The Case for Nocturnal Hemodialysis

Nocturnal hemodialysis (long nightly hemodialysis) was created to take advantage of the benefits of both daily hemodialysis, 1 as well as long duration dialysis. 2 In this article, the state of the art of nocturnal hemodialysis will be outlined, some of the future research questions will be discussed, and the future of this modality will be considered. Evolution of the Technique Nocturnal hemodialysis 3,4 is a form of home hemodialysis administered nightly for the duration of time that the patient is asleep. Duration varies nightly between 6 and 12 hours. Nocturnal hemodialysis is performed by the patient or a partner, but the presence of a partner is not obligatory. Although relatively high blood flows were used initially to maintain central venous catheter patency, flows as low as 150 ml/min have been used with very good results. Dialysate flow is also variable. An initially low dialysate flow at 100 ml/min was used to prevent possible deficiency syndromes; however, for the last few years it has been liberalized up to 800 ml/min. A typical regimen includes blood flow (Qb) of 250–300 and dialysate flow (Qd) of 300–500 ml/min. Different machines have been used, although only the Fresenius 2008H machine (Fresenius Medical Care, Lexington, MA) provides low dialysate flows. After more than 1,100 patient-months of experience, we encountered three episodes of disequilibrium syndrome in the form of headache for the first few nights of nocturnal hemodialysis, necessitating a decrease in blood and dialysate flows. Dialysate composition has remained stable with Na 140, K 2, and bicarbonate 28–35 mEq/L. On rare occasions, a potassium of 1.5 and 2.5 mEq/L were used. In our center, dialysate calcium concentration is adjusted after serum calcium, with an average value of 3.2 mEq/L. Variable amounts of calcium chloride powder are added to the “acid” concentrate by the patient, as prescribed by the physician. Other centers use a stable dialysate calcium of 3.5 mEq/L. A higher dialysate calcium is prescribed in patients with high ultrafiltration volumes. Sodium phosphate is added to either the acid or bicarbonate concentrate to maintain normal serum phosphate, pre and postdialysis. The average dialysate phosphate concentration was 1.5 mg/dl. Remote Monitoring Remote “live” monitoring has been practiced by some, but not all centers. The Cybernius DAX software (Cybernius Medical, St. Alberta, Alberta, Canada) has been used to connect the Fresenius 2008H dialysis machines to the hospital server either via telephone lines or the Internet. Although the value of remote monitoring has been questioned, the future ability to monitor blood pressure without cuff inflation, and the incorporation of the blood and dialysate leak alarms into the monitoring system, will render remote monitoring more valuable. Access Central venous catheters, arteriovenous catheters, and grafts have been used for nocturnal hemodialysis. 5 Survival of the central venous catheters on nocturnal hemodialysis has been found to be better than in-center dialysis (p = 0.03). Even poorly functioning central venous catheters (Qb < 200 ml/min) can provide excellent dialysis. The infection rate has been relatively low at 1.5 episodes per 1,000 patient-months. Intravenous antibiotics administered by the patients at home resulted in catheter salvage in the majority of patients; in most of the remaining cases, the catheter was replaced over a guidewire. Sixteen patients (of the current 33 patients) in our center use arteriovenous fistulas, one patient uses an arteriovenous (AV) graft. All patients use the buttonhole technique 6 for fistulas in either double or single needle configuration. The single needle system requires fewer punctures, whereas the lower blood flow is adequate for most patients. Initially we used plastic cannulas for fistula cannulation; however, recently steel needles were used. An enuresis alarm has been used to sense blood leaks from the venous needle, whereas, disconnection of the arterial needle would cause an “air alarm,” therefore making the enuresis alarm unnecessary. Dialyzer Reuse Dialyzer reuse as a cost-saving measure can be implemented for home dialysis. We introduced the delayed dialyzer reprocessing, 7 in which dialyzers are refrigerated at home by the patients and transported to the center for reprocessing only once a week. An intermediary location for drop-off and pick-up of the bags containing dialyzers can be used, if the distance between the home of the patient and the center is long. Patients/Training As of June 2000, more than 100 patients are on nocturnal hemodialysis in North America; 33 patients are on nocturnal hemodialysis at the Humber River Regional Hospital in Toronto. The second patient in our program has been on nocturnal hemodialysis for 75 months. Patient training usually lasts for 6 weeks or less, if the patient has previous self-care experience. The training includes nocturnal hemodialysis in the hospital during the last week of training. Although the nurse to patient ratio is usually 1:1, attempts for more efficient training are being made. Except for contraindication to systemic heparinization, no medical contraindications have been considered for use of nocturnal hemodialysis. Quality of Life The patients have been enthusiastic about the improvement of their quality of life. No patient considered returning to conventional hemodialysis. We 8 used the Sickness Impact Profile (SIP), short form (SF)-36, and the Beck Depression Index (BDI) before and after conversion of 18 patients to nocturnal hemodialysis. The SIP score and the BDI improved significantly, as did several parameters of the SF-36 questionnaire, including social functioning, physical functioning, and role physical. All uremic and dialysis related symptoms of the patients disappeared within week, and the physical appearance of the patients often changed dramatically. Lockridge et al.9 found improvement in several of the parameters of SF-36, as did Williams et al.,10 although details have not yet been published. Blood Pressure Control Improved blood pressure control has been found with nocturnal hemodialysis. 