Dialysate Sodium Concentration Research Articles

Centre-level fluid management practices in the BISTRO trial and their lack of association with participant fluid status and blood pressure in non-anuric haemodialysis patients.

Fluid assessment and management is a key aspect of good dialysis care and is affected by patient-level characteristics and potentially centre-level practices. In this secondary analysis of the BISTRO trial we wished to establish whether centre-level practices with the potential to affect fluid status were stable over the course of the trial and explore if they had any residual associations with participant's fluid status. Two surveys (S) of fluid management practices were conducted in 32 participating centres during the trial, (S1: 2017-18 and S2: 2021-22). Domains interrogated included: dialysate sodium concentration, (D-[Na+]), fluid and salt intake, residual kidney function, use of diuretics, incremental start, approaches to fluid assessment, management and dialysate temperature, (D-oC). Associations of these practices with the closeness of the participant's post-dialysis target weight to their normally hydrated weight, pre- and post-dialysis systolic (SBP) and diastolic blood pressure, (DBP), were analysed using intra-class correlations and multilevel modelling with adjustment for visit, age, sex and comorbidity burden. Variations in centre practices were reported but did not change during the trial, apart from some relaxation in salt and fluid restriction in S2. For our measures of fluid status, measured 2501 times in 439 non-anuric incident haemodialysis patients, centre-level intraclass correlations were extremely low, whereas patient-level correlations ranged between 0.12 and 0.47, strongest for pre- and post-dialysis-SBP, less so for post-dialysis-DBP. Multi-level analysis found no associations between D-[Na+], or assessment methods of fluid status. In S2, one centre, routinely using a D-Co of 35°C had more divergence between the target and normally hydrated weight, but this was not observed in S1, and no other associations were found. Centre-level fluid management practices were stable over the course of the BISTRO trial, and in contrast to patient-level factors, no centre-level associations were detected with fluid status or blood pressure. This may be because the trial imposed a standardised approach to fluid assessment in all trial participants who at least initially had residual kidney function, potentially over-riding the effects of other centre practices. Survey responses revealed substantial scope for developing and evaluating standardised protocols to optimise fluid management.

Autotaxin concentrations in peritoneal dialysis effluent reflect peritoneal function.

Peritoneal equilibration test (PET) has been used to monitor peritoneal function. A more convenient marker would be useful in clinical situations including home medical care. Autotaxin is known to leak into the interstitium as vascular permeability increases during the progression of tissue fibrosis. Therefore, we hypothesized that autotaxin concentrations in peritoneal dialysis (PD) effluent might reflect peritoneal function. This study enrolled 45 patients undergoing PD from 2016 to 2021. Autotaxin concentrations measured in PD effluent were evaluated for their associations with markers obtained from PET. Mean age was 69 years, and 33 patients were men. Univariate and multivariate analyses revealed that autotaxin concentrations are associated with dialysate/plasma creatinine ratio, end/start dialysate glucose ratio, and the dip in the dialysate sodium concentration, a marker of ultrafiltration capacity, at baseline (all p < 0.05). Autotaxin concentrations in PD effluent might be an adjunct marker that reflects peritoneal function.

Dialysate sodium and short-term blood pressure variability in patients with intradialytic hypertension: a randomized crossover study.

Increased blood pressure (BP) variability (BPV) is associated with high cardiovascular risk in hemodialysis. Patients with intradialytic hypertension (IDH) also exhibit an increased cardiovascular risk compared to hemodialysis patients without this condition. The impact of non-pharmacological BP-lowering interventions on BPV in this population remains unknown. This analysis evaluated the effect of low (137mEq/L) compared to standard (140mEq/L) dialysate sodium concentration on short-term BPV in patients with IDH. In a randomized cross-over manner, 29 IDH patients underwent 4 hemodialysis sessions with low (137mEq/L) followed by 4 sessions with standard (140mEq/L) dialysate sodium or vice versa. 48h ambulatory BP measurement was performed from the start of the 4th session on each dialysate sodium. BPV indices during the 48 h, 24 h, day-time and night-time periods were calculated. Mean 48h BP was 5.3/2.6 mmHg lower with low compared to standard dialysate sodium concentration, (p = 0.005/p = 0.007 respectively). All 48 h systolic BPV indices examined showed non-significant differences between low and standard dialysate sodium (SBP-SD: 16.99 ± 5.39 vs. 16.98 ± 4.33 mmHg, p = 0.982; SBP-wSD: 15.93 ± 5.02 vs. 16.12 ± 4.16 mmHg, p = 0.769; SBP-ARV: 11.99 ± 3.67 vs. 11.45 ± 3.35 mmHg, p = 0.392; SBP-CV: 12.36 ± 3.65 vs. 11.92 ± 3.18%, p = 0.302, with low vs. standard dialysate sodium, respectively). Diastolic BPV indices were numerically, but not statistically, lower with low dialysate sodium. Overall, significant differences were observed in some comparisons with a trend for lower BPV during day-time 2 and higher BVP during night-time 2 with low dialysate sodium. In conclusion, low dialysate sodium concentration does not affect BPV levels in patients with IDH. Future research should explore alternative interventions to reduce BP and BPV in this high-risk population.

