Symptomatic Intradialytic Hypotension Research Articles

#672 Intradialytic hypotension and adverse symptoms are not related

Abstract Background and Aims Intradialytic hypotension (IDH) is the most common side-effect of intermittent hemodialysis (HD). Yet, its definition lacks consensus about the magnitude of blood pressure (BP) drops, occurrence of adverse symptoms (AS) and/or interventions. Generally, BP is measured twice/hour, while additional readings are carried out when AS arise. Consequently, AS became a prerequisite for the diagnosis of IDH, both in the National Kidney Disease Outcomes Quality Initiative (KDOQI) and in the European Best Practice Guideline (EBPG). Yet, a large study on the associations between 8 IDH definitions and mortality, showed that an absolute nadir systolic blood pressure (SBP) <90 mmHg or <100 mmHg (with a pre-dialysis SBP < 160 mmHg or SBP ≥160 mmHg resp.) is most strongly associated with mortality. Neither AS nor interventions were related to outcome. Due to the absence of reliable studies, however, it is still unclear whether IDH and AS are related. Therefore, 1) the occurrence of (a)symptomatic IDH was evaluated according to the nadir-based definition; 2) relations between real-time AS and IDH were explored; 3) associations between IDH-susceptibility and physical intradialytic patient-reported outcome measures (PID-PROMS) were analysed. Methods Forty HD patients were cross-over randomized to standard HD (S-HD), cool HD (C-HD), low-(LV) and high-volume (HV) hemodiafiltration (HDF), each for two weeks. Every second week, BP was measured every 15 minutes during treatment. While AS were monitored real-time, PID-PROMS were documented after each modality with a modified dialysis symptom index [mDSI] questionnaire. The occurrence of symptomatic and asymptomatic IDH, defined as a SBP < 90 or 100 mmHg (depending on the pre-dialysis SBP), was evaluated. For each presentation of AS, we assessed its association with blood pressure by examining concurrent IDH using both the KDOQI/EBPG definitions and the nadir-based definition (Fig. 2). Patients were stratified into tertiles of IDH (IDH-prone, IDH-intermediate and IDH-resistant). The frequency and severity of discrete symptoms, recovery time and total symptom-burden were compared using logistic regression models and Kruskal-Willis tests. Results In 458 sessions, 222 IDH-episodes occurred of which 98% were asymptomatic. While nursing records revealed 24 real-time AS, 54% was BP-related and 17% fulfilled the nadir-based criteria, leaving 46% of AS unrelated to IDH (Fig. 2). IDH-prone patients experienced headaches more frequently (p = 0.01), and perceived dizziness (p = 0.05) and shivering (p < 0.01) more severely. No associations were found between IDH-susceptibility and symptom-burden, recovery time, or other discrete side-effects. Conclusions 1) Most IDH-episodes are asymptomatic; 2) Conversely, 46% of AS occur without IDH and (3) PID-PROMS are completely independent of IDH-susceptibility. 4) Symptom-based definitions severely underestimate IDH, when compared to a nadir-based IDH definition.

Hepatic Oxygenation Changes and Symptomatic Intradialytic Hypotension.

Clinical studies on differences among changes in cerebral and hepatic oxygenation during hemodialysis (HD) in patients with and without intradialytic hypotension (IDH) are limited. We investigated changes in intradialytic cerebral and hepatic oxygenation before systolic blood pressure (SBP) reached the nadir during HD and compared these differences between patients with and without symptomatic IDH. We analyzed data from 109 patients with (n = 23) and without (n = 86) symptomatic IDH who were treated with HD. Cerebral and hepatic regional oxygen saturation (rSO2), as a marker of tissue oxygenation and circulation, was monitored during HD using an INVOS 5100c oxygen saturation monitor. Changes in cerebral or hepatic rSO2 when SBP reached the nadir during HD were compared between the groups of patients. The cerebral rSO2 before HD in patients with and without symptomatic IDH was 49.7 ± 11.2% and 51.3 ± 9.1% (p = 0.491). %Changes in cerebral rSO2 did not significantly differ between the two groups from 60 min before the SBP nadir during HD. Hepatic rSO2 before HD in patients with and without symptomatic IDH was 58.5 ± 15.4% and 57.8 ± 15.9% (p = 0.869). The %changes in hepatic rSO2 were significantly lower in patients with symptomatic IDH than in those without throughout the observational period (p < 0.001). We calculated the area under the receiver operating characteristic curve (AUC) and estimated cutoff values for changes in hepatic rSO2 as a symptomatic IDH predictor. The predictive ability at 5 and 40 min before symptomatic IDH onset was excellent, with AUCs and cutoff values of 0.847 and 0.841, and -10.9% and -5.0%, respectively. Hepatic oxygenation significantly decreased more in patients with symptomatic IDH before its onset, than in those without symptomatic IDH, whereas changes in cerebral oxygenation did not differ. Evaluating changes in hepatic oxygenation during HD might help to predict symptomatic IDH.

