Dialysis Bath Research Articles

#496 Individualized approach in dialysate sodium prescription—safe and effective

Abstract Background and Aims The management of Na+ levels in hemodialysis (HD) patients plays a crucial role in maintaining their overall health and well-being. Na+, an essential electrolyte, is responsible for maintaining fluid balance, nerve function, and muscle contraction. However, in end-stage renal disease (ESRD) patients undergoing HD, Na+ imbalances are common and can have detrimental effects on their cardiovascular health. Furthermore, HD patients have been prescribed a standardized dialysis bath Na+ concentration (dNa+) during their HD sessions. The individualized approach aims to optimize Na+ balance, minimize adverse effects, and improve patient outcomes. Additionally, dietary Na+ intake, fluid status, and interdialytic weight gain (IDWG) also influence Na+ levels and should be considered when determining the appropriate Na+ prescription. The study aimed to assess whether an individualized dNa+ prescription can contribute to lower IDWG, expressed as a percent of prescribed dry weight (IDWG%). Method This retrospective, non-interventional study included all >18-year-old patients undergoing hemodialysis for >90 days at a single center. Patients were followed for a period of 18 months (December 2021–June 2023), during which the dNa+ concentration was gradually changed, as part of routine clinical care, until a gradient between plasma and dialysis bath Na+ of −2 mEq/L was achieved. Plasma Na+ levels were measured once monthly before a dialysis session along with other parameters such as IDWG and blood pressure. Results A total of 79 patients were enrolled in the study. The average age of the patients was 63.33 ± 12.1 years, with 43 (54.4%) being male. At baseline, the average duration of HD treatment was 255 ± 2.36 minutes, and the mean blood pump rate was 384.7 ± 42.81 ml/min. The majority of patients (98.8%) received HD treatments thrice weekly. Starting from January 2022, the mean dNa+ concentration decreased non-significantly from 139.39 ± 0.96 mmol/L to 138.99 ± 3.18 mmol/L, p = 0.13. The mean plasma Na+ concentration increased from 133.25 ± 2.9 to 136.59 ± 3.47 mmol/L, p < 0.00001, and while mean systolic blood pressure increased slightly (118.38 ± 12.25 to 122.87 ± 12.43, p = 0.01), it remained well controlled. The mean IDWG% decreased from 3.53 ± 1.34%, to 2.74 ± 1.35%, p = 0.35 and the proportion of patients with IDWG >5% decreased remarkably by more than half (11.4% to 5.1%), but due to the low patient numbers, the finding did not quite reach significance (p = 0.15, Table 1). Conclusion Our study demonstrates that individualized dNa+ management in HD patients is a beneficial approach, contributing to a decrease in the proportion of patients with severe IDWG increase, thereby addressing a crucial cardiovascular risk factor. Systolic blood pressure before dialysis remained well controlled, despite a slight, but significant increase. Our findings underscore the safety and potential benefits of an individualized approach to dialysate Na+ concentration, encouraging further exploration for enhanced HD patient care and increased overall well-being.

The highlights of dialysis in 2023

There has been a wealth of new developments in dialysis this year with the publication of several trials relating to dialysis technique, physical activity and the use of new dialysis treatments. Quality of life should be assessed and managed in all dialysis patients. Lowering the temperature of the dialysis bath in the MyTemp trial does not appear to have an effect on mortality and cardiovascular events. High volume convective hemodiafiltration currently represents the reference technique in hemodialysis; the Convince study confirms its superiority in terms of all-cause mortality. The DIATT study shows the benefit of the presence of an adapted physical activity professional to promote physical activity in dialysis patients and shows that it is necessary for this support to be reimbursed. The RENAL-AF and AXADIA-AFNET 8 studies lack power to conclude on the use of new oral anticoagulants in hemodialysis. For angiotensin receptor neprilysin inhibitors, studies are too weak to allow their use. SGLT2 inhibitors could be used in peritoneal dialysis to increase diuresis or delay the appearance of peritoneal fibrosis but to date only studies on models animals exist. Factor XI inhibitors are a new therapeutic class that could be used and would reduce the risk of thrombosis and hemorrhage. Increasingly, the feelings of patients and caregivers are more and more taken into account. Patient/caregiver communication must be at the heart of care. We will also be looking at the conservative treatment, the management of pruritus in hemodialysis and finally the care of patients with calciphylaxis.

