Dialysis dose and intradialytic hypotension: results from the HEMO study

Assessment and management of emergencies during haemodialysis

The haemodialysis unit is a complex clinical environment. Medical emergencies complicating haemodialysis treatment are relatively infrequent but are associated with high morbidity and mortality. The management of intradialytic emergencies is challenging and relevant to the practice of all nephrology and critical care clinicians. There are no dedicated resuscitation guidelines for this unique patient population. This review article provides an outline of the assessment and treatment of important intradialytic emergencies (hypotension, hypertension, haemorrhage, hypoxia, neurologic disturbances, cardiac arrest) based on the best available evidence.

Association of Calcium Channel Blocker Use With Intradialytic Hypotension in Maintenance Hemodialysis

Introduction

Calcium channel blockers (CCBs) are common antihypertensive agents among patients receiving hemodialysis (HD). Despite this, the association of CCBs with intradialytic hypotension (IDH), an important adverse outcome that is associated with cardiovascular morbidity and mortality, remains largely unexplored.

Methods

Using kinetic modeling sessions data from the Hemodialysis (HEMO) Study, random effects regression models were fit to assess the association of CCB use versus nonuse with IDH (defined as systolic blood pressure [SBP] < 90 mm Hg if pre-HD SBP < 160 mm Hg or < 100 mm Hg if pre-HD SBP ≥160 mm Hg). Models were adjusted for age, biological sex (distinguishing between males and females), race, randomized Kt/V and flux assignments, heart failure, ischemic heart disease, peripheral vascular disease, diabetes mellitus, blood urea nitrogen, ultrafiltration rate, access type, pre-HD SBP, and other antihypertensives.

Results

Data were available for 1838 patients and 64,538 sessions. At baseline, 49% of patients were prescribed CCBs. The overall frequency of IDH was 14% with a mean decline from pre- to nadir-SBP of 33 ± 15 mm Hg. CCB use was associated with lower adjusted risk of IDH, compared with no use (incidence rate ratio [IRR]: 0.84; 95% confidence interval [CI]: 0.78-0.89). The association was most pronounced for those in the pre-HD SBP lowest quartile (IRR: 0.77; 95% CI: 0.70-0.85); compared with the highest quartile (IRR: 0.86; 95% CI: 0.77-0.97; P-interaction < 0.001).

Conclusion

Among patients receiving HD, CCB use was associated with a lower risk of developing IDH, independent of pre-HD SBP and other antihypertensives use. Mechanistic studies are needed to better understand the effects of CCB and other antihypertensives on peridialytic blood pressure (BP) parameters among patients receiving HD.

Prevention of Intradialytic Hypotension in Hemodialysis Patients: Current Challenges and Future Prospects

Intradialytic hypotension, defined as rapid decrease in systolic blood pressure of greater than or equal to 20 mmHg or in mean arterial pressure of greater than or equal to 10 mmHg that results in end-organ ischemia and requires countermeasures such as ultrafiltration reduction or saline infusion to increase blood pressure to improve patient's symptoms, is a known complication of hemodialysis and is associated with several potential adverse outcomes. Its pathogenesis is complex and involves both patient-related factors such as age and comorbidities, as well as factors related to the dialysis prescription itself. Key factors include the need for volume removal during hemodialysis and a suboptimal vascular response which compromises the ability to compensate for acute intravascular volume loss. Inadequate vascular refill, incorrect assessment or unaccounted changes of target weight, acute illnesses and medication interference are further potential contributors. Intradialytic hypotension can lead to compromised tissue perfusion and end-organ damage, both acutely and over time, resulting in repetitive injuries. To address these problems, a careful assessment of subjective symptoms, minimizing interdialytic weight gains, individualizing dialysis prescription and adjusting the dialysis procedure based on patients' risk factors can mitigate negative outcomes.

An update review on hemodynamic instability in renal replacement therapy patients

BACKGROUND

Hemodynamic instability in patients undergoing kidney replacement therapy (KRT) is one of the most common and essential factors influencing mortality, morbidity, and the quality of life in this patient population.

METHOD

Decreased cardiac preload, reduced systemic vascular resistance, redistribution of fluids, fluid overload, inflammatory factors, and changes in plasma osmolality have all been implicated in the pathophysiology of hemodynamic instability associated with KRT.

RESULT

A cascade of these detrimental mechanisms may ultimately cause intra-dialytic hypotension, reduced tissue perfusion, and impaired kidney rehabilitation. Multiple parameters, including dialysate composition, temperature, posture during dialysis sessions, physical activity, fluid administrations, dialysis timing, and specific pharmacologic agents, have been studied as possible management modalities. Nevertheless, a clear consensus is not reached.

CONCLUSION

This review includes a thorough investigation of the literature on hemodynamic instability in KRT patients, providing insight on interventions that may potentially minimize factors leading to hemodynamic instability.

