Effect of central dialysis fluid delivery system on markers of inflammation in hemodialysis patients.

BACKGROUND: The utilization of ultrapure dialysate has been shown to decrease dialysate contamination and mitigate inflammatory responses. The central dialysate delivery system (CDDS) has the potential to attain a level of purity similar to ultrapure dialysate. Nevertheless, there is limited research examining the impact of CDDS on inflammation in comparison to single-patient dialysis fluid delivery system(SPDDS). This study aims to investigate the effects of CDDS utilizing ultrapure dialysate on ameliorating the microinflammatory state in hemodialysis patients. METHOD: A retrospective cohort clinical study enrolled a total of 125 hemodialysis patients, with 58 patients from the CDDS unit and 67 patients from the SPDDS unit. Each participant was monitored for a period of 6 months, and the repeated measurement data was analyzed using a generalized linear mixed models (GLMM). RESULTS: The average age of the studty cohort was 56.22 ± 12.64 years. The GLMM analysis showed a significant time*group interaction effect on hs-CRP changes over the follow-up period (ß = -1.966, FTime* CDDS group = 13.389, P < 0.001). A linear mixed model analysis with random slope showed that a different slope was observed between CDDS group and SPDDS group (ßCDDS =-0.793; ßSPDDS = 0.791), indicating a decreased hs-CRP levels in CDDS group, while increased in the SPDDS group over the follow-up period. However, no significant time*group interaction effect were observed on albumin and ß2-microglobulin levels during follow-up period(ß2-microglobulin: ß = -0.658, FTime* CDDS group = 1.228, P = 0.269; albumin: ß = 0.012, FTime* CDDS group = 1.429, P = 0.233). CONCLUSION: Using ultrapure dialysate in the CDDS is associated with an improvement in hs-CRP levels compared to standard dialysate, which might confer long-term clinical advantages.

Continuous Kidney Replacement Therapy With Adjusted Dialysate Sodium Concentration for Severe Hyponatremia in Beer Potomania: A Case Report.

Beer potomania is a condition characterized by severe hyponatremia in chronic alcoholics with poor nutritional intake. When complicated by acute kidney injury (AKI), it presents a significant management challenge. We report a case of a 32-year-old male with a history of alcoholism who presented with malaise, nausea, and vomiting. Laboratory tests revealed severe hyponatremia (serum sodium 104 mEq/L) and AKI. Conventional treatment approaches posed risks of overcorrection and osmotic demyelination syndrome (ODS). We implemented continuous kidney replacement therapy (CKRT) with meticulously adjusted dialysate sodium concentrations. This approach enabled gradual, controlled correction of serum sodium without precipitating ODS. The patient was successfully liberated from hemodialysis on the twelfth day of illness. Our findings highlight the potential of CKRT as an effective treatment modality for severe hyponatremia in beer potomania with AKI, offering a means of gradual sodium correction while addressing renal dysfunction. This case underscores the importance of tailored management strategies in complex clinical scenarios involving electrolyte imbalances and kidney injury.

The Effect of Dialysate Temperature on Dialysis Adequacy and Hemodynamic Stability: An Experimental Study with Crossover Design.

Cool dialysate has variable impact on hemodynamic stability and dialysis adequacy. Hemodynamic stability and dialysis adequacy are crucial indicators for better life expectancy and cardiovascular mortality. This research aims to evaluate the impact of cool dialysate temperature (35.5°C) compared to standard dialysate temperature (37°C) on blood pressures, pulse rate, and dialysis adequacy (Urea reduction ratio and online Kt/V) in a cross over design. Material and Methods. Consenting ESRD patients on maintenance haemodialysis (HD) with minimum 3 months dialysis vintage and functioning permanent vascular access are included for the study. Each participant had two sessions of HD at 37°C followed by two sessions at 35.5° C on a Fresenius 4008S HD machine. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and Pulse rate are measured pre-HD, every hourly and post dialysis. Pre-HD Blood urea nitrogen (BUN) and post-HD BUN are measured, and Urea reduction rate was calculated for each HD session. Kt/V was calculated by ionic conductance by HD machine for each session. Results. 25 patients (5 females and 20 males) were enrolled. The mean age was 54 ± 9.58 years. Dialysis vintage was 21.48 ± 6.9 months for study participants 10 patients (40%) were diabetic nephropathy, 9 patients (36%) were presumed chronic glomerulonephritis, 2 patients (8%) were lupus nephritis and 4 patients (16%) were chronic interstitial nephritis. There was statistically no difference between pre-HD BUN (p = 0.330), post-HD BUN (p = 0.776), URR (p = 0.718) and Kt/V (p = 0.534) among the dialysis sessions done at 37°C and 35.5°C. SBP variability in the low temperature (35.5°C) group at 4th hour and post dialysis assumed statistical significance with p = 0.05 and p = 0.025 respectively. DBP variability in the low temperature (35.5°C) group at 3rd hour, 4th hour and post-dialysis demonstrated statistical significance with p = 0.027, p = 0.36 and p = 0.016 respectively. Pulse rate variability was more in the low temperature (35.5°C) group at 3rd hour and 4th hour which showed statistical significance with p = 0.037 and p = 0.05 respectively. Conclusion. Cool dialysate is non inferior to standard dialysate temperature in terms of dialysis adequacy and is associated with less variability in diastolic blood pressure, systolic blood pressure and more pulse rate variability thereby contributing to better hemodynamic stability.

