Ultrafiltration Patterns during Automated Peritoneal Dialysis: Findings and Insights to Peritoneal Physiology.

BACKGROUND: With the growing use of automated peritoneal dialysis (APD), it is important to improve our knowledge of the clinical patterns and physiology of APD treatment sessions. The ultrafiltration (UF) achieved during each cycle of an APD treatment is assumed to be relatively linear if the delivered prescription is the same. We set out to determine if that is indeed the case. METHODS: Single-center, cross-sectional study of prevalent PD patients. All adult APD patients (> 18 years of age), who had been on PD for >3 months, and >3 months on APD were included. Continuous ambulatory PD patients or those with peritonitis within 3 months of the consent date were excluded. Individual treatment data from 7 consecutive APD treatment sessions with consistent dialysate composition for each cycler exchange were collected for each subject. RESULTS: Thirty-nine subjects met the inclusion criteria and were enrolled. The probability of yielding a positive UF was 48.9% for cycle 1, rising to 90.5% by cycle 6. Adjusting for average dextrose concentration, dwell time, fill volume, solute transfer rate, and number of cycles, we observed that cycles 2 through 6 achieved progressively higher UF volumes than cycle 1 (p < 0.001). The first and last cycles demonstrated significantly different cycle UF volumes compared to a middle cycle (-230 ml and 277 ml, respectively, p < 0.001). CONCLUSIONS: We observed a consistent increase in UF volumes achieved per cycle over the course of an APD treatment session with numerous clinical and physiologic implications. This provides the foundation for future studies investigating peritoneal inter-cycle variations and membrane physiology.

On-line hemodiafiltration therapy for end-stage kidney disease patients: Promises for the future? What's next?

On-line hemodiafiltration (OL-HDF) is currently the most advanced form of blood purification modality leading convective-based therapies in end-stage kidney disease patients. By adding a high convective component to the diffusive clearance achieved with highly permeable dialyzers, OL-HDF reinforces removal of small MWt compounds and enlarges the spectrum of uremic compounds cleared up to middle and large MWt compounds. The biological and clinical benefits of convective-based therapy are currently also being explored in a revisited hybrid modality, combining an increased internal filtration process with a more open membrane. Regular use of ultrapure dialysis fluid required by convective-based therapies improves the bio-incompatibility of the extracorporeal circuit so reducing inflammatory responses. On-line production of substitution fluid, relying on a cold sterilization by ultrafiltration, has several advantages: First, it is a safe and established process; and second, it provides an unlimited amount of substitution fluid at the same cost as regular ultrapure dialysis fluid. As such, OL-HDF is adaptable to all substitution modalities (post, pre, or mixed-HDF), thus allowing the dialytic convective dose to be adjusted to the individual patient needs. The development of OL-HDF opens new pathways such as task automation simplifying care workflow. All these features make OL-HDF the most versatile dialysis modality that can be now integrated in various treatment schedules according to session time and frequency (daily, nocturnal, or alternate day) or location (incenter, satellite, or potentially home-based therapy).

Hemodiafiltration outcomes in special situations.

This Seminars in Dialysis Hemodiafiltration Symposium includes many references regarding the outcomes of this modality in general. The results in special populations are included in some of the studies, but have not been compared in a systematic manner. The purpose of this review is to compile those outcome results in select populations.

Prescribing Home Hemodialysis.

Home hemodialysis (HHD), performed more frequently than in-center hemodialysis, is underutilized in the United States but has had a recent resurgence driven predominantly by innovative dialysis equipment that is easy to use, less intrusive to the home, and requires less storage space. There are 3 different hemodialysis machines approved for use in the home but currently NxStage™ accounts for the overwhelming majority of HHD patients. Therefore, it is the focus of this article. To minimize storage space in the home, the NxStage platform minimizes the volume of dialysate that is used per treatment. We refer to this method as the Frequent Low Dialysate Volume Approach (FLDVA). The approach to urea removal with the NxStage platform is much different compared to traditional in-center HD. To minimize the volume of dialysate per treatment, and still achieve target urea removal, the dialysate must be highly saturated. In this article, we explain how to increase the saturation of dialysate fluid. We also draw a parallel between urea removal in peritoneal dialysis and NxStage therapy and use that model to estimate an initial HHD prescription and to alter prescriptions when necessary.

Nomenclature in nephrology: preserving 'renal' and 'nephro' in the glossary of kidney health and disease.

