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.     

The Clinical Impact of Increasing the Hemodialysis Dose

Good evidence suggests that improvements in dialysis efficiency reduce morbidity and mortality of hemodialysis (HD) patients. Dialysis efficiency has also been related to better control of arterial blood pressure (BP), anemia, and serum phosphorus levels, and to improvement in patients' nutritional status. Over a 2‐year period, the present self‐controlled study of 34 HD patients (23 men, 11 women; age, 52.6 ± 14.5 years; HD duration, 55.9 ± 61.2 months) looked at the effect on clinical and laboratory parameters of increasing the delivered dialysis dose under a strict dry‐weight policy. Dialysis dose was increased without increasing dialysis time and frequency. A statistically significant increase was seen in delivered HD dose: the urea reduction ratio (URR) increased to 60% ± 10% from 52% ± 8%, and then to 71% ± 7% (p < 0.001); Kt/V_urea increased to 1.22 ± 0.28 from 0.93 ± 0.19, and then to 1.55 ± 0.29 (p < 0.001). A statistically significant increase in hemoglobin concentration also occurred—to 10.8 ± 1.9 g/dL from 10.4 ± 1.7 g/dL, and then to 11.0 ± 1.3 g/dL (p < 0.05 as compared to baseline)—with no significant difference in weekly erythropoietin dose. Statistically significant decreases occurred in the systolic and diastolic blood pressures during the first year; they then remained unchanged. Systolic blood pressure decreased to 131 ± 23 mmHg from 147 ± 24 mmHg (p < 0.001); diastolic blood pressure decreased to 65 ± 11 mmHg from 73 ± 12 mmHg (p < 0.001). Serum albumin increased insignificantly to 4.4 ± 0.4 g/dL from 4.3 ± 0.4 g/dL, and then significantly to 4.6 ± 0.3 g/dL (p = 0.002 as compared to both previous values). Normalized protein catabolic rate increased significantly to 1.16 ± 0.15 g/kg/day from 0.93 ± 0.16 g/kg/ day (p < 0.001), and then to 1.20 ± 0.17 g/kg/day (p < 0.001 as compared to baseline). We conclude that the increases achieved in average Kt/V_urea per hemodialysis session by increasing dialyzer membrane area, and blood and dialysate flows, without increasing dialysis time above 4 hours, in patients hemodialyzed thrice weekly, coupled with strict dry‐weight policy, resulted in improvements in hypertension, nutritional status, and anemia.     

Effect of Vitamin E Dialyzer Membrane on Anemia in Hemodialysis Patients

Red blood cell (RBC) survival in patients on chronic maintenance hemodialysis (HD) has been reported to be shortened due to the oxidative damage of RBC membrane. The use of antioxidants might help in the control of anemia and reduce the erythropoietin (EPO) dose needed. Objective: The objective was to determine the effects of vitamin E‐bonded dialyzer membrane (VEM) on anemia and EPO requirements in chronic HD patients. Patients and methods: We prospectively studied 19 stable patients on HD (8 males, age 58.47, range 31–76 years) who were shifted from other dialyzer membranes to VEM for 6 months. At baseline they were given a mean dose of EPO of 90.6 ± 51 U kg^–1 BW^–1 week^–1. Clinical data, dry body weight corrected pre‐dialysis RBC, hemoglobin, reticulocytes, serum iron and ferritin, complete biochemistry, iPTH, and CRP were studied at 3 and 6 months, while therapy scheme was reevaluated monthly. Results: A significant rise, compared to the baseline, was found in hemoglobin and in RBC at 3 months of treatment (12.44 ± 1.16 g/dL vs. 11.2 ± 1.2 g/dL, p = 0.002; and 4.01 ± 0.53 × 10⁶/μL vs. 3.64 ± 0.5 × 10⁶/μL, p < 0.05) and at the end of follow‐up (12.17 ± 1.33 g/dL vs. 11.2 ± 1.2 g/dL, p < 0.05; and 4.03 ± 0.53 × 10⁶/μL vs. 3.64 ± 0.5 × 106/μL, p < 0.05). No significant change in serum iron and ferritin, reticulocytes, EPO dose used, iPTH, Kt/V, or CRP was found at the end of follow‐up compared to the baseline (68.8 ± 17 mg/dL vs. 67.9 ± 18 mg/dL, p = NS; 421 ± 296 mg/dL vs. 478 ± 359 mg/dL, p = NS; 3.76 ± 0.89 × 10⁴/μL vs. 3.82 ± 0.78 × 10⁴/μL, p = NS; 90.2 ± 53 U kg^–1 BW^–1 week^–1 vs. 90.6 ± 51 U kg^–1 BW^–1 week^–1, p = NS; 157 ± 43 pg/dL vs. 148 ± 56 pg/dL, p = NS; 1.21 ± 0.22 vs. 1.2 ± 0.17, p = NS; 7.15 ± 5.42 mg/L vs. 15.38 ± 29.8 mg/L, p = NS, respectively). Conclusions: Despite the small number of patients and the short time interval of treatment, an antioxidant effect of VEM apparently achieved early a better control of anemia in HD patients.     