Development and validation of AI-based triage support algorithms for prevention of intradialytic hypotension.

Intradialytic hypotension remains one of the most recurrent complications of dialysis sessions. Inadequate management can lead to adverse outcomes, highlighting the need to develop personalized approaches for theprevention ofintradialytic hypotension. Here, we sought to develop and validate two AI-based risk models predicting the occurrence of symptomatic intradialytic hypotension at different time points. The models were built using the XGBoost algorithm and they predict the occurrence of intradialytic hypotension in the next dialysis session and in the next month. The initial dataset, obtained from routinely collected data in the EuCliD® Database, was split to perform model derivation, training and validation. Model performance was evaluated by concordance statistic and calibration charts; the importance offeatures was assessed with the Shapley Additive Explanation (SHAP) methodology. The final dataset included 1,249,813 dialysis sessions, and the incidence rate of intradialytic hypotension was 10.07% (95% CI 10.02-10.13). Our models retained good discrimination (AUC around 0.8) and a suitable calibration yielding to the selection of three classification thresholds identifying four distinct risk groups. Variables providing the most significant impact on risk estimates were blood pressure dynamics and other metrics mirroring hemodynamic instability over time. Recurrent symptomatic intradialytic hypotension could be reliably and accurately predicted using routinely collected data during dialysis treatment and standard clinical care. Clinical application of these prediction models would allow for personalized risk-based interventions forpreventing and managing intradialytic hypotension.

A Randomized Trial Examining the Impact of Timing of Intradialytic Cycling on Intradialytic Hypotension

Intradialytic cycling is often performed during the first half of hemodialysis because of concerns regarding increased frequency of intradialytic hypotension (IDH) late in hemodialysis. This increases exercise program resource needs and limits utility of intradialytic cycling to treat dialysis-related symptoms. This multicenter, randomized, crossover trial compared IDH rate when cycling during the first half versus the second half of hemodialysis in 98 adults on maintenance hemodialysis. Group A cycled during the first half of hemodialysis for 2 weeks and subsequently during the second half for 2 weeks. In group B, the cycling schedule was reversed. Blood pressure (BP) was measured every 15 minutes throughout hemodialysis. Primary outcome was IDH rate (systolic BP [SBP] decrease of >20 mmHg or SBP<90 mmHg). Secondary outcomes included symptomatic IDH rate and time to recover post hemodialysis. Data were analyzed using negative binomial and gamma distribution mixed regression. Mean age 64.7 (SD 12.0) and 64.7 (SD 14.2) years in group A (n= 52) and group B (n= 46), respectively. Proportions of females were 33% in group A and 43% in group B. Median time on hemodialysis was 4.1 (interquartile range [IQR] 2.5, 6.1]) years in group A and 3.9 years (IQR 2.5, 6.7) in group B. IDH rate per 100 hemodialysis hours (95% confidence interval [CI]) was 34.2 (26.4, 42.0) and 36.0 (28.9, 43.1) during early and late intradialytic cycling, respectively (P= 0.53). Timing of intradialytic cycling was not associated with symptomatic IDH (relative risk [RR]: 1.07 [0.75-1.53]) or time to recover post hemodialysis (odds ratio: 0.99 [0.79-1.23]). We found no association between the rate of overall or symptomatic IDH and the timing of intradialytic cycling in patients enrolled in an intradialytic cycling program. Increased use of cycling late in hemodialysis may optimize intradialytic cycling program resource use and should be studied as a possible treatment for symptoms common in late hemodialysis.

Changes of Hemodynamic Parameters after Intradialytic Glucose Injection.