#5959 CONSIDERABLE HEPARIN SAVINGS DURING 48 WEEKS OF HEMODIALYSIS WITH CITRATE-BUFFERED DIALYSIS BATH

Abstract Background and Aims There are research data suggesting a citrate-buffered dialysis bath being superior to conventional acetate-buffered dialysis. Since Heparin may lead to bleeding complications and increased costs we focused on potential Heparin savings in a cohort of 100 dialysis patients who systematically were examined in a 48 weeks comprising timeframe using a citrate-buffered dialysis bath. Method Stable dialysis patients (n = 100, 30 females, mean age 70.7 yrs.) who were treated by high flux dialysis were switched from conventional acetate-buffered dialysis (3mmol/l acetate) to a citrate-buffered dialysis bath (0.8 mmol/l citrate, 0.3 mmol/l acetate; MTN, Neubrandenburg, Germany). After a 4 weeks run-in phase on the new dialysis bath the heparin-dosing was systematically reduced. Heparin was given as a single shot prior to the start of dialysis, the dialysate flow was set on 500 mL/min constantly. Heparin-dosing in the time course was assessed on the basis of the run-in phase. Results Average treatment time was 256 minutes per session and the average blood flow at baseline 361 mL/min and 254 minutes and 369 ml/min at the end of follow-up. The average Heparin-dosing at start of the observation period was 5450 IU/session, which could be reduced to 3909 IU/ session (71% of the starting dose, p<0.01) after the first month of treatment and was further decreased to 3147 IU/session after 24 weeks treatment (58% of the initial dose, p<0.01). In the next 24 weeks of observation no further reductions of Heparin-dosing were achieved (average Heparin dose after 48 weeks 3115 IU/session). In the week before reduction of Heparin we observed 2.2% of clotting episodes and 1.6% at week 48, respectively. Conclusion Despite a reduction of the initial heparin dose by 42% the number of clotting episodes did not increase during the 48 weeks observation period. Our data indicate that long-term treatment with a citrate-buffered dialysis bath is feasible, irrespective of considerably reduced heparin-dosing which may be beneficial for the patient but also interesting from a commercial view point. Further long-term studies are ongoing to assess clinical effects like calcification, morbidity, and mortality.

Calcific uremic arteriolopathy in a young man on intermittent hemodialysis

A 42‐year‐old man with ESKD who has been on intermittent hemodialysis for 7 years, presented with extremely painful inguinal ulcer and abdominal mass. The lesion was developed 2 weeks after repairing aneurysmal cubital AVF. At first, it was a small and painful red nodule but then its size increased and a large ulcer was developed. In addition, the physical examination revealed a palpable and painful large mass at left lower side of abdominal wall. He did not have important risk factors such as diabetes mellitus, treatment with warfarin, and use of calcium containing phosphate binders, vitamin D or calcium supplements. The patient suffered a long standing and severe secondary hyperparathyroidism. The parathyroid hormone level was too high (3100 pg/ml). In addition, serum calcium and phosphorus levels were 9.4 mg/dl and 9.8 mg/dl respectively. The SPECT-CT scan with 99 m Tc-MIBI of parathyroid glands confirmed persistence of an adenoma in right lower parathyroid gland (Figure 1, green arrow). The BMI was 32 kg/m2. He had no adherence to use of phosphate binder or calcimimetic drugs. The radiological studies showed extensive microvascular calcification in soft tissues (Figure 1, small arrow) and osteitis fibrosa cystica in long bones (Figure 1, star). The patient underwent surgical debridement of ulcer and palpable abdominal mass, wound care, intensive dialysis therapy with low calcium dialysis bath, cinacalcet, sevelamer carbonate, antibiotic and analgesic therapy. The histological sample (H&E, 200X) shows Intramural calcification and obliteration of arteriole (large arrow) with extensive calcification in fat tissue (Figure 1, arrow head) which was consistent with Calcific Uremic Arteriolopathy (CUA). In addition to patient’s poor compliance to treatment of severe secondary hyperparathyroidism, the recent surgery of aneurismal AVF could also be an important trigger to development of calcific uremic arteriolopathy.