Mean annual intradialytic blood pressure decline and cardiovascular events in Japanese patients on maintenance hemodialysis

An intradialytic systolic blood pressure (SBP) decline, which defines intradialytic hypotension, may be associated with higher all-cause mortality. However, in Japanese patients on hemodialysis (HD), the association between intradialytic SBP decline and patient outcomes is unclear. This retrospective cohort study included 307 Japanese patients undergoing HD over 1 year in three dialysis clinics and evaluated the association between the mean annual intradialytic SBP decline (predialysis SBP-nadir intradialytic SBP) and clinical outcomes, including major adverse cardiovascular events (MACEs; cardiovascular death, nonfatal myocardial infarction or unstable angina, stroke, heart failure, and other severe cardiovascular events requiring hospitalization) by following up for 2 years. The mean annual intradialytic SBP decline was 24.2 (25-75th percentile, 18.3-35.0) mmHg. In the model fully adjusted for intradialytic SBP decline tertile group (T1, <20.4 mmHg; T2, 20.4 to <29.9 mmHg; T3, ≥29.9 mmHg), predialysis SBP, age, sex, HD vintage, Charlson comorbidity index, ultrafiltration rate, use of renin-angiotensin system inhibitors, corrected calcium, phosphorus, human atrial natriuretic peptide, geriatric nutritional risk index, normalized protein catabolism rate, C-reactive protein, hemoglobin, and use of pressor agents, Cox regression analyses showed that the hazard ratio (HR) was significantly higher for T3 than for T1 for MACEs (HR, 2.38; 95% confidence interval 1.12-5.09) and all-cause hospitalization (HR, 1.68; 95% confidence interval 1.03-2.74). Therefore, in Japanese patients on HD, a greater intradialytic SBP decline was associated with worse clinical outcomes. Further studies are warranted to investigate whether interventions to attenuate the intradialytic SBP decline will improve the prognosis of Japanese patients on HD.

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.

Deep Learning Using Electrocardiograms in Patients on Maintenance Dialysis

Cardiovascular morbidity and mortality occur with an extraordinarily high incidence in the hemodialysis-dependent end-stage kidney disease population. There is a clear need to improve identification of those individuals at the highest risk of cardiovascular complications in order to better target them for preventative therapies. Twelve-lead electrocardiograms are ubiquitous and use inexpensive technology that can be administered with minimal inconvenience to patients and at a minimal burden to care providers. The embedded waveforms encode significant information on the cardiovascular structure and function that might be unlocked and used to identify at-risk individuals with the use of artificial intelligence techniques like deep learning. In this review, we discuss the experience with deep learning-based analysis of electrocardiograms to identify cardiovascular abnormalities or risk and the potential to extend this to the setting of dialysis-dependent end-stage kidney disease.

Hemodynamic Tolerance of Virtual Reality Intradialysis Exercise Performed during the Last 30 Minutes versus the Beginning of the Hemodialysis Session

Background: Exercise improves the physical function of people suffering from chronic kidney disease on hemodialysis (HD). Virtual reality is a new type of intradialysis exercise that has a positive impact on physical function. Intradialysis exercise is recommended during the first 2 h, but its safety in the last part of the dialysis session is unknown. Methods: This was a pilot sub-study of a clinical trial. Several hemodynamic control variables were recorded, including blood pressure, heart rate, and intradialytic hypotensive events. These variables were recorded during three different HD sessions, one HD session at rest, another HD session with exercise during the first two hours, and one HD session with exercise during the last 30 min of dialysis. The intradialysis virtual reality exercise was performed for a maximum of 30 min. Results: During exercise sessions, there was a significant increase in heart rate (6.65 (4.92, 8.39) bpm; p < 0.001) and systolic blood pressure (6.25 (0.04,12.47) mmHg; p < 0.05). There was no difference in hemodynamic control between the sessions with exercise during the first two hours and the sessions with exercise during the last 30 min. There was no association between intra-dialytic hypotensive events at rest (five events) or exercise at any point (two vs. one event(s), respectively). Conclusion: performing exercise with virtual reality at the end of a hemodialysis session is not associated with hemodynamic instability.

The effect of levocarnitine supplementation on dialysis-related hypotension: A systematic review, meta-analysis, and trial sequential analysis

BACKGROUND

Dialysis patients have been shown to have low serum carnitine due to poor nutrition, deprivation of endogenous synthesis from kidneys, and removal by hemodialysis. Carnitine deficiency leads to impaired cardiac function and dialysis-related hypotension which are associated with increased mortality. Supplementing with levocarnitine among hemodialysis patients may diminish incidence of intradialytic hypotension. Data on this topic, however, lacks consensus.

METHODS

We conducted electronic searches in PubMed, Embase and Cochrane Central Register of Controlled Trials from January 1960 to 19th November 2021 to identify randomized controlled studies (RCTs), which examined the effects of oral or intravenous levocarnitine (L-carnitine) on dialysis-related hypotension among hemodialysis patients. The secondary outcome was muscle cramps. Study results were pooled and analyzed utilizing the random-effects model. Trial sequential analysis (TSA) was performed to assess the strength of current evidence.

RESULTS

Eight trials with 224 participants were included in our meta-analysis. Compared to control group, L-carnitine reduced the incidence of dialysis-related hypotension among hemodialysis patients (pooled OR = 0.26, 95% CI [0.10-0.72], p = 0.01, I2 = 76.0%). TSA demonstrated that the evidence was sufficient to conclude the finding. Five studies with 147 participants showed a reduction in the incidence of muscle cramps with L-carnitine group (pooled OR = 0.22, 95% CI [0.06-0.81], p = 0.02, I2 = 74.7%). However, TSA suggested that further high-quality studies were required. Subgroup analysis on the route of supplementation revealed that only oral but not intravenous L-carnitine significantly reduced dialysis-related hypotension. Regarding dose and duration of L-carnitine supplementation, the dose > 4,200 mg/week and duration of at least 12 weeks appeared to prevent dialysis-related hypotension.