Quotidian dialysis Survival in 221 patients treated by short daily hemodialysis for 315 patient years

Scanty data suggests that large solutes show a kinetic behavior that is different from urea. The question investigated in this study is whether other small water‐soluble solutes such as some guanidino compounds show a kinetic behavior comparable or dissimilar to that of urea. This study included 7 stable conventional hemodialysis patients without residual diuresis undergoing low flux polysulphone dialysis (F8 and F10HPS). Blood samples were collected from the inlet and outlet blood lines before the dialysis session, after 5, 15, 30, 120 minutes, and immediately after discontinuation of the session. Plasma concentrations of urea, creatinine (CTN), creatine (CT), guanidinosuccinic acid (GSA), guanidinoacetic acid (GAA), guanidine (G), and methylguanidine (MG) were used to calculate corresponding dialyzer clearances. A two‐pool kinetic model was fitted to the measured plasma concentration profiles, resulting in the calculation of the perfused volume (V₁), the total distribution volume (V_tot), and the inter‐compartmental clearance (K₁₂); solute generation and ultrafiltration were determined independently. No significant differences were observed between V₁ and K₁₂ for urea (6.4 ± 3.3 L and 822 ± 345 mL/min) and for the guanidino compounds. However, with respect to V_tot, GSA was distributed in a smaller volume (30.6 ± 4.2 L) compared to urea (42.7 ± 6.0 L ? P < 0.001), while CTN, CT, GAA, G, and MG showed significantly larger volumes (54.0 ± 5.9 L, 98.0 ± 52.3 L, 123.8 ± 66.9 L, 89.7 ± 21.4 L, and 102.6 ± 33.9 L, respectively). These differences resulted in markedly divergent effective solute removal: 67%(urea), 58%(CTN), 42%(CT), 76%(GSA), 37%(GAA), 43%(G), and 42%(MG). In conclusion, the kinetics of the guanidino compounds under study are different from that of urea; hence, urea kinetics are not representative for the removal of other uremic solutes, even if they are small and water‐soluble like urea.     

Regional Anticoagulation with Sodium Citrate in Pediatric Patients on Intermittent Hemodialysis Therapy with Bleeding Risks

Heparin‐free anticoagulation in hemodialysis (HD) is advocated for patients with clotting abnormalities and risk of bleeding. Objective: First publication on regional citrate anticoagulation (RCA) in children. RCA is free from systemic effects, guarantees excellent dialyzer life, but requires careful monitoring. Methods: We report on 3 patients treated by intermittent RCA HD (4 h each, high‐flux dialyzer F40, Fresenius): (1) 17‐year‐old boy (renal transplant failure, access via cubital Cimino fistula) after hypertensive intra‐cerebral hemorrhage (2 sessions); (2) 13‐year‐old girl (hemolytic uremic syndrome, access via jugular vein Shaldon catheter) after abdominal surgery and bleeding (8 sessions); and (3) 7‐year‐old boy (hyperoxaluria, access via PermCath^® jugular vein catheter) after renal transplant biopsy (3 sessions). Sodium citrate 30% was infused into the extra corporeal circuit (blood flow 150 mL/min) before dialyzer (initial flow 30 mL/min) and calcium gluconate 10% for antidote into venous line near of catheter or fistula (initial flow 40 mL/min). Post‐dialyzer extracorporeal serum Ca⁺⁺ (aim < 0.3 mmol/L) and pre‐dialyzer intra‐corporeal Ca⁺⁺ (aim > 0.9) were measured for every 30 min. Serum Na⁺, K⁺, base excess (BE), blood flow, blood pressure, heart rate, and blood out‐flow and in‐flow pressure were also monitored. Results: For adequate RCA (mean extracorporeal serum Ca⁺⁺ 0.24 ± 0.04 mmol/L), a mean citrate flow of 36.1 ± 5.9 mL/h and a mean calcium substitution rate of 40.8 ± 3.4 mL/h were needed. Intra‐corporeal Ca⁺⁺ was kept at 1.10 ± 0.07 mmol/L. Extracorporeal activated clotting time (ACT) was 194 ± 41 and intra‐corporeal ACT 90 ± 12 sec. Serum Na⁺, K⁺, and BE during HD were 138 ± 2, 3.5 ± 0.3, and ?0.6 ± 1.1 mmol/L, respectively. Mean arterial blood pressures of patients 1–3 were 117 ± 5, 103 ± 5, and 102 ± 6 mmHg. All patients were stable and without any bleeding during HD. The only adverse event was 1 episode of hypocalcemia (Ca⁺⁺ < 0.6 mmol/L) cured by stopping dialysis. Conclusions: Local anticoagulation with sodium citrate during intermittent HD can be applied safely in children and adolescents.     

