Home Dialysis Terms Defined
There are many terms and phrases associated with home dialysis that you may come across as you educate yourself about the home treatment options, and many of these terms and phrases may be unfamiliar to you.
The following is a list of commonly used home dialysis terms defined:
Arteriovenous (AV) fistula: An arteriovenous (AV) fistula is a safer form of vascular access for hemodialysis. An AV fistula is created by connecting one of a patient’s arteries to one of his or her veins using the patient’s own blood vessels. Once the fistula is created, it takes approximately three to six months for the fistula to “mature” or become developed enough to use. Fistulas are the preferred type of vascular access for all hemodialysis patients. Doctors prefer fistulas because they provide good blood flow and generally last longer than other types of access. Because a fistula is created from the patient’s own artery and vein, it is a natural part of the body.
Arteriovenous (AV) graft: An arteriovenous (AV) graft is a form of vascular access for hemodialysis. An (AV) graft is a man-made tube that is inserted into your arm to connect an artery to a vein. A graft is put in place during a surgical procedure that takes less than 90 minutes. During the surgery, the surgeon will sew one end of the graft to a vein and the other end to an artery. The surgeon either places the graft tubing in a straight line or curves it to form a loop. Grafts lie entirely under the skin and can usually be used for dialysis within two to six weeks.
Buttonhole technique: The buttonhole technique, also known as constant site cannulation, is a cannulation technique in which patients insert their dialysis needles into the same spot every time they do dialysis. This causes scar tissue to form, creating a hole much like the hole in a pierced ear. It usually takes about 10 cannulations with a sharp needle before the scar tissue forms a hole. Once the hole is created, patients can use blunt dialysis needles, which are more comfortable and safer than sharp ones.
Care partner: A care partner is someone who assists the dialysis patient with his or her at-home treatments. A care partner is strongly recommended for patients doing home hemodialysis (HHD), but is usually not required for patients doing peritoneal dialysis (PD). A care partner can be a family member such as a spouse or child, a friend or a professional caregiver. Care partners go through training with the patient so that they know how to assist in every part of the home dialysis treatment.
Continuous ambulatory peritoneal dialysis (CAPD): Continuous ambulatory peritoneal dialysis (CAPD) is a form of peritoneal dialysis in which the patient manually performs his or her exchanges. Each manual exchange takes about 30 minutes, and patients generally perform four exchanges a day. Exchanges are done by placing a bag of dialysate fluid up high on an IV pole or coat rack. Gravity then makes the dialysate flow down into the body through a tube running from the bag of dialysate to the catheter. When it’s time to drain, an empty bag is attached to the catheter and held lower to the ground so that gravity causes the dialysate to drain out.
Continuous cycling peritoneal dialysis (CCPD): Continuous cycling peritoneal dialysis (CCPD), also referred to as automated peritoneal dialysis (APD), is a form of peritoneal dialysis that uses a cycler machine to automate the filling and draining process. CCPD is done at night while the patient sleeps. The patient hooks his or her catheter up to the cycler, and the machine fills and drains the dialysate automatically.
Cycler: A peritoneal dialysis (PD) cycler is a small machine about the size of large fax machine that automates the filling and draining process of peritoneal dialysis (PD) so that patients can dialyze at night while they sleep.
Dialysate: Dialysate is a solution used during dialysis to remove waste and extra fluid from the blood. During PD, dialysate is put into the peritoneal cavity where it dwells, or stays, for a prescribed period of time while it pulls wastes and extra fluid from the blood. During home hemodialysis (HHD), dialysate flows through the dialyzer and cleans the blood.
Dwell time: The time during which the dialysate remains in the patient’s abdomen during peritoneal dialysis (PD) is known as the dwell time.
Exit site: The peritoneal catheter exit site is the place where the peritoneal dialysis (PD) catheter comes out of the body.