CONCLUSION

Supplementing oral L-carnitine for at least three months above 4,200 mg/week helps prevent dialysis-related hypotension. L-carnitine supplementation may ameliorate muscle cramps. Further well-powered studies are required to conclude this benefit.

A randomized controlled trial of two dialysate sodium concentrations in hospitalized hemodialysis patients

BACKGROUND

Several large dialysis organizations have lowered the dialysate sodium concentration (DNa) in an effort to ameliorate hypervolemia. The implications of lower DNa on intra-dialytic hypotension (IDH) during hospitalizations of hemodialysis (HD) patients is unclear.

METHODS

In this double-blind, single center, randomized controlled trial (RCT), hospitalized maintenance HD patients were randomized to receive higher (142 mmol/L) or lower (138 mmol/L) DNa for up to six sessions. Blood pressure (BP) was measured in a standardized fashion pre-HD, post-HD and every 15 min during HD. The endpoints were: (i) the average decline in systolic BP (pre-HD minus lowest intra-HD, primary endpoint) and (ii) the proportion of total sessions complicated by IDH (drop of ≥20 mmHg from the pre-HD systolic BP, secondary endpoint).

RESULTS

A total of 139 patients completed the trial, contributing 311 study visits. There were no significant differences in the average systolic blood pressure (SBP) decline between the higher and lower DNa groups (23 ± 16 versus 26 ± 16 mmHg; P = 0.57). The proportion of total sessions complicated by IDH was similar in the higher DNa group, compared with the lower DNa group [54% versus 59%; odds ratio 0.72; 95% confidence interval (95% CI) 0.36-1.44; P = 0.35]. In post hoc analyses adjusting for imbalances in baseline characteristics, higher DNa was associated with 8 mmHg (95% CI 2-13 mmHg) less decline in SBP, compared with lower DNa. Patient symptoms and adverse events were similar between the groups.

CONCLUSIONS

In this RCT for hospitalized maintenance of HD patients, we found no difference in the absolute SBP decline between those who received higher versus lower DNa in intention-to-treat analyses. Post hoc adjusted analyses suggested a lower risk of IDH with higher DNa; thus, larger, multi-center studies to confirm these findings are warranted.

Seasonal variation and predictors of intradialytic blood pressure decline: a retrospective cohort study

The risk factors for intradialytic systolic blood pressure decline remain poorly understood. We aimed to identify clinical and laboratory predictors of the intradialytic systolic blood pressure decline, considering its seasonal variation. In a retrospective cohort of 47,219 hemodialysis sessions of 307 patients undergoing hemodialysis over one year in three dialysis clinics, the seasonal variation and the predictors of intradialytic systolic blood pressure decline (predialysis systolic blood pressure--nadir intradialytic systolic blood pressure) were assessed using cosinor analysis and linear mixed models adjusted for baseline or monthly hemodialysis-related variables, respectively. The intradialytic systolic blood pressure decline was greatest and least in the winter and summer, respectively, showing a clear seasonal pattern. In both models adjusted for baseline and monthly hemodialysis-related parameters, calcium channel blocker use was associated with a smaller decline (-4.58 [95% confidence interval (CI), -5.84 to -3.33], P < 0.001; -3.66 [95% CI, -5.69 to -1.64], P < 0.001) and α blocker use, with a greater decline (3.25 [95% CI, 1.53-4.97], P < 0.001; 3.57 [95% CI, 1.08-6.06], P = 0.005). Baseline and monthly serum phosphorus levels were positively correlated with the decline (1.55 [95% CI, 0.30-2.80], P = 0.02; 0.59 [95% CI, 0.16-1.00], P = 0.007), and baseline and monthly normalized protein catabolic rates were inversely correlated (respectively, -22.41 [95% CI, -33.53 to -11.28], P < 0.001; 9.65 [95% CI, 4.60-14.70], P < 0.001). In conclusion, calcium channel blocker use, α blocker avoidance, and serum phosphorus-lowering therapy may attenuate the intradialytic systolic blood pressure decline and should be investigated in prospective trials.

Serum sodium variation is a major determinant of peridialytic blood pressure trends in haemodialysis outpatients

Intradialytic hypotension (IDH) and peridialytic blood pressure (BP) trends are associated with morbidity and mortality in haemodialysis (HD) patients. We aimed to characterise the respective influence of volume status and small solutes variation on peridialytic systolic BP (SBP) trends during HD. We retrospectively analysed the relative peridialytic SBP decrease in 647 prevalent outpatients attending for their mid-week session with corresponding pre- and post-HD bioelectrical impedance analysis. Mean SBP decreased by 10.5 ± 23.6 mmHg. Factors positively associated with the relative decrease in SBP were: serum sodium (Na) decrease, body mass index, serum albumin, dialysis vintage, ultrafiltration rate and urea Kt/V (p < 0.05 for all). Antihypertensive medications and higher dialysate calcium were negatively associated with the relative decrease in SBP (p < 0.05 for both). Age had a quadratic relationship with SBP trends (p < 0.05). Pre-HD volume status measured by extracellular to total body water ratio was not associated with SBP variation (p = 0.216). Peridialytic SBP trends represent a continuum with serum Na variation being a major determinant while volume status has negligible influence. Middle-aged and overweight patients are particularly prone to SBP decline. Tailoring Na and calcium dialysate concentrations could influence haemodynamic stability during HD and improve patient experience and outcomes.