Effects of silymarin on biochemical and oxidative stress markers in end‐stage renal disease patients undergoing peritoneal dialysis

Introduction End‐stage renal disease (ESRD) patients especially those undergoing dialysis are vulnerable to several complications, in particular those related to oxidative stress. Silymarin is an herbal medicine commonly used as an antioxidant in different pathologies. Methods To evaluate the effect of silymarin on biochemical and oxidative stress markers, 50 ESRD patients undergoing peritoneal dialysis were randomly divided into two groups of silymarin (n = 28) and control (n = 22) and received silymarin (140 mg every 8 hours) or placebo for 2 months, respectively. Ferric reducing antioxidant power and total 8‐iso‐prostaglandin F_2α were measured in plasma, while catalase enzyme activity was measured in erythrocytes of both groups before and after treatment. Findings Ferric reducing antioxidant power values after treatment were significantly decreased in silymarin group compared to before treatment values (17.2 ± 2.9 and 15.9 ± 3.1 µM equivalent of quercetin/dL, respectively, P < 0.05). Conversely, catalase levels were increased 17.3% after silymarin consumption, while it was decreased 9.1% in control group. Further, hemoglobin (from 10.94 ± 2.17 to 11.54 ± 2.03 g/dL, P < 0.05) and albumin levels (from 3.48 ± 0.67 to 3.61 ± 0.53 g/dL, P < 0.05) were significantly increased after silymarin administration. Discussion It is concluded that silymarin could be regarded as a supplementary therapy for ESRD patients undergoing peritoneal dialysis in order to reduce complications.     

Role of bicarbonate dialysis in prevention of serious arrhythmias in high‐risk cardiac patients undergoing regular hemodialysis

Background: Cardiac arrhythmias are considered as one of the most important causes of mortality in patients on hemodialysis. Arrhythmias frequently occur in patients with chronic renal failure on regular hemodialysis with reported incidences varying from 30–48% of patients. These abnormalities can span from supraventricular to severe ventricular arrhythmia. There is an increased frequency of occurrence and clustering of arrhythmias around the dialysis time. Aim of the study: To detect the difference between acetate and bicarbonate dialysis as regard to the type and frequency of arrhythmia in those patients. Study design: This study was done on 20 male patients age 51–73, all have history of heart disease. Patients were divided into 2 equal groups using acetate in group 1 and bicarbonate in group 2. All patients were on regular hemodialysis (4 hours, thrice weekly). Careful history and clinical examination were done. Pre‐dialysis investigations included serum creatinine, blood urea nitrogen, serum sodium, potassium, calcium and phosphorus, serum albumin, hemoglobin, and arterial blood gases. Post‐dialysis serum potassium and arterial blood gases were measured. ECG and forty‐eight hours ambulatory monitor (Holter monitor)(before, during, and after hemodialysis, till the end of the dialysis day and throughout the following day) were performed. Results: Group 1 showed significantly less post‐dialysis supraventricular arrhythmias than in dialysis day (210.9 ± 236 and 62.3 ± 14.4), respectively. Significantly less ventricular arrhythmias in post‐dialysis than in dialysis day (30.7 ± 50.4, and 106.2 ± 128.4), respectively. While in Group 2 there were insignificant differences regarding supraventricular arrhythmias (21.9 ± 28.9 and 16.6 ± 36.3) and ventricular arrhythmias (22.9 + 7.8 and 29.6 + 12.8) in dialysis day than in post‐dialysis day. There was significantly higher frequency of supraventricular and ventricular arrhythmias in the dialysis day in acetate hemodialysis in comparison to bicarbonate hemodialysis. Conclusion: Bicarbonate hemodialysis is less arrhythmogenic in comparison to acetate hemodialysis and has better effect on the blood pH and greater degree of base repletion. Continuous ambulatory ECG recording (Holter) is a useful tool in detecting arrhythmias in dialysis patients.     