Intradialytic hypotension (IDH) is a frequent complication of hemodialysis (HD). Current methods of IDH prevention are insufficient. We analyzed the intradialytic time course of systolic (SBP), diastolic (DBP), mean arterial (MAP), pulse pressure (PP), and heart rate (HR) in a group of chronic kidney disease (CKD) patients. First, 30 min into HD, a 40% glucose solution was injected into the venous line of the extracorporeal circulation at a dose of 0.5 g/kg of dry weight. Pressures and HR were measured in frequent intervals. Relative volume overload was determined by bioimpedance spectroscopy. Thirty-five participants were studied. SBP increased after 5, 10, and 20 min of glucose infusion. DBP increased after 2 and 3 h and also at the end of HD. PP increased after 5, 10, and 20 min of glucose infusion and fell after the 2nd and 3rd hour and also at the end of HD. MAP increased after 2 and 3 h of glucose injection and at the end of HD. Significant interactions of the time course of SBP, DBP, MAP, with HR at baseline and of the time course of PP with fluid overload were observed. Symptomatic hypotensive episodes were absent. Glucose infusions during HD prevent symptomatic IDH and do not cause severe hypertensive episodes.

Low-Dose Dopamine in the Management of Intradialysis Hypotension: A Retrospective Cohort Study in Nigeria

Introduction: Intradialytic hypotension (IDH) still remains a common finding in maintenance haemodialysis despite improvements in dialysis delivery. Measures are needed to minimise some aftermath of IDH like dialysis termination, which can impact poorly on dialysis outcome. Methods: This retrospective study assessed IDH in a low-income setting, and compared two cohorts of IDH with and without dopamine treatment. Results: Of the 416 participants, 92 (22.1%) had at least an episode of symptomatic IDH. Of these, 20 (21.7%) were treated with dopamine. Of the 2,205 sessions, 468 (21.2%) had symptomatic IDH, of which 63 (13.4%) with severe IDH were treated with dopamine. The mean age of all participants and dopamine treatment participants were 50.8 ± 9.3 years and 64.6 ± 9.5 years, respectively (P=0.001). Blood pressure (BP) reductions following dialysis were more with females (P=0.04). Dialysis dose was adequate in 7.9% and 4.2% of sessions with and without dopamine (P&lt;0.001). Improvements in glomerular filtration rate were greater in dopamine-treated sessions (P=0.03 and P=0.04, respectively). Fewer anti-hypertensives (aOR: 14.64; 95% confidence interval [CI]: 7.88–20.41), low predialysis systolic (aOR:5.59; 95% CI: 3.88–9.41), and diastolic blood pressure (aOR: 5.78; 95% CI: 4.06-9.81) were independently associated with dopamine-treated sessions. Conclusion: IDH was found in 21.2% of dialysis sessions. 13.4% with severe IDH had dopamine treatment. Participants with dopamine-treated sessions had fewer dialysis terminations and hospitalisations, and dopamine treatment improved the prescribed dialysis and gave higher dialysis doses. Considering the economic effects of dialysis termination in low-income nations, intradialytic dopamine could be very beneficial.

Mixed- versus predilution hemodiafiltration effects on convection volume and small and middle molecule clearance in hemodialysis patients: a prospective randomized controlled trial.

BackgroundThe use of newly developed mixed-dilution hemodiafiltration (HDF) can supplement the weaknesses of pre- and postdilution HDF. However, it is unclear whether mixed-HDF performs well compared to predilution HDF.MethodsWe conducted a prospective, open-labeled, randomized controlled trial from two hemodialysis centers in Korea. Between January 2017 and September 2019, 60 patients who underwent chronic hemodialysis were randomly assigned at a 1:1 ratio to receive either predilution HDF (n = 30) or mixed-HDF (n = 30) for 6 months. We compared convection volume, changes in small- and medium-sized molecule clearance, high-sensitive C-reactive protein (hs-CRP) level, and dialysis-related parameters between the two dialysis modalities.ResultsA mean effective convection volume of 41.0 ± 10.3 L/session in the predilution HDF group and 51.5 ± 9.0 L/session in the mixed-HDF group was obtained by averaging values of three time-points. The difference in effective convection volume between the groups was 10.5 ± 1.3 L/session. This met the preset noninferiority criteria, suggesting that mixed-HDF was noninferior to predilution HDF. Moreover, the β2-microglobulin reduction rate was greater in the mixed-HDF group than in the predilution HDF group, while mixed-HDF provided greater transmembrane pressure. There were no significant between-group differences in Kt/V urea levels, changes in predialysis hs-CRP levels, proportions of overhydration, or blood pressure values. Symptomatic intradialytic hypotension episodes and other adverse events occurred similarly in the two groups.ConclusionUse of mixed-HDF was comparable to predilution HDF in terms of delivered convection volume and clinical parameters. Moreover, mixed-HDF provided better β2-microglobulin clearance than predilution HDF.