Time-course concentration of ethanol, acetaldehyde and acetate in rat brain dialysate following alcohol self-administration.

The unclear mechanisms of ethanol metabolism in the brain highlight the need for a deeper understanding of its metabolic pathways. This study used in vivo microdialysis to simultaneously sample ethanol and its metabolites, acetaldehyde and acetate, in the rat striatum following self-administration of ethanol, emphasizing the natural oral exposure route. To enhance the self-administration, rats underwent two-bottle-choice and limited access training. Dialysate samples, collected every 10 minutes for 2.5 hours, were analyzed using gas chromatography with flame ionization detection (GC-FID). The measured time courses of dialysate concentrations of ethanol, acetaldehyde, and acetate provided insights into dynamics of ethanol metabolism. Notably, in a subject with low ethanol consumption (0.29 g/kg), the concentration of acetaldehyde remained below the limit of detection throughout the experiment. However, the acetate concentration was clearly increased after ethanol consumption in this subject and was comparable to that of other rats with higher ethanol consumption. Compared with focusing only on peak values in the time-courses of concentrations of ethanol and its metabolites, calculating areas under curves provided better models of the relationships between ethanol intake and individual ethanol metabolites, as indicated by the r-square values for the linear regressions. This approach of using the area under the curve accounts for both the amplitude and duration of the concentration profiles, reducing the impact of variations in individual drinking patterns. In vivo microdialysis enables concurrent sampling of brain metabolites during oral ethanol administration, contributing insights into metabolite dynamics. To our knowledge, this paper is the first to report measurement of all three analytes in the brain following self-administration of ethanol. Future studies will explore regional variations and dynamics post-ethanol dependence, further advancing our understanding of ethanol metabolism in the brain.

Reducing the carbon footprint for a 30-bed haemodialysis unit by changing the delivery of acid concentrate supplied by individual 5 L containers to a central delivery system.

BACKGROUND: Haemodialysis treatments generate greenhouse gas (GHG) emissions mainly as a result of the equipment, consumables and pharmaceuticals required. An internal audit demonstrated a 33% wastage of acid concentrate when using individual 5.0 L containers at a 1:44 dilution ratio. We therefore investigated whether changing the delivery system for acid concentrate would reduce wastage and any associated greenhouse gas emissions. METHODS: We calculated the difference for a 30-bed dialysis unit between receiving acid concentrate in single-use 5.0 L plastic containers versus bulk delivery for a central acid delivery system connected to the dialysis machines. Estimates of carbon dioxide equivalent (CO2e) emissions were made using the United Kingdom government database and other sources. RESULTS: A 30-station dialysis unit functioning at maximum capacity (3 shifts and 6 days/week), switching to bulk delivery and central acid delivery could realise an approximate total reduction of 33,841 kgCO2e/year; in reduced product wastage, saving 6192 kgCO2e, 5205 kgCO2e from fewer deliveries, and 22,444 kgCO2e saving from a reduction in packaging and waste generated, which equates approximately to a one tonne reduction in CO2e emissions per dialysis station/year. CONCLUSIONS: Switching from delivering acid concentrate in individual 5.0 L containers to a central acid delivery system can result in substantial reductions in CO2e emissions within a dialysis clinic. The emission savings from reducing the single-use plastic packaging greatly outweigh any gains from eliminating wastage of acid concentrate. Dialysis companies and clinicians should consider reviewing the design of current and future dialysis facilities and policies to determine whether reductions in CO2e emissions can be made.