Comparison of serum albumin,C‐reactive protein and carotid atherosclerosis as predictors of 10‐year mortality in hemodialysis patients

Serum albumin, C‐reactive protein (CRP), and the intima‐medial thickness of the common carotid artery (CA‐IMT) are associated with clinical outcomes in hemodialysis (HD) patients. However, it remains unclear which parameters are more reliable as predictors of long‐term mortality. We measured serum albumin, CRP, and CA‐IMT in 206 HD patients younger than 80 years old, and followed them for the next 10 years. One hundred sixty‐eight patients (age: 57 ± 11 years, time on HD: 11 ± 7 years) were enrolled in the analyses. We divided all patients into three tertiles according to their albumin levels, and conducted multivariate analyses to examine the impact on 10‐year mortality. Seventy‐three (43.5%) patients had expired during the follow‐up. Serum albumin was significantly lower in the expired patients than in the surviving patients (3.8 ± 0.3 vs. 4.0 ± 0.3, P<0.01), while CRP (4.7 ± 5.0 vs. 2.8 ± 3.5 g/L, P=0.01) and CA‐IMT (0.70 ± 0.15 vs. 0.59 ± 0.11 mm, P<0.01) were significantly higher in the expired group. The multivariate analysis revealed that there was a significantly higher risk for total mortality in HD patients with serum albumin <3.8 g/dL (odds ratio 5.04 [95% CI: 1.30–19.60], P=0.02) when compared with those with albumin >4.1 g/dL. In contrast, CRP and CA‐IMT did not associate with total death. It follows from these findings that serum albumin is more superior as a mortality predictor compared with CRP and CA‐IMT in HD patients.     

Echocardiographic Evidence of Altered Cardiac Status in Predialysis Diabetics and Those on Dialysis

Cardiovascular complications affect diabetic subjects early and the more susceptible ones are those on hemodialysis. Objective: This study was designed to observe prevalent cardiac involvement in both pre‐ and already on dialysis diabetics. Method: Sixty diabetics, 30 predialysis (predialysis diabetics, group 1), and 30 on maintenance hemodialysis (MHD, group 2) were randomly selected and their different clinical, biochemical, and echocardiographic parameters were compared. Result: Both groups of patients were matched for age, sex, and body mass index (BMI). Features like systolic and diastolic blood pressure were lower in predialysis diabetics group than in MHD group [138 ± 19 vs. 152 ± 32, p < 0.02 and 74 ± 10 vs. 87 ± 10 mmHg (p < 0.001)]; hemoglobin higher [10.3 ± 2.1 vs. 7.5 ± 1.5 g/dL (p < 0.001)]; serum creatinine was lower [3.49 ± 1.8 vs. 9.5 ± 2.5 mg/dL (p < 0.001)] (due to recruitment criteria); left ventricular muscle mass index (LVMI) also lower [137 ± 96 vs. 211 ± 77 g/m² (p < 0.001)]; left ventricular end diastolic volume index (LVEDVI) less [58 ± 21 vs. 85 ± 25 mL/m² (p < 0.001) and fractional shortening (FS, %) higher [33 ± 4.3 vs. 28 ± 5.8 (p < 0.006)]. Only 11% of Pre subjects had LV hypertrophy (LVMI >131 g/m² in male and in female LVMI >110 g/m²) whereas it was 51% in MHD (p < 0.001). Systolic dysfunction (FS = <25%) was 4% in Pre subjects and 24% in MHD (p < 0.03) group. Correlation study showed systolic and diastolic blood pressure; both had positive correlation with LVMI (r = 0.38, p < 0.008 and r = 0.32, p < 0.02) and LVEDVI (r = 0.36, p < 0.01 and r = 0.35, p < 0.01) and also similarly positive with serum creatinine (r = 0.35, p < 0.02 and r = 0.5, p < 0.001). Conclusion: It may be concluded that cardiac parameters are grossly altered in majority of diabetics on dialysis and higher serum creatinine and uncontrolled blood pressure may be responsible for this.     

