Rationale for Daily Dialysis

The kidneys maintain the body's homeostasis by removing water and waste products continuously and efficiently. The ideal dialytic treatment should emulate the functions of the kidney. Of the dialysis treatments currently available for chronic renal failure, the only continuous ones are continuous ambulatory and continuous cyclic peritoneal dialysis; however, the efficiency of peritoneal dialysis is limited by the nature of the peritoneal membrane. Extracorporeal dialysis is markedly more efficient than peritoneal dialysis, but is performed intermittently (usually 3 times/week) with large fluctuations of body fluid volumes and concentrations of various solutes and electrolytes. These fluctuations cause intercompartmental disequilibrium during dialysis, induce intradialytic and interdialytic symptoms, and create difficulties in controlling blood pressure. Daily dialysis is both frequent and efficient and therefore seems to be superior to any other form of renal replacement therapy.     

The Case for Every‐Other‐Day Dialysis

Until daily dialysis becomes widely available, we believe that hemodialysis patients would benefit enormously from every‐other‐day dialysis (EODD), which may be implemented both by home patients and in centers. Benefits of EODD over the routine, three‐times‐weekly schedule would include decreased mortality after the weekend interval without dialysis; increased weekly dose of dialysis, resulting in better rehabilitation; and improved blood pressure control.     

Survival with short‐daily hemodialysis: Association of time,site, and dose of dialysis

In thrice‐weekly hemodialysis, survival correlates with the length of time (t) of each dialysis and the dose (Kt/V), and deaths occur most frequently on Mondays and Tuesdays. We studied the influence of t and Kt/V on survival in 262 patients on short‐daily hemodialysis (SDHD) and also noted death rate by weekday. Contingency tables, Kaplan‐Meier analysis, regression analysis, and stepwise Cox proportional hazard analysis were used to study the associations of clinical variables with survival. Patients had been on SDHD for a mean of 2.1 (range 0.1–11) years. Mean dialysis time was 12.9 ± 2.3 h/wk and mean weekly stdKt/V was 2.7 ± 0.5. Fifty‐two of the patients died (20%) and 8‐year survival was 54 ± 5%. In an analysis of 4 groups by weekly dialysis time, 5‐year survival continuously increased from 45 ± 8% in those dialyzing <12 hours to 100% in those dialyzing >15 hours without any apparent threshold. There was no association between Kt/V and survival. In Cox proportional hazard analysis, 4 factors were independently associated with survival: age in years Hazard Ratio (HR)=1.05, weekly dialysis hours HR=0.84, home dialysis HR=0.50, and secondary renal disease HR=2.30. Unlike conventional HD, no pattern of excessive death occurred early in the week during SDHD. With SDHD, longer time and dialysis at home were independently associated with improved survival, while Kt/V was not. Homedialysis and dialysis 15+ h/wk appear to maximize survival in SDHD.     

Measures of blood pressure and cognition in dialysis patients

There are few reports on the relationship of blood pressure with cognitive function in maintenance dialysis patients. The Cognition and Dialysis Study is an ongoing investigation of cognitive function and its risk factors in six Boston area hemodialysis units. In this analysis, we evaluated the relationship between different domains of cognitive function with systolic and diastolic blood pressure, pulse pressure, and intradialytic changes in systolic blood pressure, using univariate and multivariable linear regression models adjusted for age, sex, race, education, and primary cause of end‐stage renal disease. Among 314 participants, mean age was 63 years; 47% were female, 22% were African American, and 48% had diabetes. The mean (SD) of systolic blood pressure, diastolic blood pressure, pulse pressure, and intradialytic change in systolic blood pressure were 141 (21), 73 (12), 68 (15), and ?10 (24) mmHg, respectively. In univariate analyses, the performance on cognitive tests primarily assessing executive function and processing speeds was worse among participants with lower diastolic blood pressure and higher pulse pressure. These relationships were not statistically significant, however, in multivariable analyses. There was no association between cognitive function and systolic blood pressure or intradialytic change in systolic blood pressure in either univariate or multivariable analyses. We found no association between different measures of blood pressure and cognitive function in cross‐sectional analysis. Longitudinal studies are needed to confirm these results.     

