Version May 2024
INTRODUCTION AND OVERVIEW — The mortality rate of patients undergoing maintenance hemodialysis is unacceptably high [1]. A high morbidity, relatively low quality of life (due in part to a high level of dependence and unemployment), and high cost of care have also been observed.
The Hemodialysis (HEMO) study found that increasing the dialysis dose within the general restrictions of a thrice-weekly regimen failed to decrease patient mortality [2]. (See "Patient survival and maintenance dialysis" and "Prescribing and assessing adequate hemodialysis".)
Instituting more intensive dialysis regimens appears to improve morbidity and possibly mortality in this patient population [3-8]. Compared with conventional thrice weekly regimens, for example, dialysis associated with longer duration and/or higher frequency correlates with improved outcomes.
Given these findings, nocturnal hemodialysis (eg, long nightly home hemodialysis) was introduced as a (possibly) more desirable alternative to conventional dialysis since it provides superior dialysis based upon dose, duration, and frequency. This can be accomplished because it is performed during nightly sleep, an otherwise unproductive time [9].
A description of nocturnal hemodialysis, particularly the exact regimen associated with the procedure, will be presented here. Outcomes associated with nocturnal hemodialysis and an overview of short daily hemodialysis are presented separately. (See "Outcomes associated with nocturnal hemodialysis" and "Short daily hemodialysis".)
DIALYSIS REGIMEN AND PRESCRIPTION
Regimen schedule — Nocturnal hemodialysis is performed either at home or in a dialysis facility. When it is done at home, the frequency of dialysis varies from three to seven nights per week. Facility-based nocturnal hemodialysis is performed three nights per week [10].
Required personnel — Facility-based dialysis is usually performed by the attending staff. Home dialysis is performed by the patient or a helper (unpaid or paid). A partner is not absolutely required for nocturnal dialysis at home, since this procedure is associated with significant hemodynamic stability.
Hemodialysis machines — Nocturnal hemodialysis can be performed with any hemodialysis machine. Attractive attributes of a home hemodialysis machine include ease of operation and disinfection, single-needle system, low noise level, an easily accessible screen that dims at night, a back-up battery to protect from power failure, and the ability to monitor the patient remotely.
Home hemodialysis machines can be high or low dialysate flow machines. Machines that have been approved for home hemodialysis in the United States are the Fresenius 2008K, NxStage System One and One S, and Tablo [11]. Additional details regarding these machines are discussed elsewhere. (See "Home hemodialysis (HHD): Establishment of a program", section on 'Dialysis equipment'.)
Dialyzer membrane — Any dialyzer membrane can be used, including smaller surface area dialyzers. Although there are no published data favoring one type of dialyzer membrane over others, most centers use high-flux dialyzers.
Time — Nocturnal hemodialysis is performed during sleep for a variable amount of time (usually six to eight hours), depending upon the length of sleep desired. For facility-based dialysis, the duration of the dialysis session is generally also dictated by facility logistics.
Dialysate composition — The composition of the dialysate varies with the type of dialysis machine (high or low flow).
High dialysate flow (conventional) machines — The typical composition of the dialysate for a conventional, high dialysate flow machine is as follows:
●Sodium – 138 mEq (mmol)/L.
●Potassium – 2 to 3 mEq (mmol)/L.
●Bicarbonate – 30 mEq (mmol)/L for nightly regimen and 35 mEq (mmol)/L for every other night or thrice-weekly regimens.
●Calcium – 2.5 to 4 mEq/L (1.25 to 2 mmol/L), with an average of 3.2 mEq/L (1.6 mmol/L). The dialysate calcium concentration is adjusted to keep parathyroid hormone (PTH) levels in the desirable range while maintaining normal predialysis calcium concentrations. The dialysate calcium concentration can be adjusted by varying the amount of calcium chloride powder that the patient adds to the dialysate (eg, 7 mL of calcium chloride powder added to 4 L of acid dialysate concentrate increases calcium concentration by approximately 0.5 mEq/L [0.25 mmol/L]).
A higher dialysate calcium is prescribed in patients with high ultrafiltration volumes to prevent a negative calcium balance. This is because the removal of calcium (ionized) with hemodialysis is generally proportionate to the volume of the fluid ultrafiltered [12]. Pregnancy or hungry bone syndrome also requires higher levels of dialysate calcium [13]. (See "Hungry bone syndrome following parathyroidectomy in patients with end-stage kidney disease".)