Comparative Biological Evaluation of <Superscript>99<Emphasis Type="Italic">m</Emphasis></Superscript>Tc-Timonacic Acid Prepared Using Different Reducing Agents as a Complex for Hepatobiliary Imaging

Timonacic acid (TCA) was labeled with ^99mTc in the presence of three different reducing agents: NaBH₄, Na₂S₂O₄, and SnCl₂·2H₂O. The optimum conditions were as follows: with Na₂S₂O₄, pH 8, 7 mg of Na₂S₂O₄, room temperature, 2 mg of TCA, 30 min (radiochemical yield 98 ± 0.3%, complex was stable for 24 h); with NaBH₄, pH 8, 10 mg of NaBH₄, room temperature, 2 mg of TCA, 30 min (radiochemical yield 95 ± 0.3%, complex was stable for 6 h). The biodistribution of the complex in mice was studied. The liver uptake depends on the reducing agent used, reaching in 30 min 33.5 ± 0.3, 18.4 ± 0.18, and 22.3 ± 0.3% ID/g for the complexes prepared using Na₂S₂O₄, NaBH₄, and SnCl₂·2H₂O, respectively.     

Malnutrition‐inflammation‐coronary calcification in pediatric patients receiving chronic hemodialysis

Malnutrition, inflammation, and renal osteodystrophy parameters with resultant coronary calcification (CC) are associated with increased cardiovascular mortality in adults. Previous pediatric studies demonstrated CC in children but none assessed for an association between inflammation, malnutrition, renal osteodystrophy, and CC. To assess CC, ultrafast computerized tomogram was obtained for 16 pediatric patients (6 females; median age 17.2 years; range 9.1–21.2 years) receiving hemodialysis for ≥2 months. Inflammation was assessed by serum IL‐6, IL‐8, and C‐reactive protein levels on the day of the computerized tomogram scan; nutrition parameters included serum albumin, cholesterol, the body mass index standard deviation score, and normalized protein catabolic rate. Renal osteodystrophy parameters included time‐averaged serum calcium, phosphorus, total PTH, and calcitriol/calcium dose. Patients received hemodialysis thrice‐weekly; mean single pool Kt/V 1.48±0.13; and mean normalized protein catabolic rate 1.27±0.17 g/kg/day. Five of 16 patients had CC. Patients with CC were older (19.1±2.1 vs. 15.4±3.1 months; P=0.03), had longer dialysis vintage (49.4±15.3 vs. 17.2±10.5 months, P=0.0002), lower serum cholesterol (122±17.7 vs. 160.4±10.6 mg/dL, P=0.02), and higher phosphorus (9.05±1.2 vs. 6.1±0.96 mg/dL, P=0.0001). Mean serum albumin and normalized protein catabolic rate did not differ for patients with CC. All patients had elevated IL‐6 and IL‐8 levels compared with healthy norms; the mean IL‐6, IL‐8, and C‐reactive protein levels were not different in patients with CC. Coronary calcification was prevalent in older children receiving maintenance hemodialysis with a longer dialysis vintage. Worse renal osteodystrophy control and malnutrition (low cholesterol) may contribute to CC development.     

Graphene‐Encapsulated FeS2 in Carbon Fibers as High Reversible Anodes for Na+/K+ Batteries in a Wide Temperature Range

Developing low cost, long life, and high capacity rechargeable batteries is a critical factor towards developing next‐generation energy storage devices for practical applications. Therefore, a simple method to prepare graphene‐coated FeS₂ embedded in carbon nanofibers is employed; the double protection from graphene coating and carbon fibers ensures high reversibility of FeS₂ during sodiation/desodiation and improved conductivity, resulting in high rate capacity and long‐term life for Na⁺ (305.5 mAh g^?1 at 3 A g^?1 after 2450 cycles) and K⁺ (120 mAh g^?1 at 1 A g^?1 after 680 cycles) storage at room temperature. Benefitting from the enhanced conductivity and protection on graphene‐encapsulated FeS₂ nanoparticles, the composites exhibit excellent electrochemical performance under low temperature (0 and ?20 °C), and temperature tolerance with stable capacity as sodium‐ion half‐cells. The Na‐ion full‐cells based on the above composites and Na₃V₂(PO₄)₃ can afford reversible capacity of 95 mAh g^?1 at room temperature. Furthermore, the full‐cells deliver promising discharge capacity (50 mAh g^?1 at 0 °C, 43 mAh g^?1 at ?20 °C) and high energy density at low temperatures. Density functional theory calculations imply that graphene coating can effectively decrease the Na⁺ diffusion barrier between FeS₂ and graphene heterointerface and promote the reversibility of Na⁺ storage in FeS₂, resulting in advanced Na⁺ storage properties.     