Nightly Home Hemodialysis: Fifteen Months of Experience in Lynchburg,Virginia

What constitutes adequate dialysis has been debated in the nephrology literature over the past eight years. The mortality rate of patients on dialysis in the United States is about 20% per year. We believed that short and infrequent dialysis sessions contributed to poor outcomes. To improve the results, Lynchburg Nephrology started the nightly home hemodialysis (NHHD) program in September 1997. Ten patients were trained in the first 15 months of the program. Patients dialyzed 7 – 9 hours, 6 nights/week, using the Fresenius 2008H machine. A standard dialysis solution with 2.0 mEq/L potassium, calcium concentration of 3.0 – 3.5 mEq/L was used. Dialysis solution flow rates were 200 – 300 mL/min. Serum phosphate levels were maintained above 2.5 mg/dL by adding 0 – 45 mL Fleet's Phosphosoda to the bicarbonate bath. Patients had marked improvement in quality of life as measured with the SF-36. Blood pressure was better controlled with fewer medications. All phosphate binders were eliminated. Caloric intake and protein intake increased to normal levels as measured by three-day dietary histories pre-NHHD, and at 3, 6, and 12 months on NHHD. Epoetin alfa dosages were reduced by about 50%. Nightly home hemodialysis should be considered as a valuable modality option for end-stage renal disease patients; it is potentially superior to conventional thrice-weekly hemodialysis.     

What limits the expansion of self‐care dialysis at home?

Self-care dialysis at home, whether peritoneal dialysis or hemodialysis, is more cost-effective than in-center dialysis and treatment outcome is at least comparable. Still, both self-care modalities are considered underutilized and we wished to identify the perceived reasons for this underutilization among nephrology professionals. A questionnaire was distributed at 5 international nephrology meetings in 2006. Questions addressed the most important stakeholders and the most important issues for patients and nephrology professionals to enable the expansion of self-care dialysis and commonly mentioned barriers were given as alternative responses. The proportion of patients considered suitable for self-care was also investigated. Seven thousand responses were collected. The listed stakeholders, i.e., health care and reimbursement authorities, nurses and physicians, and finally patients and their families, are considered approximately equally important for the process. Nephrology professionals feel that patient motivation for choosing and performing self-care dialysis is the strongest driver. The need for dedicated resources for self-care is judged to be vital for the expansion of this modality of treatment. Thirty-two percent of incident patients are considered able to perform self-care dialysis at home. This international survey among 7000 nephrology professionals has identified patient motivation as one of the strongest drivers of self-care dialysis at home. The need for dedicated resources for the staff to devote time to developing such motivation is given as one of the major reasons for the slow adoption. Under ideal conditions, it is felt that one-third of all patients starting dialysis can be trained to perform self-care dialysis.     

Automatic feedback control of relative blood volume changes during hemodialysis improves blood pressure stability during and after dialysis

Automatic feedback systems have been designed to control relative blood volume changes during hemodialysis (HD) as hypovolemia plays a major role in the development of dialysis hypotension. Of these systems, one is based on the concept of blood volume tracking (BVT). BVT has been shown to improve intra-HD hemodynamic stability. We first questioned whether BVT also improves post-HD blood pressure stability in hypotension-prone patients and second, whether BVT is effective in reducing the post-HD weight as many hypotension-prone patients are overhydrated because of an inability to reach dry weight. After a 3-week period on standard HD, 12 hypotension-prone patients were treated with two consecutive BVT treatment protocols. During the first BVT period of 3 weeks, the post-HD target weight was kept identical compared with the standard HD period (BVT-constant weight; BVT-cw). During the second BVT period of 6 weeks, we gradually tried to lower the post-HD target weight (BVT-reduced weight; BVT-rw). In the last week of each period, we studied intra-HD and 24 hr post-HD blood pressure behavior by ambulatory blood pressure measurement (ABPM). Pre- and post-HD weight did not differ between standard HD and either BVT-cw or BVT-rw. Heart size on a standing pre-dialysis chest X-ray did not change significantly throughout the study. There were less episodes of dialysis hypotension during BVT compared with standard HD (both BVT periods: p<0.01). ABPM data were complete in 10 patients. During the first 16 hr post-HD, systolic blood pressure was significantly higher with BVT in comparison with standard HD (both BVT periods: p<0.05). The use of BVT in hypotension-prone patients is associated with higher systolic blood pressures for as long as 16 hr post-HD. BVT was not effective in reducing the post-HD target weight in this patient group.     

