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.     

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.     

Modifications to bicarbonate conductivity: A way to increase phosphate removal during hemodialysis? Proof of concept

Introduction Hyperphosphatemia and cardiovascular mortality are associated particularly with end‐stage renal disease. Available therapeutic strategies (i.e., diet restriction, calcium [or not]‐based phosphate binders, calcimimetics) are associated with extrarenal blood purification. Compartmentalization of phosphate limits its depuration during hemodialysis. Several studies suggest that plasmatic pH is involved in the mobilization of phosphate from intracellular to extracellular compartments. Consequently, the efficiency of modified bicarbonate conductivity to purify blood phosphate was tested. Methods Ten hemodialysis patients with chronic hyperphosphatemia (>2.1 mmol/L) were included in the two three–sessions‐per week periods. Bicarbonate concentration was fixed at 40 mmol/L and 30 mmol/L in the first and second periods, respectively. Phosphate depuration was evaluated by phosphate mobilization clearance (K_M). Findings Although bicarbonatemia was lower during the second period (21.0 ± 2.7 vs. 24.4 ± 3.1 mmol/L, P < 0.01), no difference was observed in phosphatemia (2.4 ± 0.5 vs. 2.3 ± 0.4 mmol/L, P = NS). The in‐session variation of phosphate was lower (?1.45 ± 0.42 vs. ?1.58 ± 0.44 mmol/L, P < 0.05) and K_M was higher during the second period (82.94 ± 38.00 vs. 69.74 ± 24.48 mL/min, P < 0.05). Discussion The decrease of in‐session phosphate and the increase in K_M reflect phosphate refilling during hemodialysis. Thus, modulation of serum bicarbonate may play a role in controlling the phosphate pool. Even though correcting metabolic acidosis during hemodialysis remains important, alkaline excess can impair phosphate mobilization clearance. Clinical trials are needed to test the efficiency and relevance of a strategy where bicarbonatemia is corrected less at the beginning of sessions.     

Thermodynamics and kinetics of methane hydrate formation and dissociation in presence of calcium carbonate

Huge amount of gas hydrate deposits are identified in deep marine sediments, which may be considered as a future source of energy. Since carbonate is one of the major components of marine sediments, in the present study attention has been given to characterize methane hydrate formation and dissociation in presence of calcium carbonate. Experiments were performed with 0%, 2%, 4%, 6% and 10% by weight of calcium carbonate in distilled water. Extensive investigations have been done on pressure-temperature equilibrium behavior of hydrate formation and dissociation at varying concentrations of calcium carbonate. Hydrate formation rate was found to vary with concentration of calcium carbonate as the solubility of calcium carbonate in water is controlled by the presence of simultaneous chemical equilibria involving a high number of species like Ca²⁺, CO₃^2?, HCO₃^?, CO₂, etc. Induction time for hydrate formation has also been measured at different concentrations of carbonate. Nucleation point for the hydrate formation was observed to be slightly higher at higher concentration of calcium carbonate due to increased heat absorption. Dissociation enthalpy of hydrates was calculated by using Clausius-Clapeyron at different measured conditions. Moles consumption of methane gas during hydrate formation at different concentrations of carbonate was measured using real gas equation and found to be minimum at 10?wt%.     

Phosphate removal model: an observational study of low-flux dialyzers in conventional hemodialysis therapy

Precise assessing phosphate removal by hemodialysis (HD) is important to improve phosphate control in patients on maintenance HD. We reported a simple noninvasive model to estimate phosphate removal within a 4‐hour HD. One hundred sixty‐five patients who underwent HD 4 hours per session using low‐flux dialyzers made of polysulfone (1.2 m²) or triacetate (1.3 m²) were enrolled. Blood flows varied from 180 to 300 mL/min. Effluent dialysate samples were collected during the 4‐hour HD treatment to measure the total phosphate removal. Predialysis levels of serum phosphate, potassium, hematocrit, intact parathyroid hormone, total carbon dioxide (TCO₂), alkaline phosphatase, clinical and dialysis characteristics were obtained. One hundred thirty‐five observations were randomly selected for model building and the remaining 30 for model validation. Total amount of phosphate removal within the 4‐hour HD was mostly 15–30 mmol. A primary model (model 1) predicting total phosphate removal was Tpo₄ = 79.6 × C₄₅ (mmol/L) ? 0.023 × age (years) + 0.065 × weight (kg) ? 0.12 × TCO₂ (mmol/L) + 0.05 × clearance (mL/min) ? 3.44, where C₄₅ was phosphate concentration in spent dialysate measured at the 45 minute of HD and clearance was phosphate clearance of dialyzer in vitro conditions offered by manufacturer's data sheet. Since the parameter TCO₂ needed serum sample for measurement, we further derived a noninvasive model (model 2):Tpo₄ = 80.3 × C₄₅ ? 0.024 × age + 0.07 × weight + 0.06 × clearance ? 8.14. Coefficient of determination, root mean square error, and residual plots showed the appropriateness of two models. Model validation further suggested good and similar predictive ability of them. This study derived a noninvasive model to predict phosphate removal. It applies to patients treated by 4‐hour HD under similar conditions.     