Mechanisms for hemodynamic instability related to renal replacement therapy: a narrative review

Hemodynamic instability related to renal replacement therapy (HIRRT) is a frequent complication of all renal replacement therapy (RRT) modalities commonly used in the intensive care unit. HIRRT is associated with increased mortality and may impair kidney recovery. Our current understanding of the physiologic basis for HIRRT comes primarily from studies of end-stage kidney disease patients on maintenance hemodialysis in whom HIRRT is referred to as ‘intradialytic hypotension’. Nonetheless, there are many studies that provide additional insights into the underlying mechanisms for HIRRT specifically in critically ill patients. In particular, recent evidence challenges the notion that HIRRT is almost entirely related to excessive ultrafiltration. Although excessive ultrafiltration is a key mechanism, multiple other RRT-related mechanisms may precipitate HIRRT and this could have implications for how HIRRT should be managed (e.g., the appropriate response might not always be to reduce ultrafiltration, particularly in the context of significant fluid overload). This review briefly summarizes the incidence and adverse effects of HIRRT and reviews what is currently known regarding the mechanisms underpinning it. This includes consideration of the evidence that exists for various RRT-related interventions to prevent or limit HIRRT. An enhanced understanding of the mechanisms that underlie HIRRT, beyond just excessive ultrafiltration, may lead to more effective RRT-related interventions to mitigate its occurrence and consequences.

Dialysate temperature reduction for intradialytic hypotension for people with chronic kidney disease requiring haemodialysis

BACKGROUND

Intradialytic hypotension (IDH) is a common complication of haemodialysis (HD), and a risk factor of cardiovascular morbidity and death. Several clinical studies suggested that reduction of dialysate temperature, such as fixed reduction of dialysate temperature or isothermal dialysate using a biofeedback system, might improve the IDH rate.

OBJECTIVES

This review aimed to evaluate the benefits and harms of dialysate temperature reduction for IDH among patients with chronic kidney disease requiring HD, compared with standard dialysate temperature.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register up to 14 May 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs), cross-over RCTs, cluster RCTs and quasi-RCTs were included in the review.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted information including participants, interventions, outcomes, methods of the study, and risks of bias. We used a random-effects model to perform quantitative synthesis of the evidence. We assessed the risks of bias for each study using the Cochrane 'Risk of bias' tool. We assessed the certainty of evidence using Grades of Recommendation, Assessment, Development and Evaluation (GRADE).

MAIN RESULTS

We included 25 studies (712 participants). Three studies were parallel RCTs and the others were cross-over RCTs. Nineteen studies compared fixed reduction of dialysate temperature (below 36°C) and standard dialysate temperature (37°C to 37.5°C). Most studies were of unclear or high risk of bias. Compared with standard dialysate, it is uncertain whether fixed reduction of dialysate temperature improves IDH rate (8 studies, 153 participants: rate ratio 0.52, 95% CI 0.34 to 0.80; very low certainty evidence); however, it might increase the discomfort rate compared with standard dialysate (4 studies, 161 participants: rate ratio 8.31, 95% CI 1.86 to 37.12; very low certainty evidence). There were no reported dropouts due to adverse events. No study reported death, acute coronary syndrome or stroke.Three studies compared isothermal dialysate and thermoneutral dialysate. Isothermal dialysate might improve the IDH rate compared with thermoneutral dialysate (2 studies, 133 participants: rate ratio 0.68, 95% CI 0.60 to 0.76; I² = 0%; very low certainty evidence). There were no reports of discomfort rate (1 study) or dropouts due to adverse events (2 studies). No study reported death, acute coronary syndrome or stroke.

AUTHORS' CONCLUSIONS

Reduction of dialysate temperature may prevent IDH, but the conclusion is uncertain. Larger studies that measure important outcomes for HD patients are required to assess the effect of reduction of dialysate temperature. Six ongoing studies may provide much-needed high quality evidence in the future.

The Prevalence of Intradialytic Hypotension in Patients on Conventional Hemodialysis: A Systematic Review with Meta-Analysis

BACKGROUND

Intradialytic hypotension (IDH) is considered to be a frequent complication of hemodialysis (HD) and is associated with symptom burden, increased incidence of access failure, cardiovascular events, and higher mortality. This systematic literature review aims to analyse studies that investigated the prevalence of IDH. A complicating factor herein is that many different definitions of IDH are used in literature.

METHODS

A systematic literature search from databases, Medline, Cinahl, EMBASE, and the Cochrane library to identify studies reporting on the actual prevalence of IDH was conducted. Studies were categorized by the type of definition used for the prevalence of IDH. A meta-analysis of the prevalence of IDH was performed.

RESULTS

In a meta-analysis comprising 4 studies including 1,694 patients and 4 studies including 13,189 patients, the prevalence of HD sessions complicated by IDH was 10.1 and 11.6% for the European Best Practice Guideline (EBPG) definition and the Nadir <90 definition, respectively. The proportion of patients with frequent IDH could not reliably be established because of the wide range in cutoff values that were used to identify patients with frequent IDH. There was a large variety in the prevalence of symptoms and interventions. Major risk factors associated with IDH across studies were diabetes, a higher interdialytic weight gain, female gender, and lower body weight.