●Phosphate – 0 to 4.5 mg/dL (0 to 1.5 mmol/L), typically 1.2 mg/dL (0.4 mmol/L). Sodium phosphate (in the form of Fleet enema) is added, if needed, into the acid or bicarbonate concentrate. The dialysate phosphate concentration is adjusted to maintain pre- and postdialysis phosphate concentrations within the normal range. The typical dose is 30 to 60 mL per dialysate concentrate jug, but amounts as high as 200 mL can be used as a source of phosphate for those with higher requirements, such as patients who are pregnant or have hungry bone syndrome [13,14]. Calcium and phosphate do not precipitate in the acidic pH of the concentrate [15]. Patients on intermittent nocturnal hemodialysis are less likely to need the phosphate additive.
Low dialysate flow machines — The dialysate composition of a low dialysate flow machine (ie, NxStage) is fixed and cannot be varied during the dialysis session.
●Sodium – 140 mEq (mmol)/L
●Potassium – 1 or 2 mEq (mmol)/L
●Lactate – 40 or 45 mEq (mmol)/L
●Calcium – 3 mEq (1.5 mmol)/L
Depending on the dialysate volume used, the higher lactate concentration of 45 mEq/L used with low dialysate flow machines may increase serum bicarbonate excessively [16]. No dialysate additives are possible with the NxStage machine.
Blood and dialysate flow rates — With conventional dialysis machines, a blood flow as low as or below 200 mL/min is adequate for most patients undergoing nocturnal hemodialysis. However, a blood flow of 200 to 300 mL/min is more typical.
The blood flow rate with low dialysate flow machines (ie, NxStage) is kept high (>300 mL/min) to maintain the widest blood-to-dialysate solute gradient.
The dialysate flow rate is variable and depends upon the dialysis machine being used. For high dialysate flow machines, the dialysate flow ranges from 100 to 800 mL/min.
The dialysate flow in a low dialysate flow machine cannot be lower than 63 mL/min. Thus, the total dialysate volume needs to be adjusted to accommodate the desired length of the treatment [17].
Adequacy — For nocturnal hemodialysis, dialysis adequacy is usually not a concern. The minimum recommended dialysis dose, which follows the current Dialysis Outcomes Quality Initiative (DOQI) guidelines, is a standard weekly Kt/Vurea value of approximately 2 for all dialysis methods (see "Short daily hemodialysis", section on 'Measures of adequacy'). With conventional, high dialysate flow machines, the standard weekly Kt/V achieved with nocturnal hemodialysis is typically >3 and may be >5 depending on the number of sessions per week [18].
However, patients using low dialysate flow machines may have lower standard weekly Kt/V values depending on dialysate volumes, frequency, and duration. (See "Short daily home hemodialysis: The low dialysate volume approach", section on 'Frequent low-volume dialysate'.)
Ultrafiltration — The typical volume of ultrafiltrate removed per day is approximately 1 to 2 liters, but larger volumes are well tolerated. Patients weigh themselves daily to maintain dry weight, which is defined as normotension without the need for antihypertensive medications or edema.
Dialyzer reuse — Delayed dialyzer reprocessing has been used [19,20]. Some dialysis machines used in situ dialyzer reprocessing [21]. Most of the centers use new dialyzers.
Anticoagulation — To maintain systemic anticoagulation, the standard heparin regimen is the administration of approximately 1000 units of heparin per hour. Danaparoid and argatroban have also been used successfully in the case of heparin allergy [22]. A single dose of low-molecular-weight heparin at the beginning of dialysis has been successfully used [23].
Access — Both central venous catheters and peripheral vascular accesses have been successfully used for nocturnal hemodialysis. When peripheral accesses are used, however, more frequent access cannulation may result in decreased access survival. This was suggested by the Frequent Hemodialysis Network (FHN) Daily and Nocturnal trials, in which the primary vascular outcome was the time to first access event (including repair, loss of access, or access-related hospitalization), and the secondary vascular outcome was the time to all repairs and time to all losses [24]. (See "Outcomes associated with nocturnal hemodialysis", section on 'Vascular access complications'.)
