Seminars in Dialysis最新文献

Background: We compared predictions of phosphate removal by a 2-pool kinetic model with measured phosphate removal in spent dialysate as reported by others.

Methods: Twenty-six studies were identified that reported phosphate removal in 35 groups of patients. In almost all studies, patients were dialyzed for close to 4 h (range 3 to 6 h). For each study, group mean values of predialysis serum phosphate, body size, dialyzer K₀ A urea, blood and dialysate flow rates, and session lengths were input into the kinetic model. Predictions of group mean phosphate removal and postdialysis serum phosphate were compared with reported measured values.

Results: Mean (by patient group) predicted phosphate removal was 931 ± 170 mg/treatment, somewhat higher (p < 0.001) than the reported measured value, 900 mg ± 287. The ratio of predicted/measured removal averaged 1.15 ± 0.427. In 5/35 patient groups (3/26 studies) the predicted/measured phosphate removal was greater than 1.50. If these groups were excluded, the mean measured phosphate removal was 990 mg versus 966 predicted, with a ratio of predicted/measured removal averaging 0.993. Measured group mean postdialysis serum phosphate values (reported in 25/35) were 2.64 ± 0.54, not significantly different from predicted (2.60 ± 0.24 mg/dl, p = NS).

Conclusions: For conventional 4-h dialysis treatments, phosphate removal and postdialysis serum phosphate values predicted by a 2-pool kinetic model are similar to reported measured values.

Peritonitis remains a significant complication of peritoneal dialysis (PD), and severe episodes of peritonitis lead to structural and functional alterations of the peritoneal membrane, which can result in a permanent transfer to hemodialysis. Although PD is designed primarily to be delivered in the community setting, patients on PD get hospitalized for a number of reasons. In this commentary, we highlight the enormous risks each hospitalization has on the occurrence of peritonitis in patients on PD and the need to understand factors that predispose patients to hospital-acquired peritonitis. Furthermore, we suggest directions on several strategies that could not only reduce the risks of developing peritonitis but also improve outcomes of patients on PD who get hospitalized for an unrelated illness.

Vascular access dysfunction is associated with reduced delivery of dialysis, unplanned admissions, patient symptoms, and loss of access, making assessment of vascular access a fundamental part of routine care in dialysis. Clinical trials to predict the risk of access thrombosis based on accepted reference methods of access performance have been disappointing. Reference methods are time-consuming, affect the delivery of dialysis, and therefore cannot repeatedly be used with every dialysis session. There is now a new focus on data continuously and regularly collected with every dialysis treatment, directly or indirectly associated with access function, and without interrupting or affecting the delivered dose of dialysis. This narrative review will focus on techniques that can be used continuously or intermittently during dialysis, taking advantage of methods integrated into the dialysis machine and which do not affect the delivery of dialysis. Examples include extracorporeal blood flow, dynamic line pressures, effective clearance, dose of delivered dialysis, and recirculation which are all routinely measured on most modern dialysis machines. Integrated information collected throughout every dialysis session and analyzed by expert systems and machine learning has the potential to improve the identification of accesses at risk of thrombosis.

Background: Dialyzer reprocessing for dialyzer reuse in the same patient has been developed since the early time in hemodialysis history to save cost and time related to reassembling the new dialyzer during that time. The procedure can reduce the first-use and allergic reactions from using incompatible cellulosic dialyzer membrane by altering some manufacturing chemicals.

Methods: All of established literatures regarding recent dialyzer reprocessing methods and considerations were extensively reviewed and summarized.

