Dialysis is a procedure that removes waste products from the body. When the kidneys are not functioning correctly, these waste products build up and remain in the blood. As the quantity of these waste products rise in the blood, the patient becomes sick with symptoms such as progressive nausea and vomiting, lack of appetite, muscle cramps and itching. This is called uremia. Family members may notice that the person with uremia may become sleepy, tired or weak.
Dialysis is a cleansing procedure that removes toxins and excess water from the blood (replacing the job the patient's kidneys were doing before they stopped functioning correctly). This is necessary when the kidneys are no longer able to filter these waste products and remove the extra fluid that accumulates. Dialysis is required when your kidneys are no longer performing enough of their function of cleansing the blood of waste and excess fluid (End Stage Renal Disease [ESRD] has set in). A person can lose approximately 80-90% of their kidney function before its the time for dialysis. There are two types of dialysis, hemodialysis and peritoneal dialysis.
Hemodialysis is done using an artificial kidney machine that directly filters the blood. This occurs by removing the blood from the body via a vein (called a "vascular access," typically in the forearm), running it through the artificial kidney machine (which performs the cleansing step), and reinjecting the blood back into the same vein (but in a slightly different location).
Hemodialysis usually occurs either in a dialysis center or in the home. The dialysis center has televisions for viewing. Most dialyzing patients will either watch TV, read a book or magazine or nap. Most folks who dialyze via hemodialysis are placed on a schedule that includes three days per week of dialyzing for approximately 4 hours. This schedule will typically be either Mon.-Wed.-Fri. or Tues.-Thurs.-Sat., and will either occur in the morning or during the afternoon.
Peritoneal dialysis (PD) is a procedure in which the natural lining of the abdominal cavity is used as a filter. This lining, called the peritoneal membrane, is richly supplied with small blood vessels. Types of PD include continuous ambulatory peritoneal dialysis (CAPD) and continuous cycling peritoneal dialysis (CCPD).
PD is done by instilling about two quarts of a special fluid (dialysate) through a catheter into the abdominal cavity and periodically draining and replacing the fluid. PD requires that a permanent catheter be placed into the abdominal cavity. This soft plastic tube is about 12 inches long with only 4-5 inches remaining outside the body. It is placed below the level of the umbilicus (belly button) and usually to either side of it. The catheter iinsertion is performed in the operating room and often with local anesthesia. The main concern with peritoneal dialysis is the risk of infection. Since the catheter is a direct opening into the abdomen, strict guidelines are used to avoid infection. Patients are examined monthly as outpatients and blood work is done to make sure that the dialysis is adequate.
CAPD requires no external machine. The dialysis is done by connecting the bag of dialysate to the abdominal catheter and allowing the fluid to flow into the abdominal cavity. At this point, the patient can return to their normal activity. After about 4-6 hours, the dialysate is allowed to flow back out of the cavity into the bag (via gravity). At this point the full bag of removed fluid is disconnected and a new bag of dialysate is attached. CAPD patients perform four exchanges per day, seven days per week. The exchanges are typically done once at wakeup, once at bedtime and two more times during the day
CCPD is a modification of CAPD. People who select CCPD dialyze via an automated machine at nighttime.
Continuous Cycling Peritoneal Dialysis (CCPD)
Continuous Ambulatory Peritoneal Dialysis (CAPD)