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

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. 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. 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. 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.

Severe respiratory acidosis contributing to refractory hyperkalemia: a case series of COVID-19 patients with renal failure

Introduction: Respiratory acidosis (RA) is not known to cause severe hyperkalemia. However, an exception to this general rule was observed in three patients with severe COVID-19 complicated with renal failure in our center. Objectives: The current study investigated the explanation for hyperkalemia refractory to renal replacement therapy in patients with severe COVID-19 with hypercarbia and renal failure in a tertiary care center. Patients and Methods: In this study, we present a case series of three patients with severe COVID-19 with hypercarbia and dialysis-requiring renal failure who developed persistent hyperkalemia refractory to renal replacement therapy. We studied various causes of persistent hyperkalemia, such as acid‒base disorder, a high turnover state, exogenous administration, rhabdomyolysis, and hypoaldosteronism. Results: All three patients initially presented with episodes of severe hyperkalemia, which were ameliorated after RA was corrected. All of these patients had worsening pulmonary function, after which the hyperkalemia could not be corrected, corresponding to persistent RA. The evidence that there was a contribution of RA to hyperkalemia was further strengthened by the observations of patient 1, in whom the hyperkalemia was only corrected after changing ventilator settings and who was unresponsive to dialysis. We studied the dialysate effluent in patient 3, and the results showed satisfactory removal of potassium with no improvement in the high serum potassium levels. Another interesting finding was that although the dialysate sodium concentration was greater than the serum sodium concentration, there was a decrease in the serum sodium concentration, indicating a reduced movement of sodium into the extracellular space. Conclusion: In our study, metabolic acidosis alone could not explain the high serum potassium levels. Moreover, hyperkalemia was corrected after RA was corrected, indicating that the latter might have been the predominant cause of hyperkalemia in these scenarios. The presence of renal failure and low serum bicarbonate levels might have been the factors contributing to decreased Na+-K+-ATPase activity in the setting of RA, which contributed to severe hyperkalemia in all three patients.

Management of severe hyponatremia in a chronic kidney disease patient; a case report

Hyponatremia is a common electrolyte abnormality in chronic kidney disease (CKD). Managing severe hyponatremia in CKD is challenging, requiring the correction of biochemical imbalances and fluid overload, often through traditional hemodialysis. However, this can lead to rapid serum sodium correction, potentially causing neurological complications. We present a case of a CKD patient with a suspected stroke, who exhibited dizziness, confusion, and an unsteady gait, and was found to have azotemia, metabolic acidosis, and severe hyponatremia (101 mmol/L). We managed the case by gradually correcting the serum sodium with hypertonic saline. Subsequently, we initiated traditional hemodialysis using a dialysate sodium concentration of 130 mEq/L when the serum sodium levels increased to 122 mmol/L. The patient was discharged in a vitally and hemodynamically stable condition, with a serum sodium level of 137 mmol/L. This report highlights the intricacies of managing severe hyponatremia in a CKD patient with a suspected stroke.

Does using a higher dialysate sodium concentration result in lower sodium losses with dialysis treatments?