Relationship of a food intake during hemodialysis and symptomatic intradialytic hypotension.

Intradialytic hypotension is the most common complication during hemodialysis and is associated with increased cardiovascular disease, mortality, and overall hospital admissions. We analyzed the influence of food intake during hemodialysis on intradialytic hypotension. A total of 105 patients treated with chronic hemodialysis were observed for 8 weeks-4 weeks with a meal during hemodialysis and 4 weeks without a meal. A statistically significant decrease of hypotensive events (p < 0.001) and cramping episodes (p = 0.035) was observed during a 4-week period without a meal. Patients who were particularly susceptible to intradialytic hypotension were those who were diabetic, had low urinary excretion, and were treated with hemodialysis for a long time. On a follow up, there was a significant increase in serum albumin after 3 months (p = 0.01) and 6 months (p = 0.036) despite meal withdrawal during hemodialysis. Fasting during hemodialysis may cause a significantly lower frequency of intradialytic hypotension and cramping episodes without affecting the nutritional status.

Intradialytic hypotension and relationship with cognitive function and brain morphometry

BackgroundThe haemodynamic stress brought about by dialysis could justify the loss of structural and functional integrity of the central nervous system (CNS). The main objective of this study was to analyse the relationship between intradialytic hypotension (IDH) and cognitive function and brain morphometry.MethodsThe cross-sectional KIDBRAIN study (Cohort Study of Morphological Changes of the Brain by MRI in Chronic Kidney Disease Patients) included 68 prevalent patients with no history of neurological disorders (cerebrovascular disease and cognitive impairment) undergoing haemodialysis (HD). We analysed 18 non-consecutive dialysis sessions (first three of each month over a 6-month period) and various definitions of IDH were recorded. Global cognitive function (GCF) was assessed using the Mini-Mental State Examination (MMSE) and parameters of structural integrity of the CNS were obtained using volume morphometry magnetic resonance imaging analysis [grey matter (GM), white matter (WM) and hippocampus).ResultsA greater number of sessions with IDH were associated with less volume of WM (r = −0.359,P = 0.003) and hippocampus (r = −0.395, P = 0.001) independent of cardiovascular risk factors according to multivariable linear regression models (β = −0.198, P = 0.046 for WM; β = −0.253, P = 0.017 for hippocampus). The GCF by the MMSE was 27.3 ± 7.3.1 and was associated with WM volume (β = 0.403, P = 0.001) independent of GM and hippocampus volume. Symptomatic IDH was associated with GCF (r = −0.420, P < 0.001) in adjusted analysis (β = −0.339, P = 0.008). ConclusionsEven when asymptomatic, IDH is associated with a lower WM and hippocampus volume and reduced GCF in patients undergoing HD, thus suggesting greater vulnerability of the brain to the haemodynamic stress that may be generated by a dialysis session.

Hemodialysis crossover study using a relative blood volume change-guided ultrafiltration control compared with standard hemodialysis: the BV-UFC study

BackgroundIt has been difficult to sufficiently achieve body-fluid management using blood volume (BV) monitor during hemodialysis (HD) with constant ultrafiltration (UF) rate. Recently, a relative BV change-guided UF control (BV-UFC) system was developed by combining the concepts of an automatic feedback system that could control the UF rate and profile with real- time monitoring of relative changes in BV (%ΔBV). However, this system has limited application in the clinical setting. Therefore, in this study, we aimed to perform the crossover study on HD with BV-UFC compared to standard HD in terms of hemodynamic stability during HD.MethodsForty-eight patients entered an 8-week crossover period of standard HD or HD with BV-UFC. Prevalence of intradialytic hypotension (IDH) as a primary outcome and changes in blood pressure (BP), differences in %ΔBV, and achievement of the target ultrafiltration volume as secondary outcomes were compared. IDH was defined as a reduction in systolic BP ≥20 mmHg from the baseline value at 10 min after HD initiation.ResultsNo significant differences were found in the prevalence of IDH, frequency of intervention for symptomatic IDH, and achievement of the target ultrafiltration volume between the groups. The %ΔBV was significantly fewer (-12.1 ± 4.8% vs. -14.4 ± 5.2%, p <0.001) in the HD with BV-UFC than that in the standard HD.ConclusionsHD with BV-UFC did not reduce the prevalence of IDH compared with standard HD. The relief of a relative BV reduction at the end of HD may be beneficial in patients undergoing HD with BV-UFC.Trial RegistrationUMIN, UMIN000024670. Registered on December 1, 2016.