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.     

Determinants of metabolic acidosis among hemodialysis patients

Metabolic acidosis is frequently present, poorly controlled, and associated with adverse effects among hemodialysis patients. Potential determinants of metabolic acidosis include endogenous acid production, administration of alkali, neutralization of acid by buffers, dilution of serum bicarbonate by interdialytic fluid gain, and loss of bicarbonate in stool. Understanding the relative importance of these determinants may help guide efforts to manage metabolic acidosis. We used chart abstraction, patient interviews, and laboratory testing to assess variables related to acid production (protein breakdown), alkali administration (dialysis dose, missed treatments, dialysate bicarbonate concentration, oral bicarbonate supplements), acid buffering (phosphorus binders), dilution of bicarbonate (interdialytic weight gain), and loss of bicarbonate in stool (diarrhea) for 190 randomly selected patients from 44 hemodialysis facilities. We used multivariate analyses to determine which potential determinants were independently associated with predialysis serum bicarbonate levels. Of all patients, 30% had metabolic acidosis (serum bicarbonate level <22 mEq/L). On multivariate analysis, metabolic acidosis was more likely with increased protein nitrogen appearance (odds ratio [OR] 1.60 per 0.2 g/kg/day, p=0.001) and less likely with increased Kt/V (OR 0.61 per 0.20 increase in Kt/V, p<0.001) and with increased calcium carbonate use (OR 0.38 per 2 g/day, p=0.003). Key determinants of metabolic acidosis among hemodialysis patients are protein breakdown, dialysis dose, and specific phosphorus binders. Further work is needed to develop interventions to address these determinants.     

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.     

Assessment of intradialysis calcium mass balance by a single pool variable‐volume calcium kinetic model

Introduction: A reliable method of intradialysis calcium mass balance quantification is far from been established. We herein investigated the use of a single‐pool variable‐volume Calcium kinetic model to assess calcium mass balance in chronic and stable dialysis patients. Methods: Thirty‐four patients on thrice‐weekly HD were studied during 240 dialysis sessions. All patients were dialyzed with a nominal total calcium concentration of 1.50 mmol/L. The main assumption of the model is that the calcium distribution volume is equal to the extracellular volume during dialysis. This hypothesis is assumed valid if measured and predicted end dialysis plasma water ionized calcium concentrations are equal. A difference between predicted and measured end‐dialysis ionized plasma water calcium concentration is a deviation on our main hypothesis, meaning that a substantial amount of calcium is exchanged between the extracellular volume and a nonmodeled compartment. Findings: The difference between predicted and measured values was 0.02 mmol/L (range ?0.08:0.16 mmol/L). With a mean ionized dialysate calcium concentration of 1.25 mmol/L, calcium mass balance was on average negative (mean ± SD ?0.84 ± 1.33 mmol, range ?5.42:2.75). Predialysis ionized plasma water concentration and total ultrafiltrate were the most important predictors of calcium mass balance. A significant mobilization of calcium from the extracellular pool to a nonmodeled pool was calculated in a group of patients. Discussion: The proposed single pool variable‐volume Calcium kinetic model is adequate for prediction and quantification of intradialysis calcium mass balance, it can evaluate the eventual calcium transfer outside the extracellular pool in clinical practice.     

Glucose variability in maintenance hemodialysis patients with type 2 diabetes: Comparison of dialysis and nondialysis days

Introduction

Hemodialysis (HD) induces several physiological changes that can affect plasma glucose levels in patients with diabetes and in turn their glycemic control. Studies using continuous glucose monitoring (CGM) to assess glucose variations on dialysis days compared with nondialysis days report conflicting results. Here, we used CGM to examine glucose variations induced by HD in patients with type 2 diabetes.