血液透析机计量检测工作探讨

本文首先普及血液透析机的基本知识,进而着重介绍血液透析机的计量检测工作,主要包括血液透析液检测、血泵流量检测、置换液泵流量检测、肝素泵流量检测等。说明血液透析机计量检测工作的重要意义。     

Tailoring dialysis and resuming low‐protein diets may favor chronic dialysis discontinuation: Report on three cases

Renal function recovery (RFR), defined as the discontinuation of dialysis after 3 months of replacement therapy, is reported in about 1% of chronic dialysis patients. The role of personalized, intensive dialysis schedules and of resuming low‐protein diets has not been studied to date. This report describes three patients with RFR who were recently treated at a new dialysis unit set up to offer intensive hemodialysis. All three patients were females, aged 73, 75, and 78 years. Kidney disease included vascular‐cholesterol emboli, diabetic nephropathy and vascular and dysmetabolic disease. At time of RFR, the patients had been dialysis‐dependent from 3 months to 1 year. Dialysis was started with different schedules and was progressively discontinued with a “decremental” policy, progressively decreasing number and duration of the sessions. A moderately restricted low‐protein diet (proteins 0.6 g/kg/day) was started immediately after dialysis discontinuation. The most recent update showed that two patients are well off dialysis for 5 and 6 months; the diabetic patient died (sudden death) 3 months after dialysis discontinuation. Within the limits of small numbers, our case series may suggest a role for personalized dialysis treatments and for including low‐protein diets in the therapy, in enhancing long‐term RFR in elderly dialysis patients.     

Use of 3‐hour daily hemodialysis and paricalcitol in patients with severe secondary hyperparathyroidism: A case series

Patients with poor metabolic control receiving conventional hemodialysis are at risk for developing severe secondary hyperparathyroidism. We postulated that daily hemodialysis may be effective at controlling parathyroid hormone (PTH) in the setting of severe secondary hyperparathyroidism by improving the control of hyperphosphatemia and allowing increased use of vitamin D analogs. We present 5 patients with severe secondary hyperparathyroidism (median iPTH=1783 pg/mL) who were treated with 3‐hour daily hemodialysis (3 hours × 6 times a week). Daily hemodialysis, at 1 year, was associated with a 70.4% reduction in median PTH (1783 pg/mL [interquartile range: 1321–1983]–472 pg/mL [334, 704], P<0.001). Additionally, there was an increase in paricalcitol dose from 0 mcg/d to 10.8 (2.00, 11.7) mcg/d, a 39% reduction in calcium × phosphorus product (80.3 ± 26.8–48.9 ± 14.0, P<0.01), a 52% reduction in serum phosphorus (9.90 ± 2.34–4.75 ± 0.79 mg/dL, P<0.0001), and a 17.6% increase in serum calcium (8.18 ± 2.04–9.62 ± 0.93 mg/dL, P<0.01). Three‐hour daily hemodialysis with the use of high‐dose paricalcitol is associated with improved control of severe secondary hyperparathyroidism.     

Thyroid function in end stage renal disease and effects of frequent hemodialysis

Introduction: End‐stage renal disease (ESRD) is associated with perturbations in thyroid hormone concentrations and an increased prevalence of hypothyroidism. Few studies have examined the effects of hemodialysis dose or frequency on endogenous thyroid function. Methods: Within the Frequent Hemodialysis Network (FHN) trials, we examined the prevalence of hypothyroidism in patients with ESRD. Among those with endogenous thyroid function (without overt hyper/hypothyroidism or thyroid hormone supplementation), we examined the association of thyroid hormone concentration with multiple parameters of self‐reported health status, and physical and cognitive performance, and the effects of hemodialysis frequency on serum thyroid stimulating hormone (TSH), free thyroxine (FT4), and free tri‐iodothyronine (FT3) levels. Conventional thrice‐weekly hemodialysis was compared to in‐center (6 d/wk) hemodialysis (Daily Trial) and Nocturnal (6 nights/wk) home hemodialysis (Nocturnal Trial) over 12 months. Findings: Among 226 FHN Trial participants, the prevalence of hypothyroidism was 11% based on thyroid hormone treatment and/or serum TSH ≥8 mIU/mL. Among the remaining 195 participants (147 Daily, 48 Nocturnal) with endogenous thyroid function, TSH concentrations were modestly (directly) correlated with age (r = 0.16, P = 0.03) but not dialysis vintage. Circulating thyroid hormone levels were not associated with parameters of health status or physical and cognitive performance. Furthermore, frequent in‐center and nocturnal hemodialysis did not significantly change (baseline to month 12) TSH, FT4, or FT3 concentrations in patients with endogenous thyroid function. Discussion: Among patients receiving hemodialysis without overt hyper/hypothyroidism or thyroid hormone treatment, thyroid indices were not associated with multiple measures of health status and were not significantly altered with increased dialysis frequency.     