In the FHN Nocturnal trial, 87 participants were randomly assigned to receive in-center, six days per week hemodialysis or conventional, three days per week hemodialysis [24]. Compared with conventional dialysis, there was a nonsignificant trend toward a higher rate of first access events associated with nocturnal dialysis (32 versus 58 events per 100 patient years, respectively; hazard ratio [HR] 1.81, 95% CI 0.94-3.48). When patients with a tunneled catheter were excluded from the analysis, nocturnal dialysis was associated with a significantly increased risk of a first access event (HR 3.23, 95% CI 1.07-10.34). In the FHN Daily trial (n = 245 participants), there was a higher incidence of a first access event in the daily group compared with the conventional group. The FHN Daily trial is discussed elsewhere. (See "Short daily hemodialysis", section on 'Vascular access'.)
Catheters — Any type of central venous catheter can be used for nocturnal hemodialysis. The capability of the catheter to provide blood flow >200 mL/min is not important for most patients. A safe connection for the central catheter includes the use of pre-perforated catheter caps, which are not removed during dialysis [9,25,26]. Careful taping of the catheter-tubing connection is of paramount importance. Accidental disconnection of the venous limb can cause exsanguination without triggering machine alarms.
Complications
●Thrombosis – The local instillation of 2 mg of alteplase (tissue-type plasminogen activator [tPA]) has been successful in restoring adequate blood flow in thrombosed catheters. The instillation of lyophilized tPA has been practiced successfully by patients at home. The approach to the prevention of catheter thrombosis is variable in different centers. The prophylactic use of tPA has been advocated to prevent catheter thrombosis [27].
●Infection – Dialysis catheter-related infections can occur among patients who perform home hemodialysis using a temporary or tunneled dialysis catheter. In one study of 98 patients on nocturnal hemodialysis using catheters, 64 percent developed bacteremia over approximately seven years; the most commonly isolated organism was Staphylococcus epidermidis (51 percent) [28].
The frequency of such infections in patients on home hemodialysis may be comparable to that in patients on in-center hemodialysis. As an example, in one study comparing the rate of first catheter infections among these groups, patients on home hemodialysis had somewhat fewer infections (1.77 versus 2.03 per 100 patient-months), although the difference between the two groups was not statistically significant [29].
The diagnosis and management of tunneled dialysis catheter-related infections are discussed elsewhere. (See "Tunneled hemodialysis catheter-related bloodstream infection (CRBSI): Epidemiology, pathogenesis, clinical manifestations, and diagnosis" and "Tunneled hemodialysis catheter-related bloodstream infection (CRBSI): Management and prevention".)
Fistulas and grafts
●Arteriovenous fistulas – An arteriovenous fistula is the access of choice. The standard steel needles, blunt needles, and plastic cannulas have been used successfully. Patients on home nocturnal dialysis should receive structured training and supervision during their initial cannulation attempts and, thereafter, regular training updates to maintain cannulation competency and mitigate the risks of infections and cannulation injuries.
There are two cannulation techniques commonly used for accessing the fistula:
•Rope-ladder technique – The rope-ladder technique involves systematic insertion of needles at different sites for each hemodialysis treatment [30].
•Buttonhole technique – The buttonhole technique involves the insertion of the needle/cannula through exactly the same hole and at the same angle and depth of penetration [31-33]. After 8 to 10 cannulations (or 12 to 14 in patients with diabetes) using the buttonhole method, an epithelialized track develops that allows the use of blunt needles [32]. Sharp needles should be used for the first week, followed by blunt needles thereafter.
Most experts and the 2019 Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines recommend rope-ladder cannulation as preferred cannulation for arteriovenous fistulas and limiting buttonhole cannulation to special circumstances given its associated increased risks of infection and related adverse consequences (see "Overview of hemodialysis arteriovenous fistula maintenance and thrombosis prevention", section on 'Standard versus buttonhole technique') [34]. As such, patients receiving in-center nocturnal hemodialysis typically are cannulated via the rope-ladder technique.
However, the risk of infection associated with buttonhole cannulation may be mitigated with topical mupirocin prophylaxis [33], and the buttonhole technique is a reasonable approach for select patients on home nocturnal hemodialysis who have excellent hygiene and one or more of the following characteristics:
•An arteriovenous fistula with only a small segment available for cannulation
•Substantial pain or fear associated with the rope-ladder technique
•An arteriovenous fistula with an enlarging or large aneurysm
●Arteriovenous grafts – Arteriovenous grafts may be used successfully for nocturnal hemodialysis. The buttonhole technique is not practiced with these accesses. A different hole is used with every dialysis, following the conventional technique. Steel needles or plastic cannulas can be used.