11 The mechanism for the improvement is unclear, but it certainly includes a decrease in extracellular fluid volume. Of the 33 patients currently on nocturnal hemodialysis at the Humber River Regional Hospital in Toronto, only 6 require a small dose of a β-blocker (usually atenolol, 25 mg daily) for control of hypertension. The current approach includes progressively reducing the patient’s dry weight until they become normotensive without the use of medications. If during the process, they become tachycardic, a small dose of a β-blocker is prescribed. Anemia No significant decrease in erythropoietin (EPO) dose was found initially by our group; however, after the institution of intravenous iron treatment there was a 40% decrease in the EPO requirements. The percentage of patients not receiving EPO increased from 7 to 40% after the conversion to nocturnal hemodialysis. Similar successful results were reported by Lockridge et al.12 Phosphate Control Nocturnal hemodialysis depletes the body of phosphate. 13 All patients are taken off of phosphate binders, are put on a high phosphate diet, and the majority need additional phosphate in the dialysate in the form of a Fleet enema or Fleet Phospho-Soda (Johnson & Johnson. Merck. Guelph, Ontario, Canada) (sodium phosphate), to prevent hypophosphatemia. Nocturnal hemodialysis removes twice the amount of phosphate as compared with conventional hemodialysis. β2 Microglobulin Control Nocturnal hemodialysis removes four times the amount of β2 microglobulin than conventional hemodialysis, every week, thus leading to lower serum levels. 14 The effect of the increased removal of β2 microglobulin is unclear. Bone Disease The lack of necessity for calcium containing phosphate binders when on nocturnal hemodialysis dictates a high dialysate calcium (3–3.5 mEq/L) maintains neutral calcium balance and suppresses parathyroid hormone (PTH). Measurement of bone density with dual-energy x-ray absorptiometry techniques has been found to be useful in adjusting dialysate calcium. The ideal dialysate calcium and the role of calcitriol need to be better defined. It should be stressed that the postdialysis serum calcium needs to be significantly higher than the predialysis value, usually in the hypercalcemic range. The calcium phosphate product decreases significantly on nocturnal hemodialysis, leading to impressive dissolution of extraosseous calcifications;15 nocturnal hemodialysis promises to prevent or correct renal osteodystrophy. The effect of prolonged heparinization is unknown. The need for calcitriol administration is not clear. Bone pathology is needed to determine whether our goal has been achieved, and to fine tune the regimen. Nutrition Appetite increases in patients receiving nocturnal hemodialysis and there is a significant increase in weight, to up to 12 kg within 1 year. No significant change in serum albumin was observed on nocturnal hemodialysis. The serum, both essential and nonessential amino acids, increased in patients receiving nocturnal hemodialysis, but their pattern did not completely return to normal. 16 Hemodialysis using high flux membranes leads to amino acid loss in the dialysate. 17 To examine the possibility of a negative nitrogen balance with nocturnal hemodialysis, total body nitrogen and potassium were measured, using in vivo neutron activation techniques. Twenty four patients were evaluated every 6 months while on nocturnal hemodialysis. Seventy five percent of the patients showed an increase in total body nitrogen, suggesting that the increased protein intake compensates for the higher amino acid loss into the dialysate and that most patients are anabolic. 18 Sleep/Cognitive Function Sleep disorders, which are encountered in more than 50% of patients in end-stage renal disease (ESRD), do not improve with peritoneal dialysis or hemodialysis. Patients were studied in the sleep laboratory, before and after the conversion from conventional hemodialysis to nocturnal hemodialysis. More than 50% of the patients were found to have sleep apnea, which resolved with the institution of nocturnal hemodialysis. 19 Patients showed significant improvement (16%) in cognitive function when tested before and after the conversion to nocturnal hemodialysis, using standard psychologic testing. 20 Hospitalization Rates Lockridge et al. reported a decrease, from 0.65 to 0.08 days per patient-month, in hospitalization rates in patients receiving nocturnal hemodialysis. 9 Additional data are needed. Patient Survival The survival rate for patients receiving nocturnal hemodialysis at the Humber River Regional Hospital in Toronto, Canada (total of 45 patients over 1,100 patient-months) was 90% over a period of 3 years (unpublished observation). Finances Although the direct cost of providing daily/nocturnal hemodialysis is higher than conventional hemodialysis, the associated decrease in the cost of medications including EPO, the decrease in hospitalization rates, and the fact that nocturnal hemodialysis is performed at home, is likely to make this regimen less expensive. Mohr et al.21 calculated that nocturnal hemodialysis done at home costs $9,500 less than conventional hemodialysis, when medication and hospitalization savings are considered. The Future The main obstacle preventing the expansion of nocturnal hemodialysis is lack of adequate financial reimbursement. A detailed analysis of the cost of nocturnal hemodialysis would be useful in providing the necessary information to the funding agencies. Prospective comparison of the cost of care of patients receiving nocturnal hemodialysis with the cost of conventional hemodialysis, including the cost of medications and hospitalization would also be useful. This would provide the information necessary to the funding agencies for appropriate policy making. Patients are enthusiastic about the acceptance of nocturnal hemodialysis. If adequate funding is provided, nocturnal hemodialysis prevalence will rapidly increase, and an eventual prevalence of 20–30% for home hemodialysis modalities is not overly optimistic. The ability of patients to learn this technique may be limiting; however, this will create an incentive to design simpler hemodialysis machines, which will further increase utilization of the method. Judging from our experiences until this point, nocturnal hemodialysis is likely to have a major effect on the quality of life of ESRD patients.

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