The effect of different dialysate sodium concentrations on ambulatory blood pressure in hemodialysis patients: a prospective interventional study.

Background: Hypertension is associated with increased morbidity and mortality in hemodialysis patients. Existing recommendations suggest reduction of sodium load, but the effect of dialysate sodium on blood pressure (BP) is not fully elucidated. The aim of the present study is to investigate the effect of different dialysate sodium concentrations on 72-h ambulatory BP in hemodialysis patients. Methods: This prospective study included patients on standard thrice-weekly hemodialysis. All patients initially underwent six sessions with dialysate sodium concentration of 137 meq/L, followed consecutively by another six sessions with dialysate sodium of 139 meq/L and, finally, six sessions with dialysate sodium of 141 meq/L. At the start of the sixth hemodialysis session on each sodium concentration, 72-h ABPM was performed over the long interdialytic interval to evaluate ambulatory systolic and diastolic BP (SBP and DBP) during the overall 72-h, different 24-h, daytime and night-time periods. Results: Twenty-five patients were included in the final analysis. A significant increase in the mean 72-h SBP was observed with higher dialysate sodium concentrations (124.8 ± 16.6 mmHg with 137 meq/L vs 126.3 ± 17.5 mmHg with 139 meq/L vs 132.3 ± 19.31 mmHg with 141 meq/L, P = 0.002). Similar differences were noted for DBP; 72-h DBP was significantly higher with increasing dialysate sodium concentrations (75.1 ± 11.3 mmHg with 137 meq/L vs 76.3 ± 13.7 mmHg with 139 meq/L vs 79.5 ± 13.9 mmHg with 141 meq/L dialysate sodium, P = 0.01). Ambulatory BP during the different 24-h intervals, daytime and night-time periods was also progressively increasing with increasing dialysate sodium concentration. Conclusion: This pilot study showed a progressive increase in ambulatory BP with higher dialysate sodium concentrations. These findings support that lower dialysate sodium concentration may help towards better BP control in hemodialysis patients.

Toward acid- and heparin-free dialysis: the regional anticoagulation approach.

Background: In chronic intermittent hemodialysis, heparin is the standard anticoagulant as is the use of acid-containing dialysate. Regional anticoagulation (RA) with a calcium-free, citrate-containing dialysate has been developed. We compared RA using a calcium-free, citrate-free dialysate, routinely used in our center, versus systemic heparinization. Methods: In a retrospective, observational, single-center, crossover study, we examined 15 patients undergoing chronic hemodialysis who were at high risk of bleeding and temporarily unable to use heparin. These patients received temporary treatment with RA involving calcium-free and citrate-free dialysate. We compared the dialysis session success rates during two distinct periods: standard heparinization and RA procedure with a calcium-free and citrate-free dialysate. Results: In our study of 15 patients on chronic hemodialysis which compared 30 RA sessions versus 28 heparin-based anticoagulation session, we observed a 100% success rate with a median session duration of 240 min in both RA and heparin groups. No early extracorporeal circulation (ECC) loss was reported. However, we noted significant differences in the post-dialysis ECC thrombosis scores, with higher Global Thrombosis Index (GTI) and higher membrane coagulation scores in the RA group (P < .007 and P < .02, respectively). No hypocalcaemia or hypercalcemia symptoms occurred. Median post-filter ionized calcium levels were 0.32 (0.29-0.39) mmol/L at 30 min and median patient ionized calcium levels was 1.19 (1.135-1.28) mmol/L at 60 min. No significant difference in per-dialysis arterial blood pressure was observed between groups. Conclusion: Our study evaluated the RA approach using a calcium-free, citrate-free acetate dialysate in a chronic hemodialysis center and found it effective. Although an acid-free dialysate was not used in this study, our findings suggest it could be the next frontier in the evolution of advanced dialysis techniques.

Citrate Dialysate with and without Magnesium Supplementation in Hemodiafiltration: A Comparative Study Versus Acetate.