Preparation and Characterizations of PSS/PDADMAC Polyelectrolyte Complex Hydrogel.

Polyelectrolyte complex (PEC) hydrogel, formed via physically electrostatic crosslinks between polyanion and polycation, is an interesting hydrogel in terms of its nontoxicity and solvent-free technique. In this work, poly (sodium 4-styrenesulfonate) (PSS)/poly (diallyl dimethyl ammonium chloride) (PDADMAC) complex hydrogels were prepared. Firstly, the PSS/PDADMAC complex aggregates using various PSS/PDADMAC mole fractions that were prepared in the presence of NaCl solution. Then, the aggregates were resolubilized under stirring at 70 °C for 2 h to obtain a homogeneous PEC solution. Finally, the PEC solution was dialyzed using a dialysis membrane with 3500 molecular cut-off for 1 day. The dialysis bath was changed every interval period of 2 h to control the rate of reversible electrostatic interaction, resulting in the homogenous PEC hydrogel with porous morphology as revealed by SEM and BET investigations. The dimensional stability and viscoelasticity of the PEC hydrogel was studied by DMA experiment, which showed the viscoelastic behavior at a compressive force ranging from 0 to 0.1 N. Finally, PSS/PDADMAC hydrogels showed a high water absorbency property and excellent affinity to textile anionic dyes.

What Is the Optimal Sodium Concentration in the Dialysate?

Based on our experience in our hemodiafiltration unit we would recommend a personalized isonatremic dialysate bath. We currently prescribe 137 meq (isonatremic) or delta dialysate Na/serum Na less than 2 meq. In addition to the sodium prescribed in the dialysate, for the majority of our patients we do not restrict dietary sodium or water intake. The average sodium intake is 2775 mg per day and blood pressure is maintained without hypertensive medications. We acknowledge that part of the success for achieving dry weight may not be attributable only to the dialysate sodium but is likely the result of a combination of multiple factors such as convection therapy, cooling of dialysate, close monitoring of volume status during sessions with relative blood volume, presence of a nephrologist during all sessions and assessing volume status regularly with lung ultrasound and bioimpedance. In our experience, exercising during hemodialysis has additionally been associated with better hemodynamic status and less intradialytic hypotension. Moreover, we acknowledge there is little evidence to support a gradient dialysate to serum sodium of less than 2 meq and that our approach may not be optimal.

Vascular calcification: “The silent killer” in the hemodialysis population in Qatar

Background: Calcification is an abnormal deposition of calcium salts in vascular tissue, including valves, blood vessels, and the heart, which is highly prevalent in End Stage Renal Disease (ESRD) patients. Vascular calcification is an independent and important risk factor for cardiovascular events in hemodialysis patients and investigators have demonstrated that the extent and histo-anatomic type of vascular calcification are predictors of subsequent vascular mortality. Cardiovascular mortality risk is elevated 5-10-fold in ESRD patients compared to the general population. As we recognized the importance of early detection and delaying the complication of calcification, this study was initiated in March 2020 among 650 haemodialysis patients in Hamad General Hospital in Qatar. Methods: The haemodialysis multidisciplinary team identified patients with vascular calcification. Data was collected on available imaging study which included echocardiography, X-rays, and computed tomography (CT) to detect any kind of vascular calcification (e.g. valvular, calcified vessels). Our management protocol was updated to decrease the calcium load and active vitamin D. Abnormal serum calcium management was initiated to monitor and delay the progression of vascular calcification through interventions which included dietary control, medication, and dialysate bath. Results: We were able to screen 86% of dialysis patients (n = 559). Following the interventions, the percentage of patients with a calcium level of 2.1-2.55 mmol/l increased by 5 percentage points from 83% in March 2020 to 88% in September 2020 (p value = 0.004). Phosphorus level was maintained in the range of 0.81-1.8 mmol/l for 82% of patients () and parathyroid hormone (PTH) level in the range 150-400 pg/ml for 72% of patients (). Conclusion: We implemented a successful screening program for vascular calcification in dialysis patients combined with specific interventions. Reduced hypercalcemia episodes can delay vascular calcification. Serum calcium level was improved and maintained within the target range (2.1 - 2.55 mmol/l) for a larger number of patients.