Eating during the Hemodialysis Session: A Practice Improving Nutritional Status or a Risk Factor for Intradialytic Hypotension and Reduced Dialysis Adequacy?

Historically, eating during the hemodialysis treatment has been associated with increased risk for adverse intradialytic symptoms and events, risks that have resulted in the implementation of restrictive in-center nutrition policies. Recent studies, however, have recorded a shift in clinical practice with a higher proportion of physicians following the view that administration of intradialytic meals and supplements represents a simple and effective approach to enhance caloric intake and improve nutritional status among patients on hemodialysis. This shift towards less restrictive in-center nutrition practices is mainly supported by evidence from observational studies associating intradialytic nutritional supplementation with improvements in protein-energy wasting, inflammatory state, and health-related quality of life. In sharp contrast, earlier and recent interventional studies have documented that feeding during the hemodialysis treatment provokes a rapid postprandial decline in blood pressure and raises the incidence of symptomatic intradialytic hypotension. Furthermore, other studies have shown that postprandial redistribution in intravascular volume and enhanced blood supply to the gastrointestinal circulation may interfere with the adequacy of the delivered hemodialysis. Those who defend the position that intradialytic nutritional support is beneficial do not dispute the physiology of postprandial hemodynamic response, but they argue against its clinical significance. In this article, we provide an overview of studies that explored the effect of eating during the hemodialysis treatment on intradialytic hemodynamic stability and adequacy of the delivered hemodialysis. We reason that these risks have important clinical implications that are not counteracted by anticipated benefits of this strategy on caloric intake and nutritional status.

Falls in systolic blood pressure during dialysis which require no nursing intervention are associated with increased patient intra-dialytic symptom self-reporting and prolonged post-dialysis recovery times

BackgroundHaemodialysis (HD) patients may suffer symptoms during dialysis and take time to recover post HD. We wished to determine whether patients with symptomatic intra-dialytic hypotension (IDH), requiring nursing interventions, or an asymptomatic fall in systolic blood pressure (SBP) reported more symptoms during dialysis.MethodsSix hundred three HD patients completed self-reported intra-dialytic symptom questionnaires and recovery using a visual analogue scale, which were compared with their dialysis session records.ResultsTwenty-nine (4.8%) of patients suffered symptomatic IDH, and 187 (31.0%) had a fall in SBP of > 20 mmHg. Symptomatic patients had greater total symptom scores (30 (23–44) vs 23 (10–38), p < 0.05, versus asymptomatic patients, with increased low blood pressure, dizziness, cramps, palpitations and feeling cold reported (all p < 0.05). Patients with a SBP fall of > 20 mmHg had greater total scores compared with those with a SBP increase of > 10 mmHg (26 (13–38) vs 17 (7–34), p < 0.05), with more dizziness, cramps, backache, shortness of breath and headache reported (all p < 0.05). Although ultrafiltration rates were similar, HD weight loss was greater for patients with a SBP fall of > 20 mmHg (2.5 ± 1.1 vs 2.0 ± 1.3%, p < 0.05). Patients with highest symptoms scores (highest vs lowest quartile) had longer recovery times (40.3 vs 7.6% > 4 h), p < 0.001.Multivariable analysis showed that patients reporting more intradialytic symptoms had higher psychological distress thermometer scores (odds ratio (OR) 1.34 (95% confidence limits 1.26–1.44)), systolic blood pressure < 100 mmHg (OR 2.53 (1.04–6.1)), whereas symptom scores were lower for male gender (OR 0.34 (0.22–0.51)), and with increasing age (OR 0.99 (0.97–0.99)).ConclusionPatients with both symptomatic and asymptomatic IDH, self-reported more symptoms during dialysis, and those patients reporting more symptoms had longer recovery times. We found that younger, female patients, those with greater psychological distress, and lower systolic blood pressure self-reported more intra-dialytic symptoms. More attention is required to prevent falls in intra-dialytic blood pressure to improve the patient experience of HD and shorten post-dialysis recovery times.

Monitoring transcellular fluid shifts during episodes of intradialytic hypotension using bioimpedance spectroscopy.