The choice of dialysate buffer in hemodialysis is crucial, with acetate being widely used despite complications. Citrate has emerged as an alternative because of its favorable effects, yet concerns persist about its impact on calcium and magnesium levels. This study investigates the influence of citrate dialysates (CDs) with and without additional magnesium supplementation on CKD-MBD biomarkers and assesses their ability to chelate divalent metals compared to acetate dialysates (ADs). A prospective crossover study was conducted in a single center, involving patients on thrice-weekly online hemodiafiltration (HDF). The following four dialysates were compared: two acetate-based and two citrate-based. Calcium, magnesium, iPTH, iron, selenium, cadmium, copper, zinc, BUN, albumin, creatinine, bicarbonate, and pH were monitored before and after each dialysis session. Seventy-two HDF sessions were performed on eighteen patients. The CDs showed stability in iPTH levels and reduced post-dialysis total calcium, with no significant increase in adverse events. Magnesium supplementation with CDs prevented hypomagnesemia. However, no significant differences among dialysates were observed in the chelation of other divalent metals. CDs, particularly with higher magnesium concentrations, offer promising benefits, including prevention of hypomagnesemia and stabilization of CKD-MBD parameters, suggesting citrate as a viable alternative to acetate. Further studies are warranted to elucidate long-term outcomes and optimize dialysate formulations. Until then, given our results, we recommend that when a CD is used, it should be used with a 0.75 mmol/L Mg concentration rather than a 0.5 mmol/L one.

Vascular refilling in hemodialysis using feedback-controlled ultrafiltration profile.

BACKGROUND: The rate and the duration of ultrafiltration (UF) are considered the most important factors to affect vascular refilling. The aim of the study was to investigate whether a UF profile could improve the vascular refilling. METHODS: Dialysis was delivered by a machine providing feedback control of ultrafiltration rates. Absolute blood volume (BV) was measured by dialysate bolus method. Vascular refilling volume (Vref) was calculated as UF volume - Δ absolute BV. RESULTS: In 40 patients, refilling fraction (Vref/UF volume) was 30.5% in the first hour. Thereafter, refilling fraction steeply increased and reached maximum values in the third and fourth hour at about 95%. The cumulative refilling fraction was 68.5 ± 9.4% at the end. In 14 patients, refilling data from the feedback-controlled UF profile were compared to dialysis sessions with constant UF rates. In 12 of 14 patients, refilling fraction was significantly (p = 0.013) higher in sessions with UF profile (71.6% vs 64.4%).There was a significant negative correlation (r = -0.606; p = 0.002) between the blood volume to extracellular volume ratio and the refilling fraction. The sum of this ratio and the refilling fraction was 1.01 ± 0.06. CONCLUSIONS: Despite significant differences, a feedback-controlled UF profile has no advantage over the previous refilling studies with regard to the refilling fraction because vascular refilling seems to depend mainly on the ratio of BV to ECV. This would explain the different results in studies using BV guided UF feedback programs.

Intermittent hemodialysis as a rewarming strategy for severe hypothermia in patients without renal failure: a case report.

This case report highlights the effective use of intermittent hemodialysis (IHD) in warming a 71-year-old female patient with severe hypothermia who presented with a rectal temperature of 25 °C and signs of hemodynamic instability. The patient, found unconscious after prolonged exposure to cold exacerbated by alcohol consumption, initially showed some improvement in core temperature through active external rewarming methods. However, soon, her temperature plateaued at 27 °C. Patient was deemed unsuitable for extracorporeal membrane oxygenation (ECMO) or cardiopulmonary bypass (CPB) due to her age, and urgent IHD was initiated. This approach resulted in a stable increase in core temperature at approximately 2.0 °C/hr, along with normalization of lactic acidosis, creatinine phosphokinase, and correction of electrolyte imbalances, culminating in her full recovery and discharge after seven days in the hospital.After reviewing this case alongside similar ones from before, this case report highlights the efficacy and safety of IHD as an efficient, readily available, and less invasive method for rewarming moderate to severe hypothermic patients who are hemodynamically unstable patients but do not have cardiac arrest or renal dysfunction. IHD is especially useful when less invasive cooling devices (Artic Sun/ CoolGard) are not available or more invasive extracorporeal life support options (ECMO/ CPB) are either not indicated or unavailable. IHD can also help improve concurrent electrolyte imbalances and/or toxin buildup. The report further emphasizes the necessity of monitoring for potential complications, such as post-dialysis hypophosphatemia and rebound hyperkalemia, following successful rewarming.

Dialysate Sodium Levels, Ambulatory Aortic Blood Pressure and Arterial Stiffness in Hemodialysis Patients.