Home dialysis: Home dialysis is dialysis done at home, instead of in a dialysis center. Home dialysis is done by the patient and/or care partner. The patient and care partner are trained and supervised by professional nurses to do dialysis treatments on their own. There are two types of home dialysis: peritoneal dialysis (PD) and home hemodialysis (HHD).
Home hemodialysis (HHD): Home hemodialysis (HHD) is very similar to in-center dialysis except it is done in the home. HHD patients and their care partners are trained by a professional nurse to do their dialysis treatments at home. HHD uses a dialysis machine to clean the patient’s blood. Patients self-cannulate, or insert their own needles, and their blood travels through the dialysis machine to be cleaned, just like it does with in-center dialysis. There are two different ways of doing home hemodialysis (HHD): short daily home hemodialysis and traditional home hemodialysis.
Kt/V: Kt/V is a value used in both hemodialysis and peritoneal dialysis (PD) patients that measures how much dialysis is actually being accomplished. Inadequate dialysis may lead to illness or premature death. Monitoring Kt/V is one way to measure the effectiveness of the dialysis treatment.
Peritoneal dialysis (PD): Peritoneal dialysis (PD) is one of two types of home dialysis. PD uses the peritoneal membrane in the patient’s abdomen to clean the blood. A solution called dialysate is put into the peritoneal cavity in the patient’s lower abdomen through a catheter. The dialysate fills the peritoneal cavity and dwells there for a prescribed period of time. When the time is up, the dialysate is drained and takes excess fluid and wastes with it. The peritoneal cavity is then filled with fresh dialysate.
Peritoneal dialysis catheter: A peritoneal dialysis (PD) catheter is a soft, flexible plastic tube about the length of a ruler and the width of a pencil. A PD catheter is needed for peritoneal dialysis. The catheter is placed during a surgical procedure. During surgery, one end of the catheter is inserted into the patient’s peritoneal cavity. The rest of the catheter is placed through the patient's lower abdomen, underneath and to the side of the belly button.
Peritoneal dialysis (PD) exchange: During peritoneal dialysis (PD) treatments, a fluid called dialysate is put into the patient’s abdomen through a PD catheter. The dialysate remains in the abdomen for a specified amount of time before it is drained and replaced with fresh dialysate. When the dialysate is drained, the wastes and extra fluids are also drained. This draining, filling and dwelling process is called an exchange. Exchanges can be done manually or with a machine called a cycler.
Peritoneal equilibration test (PET): A PET test is done on peritoneal dialysis (PD) patients and measures how quickly toxins from the blood are adsorbed across the peritoneal membrane into the peritoneum after fluid is put into the abdomen. It is useful for determining an optimal PD prescription.
Rope ladder technique: The rope ladder technique is the method of cannulation most often used in dialysis clinics. With this technique, the needle insertion point is not the same every time. Instead, the needle is inserted about two inches from the place it was inserted during the last dialysis treatment.
Short daily home hemodialysis (HHD): Short daily home hemodialysis is home hemodialysis (HHD) generally performed five or six times a week for two to three hours per session, as opposed to the fewer, longer sessions of traditional in-center hemodialysis.
Self-cannulation: Self-cannulation occurs when the patient inserts his or her own dialysis needles. A patient must insert two dialysis needles into his or her vascular access so that blood can flow from the body to the dialysis machine to be cleaned and then back into the body again. In-center dialysis patients generally have a nurse insert their dialysis needles, but home hemodialysis (HHD) patients insert their own dialysis needles or have their care partner insert them.
Traditional home hemodialysis (HHD): Traditional home hemodialysis is very similar to in-center hemodialysis. Traditional home hemodialysis treatments are generally performed three times a week for four hours per session, but patients have the option of dialyzing more frequently to achieve more favorable clinical results.
Vascular access: Hemodialysis patients must have a vascular access created in either their arm or leg to allow blood to flow from their body through the dialysis machine to be cleaned, and back into their body. There are two types of vascular access: an arteriovenous (AV) fistula and an arteriovenous (AV) graft.