BackgroundTranscellular fluid shifts during dialysis treatment could be related to the frequency and severity of intradialytic hypotension (IDH). We investigated that (i) in addition to ultrafiltration, extracellular fluid (ECF) is further depleted by transcellular fluid shifts and (ii) changes in intracellular fluid (ICF), which have been overlooked so far, or if they were considered, are not understood, might be due to these fluid shifts.MethodsThirty-six patients were categorized as haemodynamically stable, asymptomatic IDH or unstable (symptomatic IDH) according to their changes in systolic blood pressure and associated clinical symptoms. Their intradialytic changes in body fluids were studied using bioimpedance spectroscopy measurements and compared among groups.ResultsFor IDH-prone patients, data showed a rapid drop in ECF that was more than expected from the ultrafiltration rate (UFR) profile and was associated with a significant increase in ICF (P = 0.001). Study of accumulative loss profiles of ECF revealed a loss in ECF up to 300 ml, more than that predicted from UFR for unstable patients.ConclusionsThe considerable discrepancy between the expected and measured loss in ECF might provide evidence of transcellular fluid shifts possibly induced by changes in plasma osmolarity due to haemodialysis. Moreover, the results suggest a pattern of fluid removal in IDH-prone patients that significantly differs from that in haemodynamically stable patients.

Does the intravascular volume status in haemodialysis patients measured by inferior vena cava ultrasound correlate with bioimpedance spectroscopy?

To evaluate the accuracy of traditional clinical predialytic fluid assessment by renal nurses and the efficacy of 2 additional fluid assessment methods focussing on the potential preventative effect for intradialytic hypotension (IDH). Predialytic fluid assessment remains a daily challenge for renal nurses, when aiming for adverse event free haemodialysis treatments. Adding further objective parameters obtained through noninvasive methods into pre- and intradialytic fluid assessment could potentially improve health outcomes for haemodialysis patients. Comparative, observational study of three fluid assessment methods on their reliability on volume status and correlation to clinical outcomes. Clinical predialytic nursing fluid assessments in 30 haemodialysis patients were compared with additional initial bioimpedance spectroscopy (BIS) measurements, and 3 serial intradialytic ultrasound scans of the inferior vena cava (IVC-US) performed by a second renal nurse concurrently during the same session. A retrospective data analysis compared all measurements in each individual for the predictive value for IDH. A STROBE checklist for observational cohort studies was used for the reporting of results. Seven subjects experienced episodes of symptomatic intradialytic hypotension (S-IDH), which would have been anticipated by IVC-US or by BIS in 5 patients (71%). Using an algorithm to predict IDH would have provided a sensitivity of 100% and specificity of 95%. Both additional fluid assessment methods would have provided critical information before and during each haemodialysis session. Therefore, we consider them as being potentially effective for the prevention of intradialytic hypotension, with IVC-US being similar to BIS. Traditional clinical nursing fluid assessment methods in haemodialysis patients do not provide sufficient information to prevent episodes of IDH. Additional objective fluid assessment methods are useful and likely to lead to improved health outcomes in HD patients when applied by renal nurses. A combination of IVC-US, MAP and BIS has potential to reduce the risk of IDH events in HD patients significantly.

Pilot Study of the Effects of High-Protein Meals During Hemodialysis on Intradialytic Hypotension in Patients Undergoing Maintenance Hemodialysis

Patients undergoing hemodialysis (HD) have high protein and energy requirements, and protein-energy wasting is common and associated with poor outcomes. Eating during dialysis may improve nutritional status by counteracting the catabolic effects of HD treatment; but eating during HD may be discouraged because of concerns of postprandial hypotension. However, little data are available to support this practice. In this study, we hypothesized that high-protein meals during HD do not lead to symptomatic intradialytic hypotension events. A 9-week, nonrandomized, parallel-arm study. A single in-center HD clinic. Eighteen patients undergoing HD from 2 shifts completed the study. Patients were aged 62±16 years with dialysis vintage of 3.4±2.6years. Patients in the intervention group (n=9) undergoing HD received meals of ∼30 g protein and ∼1/3 daily recommended intakes of sodium, potassium, phosphorus, and fluid during dialysis for 25 consecutive HD sessions. The control group (n=9) completed all aspects of the study including a visit by study personnel but were not given meals. The 25 consecutive sessions before the start of the intervention/control phase were used as a baseline comparison for each patient. Symptomatic hypotension event frequency. In the intervention arm, there were 19 symptomatic hypotension events in 5 patients prestudy and 18 events in 6 patients during the study. In the control arm, there were 16 events in 7 patients prestudy and 13 events in 7 patients during the study. Change in the frequency of symptomatic hypotension events from prestudy to during study was not different between groups (P=.71). There was no effect of meals on nutritional status, but patients reported positive attitudes toward receiving meals during dialysis. High-protein meals during HD did not increase symptomatic hypotension events. Larger, longer term studies are needed to confirm these results and evaluate whether high-protein meals on dialysis benefit nutritional status and clinical outcomes.