BACKGROUND: Increased aortic blood-pressure(BP) and arterial stiffness are associated with higher cardiovascular risk in hemodialysis. Previous works showed that lower dialysate sodium is associated with lower brachial-BP; data on aortic-BP and arterial stiffness are limited. This study aimed to investigate the effects of different dialysate sodium concentrations on 72-h aortic-BP and arterial stiffness parameters in hemodialysis patients. METHODS: This analysis is part of a prospective, non-randomized interventional study. Twenty-five hemodialysis patients underwent a set of three periods of different dialysate sodium concentrations; six sessions with dialysate sodium of 137meq/L, followed consecutively by six sessions with 139meq/L and, finally, six sessions with 141meq/L. At the start of the sixth hemodialysis session on each sodium concentration, 72-h ABPM (Mobil-O-Graph) was performed to evaluate aortic-BP and arterial stiffness indices during the overall 72-h, different 24-h, day-time and night-time periods. RESULTS: Mean 72-h aortic SBP/DBP were higher with increasing dialysate sodium concentrations (137meq/L: 114.2±15.3/77.0±11.8mmHg vs 139meq/L: 115.4±17.3/77.9±14.0mmHg vs 141meq/L: 120.5±18.4/80.5±14.7mmHg, p=0.002/p=0.057, respectively). Wave-reflections parameters (AIx, AIx(75), AP) were not significantly different between the three dialysate sodium concentrations. Ambulatory PWV was significantly higher with increasing dialysate sodium concentrations (137meq/L: 8.5±1.7m/s vs 139meq/L: 8.6±1.6m/s vs 141meq/L: 8.8±1.6m/s, p<0.001). In generalized linear-mixed-models including 72-h brachial SBP as random covariate, the adjusted marginal-means of 72-h PWV were not significantly different between-groups. CONCLUSIONS: This study showed that lower dialysate sodium concentrations are associated with significant decreases in ambulatory aortic BP and PWV. This study showed that higher dialysate sodium concentrations are associated with significant increases in ambulatory aortic BP and PWV. These findings further support the need for modification of dialysate sodium concentration in hemodialysis.

Deciphering simplified regional anticoagulation with citrate in intermittent hemodialysis: a clinical and computational study.

Regional citrate anticoagulation use in intermittent hemodialysis is limited by the increased risk of metabolic complications due to faster solute exchanges than with continuous renal replacement therapies. Several simplifications have been proposed. The objective of this study was to validate a mathematical model of hemodialysis anticoagulated with citrate that was then used to evaluate different prescription scenarios on anticoagulant effectiveness (free calcium concentration in dialysis filter) and calcium balance. A study was conducted in hemodialyzed patients with a citrate infusion into the arterial line and a 1.25 mmol/L calcium dialysate. Calcium and citrate concentrations were measured upstream and downstream of the citrate infusion site and in the venous line. The values measured in the venous lines were compared with those predicted by the model using Bland and Altman diagrams. The model was then used with 22 patients to make simulations. The model can predict the concentration of free calcium, bound to citrate or albumin, accurately. Irrespective of the prescription scenario a decrease in free calcium below 0.4 mmol/L was obtained only in a fraction of the dialysis filter. A zero or slightly negative calcium balance was observed, and should be taken into account in case of prolonged use.

Pathophysiological Mechanisms of Peritoneal Fibrosis and Peritoneal Membrane Dysfunction in Peritoneal Dialysis.

The characteristic feature of chronic peritoneal damage in peritoneal dialysis (PD) is a decline in ultrafiltration capacity associated with pathological fibrosis and angiogenesis. The pathogenesis of peritoneal fibrosis is attributed to bioincompatible factors of PD fluid and peritonitis. Uremia is associated with peritoneal membrane inflammation that affects fibrosis, neoangiogenesis, and baseline peritoneal membrane function. Net ultrafiltration volume is affected by capillary surface area, vasculopathy, peritoneal fibrosis, and lymphangiogenesis. Many inflammatory cytokines induce fibrogenic growth factors, with crosstalk between macrophages and fibroblasts. Transforming growth factor (TGF)-ß and vascular endothelial growth factor (VEGF)-A are the key mediators of fibrosis and angiogenesis, respectively. Bioincompatible factors of PD fluid upregulate TGF-ß expression by mesothelial cells that contributes to the development of fibrosis. Angiogenesis and lymphangiogenesis can progress during fibrosis via TGF-ß-VEGF-A/C pathways. Complement activation occurs in fungal peritonitis and progresses insidiously during PD. Analyses of the human peritoneal membrane have clarified the mechanisms by which encapsulating peritoneal sclerosis develops. Different effects of dialysates on the peritoneal membrane were also recognized, particularly in terms of vascular damage. Understanding the pathophysiologies of the peritoneal membrane will lead to preservation of peritoneal membrane function and improvements in technical survival, mortality, and quality of life for PD patients.

