P<0.001). Serum B2M decreased from 26.8±5.5 mg/L predialysis to 14.9±7.0 mg/L at 8 hours (P<0.01). Dialysate‐side clearances of phosphorus and creatinine were 136±13 and 143±27 cm³/min, respectively. Phosphorus clearances were steadily maintained during the 8‐hour session. A total of 904±292 mg of phosphorus was removed during the 8‐hour treatment, with 501±174 mg (55%) removed during the first 4 hours and the remaining 45% continuously removed during the latter one‐half of the session. The overall calculated B2M clearance was 55.1±40.3 cm³/min using the immediate post‐B2M value and 28.4±34.2 mg/L using the 30‐minute postdialysis value for the calculation. Serum levels of phosphorus and B2M decrease dramatically during an 8‐hour session. Future studies are necessary to determine whether the enhanced solute removal with longer HD sessions translates into an improved outcome for HD patients.     

Inappropriately elevated endothelin‐1 plays a role in the pathogenesis of intradialytic hypertension

The aim of this study is to investigate the effects of endogenous vasoactive substances on the occurrence of intradialytic hypertension (IDH) in patients during maintenance hemodialysis. Thirty‐four maintenance hemodialysis patients were enrolled in this trial, and 17 of them were diagnosed with IDH (defined as an increase in blood pressure of at least 10 mmHg during or immediately after a hemodialysis session), while 17 age‐matched and sex‐matched controls without IDH were selected for a retrospective comparison. We collected patients' blood samples before and after a dialysis session and measured the plasma levels of N‐terminal fragment brain natriuretic peptide, renin, angiotensin‐II, aldosterone (ALD), angiotensin‐converting enzyme (ACE), endothelin‐1 (ET‐1), nitric oxide (NO), norepinephrine (NOR), and adrenomedullin. The post‐dialysis serum ET‐1 concentrations were significantly higher (4.09 ± 2.06 vs. 2.75 ± 1.34 pg/mL, P < 0.05), while the post‐dialysis ratio of NO to ET‐1 was lower (17.79 ± 5.65 vs. 24.78 ± 12.04, P < 0.05) in IDH patients compared with the control group. Post‐dialysis ALD and NOR values were significantly lower (P < 0.01) and ACE levels were significantly higher (P < 0.01) than the pre‐dialysis concentrations only in the control and not in the IDH group. All other measured factors did not differ significantly between the groups and between pre‐dialysis and post‐dialysis determinations. Compared with blood angiotensin‐II, ALD, ACE, NOR, adrenomedullin, N‐terminal fragment brain natriuretic peptide, and NO status, inappropriately elevated ET‐1 plasma concentrations may play a predominant role in the pathogenesis of IDH.     

Rapid,High‐Temperature,In Situ Microwave Synthesis of Bulk Nanocatalysts

Carbon‐black‐supported nanoparticles (CNPs) have attracted considerable attention for their intriguing catalytic properties and promising applications. The traditional liquid synthesis of CNPs commonly involves demanding operation conditions and complex pre‐ or post‐treatments, which are time consuming and energy inefficient. Herein, a rapid, scalable, and universal strategy is reported to synthesize highly dispersed metal nanoparticles embedded in a carbon matrix via microwave irradiation of carbon black with preloaded precursors. By optimizing the amount of carbon black, the microwave absorption is dramatically improved while the thermal dissipation is effectively controlled, leading to a rapid temperature increase in carbon black, ramping to 1270 K in just 6 s. The whole synthesis process requires no capping agents or surfactants, nor tedious pre‐ or post‐treatments of carbon black, showing tremendous potential for mass production. As a proof of concept, the synthesis of ultrafine Ru nanoparticles (≈2.57 nm) uniformly embedded in carbon black using this microwave heating technique is demonstrated, which displays remarkable electrocatalytic performance when used as the cathode in a Li–O₂ battery. This microwave heating method can be extended to the synthesis of other nanoparticles, thereby providing a general methodology for the mass production of carbon‐supported catalytic nanoparticles.     

Hemodialysis cost in Tehran,Iran

The purpose of this study was to assess the health service cost of hemodialysis (HD) delivered at hospitals in Iran as a developing country with a well‐defined program of renal replacement therapy. A cost analysis was performed from the viewpoint of the 2 hospitals, with 3 shifts and full chairs, on current practice for dialysis maintenance. Cost and patient data were collected in 2006 and from April 1 to May 31, 2007, respectively. A total of 22,464 HD sessions were performed and 247 patients were studied during the study period. The reference year for the value of USD for different mentioned costs was 2006. Health care sector costs associated with each HD session were estimated at US$78.87. Most of the total maintenance expenditure was made up of medical supplies (36.19%), with dialyzers as the major cost driver. Staff salaries represented 17% of the cost and fixed direct capital costs accounted for 21.4%. Of the family members, 32.4% accompanied their patients. The mean cost for transportation of patients and accompanied person was US$3.15 ± 2.83 and US$1.5 ± 0.29, respectively. These findings are important in the light of limited available resources coupled with the increasing prevalence of kidney failure. A major attempt should also be made to increase peritoneal dialysis coverage as in some centers we cannot keep all chairs full, especially in some vast areas. It is highly recommended to place initial focus on strategies and treatments that slow disease progression, to postpone renal replacement therapy to save resources.     