IntroductionMany dialysis centres prescribe a uniform dialysate sodium (DialNa) concentration, but as there is no consensus on the choice of a universal DialNa, we wished to determine dialysate sodium balance comparing DialNa of 140 and < 140 mEq/L.MethodsWaste dialysate was continuously collected during sessions and thoroughly mixed, and sodium was measured in both the waste and fresh dialysate. Sodium removal was calculated as the difference in concentrations, dialysate flow rate, session time and ultrafiltration.ResultsDialysate sodium balance was measured during 139 dialysis treatments (34 DialNa 140 versus 105 DialNa < 140, median 136 mEq/L), in 111 patients, 63% male, mean age 64.0 ± 16.2 years and 33.3% diabetic. There was no difference using the higher DialNa [net loss median 482 (238–573) versus 312 (124–599) mEq], ultrafiltration losses [226 (131–280) versus 204 (125–290)mEq] and non-ultrafiltration losses [217 (0–384) versus 173 (−90 to 350)mEq]. We also compared haemodiafiltration and haemodialysis (118 versus 23 sessions), and there were no differences in net loss [311 (91–608) versus 381 (167–597)], ultrafiltration [212 (127–290) versus 169 (110–258)mEq] and non-ultrafiltration losses [180 (−51 to 386) versus 192 (−74 to 387)mEq].ConclusionsAlthough most dialysis centres prescribe a universal dialysate sodium concentration, there is no consensus on the optimum universal concentration. We found no difference in net dialysate sodium balance when comparing patients dialysing with a dialysate sodium concentration of 140 or < 140 mEq/L. Similarly, we found no differences in dialysate sodium balance between haemodiafiltration and haemodialysis sessions.

#2887 Interdialytic weight gain and low dialysate sodium concentration in patients on chronic hemodialysis: a systematic review and meta-analysis

Abstract Background and Aims In many patients on chronic hemodialysis, interdialytic weight gain (IDWG) is greater than 4.0%-4.5% of dry weight, the value recommended by the international guidelines. High IDWG is a condition associated with risk of all-cause mortality and hospitalization and it depends on elevate intake of fluids and/or foods. More specifically, high intake of water is secondary to the disturbing and constant presence of thirst in such patients, so the limitation of the IDWG is a challenge both for the patients and the physicians. Low dialysate sodium levels can significantly reduce thirst as well as the water intake in the interdialytic period because they can increase the removal of sodium during the dialytic session, and this leads to a reduced content of sodium in the body. The present systematic review and meta-analysis aims at evaluating the efficacy of low dialysate sodium concentration on interdialytic weight gain (IDWG) in chronic hemodialysis patients. Method Studies were eligible for inclusion if they were English language papers published in a peer-reviewed journal and met the following inclusion criteria: 1) Primary research studies in adult patients (over 18 years of age), 2) Included patients with end-stage renal disease on chronic hemodialysis since at least 6 months; 3) Compared standard (138-140 mmol/l) or high (&amp;gt;140 mmol/l) dialysate sodium concentration with low (&amp;lt;138 mmol/l) dialysate sodium concentration; 4) Included one outcome of interest: interdialytic weight gain. We excluded studies on pediatric patients, pre-dialysis CKD patients, acute kidney injury patients, ESRD patients with other renal replacement therapy modalities such as peritoneal dialysis and transplant. Medline, PubMed, Web of Science, and the Cochrane Library were searched for studies comparing low or high dialysate sodium concentration. Outcome of interest was IDWG. The quality of reporting for each study was performed using the Quality Assessment Tool of Controlled Intervention Studies of the National Institutes of Health. The quality of reporting of each cross-over study was performed using the Revised Cochrane Risk of Bias (RoB) tool for cross-over trials as proposed by Ding et al. Results Nineteen studies (710 patients) were included in the analysis: 15 were cross-over and 4 parallel randomized controlled studies. In cross-over studies, pooled analysis revealed that dialysate sodium concentration reduced IDWG with a pooled MD of −0.40 kg (95% CI -0.50 to −0.30; P &amp;lt; 0.00001). The systematic review of four parallel, randomized, studies revealed that the use of a low dialysate sodium concentration was associated with a significant reduction of the IDWG in two studies, sustained and almost significant (P=0.05) reduction in one study, and not significant reduction in one study. In most studies, the frequency of intradialytic hypotensive events did not differ significantly between low and high sodium dialysate hemodialysis. The GRADE methodology was used to assess the quality of the body of retrieved evidence and studies risk of bias, inconsistency and imprecision were estimated as low. Conclusion Low dialysate sodium concentration reduces the IDWG in patients on chronic hemodialysis.