Split catheters in children on chronic hemodialysis: a single-center experience

Tunneled central venous catheters (CVCs) play an increasing role as vascular access for chronic hemodialysis (HD) in children, but limited data exist about the optimal CVC choice. We analyzed the outcome, efficacy, and complications of tunneled CVCs, placed in our unit in the last 3 years. Nineteen 10 F Split‐Cath CVCs (two separate catheters fused along their length) were placed in 10 children, median age 9.19 years (range 2.15–13.31) and body weight (BW) between 10 and 40 kg. CVCs survival at 1, 3, 6, and 12 months was 94%, 77%, 51%, and 34%, respectively. Catheter survival was higher in children with BW > 20 kg than in smaller patients. Median survival was higher than that of 11 Quinton Permcath CVCs, placed in five children in the preceding 2 years (280 vs. 45 days, P < 0.05). Median blood flow rate and indices of HD adequacy were higher in children with lower BW (<20 kg vs. 20–30 kg vs. >30 kg) than in those with higher BW. Incidence of exit site and bloodstream infections was 2.32 and 0.66/1000 CVC days, respectively. One case of hemothorax due to subclavian artery puncture occurred during CVC placement. In conclusion, Split‐Cath 10 F CVC allows for effective dialysis in children undergoing HD, particularly those between 10 and 30 kg BW. Catheter survival is acceptable, but could be improved in small children.     

An unusual cause of postdialysis dyspnea: Percutaneous endovascular management

Vascular access through femoral vein is commonly used for hemodialysis treatment in patients with end‐stage renal disease. Consequently, iatrogenic complications, such as femoral arteriovenous fistula, are increasingly being reported in these patients. Percutaneous endovascular management of such iatrogenic arteriovenous fistulas with stent graft placement is a minimally invasive technique with decreased morbidity and hospital stay compared with surgical repair. Here, we report a case with postcatheterization arteriovenous fistula between superficial femoral artery and femoral vein which was successfully managed with a placement of a self‐expanding stent graft.     

A study of the extracorporeal rate of blood flow and blood pressure during hemodialysis

Hemodynamic instability is a common problem during hemodialysis (HD). The effect of blood flow rate (BFR) on blood pressure (BP) during HD has not been previously evaluated. Subjects receiving HD for the treatment of renal failure were enrolled (n=34). For each patient, during the last hour of 2 consecutive HD sessions the BFR was set at 200 mL/min for 30 min and at 400 mL/min for 30 min, during which period the fluid removal rate was kept constant. The order of the BFR alterations was randomized. The study procedure was repeated during the next HD session but with reversal of the order of the altered BFR. During each 30-min period, BP was recorded at baseline and subsequently every 10 min. During the BFR of 400 mL/min, subjects had a higher systolic BP by an average of 4.1 mmHg compared with the BFR of 200 mL/min (95% confidence interval [CI] 0.22-7.98; p=0.038). Similarly, during the BFR of 400 mL/min, subjects had a higher diastolic BP by an average of 3.04 mmHg compared with the BFR of 200 mL/min (95% CI 0.55-5.53; p=0.017). Likewise, during the BFR of 400 mL/min, subjects had a higher mean arterial pressure by an average of 3.44 mmHg (95% CI 0.77-6.11; p=0.012). The findings suggest that during HD, BPs are maintained higher at higher BFRs as compared with lower BFRs.