CONCLUSION

Our meta-analysis suggests that the prevalence of IDH is lower than 12% for both the EBPG and the Nadir <90 definition which is much lower than stated in most reviews.

The creation and maintenance of vascular access for chronic hemodialysis in the Moscow region: a five-year experience of a regional center

Aim:to analyze the results of the regional center for the creation and maintenance of vascular access for hemodialysis.

Materials and methods.We performed a retrospective analysis. In five years (2012–2016) we performed 3,837 different operations on vascular access (VA) in 1,862 patients.

Results.There is a strong dependence of type VA and the cause of CKD 5D. At the time of the HD start, the proportion of arteriovenous fistula (AVF), synthetic vascular graft (SVG) and central venous catheter (CVC) was 73.7, 0.3 and 26% for glomerulonephritis; 58.4, 0.4 and 41% for pyelonephritis; 53, 1 and 26% for diabetes mellitus; 32, 8 and 60% for polycystic disease and 33, 2 and 65% for systemic processes, respectively. After one year on HD the shares of AVF, SVG and CVC were 89, 2 and 9% for glomerulonephritis; 76, 6 and 18% of pyelonephritis; 70, 5 and 25% for diabetes mellitus; 68, 10 and 22% for polycystic disease and 53, 5 and 42% for systemic processes, respectively. In a case of start of HD via AVF, five years survival was 61% [95% CI 51.8; 71.9]; in a case of start HD via CVC with followed by conversion to AVF – 53.9% [95% CI 42.5; 67]; in a case of CVC remained the only access – 31.6% [21.4; 41.4]. Non-maturation of AVF was observed in 5.9% of new AVF (the risk increased in a case of diabetes mellitus), early thrombosis (before the first use of AVF) was observed in 12.7% of new AVF (the risk increased with diabetes, polycystic and systemic diseases). Creation of AVF a week before the start of HD or 1–2 weeks later significantly increased the risk of thrombosis. Primary patency in a year, three and five years was 77.2% (95% CI 71.7; 81.7); 48% (95% CI 41.6, 54.1); 34.1% (95% CI 27.8, 40.5) respectively; secondary patency – 87% [95% CI 83.7; 89.7]; 74.4% [95% CI 70.3; 78,12]; 60.9% [95% CI 56.4; 65.1] respectively. The use of temporary CVC is associated with a three-fold increase of the risk of infection compared with permanent CVC: IRR 3,31 (2,46; 4,43), p < 0,0001.

Conclusion.A more detailed analysis is required to identify risk factors for complications of vascular access and to optimize approaches to its creation and maintenance.

Association of Dose and Frequency on the Survival of Patients on Maintenance of Hemodialysis in China: A Kaplan-Meier and Cox-Proportional Hazard Model Analysis

Background

Dialysis frequency and dose are controversial prognostic factors of hemodialysis morbidity and mortality. The aim of this study was to find out the effect of frequency and dosage of dialysis on mortality and survival in a group of Chinese hemodialysis patients.

Material/Methods

In total, 183 patients seen from February 2008 to January 2018, who were on maintenance hemodialysis for at least 3 months, were included in the study cohort. An anonymized database of age, gender, diabetic status, comorbidities, date of initiation of dialysis, hematological characters, biochemical variables, and status of survived or died was established from DICOM (Digital Imaging and Communications in Medicine) files of patients. Kaplan-Meier and Cox-proportional hazard model was used for calculation of survival over time at 95% confidence level.

Results

Overall, the 10-year survival rate was 27%. Kaplan-Meier analysis showed patient survival as 94% at one-year, 59% at 5-years, and 27% at 10-years. Hemoglobin, serum albumin, calcium, potassium, phosphorous, calcium-phosphorous-products, and hemodialysis frequency and the dose had a significant effect on survival. Cox regression proportional hazard model showed that patients with serum albumin level of >4 g/dL were better associated with survival. Patients who underwent twice-weekly hemodialysis had 4.26 times less chance of survival as compared to patients with thrice-weekly hemodialysis. A higher dialysis dose of >1.2 spKt/V offered better survival as compared to a lower dose of <1.2 spKt/V.

Conclusions

Hypoalbuminemia, hemodialysis time, and hemodialysis frequency were significantly associated with mortality.

Pathophysiology and implications of intradialytic hypertension

PURPOSE OF REVIEW

Intradialytic hypertension occurs regularly in 10--15% of hemodialysis patients. A large observational study recently showed that intradialytic hypertension of any magnitude increased mortality risk comparable to the most severe degrees of intradialytic hypotension. The present review review discusses the most recent evidence underlying the pathophysiology of intradialytic hypertension and implications for its management.

RECENT FINDINGS

Patients with intradialytic hypertension typically have small interdialytic weight gains, but bioimpedance spectroscopy shows these patients have significant chronic extracellular volume excess. Intradialytic hypertension patients have lower albumin and predialysis urea nitrogen levels, which may contribute to small reductions in osmolarity that prevents blood pressure decreases. Intradialytic vascular resistance surges remain implicated as the driving force for blood pressure increases, but mediators other than endothelin-1 may be responsible. Beyond dry weight reduction, the only controlled intervention shown to interrupt the blood pressure increase is lowering dialysate sodium.