●Single-needle dialysis – For patients on home nocturnal hemodialysis who dialyze via an arteriovenous fistula or graft, some home nocturnal hemodialysis programs use a single-needle technique to minimize the number of access punctures. The single-needle system provides adequate blood flow (average 200 mL/min), while providing extra safety in case of accidental disconnection by triggering an air detection alarm.
SAFETY — Safety while on home hemodialysis is of paramount importance [35]. Home hemodialysis is generally considered to be safe, provided that patients are carefully selected, are well-trained, and observe prescribed safety measures. In one report from two adult home hemodialysis programs in Canada, there was one death and six potentially fatal events among 190 patients and approximately 500 patient-years of treatment; six of the seven events involved bleeding, and five of seven involved a human error with a lapse in established protocol [36]. In another observational study, severe adverse events were rare (0.009 per patient-year of home hemodialysis) and predominantly related to needle dislodgement or air embolism [37].
To ensure the safety of the procedure, adequate taping of the needle and anchoring of the blood tubing are essential; enuresis pads wrapped around the connection are also considered essential [38]. Two inexpensive moisture sensors are placed strategically on the floor to detect dialysate and blood leaks. Blood leaks trigger an audible alarm. Dedicated disposable leak sensors are available, as well as nondisposable wireless leak sensors that stop the blood pump when triggered. Additional technologic updates have been developed, such as a clamp connected to a blood-loss sensor that clamps the venous line upon sensing moisture and forcing the dialysis machine to stop and alarm [39].
As noted above, a single-needle system provides extra safety in case of accidental disconnection by triggering an air detection alarm. (See 'Fistulas and grafts' above.)
Some centers practice live remote monitoring of patients at home [38,40,41]. All the information available on the dialysis machine, including conditions that trigger alarms, is available to an observer at the center. The patient who is not awakened by the alarm is called.
Live monitoring provides the following benefits:
●Helps prevent blood from clotting in an idle extracorporeal system
●Provides reassurance to the patient
●Ensures compliance
●Aids the collection of data
Despite these benefits, such monitoring has not yet detected life-threatening conditions. Thus, its use should be considered optional [42]. Most centers do not practice remote monitoring of patients on nocturnal hemodialysis, although some centers use remote monitoring for selected patients or for short periods of time (three months).
PATIENT SELECTION AND TRAINING — All patients capable of performing home hemodialysis or those with home helpers are eligible for nocturnal hemodialysis. Exclusion criteria include acute illnesses, uncontrolled seizure activity, labile type 1 diabetes (in the absence of a helper), and a contraindication to systemic anticoagulation [42]. The presence of older age, an unstable cardiovascular system, hypotension, diabetes mellitus, and/or ascites are all indications, and not contraindications, for nocturnal hemodialysis. An aid to facilitate the home dialysis choice for patients has been published [43].
Patient groups that can be preferentially targeted for nocturnal hemodialysis include the following:
●Incident patients followed in a chronic kidney disease (CKD) clinic. To prevent the state of dependence frequently encountered in in-center dialysis units, training should be instituted early or patients should be dialyzed temporarily in self-care settings. Use of transitional care unit settings is increasing and may lead to an increase in the number of patients opting for home hemodialysis [44,45].
●Patients ineligible for kidney transplantation. Nocturnal hemodialysis can be viewed as the dialysis modality closest to kidney transplantation [46,47].
●Patients with significant morbidity, including cardiac disease, diabetes mellitus, severe hypertension, intradialytic hypotension, dialysis-related symptoms, or large intradialytic weight gains.
●Patients who require conversion from peritoneal dialysis to hemodialysis and who want to maintain independence.
●Large-size patients or patients not adequately dialyzed because of poor access flow.
●Refractory hyperkalemia or hyperphosphatemia.
●Patients who are unable to meet fluid and diet restriction goals, or who wish to liberalize their dietary intake.
All patients interested in home nocturnal hemodialysis must understand and agree to the requirements of the training program. As part of a competency assessment, patients must be evaluated for their visual acuity, dexterity, physical fitness, and home environment. (See "Choosing home hemodialysis for end-stage kidney disease".)