Results: Dialyzer reprocessing can be performed by multiple protocols but involves common steps including bedside rinsing after use, cleaning, dialyzer testing to prevent excessive drop in dialyzer clearance and membrane integrity, high-level disinfection or sterilization either by chemicals or heat, storage, and preparation for subsequent dialysis session by adequate rinsing to reduce the residual reprocessing chemical to the safe level. Compared with the single-use strategy, evidence is conflicting for the mortality advantages or disadvantages of dialyzer reuse, with some showing increased mortality in patients receiving peracetic acid sterilization. Keys for the effective and safe dialyzer reuse involve strict adherence to specific manufacturer's protocol, adequate dialysis water quality complied with the Association for the Advancement of Medical Instrumentation standard, measurement of the total cell volume to prevent inadequate hemodialysis, and infectious control consideration. In the present era, single-use strategy is increasingly adopted due to the decreased cost for dialyzer manufacturing. Environmental concerns of higher solid waste from dialyzer disposal in single-use dialysis should be compared with the liquid waste from reprocessing chemicals along with plastic waste and cardboard in reuse dialysis.

Conclusion: Dialyzer reprocessing with adequate regulation is considered as an acceptable option for cost-effective hemodialysis, compared with the single-use strategy.

The key goals for dialysis treatments are to prevent the progressive accumulation of waste products of metabolism and volume overload. Traditionally uremic solutes have been classified according to molecular weight and termed small, middle sized, and large solutes. Solute clearance during dialysis sessions will potentially be by diffusion, convection and adsorption. Dialyzer membranes act as a semi-permeable membrane restricting solute removal predominantly by size. Small molecules move faster than large molecules, so small solutes are readily removed by diffusion. Increasing the size of the pores in the membrane will potentially allow middle and larger sized solutes to pass through the dialyzer membrane, although in practice there is a limit to increasing pore sizes to prevent the loss of albumin and other important proteins. Differences in membrane surface and charge will influence protein absorption. The removal of fluid during dialysis depends in part on the hydraulic permeability of the membrane. Combining higher hydraulic permeability and larger sized pores increases convective clearance with solutes moving across the membrane with the water movement. Depending upon dialyzer design, higher hydrostatic pressure as blood enters the dialyzer leads to a variable amount of internal diafiltration, so improving the clearance of middle sized solutes. Although the dialyzer membrane plays a key role in solute clearance, the design of the casing and header also play a role in directing the countercurrent blood and dialysate flows to maximize the surface area available for diffusive and convective clearances.

Arteriovenous fistula (AVF) and/or arteriovenous graft (AVG) burdens cardiac load. It is a challenge to create a vascular access (VA) on a patient who suffers severe heart failure and also combines with contraindications of central vein catheter implantation. Superficialized radial artery (RA) could be an available VA as an outflow for continuous hemodialysis. A 57-year-old male had a left arm distal radiocephalic fistula for hemodialysis for 10 months. The patient showed gradual aggravation of heart failure. RA superficialization was performed under anesthesia protocols and surgery steps. Fourteen days after the surgery, the superficialized artery supplied the hemodialysis as an outflow without any uncomfortable and complications. The echocardiographies present the changes of the heart structures and functions during the whole period from the beginning of AVF formation to the 18-month follow-up RA superficialization. RA superficialization technique should be an alternative VA for continuous hemodialysis under suitable conditions.

Introduction: Hepcidin is a master regulator of iron utilization and takes part in the pathophysiology of anemia in maintenance hemodialysis (MHD) patients. Hepcidin is a moderate-molecular-weight substance and partially binds to plasma proteins in the circulation, which theoretically might be removed efficiently by hemoperfusion (HP). This study aimed to compare the effect of different dialysis modalities on hepcidin removal and discuss its effect on the iron and anemia status in MHD patients.

Materials and methods: In a longitudinal interventional study of 26 stable MHD patients, the serum hepcidin, β2-microglobulin (β2-MG), and intact parathyroid hormone (iPTH) were measured before and after one treatment session of hemodialysis (HD), hemodiafiltration (HDF), HD + HP, and HDF + HP, separately. One-way analysis of variance (ANOVA) was used to identify the effect of dialysis modalities on the intra-dialysis clearance ratios.