The impact of dialysate flow rate on haemodialysis adequacy: a systematic review and meta-analysis.

Background: Patients with kidney failure treated with maintenance haemodialysis (HD) require appropriate small molecule clearance. Historically, a component of measuring 'dialysis adequacy' has been quantified using urea kinetic modelling that is dependent on the HD prescription. However, the impact of dialysate flow rate on urea clearance remains poorly described in vivo and its influence on other patient-important outcomes of adequacy is uncertain. Methods: We searched Embase, MEDLINE and the Cochrane Library from inception until April 2022 for randomized controlled trials and observational trials comparing a higher dialysate flow rate (800 ml/min) and lower dialysate flow rate (300 ml/min) with a standard dialysis flow rate (500 ml/min) in adults (age ≥18 years) treated with maintenance HD (>90 consecutive days). We conducted a random effects meta-analysis to estimate the pooled mean difference in dialysis adequacy as measured by Kt/V or urea reduction ratio (URR). Results: A total of 3118 studies were identified. Of those, nine met eligibility criteria and four were included in the meta-analysis. A higher dialysate flow rate (800 ml/min) increased single-pool Kt/V by 0.08 [95% confidence interval (CI) 0.05-0.10, P < .00001] and URR by 3.38 (95% CI 1.97-4.78, P < .00001) compared with a dialysate flow rate of 500 ml/min. Clinically relevant outcomes including symptoms, cognition, physical function and mortality were lacking and studies were generally at a moderate risk of bias due to issues with randomization sequence generation, allocation concealment and blinding. Conclusion: A higher dialysate flow increased urea-based markers of dialysis adequacy. Additional high-quality research is needed to determine the clinical, economic and environmental impacts of higher dialysate flow rates.

The Effects of Early-Phase, Low- or Standard-Intensity Continuous Renal Replacement Therapy on Acid-Base Control and Clinical Outcomes: An Observational Study.

INTRODUCTION: The Kidney Disease Improving Global Outcomes (KDIGO) clinical practice guideline recommends administering an effluent volume of 20-25 mL/kg/h during continuous renal replacement therapy (CRRT) for acute kidney injury. Recent evidence on CRRT initiation showed that less intervention might be beneficial for renal recovery. This study aimed to explore the association between early-phase low CRRT intensity and acid-base balance corrections and clinical outcomes. METHODS: This was a single-centre, retrospective, observational study at a tertiary intensive care unit (ICU) in Japan. All adult patients requiring CRRT in the ICU were included. Eligible patients were classified into the Low group (dialysate flow rate [QD] 10.0-19.9 mL/kg/h) and the Standard group (QD ≥20 mL/kg/h) by the intensity of CRRT at the beginning. The primary outcomes were acid-base parameters 6 h after CRRT initiation. We used an inverse probability of treatment weighting analysis to estimate the association between the intensity group and the outcomes. RESULTS: Overall, 194 patients were classified into the Low group (n = 144) and the Standard group (n = 50). The Standard group presented with more severe acid-base disturbances, including lower pH and base excess (BE) at baseline. At 6 h after CRRT initiation, pH, BE, and strong ion difference values were comparable, even after adjusting for baseline severity. Despite the efficient correction, no evident differences were observed in clinical outcomes between the two groups. CONCLUSIONS: The initial standard intensity appeared to be efficient in correcting acid-base imbalance at the early phase of CRRT; however, further studies are needed to assess the impact on clinical outcomes.

Calcium-Free Dialysate Hemodialysis: A Simplified Approach.