Details regarding training of patients for home hemodialysis are presented at length elsewhere. (See "Home hemodialysis (HHD): Establishment of a program", section on 'Training of the patient' and "Choosing home hemodialysis for end-stage kidney disease".)
The adoption of nocturnal hemodialysis may be hampered by patient-perceived barriers, including lack of confidence in their ability to perform necessary duties (eg, self-cannulation), fear of a possible catastrophic event, and the reluctance to burden family members or caregivers [48]. Financial barriers can be significant [49]. Costs include increased home utility fees for the patients and low dialysis reimbursement rates, especially when more than thrice-weekly dialysis is planned. (See "Home hemodialysis (HHD): Establishment of a program", section on 'Barriers to implementation of HHD'.)
MAINTAINING PATIENTS ON NOCTURNAL HEMODIALYSIS — Specific strategies to prevent technique failure among patients on home hemodialysis are necessary. According to 2022 United States Renal Data System (USRDS) data, the longevity of home hemodialysis as a modality is only about 30 percent after 24 months (figure 1).
Reasons for technique discontinuation — Both psychosocial and medical reasons can lead to discontinuation of home nocturnal hemodialysis. Risk factors for home hemodialysis discontinuation include older age, cardiac disease, diabetes, drug use, alcohol, and smoking [50-52]. In one report of patients who exited a home hemodialysis program, medical instability was the predominant reason for modality change (65 percent), followed by patient or caregiver burnout (13 and 6 percent, respectively) and patient choice (9 percent) [53]. In another study, the primary reasons for switching from home hemodialysis were medical issues, lack of motivation, lack of confidence, and inability to cope with stress [54].
Strategies for prevention of technique failure in nocturnal hemodialysis — Key strategies to maintain patients on home nocturnal hemodialysis include the following:
●Addressing psychosocial needs
●Providing multidisciplinary extra support and monitoring
●Focusing on patient education and training
●Improving physician expertise
SUMMARY AND RECOMMENDATIONS
●Nocturnal hemodialysis regimen and personnel – Nocturnal hemodialysis can be practiced in the facility (thrice weekly) or at home (three to seven nights per week). Home nocturnal hemodialysis is performed either by the patient or partner (a partner not being absolutely required) during sleep for a variable amount of time, based upon the length of sleep desired (usually 6 to 8 hours in total). (See 'Required personnel' above and 'Time' above.)
●Dialysis prescription – Compared with conventional hemodialysis and depending on the frequency, the dialysate contains lower levels of bicarbonate, higher levels of calcium, and often contains phosphate. Typical flow rates are a blood flow rate of 200 to 300 mL/min and a dialysate flow rate of 300 mL/min. The typical volume of ultrafiltrate removed per day is approximately 1 to 2 liters, but higher volumes are well tolerated. (See 'Dialysate composition' above and 'Ultrafiltration' above and 'Blood and dialysate flow rates' above.)
●Anticoagulation and access – To maintain systemic anticoagulation, the standard heparin regimen is the administration of approximately 1000 units of heparin per hour. Central venous catheters, arteriovenous fistulas, and arteriovenous grafts have been successfully used for nocturnal hemodialysis. Safety devices are important to prevent accidental access disconnection and bleeding during sleep. An arteriovenous fistula is the preferred vascular access. (See 'Anticoagulation' above and 'Access' above.)
●Safety – Some centers practice live remote monitoring of patients at home, either via regular telephone lines or the internet, while others do not practice remote monitoring. Its use should be considered optional. (See 'Safety' above.)
●Patient selection and training – All patients capable of performing home hemodialysis are eligible for nocturnal hemodialysis. Exceptions include acute illnesses, uncontrolled seizures, labile type 1 diabetes in the absence of a helper, and contraindication to systemic anticoagulation. Significant comorbidities can be indications rather than contraindications for nocturnal hemodialysis. (See 'Patient selection and training' above.)
●Maintaining patients on nocturnal hemodialysis – Key strategies to maintain patients on home nocturnal hemodialysis include addressing psychosocial patient needs, providing multidisciplinary support and monitoring, focusing on patient education and training, and improving physician expertise.
ACKNOWLEDGMENT — We are saddened by the death of Andreas Pierratos, MD, FRCPC, who passed away in November 2022. UpToDate wishes to acknowledge Dr. Pierratos' many valuable contributions, including his past work as an author for this topic.
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