High serum bicarbonate and adverse outcomes in hemodialysis patients

Metabolic acidosis is a usual complication of progressive chronic kidney disease and is associated with morbidity and mortality. The correction of metabolic acidosis is a main goal of dialysis. In prevalent hemodialysis patients, acid-base homeostasis depends on many factors, mainly net acid production, amount of alkali given by the dialysate bath and duration of the interdialytic period. At present, the main concern in prevalent hemodialysis patients is not over patients with metabolic acidosis, but rather about the growing numbers of patients with metabolic alkalosis. Several large cohort studies have shown significant associations between high predialysis bicarbonate, as well as blood pH, and morbidity and mortality risk. Based on recent guidelines, we should keep predialysis serum bicarbonate concentrations at 24-26 mEq/L, although this is opinion-based and there is no consensus on the issue. Furthermore, there should be specific focus on the patient´s nutritional status and reversible comorbidities.

Updates on hemodialysis techniques with a common denominator: The personalization of the dialytic therapy.

Hemodialysis (HD) is a life-saving therapy for patients with end-stage renal disease. In dialyzed patients, the prevalence of multi-morbidity is rising driven by various factors, such as the population aging, the incomplete correction of uremia, and the side effects of the dialysis therapy itself. Each dialyzed patient has their own specific clinical and biochemical problems. It is therefore unthinkable that the same dialysis procedure can be able to meet the needs of every patient on chronic dialysis. We have very sophisticated dialysis machines and different dialysis techniques and procedures beyond conventional HD, such as hemodiafiltration (HDF) with pre- and post-dilution, acetate-free biofiltration (AFB), hemofiltration (HF), and expanded HD. Each of these techniques has its own specific characteristics. To solve some intradialytic clinical issues, such as arterial hypotension and arrhythmias, we have biofeedback systems with automatic regulation of the blood volume, body temperature, arterial pressure, as well as potassium profiling techniques in the dialysis bath. New technical innovations, such as citrate-containing dialysate or heparin-coated membranes, could reduce the risk of bleeding. To better address to patient needs, the strengths and weaknesses of each of these systems must be well-known, in order to have a personalized dialysis prescription for each patient.

Usefulness of ABPM and bioimpedance for the treatment and control of hypertension in patients on chronic haemodialysis

IntroductionHypertension is very common in haemodialysis (HD) patients, and is associated with increased morbidity and mortality rates.The goals of our research were to: 1. Measure blood pressure (BP) during HD sessions; 2. Study BP in between HD sessions with 44-h Ambulatory Blood Pressure Monitoring (ABPM); 3. Evaluate changes in treatment after the ABPM; 4. Perform bioimpedance spectroscopy (BIS) on all patients and, in those hyper-hydrated or hypertensive according to ABPM, assess for changes in BP after adjusting the dry weight; 5. Identify factors associated with average systolic and diastolic BP measured by ABPM. Material and methodsProspective observational study, which included 100 patients from our dialysis unit. We measured BP before and after the HD sessions for two weeks and then, mid-week, we attached the ABPM device to the patients for 44 h. Before starting the following dialysis session, we performed BIS. A second ABPM was performed on hyper-hydrated patients and patients hypertensive according to ABPM to evaluate changes in BP values. ResultsAccording to the ABPM, 65% of patients had daytime BP > 135/85 mmHg, 90% night-time BP > 120/70 mmHg and 76% average BP > 130/80 mmHg; 11% had a dipper pattern, 51% non-dipper and 38% riser. The average systolic and diastolic BP readings were 4.7 mmHg (3.8%) and 1.1 mmHg (1.64%) higher on the second day. The dose of antihypertensive medication had to be lowered in 6% of patients, 9% had to stop taking it, 28% needed increased doses and 17% had to add a new drug. The pre-HD diastolic BP best matched the ABPM. After performing the bioimpedance and adjusting dry weight, there was a statistically significant decrease in all BP values. The univariate analysis showed that the average systolic BP was higher in patients with a high-calcium dialysis bath, more antihypertensive drugs and higher doses of EPO. The multivariate analysis showed significant association for EPO and number of drugs (p < 0.01). The average diastolic BP was higher in younger patients and patients with lower Charlson index, lower body mass index and less diuresis, those on higher doses of EPO and non-diabetics. The linear regression study showed age (p < 0.005), body mass index (p < 0.03) and EPO (p < 0.03) as significant variables. ConclusionsOur study shows: 1. The variability of hypertension criteria according to use of BP values from during the HD session or ABPM; 2. The variability of BP in the interdialysis period; 3. That the pre-dialysis diastolic BP best corresponds with the ABPM. 4. That the use of both BIS and ABPM improves the control of BP; 5. That the dose of EPO is the most important factor associated with hypertension in our patients.