Intermittent hemodialysis (HD) in high-bleeding-risk patients presents a challenge as circuit anticoagulation using heparin is contraindicated in such cases. Recently, the use of calcium-free citrate-containing dialysate with calcium supplementation emerged as a viable alternative to heparin-circuit anticoagulation. This is a retrospective, monocentric study to evaluate dialysis efficacy using calcium-free citrate-containing dialysate with calcium reinjection into the venous line in hemodialysis patients at risk of bleeding. A total of 53 patients were analyzed: 52 had a temporary contraindication to systemic anticoagulation (active bleeding or surgical intervention), and 1 chronic HD patient had prolonged bleeding time due to inoperable arteriovenous fistula stenosis. Only 7 out of 79 dialysis sessions performed were prematurely terminated (vascular access dysfunction). The median dialysis time was 240 min (range: 150-300). The chronic dialysis patient had 108 sessions with no premature termination. Frequent monitoring of ionized calcium was performed throughout the dialysis sessions: levels remained stable at T0 and T + 60 min (1.08 ± 0.08 mmol/L) and slightly increased at the end of the dialysis session (1.19 ± 0.13 mmol/L), remaining within normal limits. Target postfilter ionized calcium <0.4 mmol/L was achieved in all sessions (0.31 ± 0.07 mmol/L). There were no cases of symptomatic hypo-/hypercalcemia and no need for calcium infusion rate adjustment throughout the sessions. Hemodialysis with calcium-free citrate-containing dialysate and calcium reinjection into the venous line is efficient and safe in HD patients with contraindications to systemic anticoagulation.

Can regional anticoagulation with calcium-free dialysate be extended to maintenance hemodialysis?

BACKGROUND: Regional anticoagulation in hemodialysis avoids the use of heparin, which is responsible for both hemorrhagic and non-hemorrhagic complications. Typically, blood is decalcified by injecting citrate into the arterial line of the extracorporeal circuit. Calcium-free dialysate improves anticoagulation efficacy but requires injection of a calcium-containing solution into the venous line and strict monitoring of blood calcium levels. Recent improvements have made regional anticoagulation with calcium-free dialysate safer and easier. OBSERVATIONS: (1) Adjusting the calcium injection rate to ionic dialysance avoids the risk of dyscalcemia, thus making unnecessary the monitoring of blood calcium levels. This adjustment could be carried out automatically by the hemodialysis monitor. (2) As calcium-free dialysate reduces the amount of citrate required, this can be supplied by dialysate obtained from currently available concentrates containing citric acid. This avoids the need for citrate injection and the risk of citrate overload. (3) Calcium-free dialysate no longer needs the dialysate acidification required for avoiding calcium carbonate precipitation in bicarbonate-containing dialysate. CONCLUSIONS: Regional anticoagulation with calcium-free dialysate enables an acid- and heparin-free procedure that is more biocompatible and environmentally friendly than conventional bicarbonate hemodialysis. The availability of specific acid-free concentrates and adapted hemodialysis monitors is required to extend this procedure to maintenance hemodialysis.

Hemodynamic effects of low versus high dialysate bicarbonate concentration in hemodialysis patients.

INTRODUCTION: Hemodialysis treatment using standard dialysate bicarbonate concentrations cause transient metabolic alkalosis possibly associated with hemodynamic instability. The aim of this study was to perform a detailed comparison of high and low dialysate bicarbonate in terms of blood pressure, intradialytic hemodynamic parameters, orthostatic blood pressure, and electrolytes. METHODS: Fifteen hemodialysis patients were examined in a single-blind, randomized, controlled, crossover study. Participants underwent a 4-h hemodialysis session with dialysate bicarbonate concentration of 30 or 38 mmol/L with 1 week between interventions. Blood pressure was monitored throughout hemodialysis, while cardiac output, total peripheral resistance, stroke volume, and central blood volume were assessed with ultrasound dilution technique (Transonic). Orthostatic blood pressure was measured pre- and post-hemodialysis. FINDINGS: With similar ultrafiltration (UF) volume (2.6 L), systolic blood pressure (SBP) tended to decrease more during high dialysate bicarbonate compared to low dialysate bicarbonate; the mean (95% confidence interval) between treatment differences in SBP were: 8 (-4; 20) mmHg (end of hemodialysis) and 7 (0; 15) mmHg (post-hemodialysis). Stroke volume decreased whereas total peripheral resistance increased significantly more during high dialysate bicarbonate compared to low dialysate bicarbonate with mean between treatment differences: Stroke volume: 12 (1; 23) mL; Total peripheral resistance: -2.9 (-5.3; -0.5) mmHg/(L/min). Cardiac output tended to decrease more with high dialysate bicarbonate compared to low dialysate bicarbonate with mean between treatment difference 0.7 (0.0; 1.4) L/min. High dialysate bicarbonate caused alkalosis, hypocalcemia, and lower plasma potassium, whereas patients remained normocalcemic with normal pH during low dialysate bicarbonate. Orthostatic blood pressure response after dialysis did not differ significantly. DISCUSSION: The use of high dialysate bicarbonate compared to low dialysate bicarbonate was associated with hypocalcemia, alkalosis, and a more pronounced hypokalemia. During hemodialysis with UF, a better preservation of blood pressure, stroke volume, and cardiac output may be achieved with low dialysate bicarbonate compared to high dialysate bicarbonate.