#1478 Effect of low vs standard dialysate sodium on 48-h ambulatory blood pressure in patients with intradialytic hypertension: a randomized crossover study

Abstract Background and Aims Intradialytic hypertension (IDH) is associated with increased risk for cardiovascular events and mortality. Patients with IDH exhibit higher 48-h blood pressure (BP) levels than patients without this condition. Volume and sodium excess are considered a major factor contributing in the development of this phenomenon. This study evaluated the effect of low (137 mEq/L) compared to standard (140 mEq/L) dialysate sodium concentration on 48-h BP in patients with IDH. Method In this randomized, single-blind, crossover study, 29 patients with IDH underwent 4 hemodialysis sessions with low (137 mEq/L) followed by 4 sessions with standard (140 mEq/L) dialysate sodium or vice-versa. Mean 48-h BP, pre-/post-dialysis and intradialytic BP, pre-dialysis weight, interdialytic weight gain (IDWG) and lung ultrasound B-lines were assessed. Results Mean 48-h SBP/DBP were significantly lower with low compared to standard dialysate sodium concentration (137.6 ± 17.0/81.4 ± 13.7 mmHg with low vs 142.9 ± 14.5/84.0 ± 13.9 mmHg with standard dialysate sodium, p = 0.005/p = 0.007 respectively); SBP/DBP levels were also significantly lower during the 44-h and different 24-h periods. Low dialysate sodium significantly reduced post-dialysis (SBP/DBP: 150.3 ± 22.3/91.2 ± 15.1 mmHg with low vs 166.6 ± 17.3/94.5 ± 14.9 mmHg with standard dialysate sodium, p &amp;lt; 0.001/p = 0.134 respectively) and intradialytic (141.4 ± 18.0/85.0 ± 13.4 mmHg with low vs 147.5 ± 13.6/88.1 ± 12.5 mmHg with standard dialysate sodium, p = 0.034/p = 0.013, respectively) BP compared with standard dialysate sodium. Pre-dialysis weight, IDWG and pre-dialysis B-lines were also significantly decreased with low dialysate sodium. Conclusion Low dialysate sodium concentration significantly reduced 48-h ambulatory BP compared with standard dialysate sodium in patients with IDH. These findings support low dialysate sodium as a major non-pharmacologic approach for BP management in patients with IDH. Registered at ClinicalTrials.gov with study number NCT05430438.

#1488 Dialysate sodium and short-term blood pressure variability in patients with intradialytic hypertension: a randomized crossover study

Abstract Background and Aims Increased blood pressure (BP) variability (BPV) is associated with high cardiovascular risk in hemodialysis. Patients with intradialytic hypertension (IDH) also exhibited an increased cardiovascular risk than hemodialysis patients without this condition. The impact of non-pharmacological BP-lowering interventions on BPV in this population remains unknown. This analysis evaluated the effect of low (137 mEq/L) compared to standard (140 mEq/L) dialysate sodium concentration on short-term BPV in patients with IDH. Method In a randomized cross-over manner, 29 patients with IDH underwent 4 hemodialysis sessions with low (137 mEq/L) followed by 4 sessions with standard (140 mEq/L) dialysate sodium or vice versa according to randomization arm. 48-h ABPM was performed from the start of the 4th session on each dialysate sodium. BPV indices during the 48-h, 24-h, day-time and night-time periods were calculated with validated formulas. Results Mean 48-h BP was lower by 5.3/2.6 mmHg with low compared to standard dialysate sodium concentration, (p = 0.005/p = 0.007) respectively). All 48-h systolic BPV indices examined showed non-significant differences between low and standard dialysate sodium (SBP-SD: 16.99 ± 5.39 vs. 16.98 ± 4.33 mmHg; p = 0.982; SBP-wSD: 15.93 ± 5.02 vs. 16.12 ± 4.16 mmHg, p = 0.769; SBP-ARV: 11.99 ± 3.67 vs. 11.45 ± 3.35 mmHg, p = 0.392 and SBP-CV: 12.36 ± 3.65 vs. 11.92 ± 3.18%, p = 0.302, with low vs. standard dialysate sodium, respectively). Diastolic BPV indices were numerically, but not statistically, lower with low dialysate sodium. Overall, significant differences were observed in some further comparisons relevant to a trend for lower BPV during daytime 2 and higher BVP during nighttime 2 during treatment with low dialysate sodium. Conclusion Low dialysate sodium concentration does not affect BPV levels in patients with IDH. Future research should further explore alternative interventions to reduce BP and BPV in this high-risk population.

Low dialysate sodium and 48-h ambulatory blood pressure in patients with intradialytic hypertension: a randomized crossover study.