A recently published nomenclature by a "Kidney Disease Improving Global Outcomes" (KDIGO) Consensus Conference suggested that the word "kidney" should be used in medical writings instead of "renal" or "nephro" when referring to kidney disease and kidney health. Whereas the decade-old move to use "kidney" more frequently should be supported when communicating with the public-at-large, such as the World Kidney Day, or in English speaking countries in communications with patients, care-partners, and non-medical persons, our point of view is that "renal" or "nephro" should not be removed from scientific and technical writings. Instead, the terms can coexist and be used in their relevant contexts. Cardiologists use "heart" and "cardio" as appropriate such as "heart failure" and "cardiac care units" and have not replaced "cardiovascular" with "heartvessel", for instance. Likewise, in nephrology, we consider that "chronic kidney disease" and "continuous renal replacement therapy" should coexist. We suggest that in scientific writings and technical communications, the words "renal" and "nephro" and their derivatives are more appropriate and should be freely used without any pressure by medical journals to compel patients, care-partners, healthcare providers, researchers and other stakeholders to change their selected words and terminologies. We call to embrace the terms "kidney", "renal" and "nephro" as they are used in different contexts and ask that scientific and medical journals not impose terminology restrictions for kidney disease and kidney health. The choice should be at the discretion of the authors, in the different contexts including in scientific journals.

Quantifying the risk of insertion-related peritoneal dialysis catheter complications following laparoscopic placement: Results from the North American PD Catheter Registry.

BACKGROUND: Peritoneal dialysis (PD) is a more cost-effective therapy to treat kidney failure than in-center hemodialysis, but successful therapy requires a functioning PD catheter that causes minimal complications. In 2015, the North American Chapter of the International Society for Peritoneal Dialysis established the North American PD Catheter Registry to improve practices and patient outcomes following PD catheter insertion. AIMS: The objective of this study is to propose a methodology for defining insertion-related complications that lead to significant adverse events and report the risk of these complications among patients undergoing laparoscopic PD catheter insertion. METHODS: Patients undergoing laparoscopic PD catheter insertion were enrolled at 14 participating centers in Canada and the United States and followed using a Web-based registry. Insertion-related complications were defined as flow restriction, exit-site leak, or abdominal pain at any point during follow-up. We also included infections or bleeding within 30 days of insertion, and any immediate postoperative complications. Adverse events were categorized as PD never starting or termination of PD therapy, delay in the start of PD therapy or interruption of PD therapy, an emergency department visit or hospitalization, or need for invasive procedures. Cause-specific cumulative incidence functions were used to estimate risk. RESULTS: Five hundred patients underwent laparoscopic PD catheter insertion between 10 November 2015 and 24 July 2018. The cumulative risk of insertion-related complications 6 months from the date of insertion that led to an adverse event was 24%. The risk of flow restriction, exit-site leak, and pain at 6 months was 10.2%, 5.7%, and 5.3%, respectively. PD was never started or terminated in 6.4% of patients due to an insertion-related complication. Leaks and flow restrictions were most likely to delay or interrupt PD therapy. Flow restrictions were the primary cause of invasive procedures. Fifty percent of the complications occurred before the start of PD therapy. CONCLUSIONS: Insertion-related complications leading to significant adverse events following laparoscopic placement of PD catheters are common. Many complications occur before the start of PD. Insertion-related complications are an important area of focus for future research and quality improvement efforts.

Strategies to Prevent Peritonitis after Procedures: Our Opinions.

Peritoneal Dialysis (PD) patients are at increased risk of peritonitis following elective colonoscopy and other potentially invasive dental or gynecological procedures. The increased risk of iatrogenic peritonitis is attributed to procedure-related factors such as instrumentation, biopsies, tissue injury, and peri-procedural bacterial contamination. Also contributory are patient-related factors such as the effect of the immunocompromised status of end-stage renal disease and the presence of intraperitoneal dialysate on the disruption of natural host defense mechanisms. We propose the use of standard peri-procedure protocols, including procedure-specific prophylactic antibiotics, and discuss the enhanced defense rationale for a dry abdomen during and sometimes after procedures. Depending on the procedure and its inherent risk of causing peritonitis, as well as the patient's ability to withhold PD for up to 3 days, we sometimes increase the intensity of PD before the procedure. We conclude that it is imperative that proceduralists and nephrologists be aware of and proactive about how to mitigate postprocedure PD complications.

Exploring Barriers and Potential Solutions in Home Dialysis: An NKF-KDOQI Conference Outcomes Report.