Utilidad del MAPA y bioimpedancia para el tratamiento y control de la HTA en pacientes en hemodiálisis crónica

IntroductionHypertension is very common in haemodialysis (HD) patients, and is associated with increased morbidity and mortality rates.The goals of our research were to: 1. Measure blood pressure (BP) during HD sessions; 2. Study BP in between HD sessions with 44-hour Ambulatory Blood Pressure Monitoring (ABPM); 3. Identify differences between the BP recorded during HD and with the ABPM; 4. Evaluate changes in treatment after the ABPM; 5. Perform bioimpedance spectroscopy (BIS) on all patients and, in those hyper-hydrated or hypertensive according to ABPM, assess for changes in BP after adjusting the dry weight; 6. Identify factors associated with average systolic and diastolic BP measured by ABPM. Material and methodsProspective observational study, which included 100 patients from our dialysis unit. We measured BP before and after the HD sessions for two weeks and then, mid-week, we attached the ABPM device to the patients for 44 hours. Before starting the following dialysis session, we performed BIS. A second ABPM was performed on hyper-hydrated patients and patients hypertensive according to ABPM to evaluate changes in BP values. ResultsAccording to the ABPM, 65% of patients had daytime BP > 135/85 mmHg, 90% night-time BP > 120/70 mmHg and 76% average BP > 130/80 mmHg; 11% had a dipper pattern, 51% non-dipper and 38% riser. The average systolic and diastolic BP readings were 4.7 mmHg (3.8%) and 1.1 mmHg (1.64%) higher on the second day. The dose of antihypertensive medication had to be lowered in 6% of patients, 9% had to stop taking it, 28% needed increased doses and 17% had to add a new drug. The pre-HD diastolic BP best matched the ABPM. After performing the bioimpedance and adjusting dry weight, there was a statistically significant decrease in all BP values. The univariate analysis showed that the average systolic BP was higher in patients with a high-calcium dialysis bath, more antihypertensive drugs and higher doses of EPO. The multivariate analysis showed significant association for EPO and number of drugs (p < 0.01). The average diastolic BP was higher in younger patients and patients with lower Charlson index, lower body mass index and less diuresis, those on higher doses of EPO and non-diabetics. The linear regression study showed age (p < 0.005), body mass index (p < 0.03) and EPO (p < 0.03) as significant variables. ConclusionsOur study shows: 1. The variability of hypertension criteria according to use of BP values from during the HD session or ABPM; 2. The variability of BP in the interdialysis period; 3. That the pre-dialysis diastolic BP best corresponds with the ABPM. 4. That the use of both BIS and ABPM improves the control of BP; 5. That the dose of EPO is the most important factor associated with hypertension in our patients.

On the CO2 gain in on-line hemodiafiltration.

The dialysis bath holds up to 90mmHg carbon dioxide (CO2 ) in order to keep pH low and salts in their soluble forms. CO2 crosses the dialyzer membrane and diffuses to patients. In post-dilution on-line hemodiafiltration (HDF) many liters of CO2 -containing dialysis bath - in the form of infusate - are delivered directly to patients bypassing the filtering membrane, but the precise amount of CO2 delivered is unknown. To gain insights on this issue 18 outpatients undergoing their regular on-line HDF were investigated by means of blood gas analysis. Arterial pre-dialysis samples show slight hypocapnia (35.40±3.22mmHg) consistent with the secondary compensatory response to metabolic acidosis. In blood coming back to patients (venous line of extracorporeal circuit) pCO2 doubled, amounting to 69±5.5mmHg (P<.0001 with respect to pre-dialysis values) hence in on-line HDF a CO2 gain does occur. Turning off the infusate flux pump, pCO2 decreased to 63.1±5.8mmHg (P=.004) meaning that delivery of infusate in post-dilution mode significantly contributes to CO2 gain, albeit by a small amount. On-line HDF is featured by CO2 delivery to patients, in part dragged by the infusate.