Intradialytic-hypertension (IDH) is associated with increased risk for cardiovascular events and mortality. Patients with IDH exhibit higher 48-h blood pressure (BP) levels than patients without this condition. Volume and sodium excess are considered a major factor contributing in the development of this phenomenon. This study evaluated the effect of low (137mEq/L) compared to standard (140mEq/L) dialysate sodium concentration on 48-h BP in patients with IDH. In this randomized, single-blind, crossover study, 29 patients with IDH underwent 4 hemodialysis sessions with low (137mEq/L) followed by 4 sessions with standard (140mEq/L) dialysate sodium or vice-versa. Mean 48-h BP, pre-/post-dialysis and intradialytic BP, pre-dialysis weight, interdialytic weight gain (IDWG) and lung ultrasound B-lines were assessed. Mean 48-h SBP/DBP were significantly lower with low compared to standard dialysate sodium concentration (137.6±17.0/81.4±13.7mmHg with low vs 142.9±14.5/84.0±13.9mmHg with standard dialysate sodium, p=0.005/p=0.007 respectively); SBP/DBP levels were also significantly lower during the 44-h and different 24-h periods. Low dialysate sodium significantly reduced post-dialysis (SBP/DBP: 150.3±22.3/91.2±15.1mmHg with low vs 166.6±17.3/94.5±14.9mmHg with standard dialysate sodium, p<0.001/p=0.134 respectively) and intradialytic (141.4±18.0/85.0±13.4mmHg with low vs 147.5±13.6/88.1±12.5mmHg with standard dialysate sodium, p=0.034/p=0.013, respectively) BP compared with standard dialysate sodium. Pre-dialysis weight, IDWG and pre-dialysis B-lines were also significantly decreased with low dialysate sodium. Low dialysate sodium concentration significantly reduced 48-h ambulatory BP compared with standard dialysate sodium in patients with IDH. These findings support low dialysate sodium as a major non-pharmacologic approach for BP management in patients with IDH.Registered at ClinicalTrials.gov with study number NCT05430438.

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

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. This prospective study included patients on standard thrice-weekly hemodialysis. All patients initially underwent six sessions with dialysate sodium concentration of 137meq/L, followed consecutively by another six sessions with dialysate sodium of 139meq/L and, finally, six sessions with dialysate sodium of 141meq/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. 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±16.6mmHg with 137meq/L vs 126.3±17.5mmHg with 139meq/L vs 132.3±19.31mmHg with 141meq/L, P=0.002). Similar differences were noted for DBP; 72-h DBP was significantly higher with increasing dialysate sodium concentrations (75.1±11.3mmHg with 137meq/L vs 76.3±13.7mmHg with 139meq/L vs 79.5±13.9mmHg with 141meq/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. 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.

Prescribing the optimal dialysate sodium concentration for managing hypertension and volume overload in hemodialysis: one size does not fit to all patients.

Prescribing the optimal dialysate sodium concentration for managing hypertension and volume overload in hemodialysis: one size does not fit to all patients.

The Impact of Low Sodium Dialysate on Different Echocardiographic Parameters in Prevalent Hemodialysis Patients

Abstract Background ESRD affects about 15% of adult population, leading to increased morbidity and mortality. Historically, hemodialysis treatments used low dialysate sodium (D-NA) in the range of 120 mEq/L to enable elimination of excess sodium from the body. Over time, higher D-Na (∼140 mEq/L) was used to improve hemodynamic stability during dialysis. Aim of the Work To determine the impact of decreased dialysate Na on cardiac functions and different echocardiographic parameters in prevalent heamodialysis patients. Patients and Methods A Prospective study was conducted, consisted of 45 patients on regular Hemodialysis at Rod Elfarag Hospital dialysis unit for 6 months. Results In the current study, there was high statistically significant difference between baseline lab investigation and after 6 months lab investigation as regard Hemoglobin, WBCs, Platelets, Ht, URR, serum albumin, Ca, Na, Phosphorus and BNP (p &amp;lt; 0.001). We found that there was high statistically significant difference between baseline ECG and after 6 months ECG as regard PR interval, QRS duration and QT interval (p &amp;lt; 0.001). There was high statistically significant difference between baseline Echocardiography and after 6 months Echocardiography as regard left atrium diameter, EF%, Diastolic BP and Systolic BP (p &amp;lt; 0.001). Conclusion A reduction of the dialysate sodium concentration based on the predialysis sodium levels of the patients could reduce the SBP and decrease the volume load on heart. Within this short period, DBP could not be lowered. The effect of this approach should be studied in broad and lengthy series.