Modification of Dialysate Na+ Concentration but not Ultrafiltration or Dialysis Treatment Time Affects Tissue Na+ Deposition in Patients on Hemodialysis.

Introduction: Tissue Na+ overload is present in patients receiving hemodialysis (HD) and is associated with cardiovascular mortality. Strategies to actively modify tissue Na+ amount in these patients by adjusting the HD regimen have not been evaluated. Methods: In several substudies, including cross-sectional analyses (n = 75 patients on HD), a cohort study and a cross-over interventional study (n = 10 patients each), we assessed the impact of ultrafiltration (UF) volume, prolongation of dialysis treatment time, and modification of dialysate Na+ concentration on tissue Na+ content using 23Na magnetic resonance imaging (23Na-MRI). Results: In the cross-sectional analysis of our patients on HD, differences in dialysate sodium concentration ([Na+]) were associated with changes in tissue Na+ content, whereas neither UF volume nor HD treatment time affected tissue Na+ amount. Skin Na+ content was lower in 17 patients on HD, with dialysate [Na+] of <138 mmol/l compared to 58 patients dialyzing at ≥138 mmol/l (20.7 ± 7.3 vs. 26.0 ± 8.8 arbitrary units [a.u.], P < 0.05). In the cohort study, intraindividual prolongation of HD treatment time was not associated with a reduction in tissue Na+ content. Corresponding to the observational data, intraindividual modification of dialysate [Na+] from 138 to 142 to 135 mmol/l resulted in concordant changes in skin Na+ (24.3 ± 7.6 vs. 26.3 ± 8.0 vs. 20.8 ± 5.6 a.u, P < 0.05 each), whereas no significant change in muscle Na+ occurred. Conclusion: Solely adjustment of dialysate [Na+] had a reproducible impact on tissue Na+ content. 23Na-MRI could be utilized to monitor the effectiveness of dialysate [Na+] modifications in randomized-controlled outcome trials.

A Pilot Study on the Safety and Adequacy of a Novel Ecofriendly Hemodialysis Prescription-Green Nephrology.

Introduction: Hemodialysis (HD) units require large quantities of water. To reduce water consumption without compromising the adequacy and safety of dialysis, we studied a novel HD prescription with high temperature and low flow dialysate. Methods: This was a single-center nonrandomized open-label cross-over pilot trial in patients with end-stage kidney disease on maintenance HD. Each participant was subjected to 3 different dialysis prescriptions for 1 month each as follows: (i) normal temperature with normal flow dialysate (NTNF prescription), (ii) high temperature with normal flow dialysate (HTNF prescription), and (iii) high temperature with low flow dialysate (HTLF prescription). The primary outcome, assessed at the end of each dialysis session, was the delivery of "adequate" dialysis, as defined by a single-pool Kt/V (spKt/V) ≥1.2. Outcomes were evaluated by comparing the NTNF and HTLF prescriptions. Results: A total of 863 sessions of HD were performed in 30 patients over 3 months, with 287 to 288 sessions in each of the 3 dialysis prescriptions. The primary outcome was not significantly different between the NTNF prescription (202 sessions [70.14%]) and the HTLF prescription (198 sessions [68.75%]) (odds ratio, 1.07; 95% confidence interval, 0.75 to 1.52; P = 0.45). The mean spKt/V and urea reduction ratio (URR) were not significantly different. Clinically evident hemodynamic instability occurred in only 1 dialysis session in the HTNF prescription. Conclusion: Increasing dialysate temperature while reducing dialysate flow rate (QD) can be used as a water conservation strategy without compromising the adequacy and safety of dialysis in young and hemodynamically stable patients. Reducing the QD from 500 ml/min to 300 ml/min reduces water consumption by 40%.