P1599USE OF ASCORBATE-RICH DIALYSATE IN HEMODIALYSIS PATIENTS

Abstract Background and Aims Increments of oxidative stress have been addressed as one potential cause for the accelerated atherosclerosis of chronic kidney disease patients. Ascorbate (vitamin-C) represents one of the most prominent antioxidants both in plasma and intracellulary. Unsupplemented dialysis patients have reportedly lower plasma levels of ascorbate in comparison to healthy controls, mostly due to a loss into the dialysate. Purpose of our study was the recording of the experience of the use of Ascorbate-Rich Dialysate in patients under hemodialysis (HD). Method 11 HD patients were recruited for the study. During a period of 8 weeks they were receiving Ascorbate-Rich Dialysate (2g/lt). Ascorbic acid levels were estimated before and at the end of the study period. We also monitored patients’ anemia profile (Hb, Hct, ferritin, TSAT, rhEPO dose), lipid and nutrition status. Results Ascorbic acid values were towards the lower accepted levels in our patients (3.25±1.01 mg/l) at the beginning of the study period. After 8 weeks receiving Ascorbate-Rich Dialysate, acorbic-acid levels were significantly increased (6.87±1.50 mg/l) without transcending the upper accepted limit. During the notice period, our patients were behaved normally without any sort of adverse events. Mean Hct levels remained stable (39.10±3.70% with conventional dialysate vs 39.67±1.59 % with usage of ascorbate-rich dialysate ). The same conclusion was noticed with Hb levels (12.85±1.20 vs 13.15±0.49). Mean rhEPO dose per week (epoetin- alfa) decreased (9000±5200 iu vs 6250±4300 iu, p=NS) and administration of Fe stopped to all of our patients. Ferritin (&amp;gt;700), TSAT (&amp;gt;35) remained stable over the whole study period. Cholesterol, triglycerides and albumin levels did not change significantly with the change of the conventional dialysate to ascorbic-rich one. Conclusion Although our study is limited by small numbers of subjects, short durations of follow-up, our results suggest that compared with standard care, ascorbic acid in dialysate bath is a safe choice to increase ascorbic-acid levels in traditionally vitamic C depleted HD patients within safe limits. This raise seems to favors anemia profile of HD population. Longer term studies are required to confirm these results, determine whether these changes translate into improved patient outcomes and cost-effectiveness.

Dialysis-specific factors and incident atrial fibrillation in hemodialysis patients

Background Atrial fibrillation (AF) is common in end-stage renal disease patients. Besides the traditional risk factors, we aimed to find dialysis-specific factors for developing incident AF. Methods From March 2017 to August 2018, we retrospectively reviewed all outpatient-based prevalent hemodialysis patients in our artificial kidney room, and they were followed up until August 2019. Dialysate calcium concentration (3 versus 2.5 mEq/L), time length (4 versus 3.5 h), frequency (thrice weekly versus twice weekly), dialyzer size (effective surface area of 1.4 m2 versus 1.8 m2), membrane permeability (high flux versus low flux), ultrafiltration rate (mL/kg/hour), and blood flow rate (mL/min) were evaluated. Results Among a total of 84 patients, 15 (17.9%) had newly detected AF with a follow-up period of 21 (13.3–24) months. By performing multivariate Cox regression analysis, blood flow rate (mL/min) and ultrafiltration rate (mL/kg/h) were considered significant factors for developing incident AF (adjusted hazard ratio [HR], 0.977; p = 0.011 and adjusted HR, 1.176; p = 0.013, respectively), while dialysis bath, time length, and frequency, dialyzer size, and membrane type were not considered significant factors. Ultrafiltration cutoff rate of 8.6 mL/kg/h was the best predictive factor for incident AF (area under the curve-receiver operating characteristic [AUC-ROC], 0.746; p < 0.005), while blood flow rate was not considered a significant factor for incident AF in ROC analysis (AUC-ROC, 0.623; p = 0.126). Ultrafiltration rate was largely dependent on interdialytic weight gain (p < 0.005, linear-by-linear association). Conclusion Higher ultrafiltration rate was associated with incident AF in hemodialysis patients.