#3528 DIALYSATE SODIUM: IS IT STILL MYTH OR NOT?

Abstract Background and Aims Pre-hemodialysis serum sodium levels can vary among patients, therefore, a single dialysate sodium prescription may not be appropriate for all patients. The aim of the study was to investigate whether dialysis patients will have some beneficial effects of prescription of different models of dialysate sodium. Method 77 nondiabetic subjects performed 12 months hemodialysis (HD) sessions with dialysate sodium concentration set up at 138 mmol/L, followed by additional 4 models of dialysate sodium (each one 4 months sessions lasted) wherein dialysate sodium was set up: model 1: according to pre-hemodialysis serum sodium concentration, model 2: sodium concentration in UF fluid, model 3: sodium profiling (144-136 mmol/L, every hour decreasing of dialysate sodium during dialysis), model 4: stepwise dialysate sodium (starting dialysis with a dialysate sodium of 138 mmol/L and reducing it every week by 1 mmol/L sodium for the next 4 weeks). Blood pressure (BP), interdialytic weight gain (IDWG), thirst score, sodium gradient were analysed. After the standard dialysate sodium hemodialyses, the subjects were divided into normotensive, hypertensive and hypotensive based on the average pre-hemodialysis systolic BP during the standard dialysate sodium hemodialyses. Results Model 1: resulted in significantly lower BP (153.60±14.26 versus 133,61±11.88 mmHg; p = 0.000) and IDWG (2.21±0.93 versus 1.87±0.92 kg; p = 0.018) in hypertensive patients, whereas normotensive patients showed only significant decrease in IDWG (p = 0,004). Hypertensive patients had significant highest sodium gradient compared to other patients (p&amp;lt;0.05), followed by significant increase of 0,6% IDWG confirmed with univariate regression analysis. Thirst score was significantly lower in all patients with individualized-sodium HD and no relationship between the sodium gradient and the subjective feeling of thirst was confirmed (p = 0.368). Model 2: resulted in significantly lower BP in normotensive and hypertensive patients, with no influence on IDWG and thirst score compared to standard dialysate sodium (p = 0.474 and p = 0.212, retrospectively). Patients who were hypotensive, due to frequent collapses and unmeasurable blood pressure values, as well as for ethical reasons, were excluded from analysis with this dialysate sodium model. Model 3: confirmed significantly higher BP and IDWG in all 3 groups (p = 0.006) and significantly higher thirst score in normo and hipotensive patients (p = 0.000), with no influence in hypertensive patients. Model 4: significant decrease in SBP and DBP in hypertensive patients and insignificant increase in IDWG, but with no effects in normotensive and hypotensive patients on BP, IDWG and thirst score. Conclusion Model 1 resulted in better clinical outcome in hypertensive and normotensive patients compared to standard dialysate sodium, whereas other 3 models didn't show any clinical benefits.

#6780 EFFECTS OF ISONATREMIC DIALYSIS ON INTERDIALYTIC WEIGHT GAIN RELYING ON AN AUTOMATED SODIUM CONTROL ALGORITHM: INTERIM ANALYSIS OF DISON-IRC STUDY