Kinetic Studies on Urea Extraction with Hemodialysis in Adolescents by On‐line Monitoring of Dialysate Urea

Kinetics of urea extraction during a single dialysis session in children are unknown, because analysis of solutes in dialysate is difficult due to their extreme dilution. >Objective: A novel urea monitor of the Gambro Company might be of help in studying urea kinetics also in children. Methods: We studied 107 urea kinetics in 5 adolescents aged 13–19 years, weighing 26–58 kg, and looked for influences of membrane size, blood flow, and duration of one dialysis session. Urea measurement applies to the change of electric dialysate conductivity due to ionization because of urea splitting by urease. Bicarbonate dialysis regimen was 4–5 h each, 3 times a week, using polysulfone high‐flux dialyzers (Fresenius F60 or F80, depending on body size). Results: Average 4‐h urea Kt/V values for F60 (n = 85) were 1.69±0.53 and for F80 (n = 21) 1.63±0.25, extracted urea mass was 16.0±5.4 g and 32.5±5.4 g, respectively (p < 0.05); Kt/V urea results for blood flows of 180–220 mL/min were 1.36±0.52 and for <180 mL/min 1.10±0.43; extracted urea mass was 17.3±8.0 and 11.7±4.9 g, respectively (p < 0.05). Total average urea extraction ratio after 2 h of dialysis (n = 107) was 64.8±5.6%. Extraction ratio during the 4^th h of dialysis was only 15.3±4.1% and during the 5^th h not more than 9.0±3.6% of total urea extraction. Conclusion: Kinetics of urea extraction helps understanding dialysis processes in children. Adapting the size of the dialyzer according to body size raises urea extraction and maintains urea clearance Kt/V at the desired quality level. An inadequate blood flow lowers both urea extraction and urea clearance Kt/V. Prolonging dialysis beyond 4 h is, at least in concern of urea kinetic modelling, a rather ineffective means. We speculate that children with blood flow problems should be dialysed more often.     

Hepatitis B Virus Vaccine Response in Hemodialysis: Baseline Patient Characteristics

Background: Hepatitis B virus (HBV) vaccination is recommended for all individuals with renal failure. Nevertheless, the response rate for this vaccine in hemodialysis (HD) patients is low, ranging from 50% to 80%. The goal of this study was to determine patient characteristics at the initiation of HD that influence HBV vaccine response. Methods: Patients new to HD in an urban population in the United States were retrospectively examined. Analyzed patients were HBV antibody and antigen negative and hepatitis C virus antibody negative at the start of HD, who received HBV recombinant vaccine. Nonresponse was defined as failure to seroconvert (>10 UI/L) after six deltoid intramuscular injections of vaccine. Response was defined as a lasting seroconversion (at least two consecutive positive titers) with ≤6 injections. Demographic, laboratory, and kinetic modeling data were examined. Results: A total of 33 nonresponders and 64 responders were identified. Univariate analysis demonstrated that nonresponders were older (59 vs. 51 years), had a higher prevalence of diabetes mellitus (DM) (70 vs. 39%), had lower serum albumin levels (3.2 vs. 3.3 g/dL), and had higher dry weights (84 vs. 71 kg) than responders at HD start. In addition, nonresponders had lower normalized protein catabolic rates (0.74 vs. 0.85 g/kg/day) and lower (single‐pool) spKt/V _urea values (0.95 vs. 1.19). Nonresponders had lower serum creatinine levels than responders, despite the greater dry weights. In a multiple logistic analysis model, the presence of DM, age ≥ 55 years, body weight ≥80 kg, and normalized protein catabolic rate ≤0.75 g/kg/day were associated with HBV vaccination nonresponse. At the end of the vaccination period, nonresponders versus responders continued to have lower serum albumin (3.5 vs. 3.8 g/dL) and creatinine levels (7.8 vs. 10.0 mg/dL) and spKt/V _urea (1.27 vs. 1.39). Conclusion: Hepatitis B vaccine nonresponders on HD are older, are more likely to have DM, are more malnourished, and have lower spKt/V_urea than responders. Nonresponders may also have a different body composition with a lower ratio of lean to total body mass.     