Aiming for the optimal bicarbonate prescription for maintenance hemodialysis therapy in end-stage renal disease.

Acidemia and alkalemia, as a result of gradual depletion of the body's buffers followed by rapid repletion during hemodialysis (HD), are linked to adverse consequences. We examined the acid-base status with dialysis bath of higher bicarbonate (HC03- ) concentration or standard HC03- bath plus oral HC03- supplementation. A total of 60 stable HD patients (pts) were evaluated according to their pre-dialysis acid-base status both before the first and the second session of the week dialyzed against standard base dialysate of 35 mmol/L. Those who presented predialysis HC03- <22 mmol/L (25 pts) were assigned to dialysis against bath of increased HC03- levels (37 mmol/L) for 2 weeks (period A) and subsequently to dialysis with the standard dialysate bath plus daily oral sodium bicarbonate at a dose of 5 g/day for 2 weeks (period B). Pre and post-dialysis acid-base status at each study period and relevant laboratory tests were recorded. Pre-dialysis acid-base values were similar between the first and the second dialysis session. Twenty-five points had pre-dialysis pH <7.35, while 42 (the younger ones) presented pre-dialysis HC03- <22 mmol/L. After dialysis session 18 pts had pH >7.45. Comparing the two study periods, interdialytic weight was similar, pre-dialysis HC03- levels were improved with oral bicarbonate, while post-dialysis HC03- were higher during period A. Three pts could not tolerate the symptoms of alkalemia during period A. The impact of conventional HC03- concentrations of 35 mmol/L results in a considerable degree of pre-dialysis acidemia. Increasing the HC03- in bath results in more prominent post-dialysis alkalemia, however, it is not sufficient to maintain acid-base status during the interdialytic period. Oral bicarbonate supplement at a dose of 5 g/day (divided in three daily doses) results in a more balanced acid-base status, avoiding post-dialysis alkalemia.

P3511Interest and potential risk of increasing concentration potassium in the dialysis bath in patients on chronic hemodialysis

P3511Interest and potential risk of increasing concentration potassium in the dialysis bath in patients on chronic hemodialysis

Dialysate bicarbonate concentration: Too much of a good thing?

Acid-base equilibrium is a complex and vital system whose regulation is impaired in chronic kidney disease (CKD). Metabolic acidosis is a common complication of CKD. It is typically due to the accumulation of sulfate, phosphorus, and organic anions. Metabolic acidosis is correlated with several adverse outcomes, such as morbidity, hospitalization and mortality. In patients undergoing hemodialysis, acid-base homeostasis depends on many factors: net acid production, amount of alkali given by the dialysate bath, duration of interdialytic period, as well as residual diuresis, if any. Recent literature data suggest that the development of postdialysis metabolic alkalosis may contribute to adverse clinical outcomes. Unfortunately, no randomized studies exist about the effect of different dialysate bicarbonate concentrations on hard outcomes, such as mortality. Like everything else in dialysis, the quest for the "ideal" dialysate bicarbonate concentration is far from over. The Latin aphorism "ne quid nimis" ie "nothing in excess" (excess of neither acid nor base) probably best summarizes our current state of knowledge in this field. For the present, the clinician should understand that target values for predialysis serum bicarbonate concentrations have been established primarily based on observational studies and expert opinion. On the basis of this information, we should keep predialysis serum bicarbonate concentrations at least at 22mEq/L. Furthermore, a specific focus should be addressed to the clinical and nutritional status of the major outliers on both the acid and alkaline sides of the curve.

Overcoming glucose delivery by on-line hemodiafiltration: a feasible chimera for diabetics on dialysis.