Impact of salt reduction in meals consumed during hemodialysis sessions on interdialytic weight gain and hemodynamic stability.

Patients on hemodialysis (HD) are advised to limit daily water- and salt intake to reduce interdialytic weight gain (IDWG). To counterbalance protein-losses, protein-rich meals are sometimes provided during HD sessions, but their salt content is not always taken into account. The aim of this study was to assess the influence of a lower salt content of meals provided during HD sessions on IDWG, blood pressure (BP), and hemodynamic stability during dialysis. This monocentric, interventional study was proposed to all the patients treated with three weekly HD sessions. The first two months of the study (high salt period), the patients continued to receive one sandwich containing 2.4 g of salt per session. Then, we reduced its salt content from 2.4 to 1.4 g, and patients received this "low-salt sandwich" at each dialysis session for four months. The mean values of IDWG, BP, and dry weight of the first two months were compared with those collected during the low salt periods (2-6 months). Forty out of 76 patients who initially agreed to participate were free of hospitalization, transplantation, and transfer to another center or death during the study period and were included in the final analysis (35% women). Median age was 63 years (range 28-90), 22.5% had a residual diuresis > 0.5 L/day. IDWG baseline decreased from 2.17 ± 0.98 to 2.03 ± 1 kg (P = 0.001) two months and to 2.09 ± 1.01 kg (P = 0.009) four months after we had lowered the salt content of the sandwich. The number of symptomatic intradialytic hypotension was also reduced (6.1% vs., respectively, 3.2% and 3.3% of HD sessions; P = 0.004). IDWG was reduced and hemodynamic stability improved after the reduction of the salt content of perdialytic meals. This suggests that salt consumed during HD matters and might influence salt and water intake outside the dialysis unit.

Randomized Crossover Trial of Blood Volume Monitoring-Guided Ultrafiltration Biofeedback to Reduce Intradialytic Hypotensive Episodes with Hemodialysis.

Intradialytic hypotension (IDH) is associated with morbidity. The effect of blood volume-guided ultrafiltration biofeedback, which automatically adjusts fluid removal rate on the basis of blood volume parameters, on the reduction of IDH was tested in a randomized crossover trial. We performed a 22-week, single blind, randomized crossover trial in patients receiving maintenance hemodialysis who had >30% of sessions complicated by symptomatic IDH in five centers in Calgary, Alberta, Canada. Participants underwent a 4-week run-in period to standardize dialysis prescription and dry weight on the basis of clinical examination. Those meeting inclusion criteria were randomized to best clinical practice hemodialysis (control) or best clinical practice plus blood volume-guided ultrafiltration biofeedback (intervention) for 8 weeks, followed by a 2-week washout and subsequent crossover for a second 8-week phase. The primary outcome was rate of symptomatic IDH. Thirty-five participants entered, 32 were randomized, and 26 completed the study. The rate of symptomatic IDH with biofeedback was 0.10/h (95% confidence interval, 0.06 to 0.14) and 0.07/h (95% confidence interval, 0.05 to 0.10) during control (P=0.29). There were no differences in the rate or proportion of sessions with asymptomatic IDH or symptoms alone. Results remained consistent when adjusted for randomization order and study week. There were no differences between intervention and control in the last study week in interdialytic weight gain (difference [SD], -0.02 [0.8] kg), brain natriuretic peptide (1460 [19,052] ng/L), cardiac troponins (3 [86] ng/L), extracellular water-to-intracellular water ratio (0.05 [0.33]), ultrafiltration rate (1.1 [7.0] ml/kg per hour), and dialysis recovery time (0.43 [19.25] hours). The use of blood volume monitoring-guided ultrafiltration biofeedback in patients prone to IDH did not reduce the rate of symptomatic IDH events.

Feeding during dialysis-risks and uncertainties.