Home dialysis therapy, including home hemodialysis and peritoneal dialysis, is underused as a modality for the treatment of chronic kidney failure. The National Kidney Foundation-Kidney Disease Outcomes Quality Initiative sponsored a home dialysis conference in late 2017 that was designed to identify the barriers to starting and maintaining patients on home dialysis therapy. Clinical, operational, policy, and societal barriers were identified that need to be overcome to ensure that dialysis patients have the freedom to choose their treatment modality. Education of patients and patient partners, as well as health care providers, about home dialysis therapy, if offered at all, is often provided in a cursory manner. Lack of exposure to home dialysis therapies perpetuates a lack of familiarity and thus a hesitancy to refer patients to home dialysis therapies. Patient and care partner support, both psychosocial and financial, is also critical to minimize the risk for burnout leading to dropout from a home dialysis modality. Thus, the facilitation of home dialysis therapy will require a systematic change in chronic kidney disease education and the approach to dialysis therapy initiation, the creation of additional incentives for performing home dialysis, and breakthroughs to simplify the performance of home dialysis modalities. The home dialysis work group plans to develop strategies to overcome these barriers to home dialysis therapy, which will be presented at a follow-up home dialysis conference.

Incremental dialysis: review of recent literature.

PURPOSE OF REVIEW: There are clinical, physiological, financial, and practical reasons to perform incremental hemodialysis in selected patients, incident to end-stage renal disease. Recent papers inform us further, especially in the large database studies. RECENT FINDINGS: Small studies suggested, then a larger study corroborated, that incremental hemodialysis was associated with preservation of residual kidney function whenever compared with conventional hemodialysis. The well tolerated nutritional status of incremental hemodialysis was questioned in a small study but a larger study was more reassuring. The mortality rate of patients undergoing incremental hemodialysis is similar to that in conventional hemodialysis, but only if the comorbidity burden is low. SUMMARY: Incremental hemodialysis in incident patients can be performed safely, and probably is associated with preserved residual kidney function and a similar mortality rate to convention initiation of hemodialysis. Patients must be prudently selected and managed for this approach to the initiation of dialysis.

Reproducibility of serial creatinine excretion measurements in peritoneal dialysis.

AIM: To test whether muscle mass evaluated by creatinine excretion (EXCr) is maintained in patients with end-stage kidney disease (ESKD) treated by peritoneal dialysis (PD), we evaluated repeated measurements of EXCr in a PD population. METHODS: One hundred and sixty-six PD patients (94 male, 72 female) receiving the same PD dose for the duration of the study (up to approximately 2.5 years) had repeated determinations of total (in urine plus spent dialysate) 24-h EXCr (EXCr T) to assess the adequacy of PD by creatinine clearance. All 166 patients had two EXCr T determinations, 84 of the 166 patients had three EXCr T determinations and 44 of the 166 patients had four EXCr T measurements. EXCr T values were compared using the paired t test in the patients who had two studies and by repeated measures ANOVA in those who were studied three or four times. RESULTS: In patients who were studied twice, with the first and second EXCr T measurements performed at 9.2 ± 15.2 mo and 17.4 ± 15.8 mo after onset of PD, respectively, EXCr T did not differ between the first and second study. In patients studied three times and whose final assessment occurred 24.7 ± 16.3 mo after initiating PD, EXCr T did not differ between the first and second study, but was significantly lower in the third study compared to the first study. In patients who were studied four times and whose fourth measurement was taken 31.9 ± 16.8 mo after onset of PD, EXCr T did not differ between any of the studies. The average EXCr T value did not change significantly, with the exception of the third study in the patients studied thrice. However, repeated determinations of EXCr T in individuals showed substantial variability, with approximately 50% of the repeated determinations being higher or lower than the first determination by 15% or more. CONCLUSION: The average value of EXCr T remains relatively constant for up to 2.5 years of follow-up in PD patients who adhere to the same PD schedule. However, repeated individual EXCr T values vary considerably in a large proportion of the patients. Further studies are needed to evaluate the clinical significance of varying EXCr T values and the stability of EXCr T beyond 2.5 years of PD follow-up.

Incremental Hemodialysis: How I Do It.

Incremental hemodialysis (incrHD) is not widely used nor is it well understood. In addition, and perhaps with more impact, governmental regulations in the United States and their consequential influences on dialysis provider organizations have made the practice of incrHD more difficult than traditional thrice weekly in-center HD. IncrHD is critically dependent on the amount of residual kidney function (RKF) as well as the individualized goals of end-stage renal disease (ESRD) management. RKF has to be assessed frequently and dialysis adjusted accordingly. Home HD lends itself to an incremental approach more so than in-center HD. This may be due to more experience of the provider, more knowledge of the therapy by the patient and family, the availability of dialysis platforms conducive to incrHD, and/or that its less onerous regulation by the government. I have had a long and successful experience performing incremental dialysis (both peritoneal and hemodialysis) and share here my practice strategies and approaches for incrHD.