The increasing number of patients with diabetes undergoing renal replacement therapy has raised interest in the issue of glucose delivery with the substitution fluid-over 20g per session. The ideal situation would be to have a glucose-containing bath to avoid glycemic disarrays and a glucose-free substitution fluid. But this seems a chimera because the substitution fluid is nothing else than an ultrapure dialysis bath. In this technical note, we present a cheap solution to realize the desired mix, using a commercially available glucose-free dialysate and adding glucose in the inlet dialysate compartment of the dialyzer by means of a common pump and a unique handmade T-tube. Our in vitro experiments showed glucose levels in the dialysate (mean ± SD, mg/dl): 99.7 ± 4.6at baseline, 100.7 ± 7.3at mid-session and 100.7 ± 2.1at the end of dialysis, whereas measurements in the substitution fluid always gave a "low" output (p < 0.0001). Similar results were obtained in single 1- and 4-h in vivo experiments carried out in a non-diabetic overweight hemodialysis patient. Our simple, yet unequivocal, results lay the foundation for assembling a hemodialysis machine equipped with an infusion pump to modify the on-line substitution fluid without affecting the dialysate. This would overcome the ethical issue of delivering glucose intravenously in certain groups of patients.

Delayed Allergic Cutaneous Hypersensitivity to Icodextrin

Rashes pose a unique challenge to general internists. Here we present a case of a 51-year-old female with end-stage renal disease (ESRD) on peritoneal dialysis who presented to a General Internal Medicine clinic with a vesiculobullous rash on palms and soles 6 months after using icodextrin dialysate, a widely used osmotic agent in peritoneal dialysis. The investigations were positive for an elevated eosinophil count, elevated IgE level and a skin biopsy consistent with an allergic reaction. Her symptoms and labs normalized after stopping icodextrin. There are some reports of allergic reactions to icodextrin which usually occur within a month of initiation of the agent and are self-limiting. Here we hope to report a case of a reaction that occurred 6 months after using icodextrin.&#x0D; Resume&#x0D; Les éruptions cutanées posent un défi particulier aux internistes généraux. Nous rapportons ici le cas d’une femme de 51 ans atteinte d’insuffisance rénale terminale (IRT), sous dialyse péritonéale, qui se présente à une clinique de médecine interne générale avec une éruption cutanée vésiculo-bulleuse sur les paumes et la plante des pieds. Depuis six mois, la patiente utilise un dialysat d’icodextrine, un agent osmotique largement utilisé en dialyse péritonéale. Les analyses ont révélé une numération élevée des éosinophiles, un taux élevé d’IgE et une biopsie cutanée a indiqué la présence d’une réaction allergique. Les symptômes et les résultats d’analyses se sont normalisés après l’arrêt de l’icodextrine. Des réactions d’allergie à l’icodextrine ont déjà été rapportées, mais celles-ci surgissent habituellement dans le mois suivant le début de l’usage de l’agent et se résorbent d’elles-mêmes. Nous désirons signaler un cas de réaction survenue six mois après le début de l’utilisation de l’icodextrine.&#x0D; &#x0D; &#x0D;

Clearance of Sclerostin, Osteocalcin, Fibroblast Growth Factor 23, and Osteoprotegerin by Dialysis

Introduction: Fibroblast growth factor (FGF23), sclerostin, osteocalcin, and osteoprotegerin are important factors that control mineral bone metabolism. End-stage renal disease is associated with the pronounced dysregulation of mineral bone metabolism; however, the impact and clearance of mineral bone metabolism factors during dialysis remain largely undescribed. Methods: In a cross-sectional study, 10 chronic hemodialysis patients were treated with hemodialysis for 8 h using a high-flux filter and a dialysate bath of 50% calculated total body water continuously recycled at a rate of 500 mL/min. Plasma and dialysate concentrations of FGF23, sclerostin, osteoprotegerin, and osteocalcin were measured at 1, 2, 4, 6, and 8 h permitting the estimation of dialysis clearance. Results: Clearance of FGF23 was 7.7 mL/min, of sclerostin was 7.6 mL/min, of osteoprotegerin was 1.2 mL/min, and of osteocalcin was 19.7 mL/min. Clearance of FGF23 was correlated to sclerostin and osteoprotegerin clearance and also to the ultrafiltration rate. Although, osteocalcin blood concentrations decreased during dialysis, they rebounded within 6 h. Overall, no significant changes in blood concentrations of the measure mineral bone metabolism factors were observed. Conclusions: The intradialytic clearance of osteocalcin, FGF23, sclerostin, and osteoprotegerin occurs; however, only clearance of FGF23 is directly correlated with the ultrafiltration rate. The effects of dialytic clearance on mineral bone metabolism are, however, uncertain and intradialytic plasma concentrations of the studied substrates remained largely unchanged.