SUMMARY

Patients with recurrent intradialytic hypertension should be identified as high-risk patients. Dry weight should be re-evaluated, even if patients do not clinically appear volume overloaded. Antihypertensive drugs should be prescribed because of the persistently elevated ambulatory blood pressure. Dialysate sodium reduction should be considered, although the long term effects of this intervention are uncertain.

Levocarnitine Decreases Intradialytic Hypotension Episodes: A Randomized Controlled Trial

Intradialytic hypotension is common complication in stage 5 chronic kidney disease patients on hemodialysis. Incidence ranges from 15 to 30%. These patients have levocarnitine deficiency. A randomized, placebo-controlled quadruple-blinded trial was designed to demonstrate the levocarnitine efficiency on intradialytic hypotension prevention. Patients were randomized into four groups, to receive levocarnitine or placebo. During the intervention period, levocarnitine and placebo was administered 0 and 30 min before each hemodialysis session, respectively. During the trial, 33 patients received 1188 hemodialysis sessions. We identified 239 (21.3%) intradialytic hypotension episodes. The intradialytic hypotension episodes were less frequent in the levocarnitine group (9.3%, 60 IH events) (P < 0.001). Hemodialysis is frequently perplexed by intradialytic hypotension episodes. Levocarnitine supplementation before each hemodialysis session efficiently diminishes the intradialytic hypotension episodes. This is a new application method that must be considered and explored.

The impact of dialysis modality and membrane characteristics on intradialytic hypotension

The risk of intradialytic hypotension (IDH) is determined by various factors, among them dialysis modality and dialyzer membrane. We conducted a literature search in PubMed on November 1, 2016 and selected relevant randomized controlled and cross-over trials, and prospective and retrospective cohort studies published in English that investigated the association between IDH and dialysis modality and membrane, respectively. This literature search revealed 669 publications on dialysis modality, 64 on dialysis membrane, and 24 on acetate/bicarbonate dialysate. After omission of duplicate papers and publications outside the scope of this review, we selected 34 papers for inclusion, 19 on dialysis modality, 8 on dialyzer membrane, and 7 on acetate/bicarbonate dialysate. Several strands of evidence indicate that hemodiafiltration (HDF) is associated with lower IDH rates compared to hemodialysis (HD). Data do not show an unequivocal benefit of synthetic vs nonsynthetic dialyzer membranes with respect to IDH occurrence. Acetate-based vs bicarbonate-based dialysate appears to be associated with an increased IDH rate.

Osmolality and blood pressure stability during hemodialysis

Homeostatic regulation of plasma osmolality (POsm) is critical for normal cellular function in humans. Arginine vasopressin (AVP) is the major hormone responsible for the maintenance of POsm and acts to promote renal water retention in conditions of increased POsm. However, AVP also exerts pressor effects, and its release can be stimulated by the development of effective arterial blood volume depletion. Patients with end-stage renal disease on hemodialysis, particularly those with minimal or no residual renal function, have impaired ability to regulate water retention in response to AVP. While hemodialysis can assist with this task, patients are subject to relatively rapid shifts in volume and electrolytes during the procedure. This can result in the development of transient osmotic gradients that lead to the movement of water from the extracellular to the intracellular space. Hypotension may result-both as a consequence of water movement out of the intravascular compartment, but also from impaired AVP release and inadequate vascular tone. In this review, we explore the evidence for POsm changes during hemodialysis, associations with adverse outcomes, and methods to minimize the rapidity of changes in POsm in an effort to reduce patient symptoms and minimize intra-dialytic hypotension.

Comparison of Urine Output among Patients Treated with More Intensive Versus Less Intensive RRT: Results from the Acute Renal Failure Trial Network Study

BACKGROUND AND OBJECTIVES

Intensive RRT may have adverse effects that account for the absence of benefit observed in randomized trials of more intensive versus less intensive RRT. We wished to determine the association of more intensive RRT with changes in urine output as a marker of worsening residual renal function in critically ill patients with severe AKI.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Acute Renal Failure Trial Network Study (n=1124) was a multicenter trial that randomized critically ill patients requiring initiation of RRT to more intensive (hemodialysis or sustained low-efficiency dialysis six times per week or continuous venovenous hemodiafiltration at 35 ml/kg per hour) versus less intensive (hemodialysis or sustained low-efficiency dialysis three times per week or continuous venovenous hemodiafiltration at 20 ml/kg per hour) RRT. Mixed linear regression models were fit to estimate the association of RRT intensity with change in daily urine output in survivors through day 7 (n=871); Cox regression models were fit to determine the association of RRT intensity with time to ≥50% decline in urine output in all patients through day 28.

RESULTS

Mean age of participants was 60±15 years old, 72% were men, and 30% were diabetic. In unadjusted models, among patients who survived ≥7 days, mean urine output was, on average, 31.7 ml/d higher (95% confidence interval, 8.2 to 55.2 ml/d) for the less intensive group compared with the more intensive group (P=0.01). More intensive RRT was associated with 29% greater unadjusted risk of decline in urine output of ≥50% (hazard ratio, 1.29; 95% confidence interval, 1.10 to 1.51).

CONCLUSIONS

More intensive versus less intensive RRT is associated with a greater reduction in urine output during the first 7 days of therapy and a greater risk of developing a decline in urine output of ≥50% in critically ill patients with severe AKI.

French patients on daily hemodialysis: clinical characteristics and treatment trajectories

BACKGROUND

Increasing the weekly frequency of hemodialysis sessions has positive effects, on the control of several biological data of patients. However, knowledge about Daily HemoDialysis (DHD) practices is limited in France. The aim of the present study was to describe the characteristics and treatment trajectories of all French patients undergoing DHD.

