Normal kidneys perform important functions such as regulation of body fluid volume, removal of metabolic waste products, discharge of toxins, regulation of blood pressure and the production of various hormones. Patients with end stage renal disease (ESRD) cannot effectively perform these functions. Renal replacement therapy (RRT) artificially performs two major functions – ‘cleaning’ the blood and regulation of fluid status. RRT can be performed by one of two methods – hemodialysis (HD) and peritoneal dialysis (PD).
The most commonly used method of renal replacement in the United States is in-center thrice weekly hemodialysis. With this method, patients undergo hemodialysis three times a week for 3-4 hours per session under the supervision of trained health care workers. However, studies have consistently shown that this method does not match normal kidney function well enough. Extended periods of dialysis or more frequent dialysis sessions have been shown to be associated with fewer deaths. Since longer dialysis sessions may last from 6-10 hours, nocturnal sessions are preferred as they free up patients for other activities during the day. When performed at home, there is the added advantage of the increased flexibility in patients’ daily schedules. Both modalities when performed at home require enough space to store equipment and supplies and both need to be performed in clean and hygienic environments to prevent infection.
Between hemodialysis and peritoneal dialysis, some patients may be better suited for one method as compared to the other. In many cases however, the choice is left to the patient. Here we discuss the relative differences in technique and the risks verses benefits of each modality.
Nocturnal Peritoneal Dialysis: Peritoneal dialysis requires dialysate to be placed into the abdominal cavity. This is done through a catheter that is surgically placed into the abdominal cavity. Peritoneal catheters may be complicated by infection at the catheter insertion site and peritonitis (an infection of the abdominal cavity).
Advantages as compared to PD:
Disadvantages as compared to PD:
A. In center nocturnal hemodialysis:
Depending on individual needs, in-center nocturnal hemodialysis is administered at the dialysis center as 8-10 hour sessions under the supervision of trained health care professionals. A typical session begins in the late evening and goes into the early morning. The patient can bring dinner, read, watch television, sleep or carry on any other activity that they can do while attached to a dialysis machine. Sessions are concluded in the early morning and the patient’s day is effectively freed up for other activities.
Advantages as compared to home nocturnal HD:
Disadvantages as compared to home nocturnal HD:
B. Home nocturnal hemodialysis:
Depending on individual needs, home nocturnal hemodialysis is administered in the patients home as 5-6 hour sessions, for 5/6 days a week, either by the patient himself or a partner. Dialysis sessions are remotely monitored over an internet connection by a centrally located unit. Complications, if any, are recognized by the staff at this unit and the patient is alerted by a phone call.
Nocturnal Peritoneal Dialysis: Dialysate fluid is placed into the abdomen. Blood contained within blood vessels lining the abdomen interacts with the fluid across the peritoneum, the natural membrane that lines the abdomen. Here again, the make-up of the dialysate fluid is such that toxins and waste products move from the blood into the dialysate fluid. The ‘impure or not clean’ dialysate is then removed, replaced with fresh dialysate and the process is repeated several times over. PD is usually performed in the home.
Peritoneal dialysis can be done either by continuous ambulatory peritoneal dialysis (CAPD) or nocturnal peritoneal dialysis. CAPD involves 2-5 fluid exchanges which are done manually during the day. Nocturnal PD is done at night using a machine called a cycler. Large bags of the dialysate are hung next to the bed connected to the cycler and to the PD catheter. The cycler performs 3-5 fluid exchanges while the patient sleeps, over an 8-10 hour period. Depending on individual needs, patients may leave their abdomen empty during the day. Others may have to perform an exchange during the day.