Modality Definitions

Haemodialysis is a procedure used to maintain a patient with end stage renal failure by using an artificial kidney machine (or "dialysis machine") to replace the excretory function of the failed kidneys.  Blood from the patient is pumped from the body through special tubing to the dialysis machine, where it travels through the dialyser and back to the patient.  The procedure is usually carried out three times per week and takes four to five hours.

Home dialysis is the preferred option for many patients.  If home haemodialysis is chosen, the individual is fully trained to manage their own dialysis with the assistance of a partner or spouse, parent or friend.  In conventional home haemodialysis, patients dialyse for 4-5 hours, three times per week during daytime hours. 

Nocturnal home haemodialysis occurs overnight while the patient sleeps.  Patients are trained to self-care at home and do not need a carer or family member to assist.  Patients will dialyse for up to 8-10 hours either every second night or 6 times per week while they sleep.

This dialysis procedure is carried out at the hub unit only.  Dialysis in a hub unit is best reserved for those with serious medical problems who need immediate access to medical care during dialysis or who, for clinical reasons, are not suitable to receive their dialysis in a satellite centre.  Patients are also admitted to the hub for training or while waiting placement in a satellite.  Hospital haemodialysis may also be called in-patient haemodialysis.  Patients receiving routine maintenance dialysis (due to inability to access suitable dialysis close to the patient’s home) in a hub facility should be defined as satellite patients.

The dialysis procedure is carried out in a hospital or self care facility located away from the hub site.  Satellite units may be wholly operated and staffed by a hub, or staffed and run by another hospital.

In peritoneal dialysis the dialysing fluid is inserted into the peritoneal (abdominal) cavity at regular intervals, and the waste products diffuse into it.  The peritoneum is the membrane that lines the abdominal cavity and it is across this membrane that the chemical exchange between the blood capillaries and the dialysing fluid takes place.  After a period of time the dialysing fluid is drained from the cavity.

CAPD is usually performed four times per day.  Each exchange takes about 30 minutes to perform, and can be done almost anywhere, provided a clean area is available.  In between each exchange the patient is free to undertake the regular activities of daily living.

This requires a machine to regulate the movement of fluid into and out of the peritoneal cavity.  The patient is attached to the machine at night before going to sleep, and while they sleep the machine performs 6-8 exchanges.  During the day, solution is left in the peritoneal cavity so that dialysis can still occur slowly.

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