Abstract Background and Aims Sodium (Na) is a major determinant of extracellular fluid volume and osmolarity homeostasis. Chronic fluid overload (FO) is present in 30 to 50% of hemodialysis patients (HD). HD patients are mostly treated with fixed dialysate Na concentration irrespective of plasma Na concentration. This fixed approach tends to displace patient's osmolar set point and stimulates thirst and weight gain. An automated personalized dialysate Na alignment to patient's natremia to avoid unwanted diffusive Na gain and tonicity change induced by HD seems preferable. Several studies exploring individualized dialysate Na prescription have reported inconsistent results. In this prospective interventional multicenter study, we aimed to explore the impact of dialysate Na individualization through isonatremic HD on interdialytic weight gain (IDWG) (primary outcome) and dialytic HD-related symptoms (secondary outcome). For this purpose, we have used the automated “Na Control” option for adjusting dialysate Na to minimize dialysate-plasma sodium gradient and deliver an isonatremic dialysis. Method This is a longitudinal study comparing 2 periods: Period-1 = observational phase (2 months) → Period-2 = isonatremic phase by activation of “Na Control” in isonatremic mode (2 months) → comparison of IDWG between both periods. The embedded “sodium control” option in HD machine was used in all cases of Period-2 to actively align dialysate sodium concentration to natremia and quantify net sodium mass transfer. Results are expressed as mean±SD or median [25th-75th]. Results We present preliminary results obtained through 6 dialysis facilities including 51 patients, 33 (64.7%) females, 75 [65-81] years old, dry weight 71.9 [60.5-78.0] kg. Main findings are as follows: Firstly, an excellent agreement was observed between plasma Na concentrations, measured (laboratory) and estimated (machine) from HD monitor (mean difference before dialysis: 0.05, after dialysis: 0.62); Secondly, plasma Na estimated was as follows: before dialysis plasma Na (137.6 [136.2-139.0] vs 137.2 [136.0-139.3] and after dialysis plasma Na (139.0 [137.6-139.7] vs 137.1 [135.7-138.9]) in Period-1 and Period-2 respectively; Thirdly, the primary outcome (IDWG) as well as the diffusive Na balance were significantly reduced by isonatremic dialysis condition (IDWG: 2.17±0.92 versus 1.95±0.86 kg, p&amp;lt;0,0001; diffusive Na balance (3.9 [1.9-5.1] versus 0.7 [0.0-2.7] g of Na, p&amp;lt;0.0001). Conclusion Isonatremic dialysis condition automatically driven by “Na control” embedded In HD monitor was confirmed safe and easily implemented in clinical workflow. In addition, these preliminary results show that isonatremic dialysis improved dialysis patient perception and significantly reduced IDWG.

#5069 THE EFFECT OF DIFFERENT DIALYSATE SODIUM CONCENTRATIONS ON AMBULATORY BLOOD PRESSURE AND PULSE WAVE VELOCITY ON HEMODIALYSIS PATIENTS

Abstract Background and Aims Hypertension and arterial stiffness are associated with increased morbidity and mortality in dialysis patients. The purpose of the present study is to investigate the effect of sodium concentration in the dialysate on 72h ambulatory blood pressure and arterial stiffness, as well as its effect on body weight. Method The study involved adult patients on thrice weekly maintenance hemodialysis program. All patients initially underwent six sessions with dialysate sodium concentration of 137 meq/l, subsequently another six sessions with dialysate sodium concentration of 139 meq/l and finally six sessions with dialysate sodium concentration of 141 meq/l. At the start of the sixth hemodialysis session at each different sodium dialysate concentration, the Mobil-o-graph device was placed for 72h in order to cover the 3-day interdialytic interval. The parameters evaluated by the Mobil-o-graph device were peripheral and central systolic (pSBP and cSBP) and diastolic (pDBP and cDBP) blood pressure and pulse wave velocity (PWV). All patients were screened for hydration status with lung ultrasound before entering the study and body weight was actively monitored before each session. Results Overall, 29 patients with a mean age of 57.9±14.9 years were included in this prospective interventional study. Body weight did not change significantly between the 3 dialysate concentrations. There was a significant increase of 6 mmHg in the mean pSBP with the change in sodium concentration from 137 to 139 and to 141 meq/l (from 122.7 to 125,6 and to 128.3 mmHg respectively, p = 0.032). Mean cSBP was also significantly increased by 5 mmHg (from 110.3 to 112.6 and to 115.1 mmHg respectively, p = 0.02). Peripheral and central DBP did not change significantly (from 71.4 to 73.2 and to 74.1 mmHg, p = ns and from 73.9 to 74.8 and to 75.3 mmHg, p = ns, respectively), as well as PWV (from 8.4 to 8.2 cm/sec, p = ns). Conclusion The increasing sodium concentration in the dialysate causes a significant increase in systolic blood pressure and body weight, without a change in PWV.

Management of Intermittent Hemodialysis in the Critically Ill Patient.