Allowing dialysis patients to eat during the treatment is controversial. It is, therefore, no surprise that practices and policies with respect to intradialytic food consumption vary considerably from unit to unit and from country to country. Those who defend the position of feeding during dialysis reason that intradialytic meals offer a supervised and effective therapy for protein-energy wasting. Those who take the opposite view argue that intradialytic food intake should be avoided for the following three reasons. First, interventional studies show that eating during dialysis causes a clinically significant reduction in systemic blood pressure during the postprandial period and elevates the risk of symptomatic intradialytic hypotension; the latter is associated with increased mortality risk. Second, clinical studies have shown that eating during dialysis interferes with the adequacy of the delivered dialysis, whereas eating 2-3 h before the dialysis session has no impact on the efficiency of the subsequent dialysis treatment. And third, randomized studies show that eating during dialysis focus on the positive outcomes but do not adequately balance this potential benefit against the risk of intradialytic hemodynamic instability and poor quality of delivered dialysis. Even after half a century of providing long-term dialysis, definitive randomized trials that balance risks and benefits of eating during dialysis are missing. These knowledge gaps require randomized trials. Since there is a real possibility of harm with eating during dialysis, we caution that instead of encouraging the widespread use of intradialytic meals, practices and policies should focus on adequate nutrient intake during the interdialytic interval.

Treatment tolerance and patient-reported outcomes favor online hemodiafiltration compared to high-flux hemodialysis in the elderly

Large cohort studies suggest that high convective volumes associated with online hemodiafiltration may reduce the risk of mortality/morbidity compared to optimal high-flux hemodialysis. By contrast, intradialytic tolerance is not well studied. The aim of the FRENCHIE (French Convective versus Hemodialysis in Elderly) study was to compare high-flux hemodialysis and online hemodiafiltration in terms of intradialytic tolerance. In this prospective, open-label randomized controlled trial, 381 elderly chronic hemodialysis patients (over age 65) were randomly assigned in a one-to-one ratio to either high-flux hemodialysis or online hemodiafiltration. The primary outcome was intradialytic tolerance (day 30-day 120). Secondary outcomes included health-related quality of life, cardiovascular risk biomarkers, morbidity, and mortality. During the observational period for intradialytic tolerance, 85% and 84% of patients in high-flux hemodialysis and online hemodiafiltration arms, respectively, experienced at least one adverse event without significant difference between groups. As exploratory analysis, intradialytic tolerance was also studied, considering the sessions as a statistical unit according to treatment actually received. Over a total of 11,981 sessions, 2,935 were complicated by the occurrence of at least one adverse event, with a significantly lower occurrence in online hemodiafiltration with fewer episodes of intradialytic symptomatic hypotension and muscle cramps. By contrast, health-related quality of life, morbidity, and mortality were not different in both groups. An improvement in the control of metabolic bone disease biomarkers and β2-microglobulin level without change in serum albumin concentration was observed with online hemodiafiltration. Thus, overall outcomes favor online hemodiafiltration over high-flux hemodialysis in the elderly.

Haemodiafiltration at Higher Volumes and Patient Survival.

Patient morbidity and mortality rates are still very high in standard low-flux haemodialysis (lf-HD). On-line haemodiafiltration (OL-HDF) is considered the most efficient dialysis technique, as clearances of small solutes, like urea, may be even higher than in lf-HD and clearances of middle solutes, like β2-microglobulin, are much higher than in lf-HD. OL-HDF has been suggested to reduce mortality compared to HD, possibly due to more effective removal of larger uraemic retention solutes and/or better fluid removal. Only 1 out of the 3 largest randomized trials was able to demonstrate a positive effect of OL-HDF on patient survival in comparison to those randomized to HD. Post hoc analyses of these studies consistently showed that the patients randomized to OL-HDF who received the highest convection volumes had a lower risk of mortality and cardiovascular events than those randomized to HD. Four meta-analyses showed inconsistent results concerning the effect of convective treatments in improving general and cardiovascular survival, while they showed a significant reduction of the intradialytic symptomatic hypotension. An individual pooled participant analysis of the 4 largest trials confirmed these findings, suggesting a better survival when a convection volume of at least 23 litres/session was delivered, while other studies did not confirm these conclusions. Even after extensive statistical adjustments, residual confounding always remain; therefore, randomized control trials targeting different convection volumes are required to definitively confirm a dose-response effect of OL-HDF convection volume on patient survival.