Methods

Patients with type 2 diabetes undergoing maintenance HD were included. CGM (Ipro2®, Medtronic) was performed at baseline and Week 4, 8, 12, and 16 for up to 7 days at each visit. CGM profiles on days where participants received HD were compared with days without HD using a linear mixed model.

Findings

Twenty-seven patients were included. The median number of CGM days performed was 8 (interquartile range [IQR] 6–10) for dialysis days and 16 (IQR 12–17) for nondialysis days. The median sensor glucose was 9.4 (95% confidence interval [CI] 8.8–10.2) mmol/L on dialysis days compared with 9.5 (95% CI 8.9–10.2) mmol/L on nondialysis days (p = 0.58). Nocturnal mean sensor glucose was higher on dialysis days compared with nondialysis days: 8.8 (95% CI 8.0–9.6) mmol/L versus 8.4 (95% CI 7.7–9.2) mmol/L (p = 0.029).

Discussion

Similar median sensor glucose values were found for days on and off HD. Nocturnal glucose levels were modestly increased on dialysis days. Our findings indicate that antidiabetic treatment does not need to be differentiated on dialysis versus nondialysis days in patients with type 2 diabetes undergoing maintenance HD.     

Removal of vancomycin administered during dialysis by a high‐flux dialyzer

Introduction: Hemodialysis patients frequently receive vancomycin for treatment of gram‐positive bacterial infections. This drug is most conveniently administered in outpatient dialysis units during the hemodialysis treatment. However, there is a paucity of data on the removal of vancomycin by high‐flux polyamide dialyzers. Methods: This is a prospective crossover study in which seven uninfected chronic hemodialysis patients at three dialysis units received vancomycin 1 gram intravenously over one hour immediately after the dialysis treatment (Phase 1), and vancomycin 1.5 grams during the last hour of dialysis treatment using a polyarylethersulfone, polyvinylpyrrolidone, polyamide high‐flux (Polyflux 24R) dialyzer (Phase 2). There was a three‐week washout period between phases. Serial serum vancomycin concentrations were used to determine the removal of vancomycin when administered during dialysis. Findings: Dialysis removed 35 ± 15% (range 18‐56%) of the vancomycin dose when administered during the last hour of dialysis. The calculated area under the curve (AUC) of vancomycin levels for 0‐44.5 hours from the start of infusion were similar between the two phases (AUC_{Phase 1} 884 ± 124 mg‐hr/L, mean ± SD; AUC_{Phase 2} 856 ± 208 mg‐hr/L; P=0.72). Serum vancomycin concentrations immediately prior to the next dialysis treatment following vancomycin administration were also similar between the two phases (13.1 ± 2.7 mg/L in Phase 1 and 12.3 ± 3.3 mg/L in Phase 2; P=0.55). Discussion: When using a polyarylethersulfone, polyvinylpyrrolidone, and polyamide high‐flux HD membrane with a 24R Polyflux dialyzer, vancomycin can be administered during the last hour of dialysis if the dose that is prescribed for intra‐dialysis dosing is empirically increased to account for intra‐dialytic drug removal.     

Comparison of calcium phosphate product values using measurement of plasma total calcium and serum ionized calcium

Calcium phosphate product (Ca x Pi) is a clinically relevant tool to estimate the cardiovascular risk of patients with renal failure. In reports, mostly total serum calcium has been used. As measurement of serum ionized calcium has some benefits and is being used increasingly, we estimated the respective levels of calcium phosphate product using both total (t-Ca x Pi) and ionized calcium (ion-Ca x Pi). Fifty-eight healthy individuals and 180 hemodialysis (HD) patients from 2 centers were studied. Diagnostic accuracies for corresponding values of the t-Ca x Pi and ion-Ca x Pi were calculated using a GraphROC program. Of HD patients, 64% had t-Ca x Pi <4.4 mmol(2)/L(2) regarded as a desirable goal, and 10% had values over 5.6 mmol(2)/L(2) associated with a high cardiovascular risk. Based on GraphROC analysis, t-Ca x Pi of 4.4 mmol(2)/L(2) corresponded to a value of 2.2 mmol(2)/L(2) of ion-Ca x Pi and, respectively, t-Ca x Pi of 5.6 mmol(2)/L(2) corresponded 2.8 mmol(2)/L(2) of ion-Ca x Pi. Owing to the good agreement between the results in the 2 centers, these values for risk levels can be used in both centers. When measurement of ionized calcium is used, Ca x Pi values of 2.2 and 2.8 mmol(2)/L(2) can be used instead of generally used values of 4.4 and 5.6 mmol(2)/L(2) with total calcium.     

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.     