Results: The combined dialysis modalities (HD + HP and HDF + HP) achieved greater clearance ratios of serum hepcidin than HD and HDF alone, HD + HP vs. HD (16 ± 15% vs. 4 ± 13%, p < 0.001), HDF + HP vs. HDF (18 ± 5% vs. 10 ± 13%, p = 0.0036). Similarly, the combined dialysis modalities also performed better than HD and HDF alone in removing β2-MG. There was no significant difference in iPTH clearance among these four modalities, except that HDF + HP achieved a greater clearance ratio than HD. Furthermore, the anemia was improved after the 6-month treatment with regular HD/HDF plus HP, which was indicated by increasing hemoglobin (p = 0.0004) and reduction of erythropoiesis-stimulating agents (ESAs) resistance index (ERI) (p = 0.0431).

Conclusions: Our findings suggest that the combined dialysis modalities of HD/HDF plus HP could achieve better clearance ratios of hepcidin than HD/HDF alone, thereby, might improve iron utilization, and benefit anemia management in MHD patients. Further studies with larger sample-size patients and longer follow-up duration are still needed.

Background: Hemodialysis is the most common treatment modality for patients with chronic kidney disease (CKD). Excessive daytime sleepiness and poor nighttime sleep is a common problem among these patients. Patients on maintenance hemodialysis (MHD) are regularly exposed to impaired fluid balance, which may cause overhydration of varying degree. However, the role of hydration status in sleep quality has not been explored in Indian setting. Hence, this study was undertaken to assess the factors affecting sleep quality among patients on MHD in a tertiary care hospital.

Material and methods: Patients (N = 55) were enrolled if they aged above18 years, on MHD for at least 3 months, and gave consent. The daytime sleep quality was assessed using Epworth Sleepiness Scale (ESS) and Insomnia Severity Index (ISI). The data were analyzed using SPSS version 20 and STATA software.

Results: The mean age of the patients was 40.4 ± 14.7 years. The prevalence rate of predialysis fluid overload was 85.4%. The median ESS score was 7 and ISI score was 3 indicating normal daytime sleep and not significant insomnia. Multivariate regression with variables adjustment showed that interdialytic weight gain (P = 0.33), tingling sensation (P = 0.36) and numbness (P = 0.35) were significant predictive factors for quality of sleep.

Conclusion: The major factors affecting sleep quality were numbness, tingling sensation, and interdialytic weight gain. Fluid overload did not play any role in sleep quality. Another study may be carried out on assessment of pattern, duration, quality of sleep in multiple dialysis sessions, and effect of optimizing fluid status on the sleep parameters.

Background: Calprotectin is an important molecule in the initiation and progression of the inflammatory process. Systemic and local intraperitoneal inflammation are distinct processes and consequences in peritoneal dialysis (PD). We aimed to evaluate dialysate calprotectin levels and its associations with peritonitis and dialysis adequacy in PD patients.

Methods: Forty-four PD patients were included in this prospective study. Calprotectin concentration was evaluated in 24-h peritoneal drainage fluid. Patients were followed-up for 1 year, and peritonitis episodes were recorded. Dialysate calprotectin levels were compared to dialysis adequacy parameters and peritonitis frequency.

Results: The mean age of patients was 54.9±12.7 years. Median PD duration was 54 (23-76) months. Seventeen patients (38.6%) had previous peritonitis episodes. During follow-up, 15 of 44 patients (34.1%) had peritonitis. The median calprotectin concentration was 79.5 (75.2-86.3) ng/ml. The patients were divided into low and high calprotectin groups according to median value. In the high calprotectin group, BMI was found higher (p = 0.04). There was no significant relationship between calprotectin concentration and peritonitis during follow-up (p = 0.29). However, the patients that have had previous peritonitis had higher calprotectin concentrations (p = 0.02). The patients who had higher erythrocyte sedimentation rate (ESR) levels also had higher calprotectin concentrations (p = 0.01).

Conclusion: Peritoneal calprotectin concentrations were correlated with higher BMI and ESR, and it was higher in patients with previous peritonitis episodes. To our knowledge, this is the first study to examine the peritoneal calprotectin levels in PD patients. Further studies are needed to determine the use of peritoneal calprotectin as an inflammatory marker in PD.