METHODS

All patients older than 18 years who started DHD between 2003 and 2012 in France were included and followed until December 31, 2013. The patients' demographic and clinical characteristics and treatment modalities were extracted from the French Renal Epidemiological and Information Network (REIN) registry.

RESULTS

During the inclusion period, 753 patients started DHD in France. Based on their median age (64 years), patients were classified in two groups: "old" group (≥64 years) and "young" group (<64 years). Patients in the old group had more comorbidities than in the young group: 48 % had diabetes (vs 29 % in the young group), 17 % an active malignancy (vs 10 %) and 80 % ≥1 cardiovascular disease (vs 41 %). Concerning patients' treatment trajectories, 496 (66 %) patients started with another dialysis before switching to DHD and 257 (34 %) directly with DHD. At the end of the follow-up, 69 % of patients in the old group were dead (27.4 % in the young group) and kidney transplantation was more frequent in the young group (30.4 % vs 0.5 %).

CONCLUSION

In France, DHD is proposed not only to young in rather good clinical conditions and waiting for kidney transplantation, but also to old and frail patients with higher mortality.

Antidepressants for treating depression in adults with end-stage kidney disease treated with dialysis

BACKGROUND

Depression affects approximately one-quarter of people treated with dialysis and is considered an important research uncertainty by patients and health professionals. Treatment for depression in dialysis patients may have different benefits and harms compared to the general population due to different clearances of antidepressant medication and the severity of somatic symptoms associated with end-stage kidney disease (ESKD). Guidelines suggest treatment of depression in dialysis patients with pharmacological therapy, preferably a selective serotonin reuptake inhibitor. This is an update of a review first published in 2005.

OBJECTIVES

To evaluate the benefit and harms of antidepressants for treating depression in adults with ESKD treated with dialysis.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register to 20 January 2016 through contact with the Information Specialist using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing antidepressant treatment with placebo or no treatment, or compared to another antidepressant medication or psychological intervention in adults with ESKD (estimated glomerular filtration rate < 15 mL/min/1.73 m(2)).

DATA COLLECTION AND ANALYSIS

Data were abstracted by two authors independently onto a standard form and subsequently entered into Review Manager. Risk ratios (RR) for dichotomous data and mean differences (MD) for continuous data were calculated with 95% confidence intervals (95% CI).

MAIN RESULTS

Four studies in 170 participants compared antidepressant therapy (fluoxetine, sertraline, citalopram or escitalopram) versus placebo or psychological training for 8 to 12 weeks. In generally very low or ungradeable evidence, compared to placebo, antidepressant therapy had no evidence of benefit on quality of life, had uncertain effects on increasing the risk of hypotension (3 studies, 144 participants: RR 1.72, 95% CI 0.75 to 3.92), headache (2 studies 56 participants: RR 2.91, 95% CI 0.73 to 11.57), and sexual dysfunction (2 studies, 101 participants: RR 3.83, 95% CI 0.63 to 23.34), and increased nausea (3 studies, 114 participants: RR 2.67, 95% CI 1.26 to 5.68). There were few or no data for hospitalisation, suicide or all-cause mortality resulting in inconclusive evidence. Antidepressant therapy may reduce depression scores during treatment compared to placebo (1 study, 43 participants: MD -7.50, 95% CI -11.94 to -3.06). Antidepressant therapy was not statistically different from group psychological therapy for effects on depression scores or withdrawal from treatment and a range of other outcomes were not measured.

AUTHORS' CONCLUSIONS

Despite the high prevalence of depression in dialysis patients and the relative priority that patients place on effective treatments, evidence for antidepressant medication in the dialysis setting is sparse and data are generally inconclusive. The relative benefits and harms of antidepressant therapy in dialysis patients are poorly known and large randomised studies of antidepressants versus placebo are required.

Prevalence of intradialytic hypotension, clinical symptoms and nursing interventions--a three-months, prospective study of 3818 haemodialysis sessions

Background

Intradialytic hypotension (IDH) is considered one of the most frequent complications of haemodialysis with an estimated prevalence of 20–50 %, but studies investigating its exact prevalence are scarce. A complicating factor is that several definitions of IDH are used. The goal of this study was, to assess the prevalence of IDH, primarily in reference to the European Best Practice Guideline (EBPG) on haemodynamic instability: A decrease in systolic blood pressure (SBP) ≥20 mmHg or in mean arterial pressure (MAP) ≥10 mmHg associated with a clinical event and the need for nursing intervention.

Methods

During 3 months we prospectively collected haemodynamic data, clinical events, and nursing interventions of 3818 haemodialysis sessions from 124 prevalent patients who dialyzed with constant ultrafiltration rate and dialysate conductivity. Patients were considered as having frequent IDH if it occurred in >20 % of dialysis sessions.

Results

Decreases in SBP ≥20 mmHg or MAP ≥10 mmHg occurred in 77.7 %, clinical symptoms occurred in 21.4 %, and nursing interventions were performed in 8.5 % of dialysis sessions. Dialysis hypotension according to the full EBPG definition occurred in only 6.7 % of dialysis sessions. Eight percent of patients had frequent IDH.