Left atrial volume index as a predictor of ventricle repolarization abnormalities in adult dialyzed patients

This study was performed to investigate the relationship between left atrium (LA) volume index (LAVI) and left ventricle electrical activity presumably repolarization in end‐stage renal disease patients. Study group was consisted of 120 dialyzed patients divided into two subgroups: 57 (age 50.7 ± 7.1) were on continuous ambulatory peritoneal dialysis (CAPD) and 73 (age 51.6 ± 7.6) were hemodialyzed (HD). All patients were undergoing three‐dimensional vectorcardiographic (VCG) monitoring to assess parameters concerning T vector: QRS‐T angle, Tel, and Taz. Standard echocardiography was performed to assess: LA_max, LA_short, LA_long. LAVI was calculated due to formula: LAVI = (π/6X [LA_max × LA_short × LA_long])/m². LAVI in HD as well as in CAPD patients was significantly higher compared with controls (respectively: 36.29 ± 10.92; 36.41 ± 11.06; 20.64 ± 6.77 mL/m²). The calculated cutoff value of LAVI was 36.32 mL/m². In HD patients, the strong correlations between LAVI and QRS‐T angle and Tel were determined (respectively: r = 0.407, P < 0.001 and r = 0.359, P = 0.006). Similarly in CAPD group were significant associations between LAVI and QRS‐T angle and Tel (respectively: r = 0.423, P < 0.001 and r = 0.374, P = 0.004). The QRS‐T angle, Tel and Taz are independently and markedly associated with LAVI in both HD and CAPD patients. LAVI and VCG indices are higher in both HD and CAPD patients. Correlation between QRS‐T angle and LAVI may reflect unfavorable influence on the electrical activity of the heart in dialyzed patients with left ventricle diastolic dysfunction. LAVI cutoff value is useful biomarker for stratification of ventricle repolarization disturbances in those patients.     

Coagulation–flocculation process with metal salts,synthetic polymers and biopolymers for the removal of trace metals (Cu,Pb, Ni,Zn) from municipal wastewater

To ensure compliance with regulatory standards, it is important to examine the potential of treatment technologies to enhance trace metal removal from wastewater. This study investigated the effectiveness of coagulation–flocculation at removing trace metals from humus effluent with ferric chloride (FeCl₃), the synthetic polymer polyethyleneimine (PEI) and the biopolymers chitosan and floculan. Effluent samples were collected from a trickling filter treatment works operating in the UK and contained 21 ± 4 μg/L Cu, 0.8 ± 0.1 μg/L Pb, 4 ± 1 μg/L Ni and 43 ± 9 μg/L Zn. The influence of coagulant dosage and the velocity and time of the slow mixing stage were studied via a series of jar tests. Chitosan and PEI had a moderate effect on the removal of trace metals (≤ 35%). FeCl₃ removed 48% Cu, 56% Pb and 41% Zn at the optimised dose of 0.10 mg/L. At the optimised dose of 0.25 mg/L, floculan removed 77% Cu, 68% Pb and 42% Zn. The dominant mechanism for particle removal by FeCl₃ was enmeshment in the precipitates (i.e. sweep flocculation), whereas, for floculan, inter-particle bridging was the dominant removal mechanism. Overall, FeCl₃ and floculan were found to be most effective at removing trace metals from wastewater.

     

Metformin intoxication requiring dialysis

Metformin (MTF) is one of the most common oral agents used to treat diabetes mellitus. Intoxication is associated with lactic acidosis and has significant clinical consequences. We report 12 cases requiring dialytic intervention. Twelve patients were analyzed from 2005 to 2010; 10 of these patients were treated with dialysis. Conventional hemodialysis (HD) and continuous veno-venous hemodialysis treatments with bicarbonate dialysis were used, and the results were presented as mean and standard deviation. The results are as follows: 33% of the patients were male, hospital stay was 9.3 (± 12) days, average MTF dose 1.7 g/day, mortality was 25%. Baseline glomerular filtration rate for these patients was 51.5?mL/min, with an average age of 64 (± 11) years. On presentation, all had acute kidney injury with blood urea nitrogen/creatinine 75 (± 30)/8.1 (± 3.7) mg/dL, lactic acid 12.4 (± 8.1) mmol/L, pH?7.04 (± 0.19), bicarbonate 7.2 (± 4.5) mmol/L. Metformin level was 25 (± 17) μg/mL; anion gap was 28 (± 9), and serum potassium was 5.4 (± 1.3) mEq/L. Seventy percent of patients were treated with conventional HD. Patients required 4 (± 5) dialysis treatments at blood flow QB 330 (± 53), dialysis flow QD 571 (± 111) for 305 (± 122) minutes. Postdialysis, the acidosis parameters improved: bicarbonate 19.2 (± 4.1) mmol/L, lactic acid 6 (± 4) mmol/L and MTF levels decreased 8.9 (± 5.7) μg/mL. Metformin percentage removal was calculated to be 60% (± 24). No difference was found between HD and continous veno-venous hemodialysis. The only difference between survivors was the age 53 (± 7) vs. 78 (± 10) (P?相似文献   

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.     