Factors predicting failure of AV “fistula first” policy in the elderly

An arteriovenous fistula (AVF) is the preferential hemodialysis (HD) access. The goal of this study was to identify factors associated with pre‐dialysis AVF failure in an elderly HD population. We used United States Renal Data System + Medicare claims data to identify patients ≥67 years old who had an AVF as their initial vascular access placed pre‐dialysis. Failure of the AVF to be used for initial HD, was used as the outcome. Logistic regression model was used to identify factors associated with AVF failure. The study cohort consisted of 20,360 subjects (76.2 ± 6.02 year old, 58.5% men). Forty‐eight percent of patients initiated dialysis using an AVF, while 52% used a catheter or an AVG. The following variables found to be associated with AVF failure when an AVF was created at least 4 months pre‐HD initiation: older age (odds ratio [OR] 1.01; 95% confidence interval [CI] 1.00–1.02), female gender (OR 1.69; 95% CI 1.55–1.83), black race (OR 1.41; 95% CI 1.26–1.58), history of diabetes (OR 1.22; 95% CI 1.06–1.39), cardiac failure (OR 1.26; 95% CI 1.15–1.37), and shorter duration of pre–end‐stage renal disease (ESRD) nephrology care (OR for a nephrology care of less than 6 months prior to ESRD of 1.22 compared with a pre‐ESRD nephrology follow up of more than 12 months; 95% CI 1.07–1.38). OR for AVF failure for the entire cohort showed similar findings. In an elderly HD population, there is an association of older age, female gender, black race, diabetes, cardiac failure and shorter pre‐ESRD nephrology care with predialysis AVF failure.     

Trends in Microelectronics,Optical Detectors,and Biosensors

The ultimate downsizing of the minimum feature size is hampered by physical, technological, and economical limitations. To ensure Moore’s law below 100 nm technology nodes both front‐ and back‐end processing have to face technological challenges as clearly stipulated by the International Technology Roadmap for Semiconductors (ITRS). Lithography, gate stack, shallow junctions, high‐ and low‐k dielectrics, and interconnect schemes are nowadays amongst the hot research issues leading to a global collaboration. This paper reviews some of the on‐going research efforts to come to cost‐effective solutions forming the backbone for future technology generations. Moreover the status and evolution of complementary metal oxide semiconductor (CMOS) compatible image sensors, infrared (IR) detectors, and of biosensors is treated.     

Effects of citrate‐enriched bicarbonate based dialysate on anticoagulation and dialyzer reuse in maintenance hemodialysis patients

Systemic anticoagulation with unfractionated heparin is commonly used in maintenance hemodialysis (HD), but it increases the risk of bleeding complications. We investigated whether the use of citrate‐enriched bicarbonate based dialysate (CD) would reduce systemic anticoagulation without compromising the efficacy of reprocessed dialyzers. This is a crossover study in which half of a total of 30 patients initially underwent HD with acetate‐enriched bicarbonate based dialysate and a standard heparin dose of ～100 IU/kg (Treatment A), whereas the remaining patients were treated with CD and a 30% reduced heparin dose (Treatment B). After 12 consecutive HD sessions in each treatment, the dialysate and heparin doses were reversed, then followed for another period of 12 HD sessions. The two treatment phases were split by a washout period of six HD sessions using acetate‐enriched bicarbonate based dialysate and standard heparin dose. Systemic anticoagulation was higher in Treatment A. The activated partial thromboplastin time at the end of HD session was 68 ± 36 seconds in Treatment A and 47 ± 16 seconds in Treatment B (P = 0.005). Sixty‐eight percent of the dialyzers remained adequate until the 12th use in Treatment A and 61% did so in Treatment B (P = 0.63). Patients had three and 24 cramps episodes during Treatment A and B, respectively (P < 0.001). Nine and 26 symptomatic intradialytic hypotension episodes were seen in Treatment A and B, respectively, (P = 0.003). In conclusion, the use of CD had a favorable effect on anticoagulation in the extracorporeal circuit in patients on maintenance HD, but it was also associated with more hypotension and cramps.