Conclusions

The prevalence of IDH according to the EBPG definition is low. The dominant determinant of the EBPG definition was nursing intervention since this was the component with the lowest prevalence. IDH seems to be less common than indicated in the literature but a proper comparison with previous studies is complicated by the lack of a uniform definition.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0231-9) contains supplementary material, which is available to authorized users.

Impact of extracorporeal blood flow rate on blood pressure, pulse rate and cardiac output during haemodialysis

BACKGROUND

If blood pressure (BP) falls during haemodialysis (HD) [intradialytic hypotension (IDH)] a common clinical practice is to reduce the extracorporeal blood flow rate (EBFR). Consequently the efficacy of the HD (Kt/V) is reduced. However, only very limited knowledge on the effect of reducing EBFR on BP exists and data are conflicting. The aim of this study was to evaluate the effect and the potential mechanism(s) involved by investigating the impact of changes in EBFR on BP, pulse rate (PR) and cardiac output (CO) in HD patients with arteriovenous-fistulas (AV-fistulas).

METHODS

We performed a randomized, crossover trial in 22 haemodynamically stable HD patients with AV-fistula. After a conventional HD session each patient was examined during EBFR of 200, 300 and 400 mL/min in random order. After 15 min when steady state was achieved CO, BP and PR were measured at each EFBR, respectively.

RESULTS

Mean (SD) age was 71 (11) years. Systolic BP was significantly higher at an EBFR of 200 mL/min as compared with 300 mL/min [133 (23) versus 128 (24) mmHg; P < 0.05], but not as compared with 400 mL/min [133 (23) versus 130 (19) mmHg; P = 0.20]. At EBFR of 200, 300 and 400 mL/min diastolic BP, mean arterial pressure, PR and CO remained unchanged.

CONCLUSION

Our study does not show any consistent trend in BP changes by a reduction in EBFR. Reduction in EBFR if BP falls during IDH is thus not supported. However, none of the patients experienced IDH. Further studies are required to evaluate the impact of changes in EBFR on BP during IDH.

Association of Predialysis Calculated Plasma Osmolarity With Intradialytic Blood Pressure Decline

BACKGROUND

The rapid reduction in plasma osmolality during hemodialysis (HD) may induce temporary gradients that promote the movement of water from the extracellular to the intracellular compartment, predisposing to the development of intradialytic hypotension (IDH).

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

3,142 prevalent patients receiving thrice-weekly HD from a single dialysis provider organization.

PREDICTOR

Predialysis calculated plasma osmolarity (calculated after the 2-day interval as 2 × serum sodium + serum urea nitrogen/2.8 + serum glucose/18).

OUTCOME

Magnitude of systolic blood pressure (SBP) decline (predialysis SBP - nadir intradialytic SBP) and risk of IDH (SBP decline > 35 or nadir SBP < 90 mm Hg).

MEASUREMENTS

Unadjusted and multivariable-adjusted generalized linear models were fit to estimate the association of calculated osmolarity with intradialytic SBP decline and the odds of developing IDH.

RESULTS

Mean age of participants was 62.6±15.2 (SD) years, 57.1% were men, and 61.0% had diabetes. Mean predialysis calculated osmolarity during follow-up was 306.4 ± 9.5 mOsm/L. After case-mix adjustment, each 10-mOsm/L increase in predialysis calculated osmolarity was associated with 1.48 (95% CI, 0.86-2.09) mm Hg (P < 0.001) greater decline in intradialytic SBP and 10% greater odds of IDH (OR, 1.10; 95% CI, 1.05-1.15). In adjusted models, lower predialysis sodium and higher serum urea nitrogen and serum glucose levels were associated with greater decline in intradialytic SBP.

LIMITATIONS

Measured serum osmolality, timing of changes in intradialytic osmolality, dialysate osmolality, and dialysate temperature were not available.

CONCLUSIONS

Higher predialysis calculated osmolarity is associated with greater decline in intradialytic SBP and greater risk of IDH in maintenance HD patients. Strategies to minimize rapid shifts in osmolality should be tested prospectively to minimize excess SBP decline in susceptible patients.

Effect of dialysis dose and membrane flux on hemoglobin cycling in hemodialysis patients

Many studies found that hemoglobin (Hb) fluctuation was closely related to the prognosis of the maintenance hemodialysis patients. We investigated the association of factors relating dialysis dose and dialyzer membrane with Hb levels. We undertook a randomized clinical trial in 140 patients undergoing thrice-weekly dialysis and assigned patients randomly to a standard or high dose of dialysis; Hb level was measured every month for 12 months. In the standard-dose group, the mean (±SD) urea reduction ratio was 65.1% ± 7.3%, the single-pool Kt/V was 1.26 ± 0.11, and the equilibrated Kt/V was 1.05 ± 0.09; in the high-dose group, the values were 73.5% ± 8.7%, 1.68 ± 0.15, and 1.47 ± 0.11, respectively. The standard deviation (SD) and residual SD (liner regression of Hb) values of Hb were significantly higher in the standard-dose group and low-flux group. The percentage achievement of target Hb in the high-dose dialysis group and high-flux dialyzer group was significantly higher than the standard-dose group and low-flux group, respectively. Patients undergoing hemodialysis thrice weekly appear to have benefit from a higher dialysis dose than that recommended by current KDQQI (Kidney Disease Qutcome Quality Initiative) guidelines or from the use of a high-flux membrane, which is in favor of maintaining stable Hb levels.