Intermittent hemodialysis remains a cornerstone of extracorporeal KRT in the intensive care unit, either as a first-line therapy for AKI or a second-line therapy when patients transition from a continuous or prolonged intermittent therapy. Intermittent hemodialysis is usually provided 3 days per week in this setting on the basis that no clinical benefits have been demonstrated with more frequent hemodialysis. This should not detract from the importance of continually assessing and refining the hemodialysis prescription (including the need for extra treatments) according to dynamic changes in extracellular volume and other parameters, and ensuring that an adequate dose of hemodialysis is being delivered to the patient. Compared with other KRT modalities, the cardinal challenge encountered during intermittent hemodialysis is hemodynamic instability. This phenomenon occurs when reductions in intravascular volume, as a consequence of ultrafiltration and/or osmotic shifts, outpace compensatory plasma refilling from the extravascular space. Myocardial stunning, triggered by intermittent hemodialysis, and independent of ultrafiltration, may also contribute. The hemodynamic effect of intermittent hemodialysis is likely magnified in patients who are critically ill due to an inability to mount sufficient compensatory physiologic responses in the context of multiorgan dysfunction. Of the many interventions that have undergone testing to mitigate hemodynamic instability related to KRT, the best evidence exists for cooling the dialysate and raising the dialysate sodium concentration. Unfortunately, the evidence supporting routine use of these and other interventions is weak owing to poor study quality and limited sample sizes. Intermittent hemodialysis will continue to be an important and commonly used KRT modality for AKI in patients with critical illness, especially in jurisdictions where resources are limited. There is an urgent need to harmonize the definition of hemodynamic instability related to KRT in clinical trials and robustly test strategies to combat it in this vulnerable patient population.

Sodium flux during hemodialysis and hemodiafiltration treatment of acute kidney injury: Effects of dialysate and infusate sodium concentration at 140 and 145 mmol/L.

A higher sodium (Na) dialysate concentration is recommended during renal replacement therapy (RRT) of acute kidney injury (AKI) to improve intradialytic hemodynamic tolerance, but it may lead to Na loading to the patient. We aimed to evaluate Na flux according to Na dialysate and infusate concentrations at 140 and 145 mmol/L during hemodialysis (HD) and hemodiafiltration (HDF). Fourteen AKI patients that underwent consecutive HD or HDF sessions with Na dialysate/infusate at 140 and 145 mmol/L were included. Per-dialytic flux of Na was estimated using mean sodium logarithmic concentration including diffusive and convective influx. We compared the flux of sodium between HD140 and 145, and between HDF140 and 145. Nine HD140, ten HDF140, nine HD145, and 11 HDF145 sessions were analyzed. A Na gradient from the dialysate/replacement fluid to the patient was observed with dialysate/infusate Na at 145 mmol/L in both HD and HDF (p=0.01). The comparison of HD145 to HD140 showed that higher Na dialysate induced a diffusive Na gradient to the patient (163 mmol vs. -25 mmol, p=0.004) and that of HDF145 to -140 (211 vs. 36 mmol, p=0.03) as well. Intradialytic hemodynamic tolerance was similar across all RRT sessions. During both HD and HDF, a substantial Na loading occurred with a Na dialysate and infusate at 145 mmol/L. This Na loading is smaller in HDF with Na dialysate and infusate concentration at 140 mmol/L and inversed with HD140. Clinical and intradialytic hemodynamic tolerance was fair regardless of Na dialysate and infusate.

Association of Bradycardia and Asystole Episodes with Dialytic Parameters: An Analysis of the Monitoring in Dialysis (MiD) Study.

Bradycardia and asystole events are common among patients treated with maintenance hemodialysis. However, triggers of these events in patients on maintenance hemodialysis (HD), particularly during the long interdialytic period when these events cluster, are uncertain. The Monitoring in Dialysis Study (MiD) enrolled 66 patients on maintenance HD who were implanted with loop recorders and followed for 6 months. We analyzed associations of predialysis laboratory values with clinically significant bradyarrhythmia or asystole (CSBA) during the 12 hours before an HD session. Associations with CSBA were analyzed with mixed-effect models. Adjusted negative binomial mixed-effect regression was used to estimate incidence rate ratios (IRR) for CSBA. We additionally evaluated associations of CSBA at any time during follow-up with time-averaged dialytic and laboratory parameters and associations of peridialytic parameters with occurrence of CSBA from the start of one HD session to the beginning of the next. There were 551 CSBA that occurred in the last 12 hours of the interdialytic interval preceding 100 HD sessions in 12% of patients and 1475 CSBA events in 23% of patients overall. We did not identify significant associations between dialytic parameters or serum electrolytes and CSBA in the last 12 hours of the interdialytic interval in adjusted analyses. Median time-averaged ultrafiltration rate was significantly higher in individuals without CSBA (9.8 versus 8, P=0.04). Use of dialysate sodium concentrations ≤135 (versus 140) mEq/L was associated with a reduced risk of CSBA from the start of one session to the beginning of next. Although a few factors had modest associations with CSBA in some analyses, we did not identify any robust associations of modifiable parameters with CSBA in the MiD Study. Further investigation is needed to understand the high rates of arrhythmia in the hemodialysis population.