Pre‐ and Post Hemodialysis Procalcitonin Levels and Their Relationships with Immunoregulatory,Proinflammatory Cytokines in Chronic Hemodialysis Patients

Arteriosclerosis is characterized by stiffening of arteries. The incremental elastic modulus (Einc) measurement is a good marker of arterial wall stiffness. Arteriosclerosis is characterized by stiffening of arteries. Metabolic, inflammatory, and hemodynamic alterations cause structural changes and vascular complications in end‐stage renal disease. The aim of the present study was to evaluate the factors that may affect the development of arteriosclerosis by measurement of Einc in hemodialysis (HD) patients. Thirty‐two patients (16 men and 16 women) on chronic HD with a mean age of 42.2 ± 19.3 (range, 15–80) were included in the study. The carotid Einc was measured to determine arteriosclerosis by high‐resolution echo‐tracking system. Einc measurement was calculated from transcutaneous measurements of carotid arterial internal diameter and wall thickness and carotid pulse pressure. Common carotid compliance (CCC) and distensibility (CCD) were determined from changes in carotid artery diameter during systole and simultaneously measured carotid pulse pressure. Serum levels of calcium (Ca), phosphorus (P), parathormone (PTH), ferritin, C‐reactive protein (CRP), predialysis systolic blood pressure (SBP), predialysis diastolic blood pressure (DBP), pulse pressure (PP), age, HD duration, CCC, and CCD were correlated with Einc in all patients. A significant positive correlation was found between Einc and age (r = 0.40, p < 0.02), SBP (r = 0.39, p < 0.02), PP (r = 0.40, p < 0.02), Ca (r = 0.43, p < 0.01), CRP (r = 0.38, p < 0.02). As expected, Einc was correlated inversely with CCD (r = ?0.77, p < 0.0001). The correlation between Einc and HD duration, DBP, ferritin, P, PTH, and CCC was not significant. In conclusion, the stiffening of carotid artery in HD patients is related not only to hemodynamic changes (increased SBP and PP) but also to metabolic (increased Ca) and inflammatory (increased CRP) responses. Carotid Einc is an accepted independent risk factor for cardiovascular mortality. Because of the positive correlation between Einc and serum Ca, vitamin D and Ca‐containing P binder should be used carefully in HD patients.     

Using a synthetic body fluid (SBF) solution of 27 mM HCO3− to make bone substitutes more osteointegrative

A Tris–HCl-buffered synthetic body fluid (SBF) solution, mimicking the human blood plasma, with the following ion concentrations of 27 mM HCO₃⁻, 2.5 mM Ca²⁺, 1.0 mM HPO₄²⁻, 142 mM Na⁺, 125 mM Cl⁻, 5 mM K⁺, 1.5 mM Mg²⁺, and 0.5 mM SO₄²⁻ was used as an aqueous medium to process a number of bone substitute materials under the so-called biomimetic conditions of 37 °C and pH 7.4. This solution was named as Tris–SBF-27 mM. Firstly, collagen sponges were soaked in Tris–SBF-27 mM solution at 37 °C and were found to be fully covered with nanoporous apatitic calcium phosphate (Ap-CaP). The composites of collagen–Ap-CaP biomaterials are expected to be used in orthopedic and dental surgery. Secondly, Ap-CaP short whiskers or microrods with a novel nanotexture and surface areas higher than 45 m²/g were synthesized in Tris–SBF-27 mM solution. Thirdly, calcium sulfate cements doped with CaHPO₄ (monetite), were shown to have apatite-inducing ability upon ageing in Tris–SBF-27 mM. CaHPO₄ addition in calcium sulfate was found to improve its mechanical strength, measured after cement setting reaction. Pure calcium sulfate cement pellets were not stable in Tris–SBF-27 mM solutions and crumbled into a powder. All the samples were characterized by SEM, XRD, FTIR, surface area and mechanical strength measurements.