Lipid Metabolism and Cardiovascular Morbidity and Mortality in Hemodialysis Patients: Role of Factors Modulating Cytosolic Calcium

Animal studies indicate that insulin resistance and glucose intolerance leading to dyslipidemia in uremic rats are associated with increased cytosolic calcium ([Ca⁺⁺ i]). The resistance and intolerance are reversed with verapamil, but recur after its discontinuation. This finding suggests that hyperparathyroid‐induced [Ca ⁺⁺ i] increase is responsible for the metabolic derangement. We retrospectively examined, over a 12‐year period, the effects of factors that lower [Ca ⁺⁺i] on total serum cholesterol and triglycerides in 332 hemodialysis (HD) patients. Because the study was retrospective, detailed lipid profiles were not available. We therefore relied on morbidity and mortality outcomes related to atherosclerotic vascular disease. Patients with diabetes mellitus were excluded, because their dyslipidemia and vascular disease are mediated via a different mechanism. Four groups emerged: group I [high parathormone (PTH) in the absence of calcium channel blockers (CCBs), n = 107], representing the highest [Ca⁺⁺ i]; group II (high PTH in the presence of CCBs, n = 76) and group III (lower PTH in the absence of CCBs, n = 66), representing intermediate [Ca ⁺⁺ i]; and group IV (lower PTH in the presence of CCBs, n = 83) representing the lowest [Ca ⁺⁺i]. The theoretically lower [Ca ⁺⁺ i] was achieved via CCB therapy or lower PTH, or both. The mean serum cholesterol in group I was 322 ± 24 mg/dL and the level of triglycerides was 398 ± 34 mg/dL. Group II had mean serum cholesterol of 196 ± 16 mg/dL and triglycerides of 157 ± 17 mg/dL. Group III had a mean serum cholesterol of 202 ± 19 mg/dL and triglycerides of 160 ± 15 mg/dL. Group IV had a mean serum cholesterol of 183 ± 9 mg/dL and triglycerides of 94 ± 6 mg/dL. The differences in cholesterol and triglyceride levels among four groups were significant (p < 0.001) by one‐way analysis of variance (ANOVA). The incidence of cardiovascular morbidity and mortality events was 61% in group I, 24% in group II, 28% in group III, and 18% in group IV (χ ² = 47.7, p < 0.001). We conclude that, in non diabetic HD patients, hyperparathyroidism, especially in the absence of CCBs, is associated with severe dyslipidemia and increased risk of cardiovascular morbidity and mortality. Dyslipidemia may be related to a hyperparathyroid‐induced increase in cytosolic calcium [Ca⁺⁺i]. Lowering [Ca⁺⁺i] by decreasing PTH or by blocking calcium entry into cells (via CCBs), or both, is associated with less dyslipidemia and improved long‐term cardiovascular morbidity and mortality. Prospective randomized studies, with actual measurement of [Ca ⁺⁺i], are needed to verify the results of this study.     

Nocturnal dialysis: Comparing six night/week with alternate night therapy

The biochemical, haemodynamic, clinical, and nutritional benefits of nocturnal haemodialysis (NHD) compared with (c/w) 4 hr, 3/week conventional haemodialysis (CHD) are well known and accrue by increasing dialysis time and frequency either for 8 hrs alternate night/week (NHD_3.5) or for 8 hrs 6 nights/week NHD (NHD₆). However, there is little data yet comparing NHD_3.5 with NHD₆. 13 NHD₆(8.15 hrs/night) were c/w 14 NHD_3.5(7.8 hrs/night), all with similar demographic profiles. NHD₆ had unrestricted diet and fluid intake but NHD_3.5 needed some restriction. Before (_b) and after (_a) HD phosphate (PO₄) control was ideal though _bPO₄ levels for NHD₆ were lower (1.64 mmol/l) c/w NHD_3.5(1.83 mmol/l). All NHD₆ needed PO₄ supplementation c/w 2/14 NHD_3.5 but 5/14 NHD_3.5 needed PO₄ binders c/w 0/13 NHD₆. Both had normal blood pressures with 3/14 NHD_3.5 needing anti‐hypertensives c/w 2/13 NHD₆. The _bHb was 122.8 g/l (NHD₆) c/w 127.7 g/l (NHD_3.5) and the _balbumin was 38.3 g/l (NHD₆) c/w 37.7 g/l (NHD_3.5). NHD₆ had lower _b blood urea (10.2 c/w 19.5 mmol/l) and less interdialytic urea and creatinine fluctuation. NHD₆ ultrafiltration rates (UFR) and intradialytic weight gains (mean ± SEM) were significantly lower (248 ± 22.7 ml/hr and 2.03 ± 0.19 kg) c/w NHD_3.5(453 ± 34.6 ml/hr and 2.85 ± 0.27 kg): UFR p < 0.10. We conclude that NHD₆ offers the optimum biochemical, volume, and clinical outcome but NHD_3.5 still has a clear and major advantage over CHD and a dual additional appeal to providers seeking home‐based therapy cost advantages and consumable expenditure control. A flexible dialysis program should offer all the time and frequency options of NHD but, in particular, should support NHD at a frequency sympathetic to the clinical, rehabilitation, and lifestyle aspirations of individual patients.     