Catheter Insertion and Perioperative Practices Within the ISPD North American Research Consortium.

UNLABELLED: ♦ BACKGROUND: In general, efforts to standardize care based on group consensus practice guidelines have resulted in lower morbidity and mortality. Although there are published guidelines regarding insertion and perioperative management of peritoneal dialysis (PD) catheters, variation in practice patterns between centers may exist. The objective of this study is to understand variation in PD catheter insertion practices in preparation for conducting future studies. ♦ METHODS: An electronic survey was developed by the research committee of the International Society for Peritoneal Dialysis - North American Research Consortium (ISPD-NARC) to be completed by physicians and nurses involved in PD programs across North America. It consisted of 45 questions related to 1) organizational characteristics; 2) PD catheter insertion practices; 3) current quality-improvement initiatives; and 4) interest in participation in PD studies. Invitation to participate in the survey was given to nephrologists and nurses in centers across Canada and the United States (US) identified by participation in the inaugural meeting of the ISPD-NARC. Descriptive statistics were applied to analyze the data. ♦ RESULTS: Fifty-one ISPD-NARC sites were identified (45% in Canada and 55% in the US) of which 42 responded (82%). Center size varied significantly, with prevalent PD population ranging from 6 - 300 (median: 60) and incident PD patients in the year prior to survey administration ranging from 3 - 180 (median: 20). The majority of centers placed fewer than 19 PD catheters/year, with a range of 0 - 50. Availability of insertion techniques varied significantly, with 83% of centers employing more than 1 insertion technique. Seventy-one percent performed laparoscopic insertion with advanced techniques (omentectomy, omentopexy, and lysis of adhesions), 62% of sites performed open surgical dissection, 10% performed blind insertion via trocar, and 29% performed blind placement with the Seldinger technique. Use of double-cuff catheters was nearly universal, with a near even distribution of catheters with pre-formed bend versus straight inter-cuff segments. There was also variation in the choice of perioperative antibiotics and perioperative flushing practices. Although 86% of centers had quality-improvement initiatives, there was little consensus as to appropriate targets. ♦ CONCLUSIONS: There is marked variability in PD catheter insertion techniques and perioperative management. Large multicenter studies are needed to determine associations between these practices and catheter and patient outcomes. This research could inform future trials and guidelines and improve practice. The ISPD-NARC is a network of PD units that has been formed to conduct multicenter studies in PD.

Is hemodiafiltration ready for broader use?

Hemodiafiltration is practiced throughout Europe and in a few additional countries but, because of regulatory restrictions, is not currently available in the United States. Hemodiafiltration removes uremic species more broadly than is achieved by diffusion dialysis, perhaps explaining its better outcome profile.

Arteriovenous fistula creation may slow estimated glomerular filtration rate trajectory.

BACKGROUND: We practice the timely placement of an arteriovenous fistula (AVF) in patients facing chronic hemodialysis. We have anecdotally observed after AVF creation that there appears to be a slowing of the decline in kidney function as measured by the estimated glomerular filtration rate (eGFR). There are physiologically plausible explanations as to how an AVF might alter kidney function, but this clinical observation has been attributed to improved compliance and/or other practices. The present retrospective observational analysis was performed to assess the possibility that a successfully created AVF could be associated with the slowing of the eGFR trajectory. METHODS: We identified 123 patients between 2005 and 2010 with at least two eGFR determinations for 2 years before and up to 2 years after AVF creation. Inclusion eligibility was that the fistula was maturing by the nephrologists' initial post-creation examination. Termination events were death, starting dialysis or transplantation. Each subject served as their own control for the pre- and post-AVF-creation eGFR measurements. RESULTS: Subjects' median age was 68 years and 56% were diabetic. The rate of change of the eGFR for the 2 years prior to AVF creation was -5.9 mL/min/year (95% CI: -5.3, -6.5) and after AVF creation -0.5 mL/min/year (95% CI: -1.1, 0.1) (interaction (P < 0.001). CONCLUSIONS: A functioning AVF may be associated with a slowing of the eGFR decline. Agreeing to timely AVF creation selects patients in an otherwise typical population and other confounders have not yet been eliminated. To do so a thorough prospective observational study is indicated.