Construction of Bimetallic Selenides Encapsulated in Nitrogen/Sulfur Co‐Doped Hollow Carbon Nanospheres for High‐Performance Sodium/Potassium‐Ion Half/Full Batteries

Metallic selenides have been widely investigated as promising electrode materials for metal‐ion batteries based on their relatively high theoretical capacity. However, rapid capacity decay and structural collapse resulting from the larger‐sized Na⁺/K⁺ greatly hamper their application. Herein, a bimetallic selenide (MoSe₂/CoSe₂) encapsulated in nitrogen, sulfur‐codoped hollow carbon nanospheres interconnected reduced graphene oxide nanosheets (rGO@MCSe) are successfully designed as advanced anode materials for Na/K‐ion batteries. As expected, the significant pseudocapacitive charge storage behavior substantially contributes to superior rate capability. Specifically, it achieves a high reversible specific capacity of 311 mAh g^?1 at 10 A g^?1 in NIBs and 310 mAh g^?1 at 5 A g^?1 in KIBs. A combination of ex situ X‐ray diffraction, Raman spectroscopy, and transmission electron microscopy tests reveals the phase transition of rGO@MCSe in NIBs/KIBs. Unexpectedly, they show quite different Na⁺/K⁺ insertion/extraction reaction mechanisms for both cells, maybe due to more sluggish K⁺ diffusion kinetics than that of Na⁺. More significantly, it shows excellent energy storage properties in Na/K‐ion full cells when coupled with Na₃V₂(PO₄)₂O₂F and PTCDA@450 °C cathodes. This work offers an advanced electrode construction guidance for the development of high‐performance energy storage devices.     

Relation between Access-Related Infection and Preinfection Serum Albumin Concentration in Patients on Chronic Hemodialysis

Background: Hemodialysis (HD) access‐related infection is a major cause of morbidity and mortality in HD patients. We tested whether hypoalbuminemia is a risk factor for HD access infection and whether mortality of HD catheter infection is affected by removal of the infected catheter. Methods: We analyzed the records of 87 patients on chronic HD who were hospitalized for HD access‐related infection. We obtained data on age, sex, preinfection serum albumin level, comorbidities, complications, infecting organism, type of infection, mode of management, and mortality. We compared preinfection serum albumin levels in 79 patients with HD access infection with the serum albumin levels of 198 control patients on chronic HD without HD access infection admitted to the hospital during the same time for other reasons. In the HD catheter infection subgroup, we compared mortalities between patients treated with catheter removal plus antibiotics as the primary mode of management and those treated initially with antibiotics alone. Results: Preadmission serum albumin level was lower in the HD access infection group (2.4 ± 0.6 g/dL) than in the control group (3.2 ± 0.6 g/dL, P < 0.0001). Logistic regression identified preadmission serum albumin level as a strong independent predictor of HD access infection. In a logistic regression model, with age, sex, HIV status, diabetes, and type of HD vascular access (excluding arterovenous fistula) as the covariates, the odds ratio of HD access infection was 9.8 (95% confidence interval [CI] 4.9–19.7) for a serum albumin level ≤ 3.0 g/dL (P < 0.0001), 10.4 (95% CI 4.97–21.6) for a serum albumin level ≤ 2.5 g/dL (P < 0.0001), and 28.0 (95% CI 5.8–135.9) for a serum albumin level ≤ 2.0 g/dL (P < 0.0001). Case mortality was 25.0% (4/16) in patients with tunneled HD catheter infection initially treated with antibiotics alone and 2.8% (2/71) in those treated with catheter removal plus antibiotics at the time of presentation (P = 0.0096). Conclusion: Hypoalbuminemia is associated with increased risk of HD access infection. Treatment of HD access infection with antibiotics alone is associated with increased risk of death.