CAPD is usually done during the day. The dialysis fluid is introduced into the abdomen. The person goes about his or her normal activities for four or five hours. Dialysis is occurring continuously during that time using the peritoneal membrane as a filter. At the end of the time period, the person drains the used fluid by attaching a bag to the port in his or her abdomen and placing the bag on the floor.
Gravity drains the fluid into the bag.
Fresh fluid is introduced through the port. Then, the person is again able to resume his or her normal schedule for another four to five hours. APD works in the same manner as CAPD, except that the exchanges are usually done at night. A machine called a cycler is needed to warm the exchange fluid and pump the right amount into and out of the abdominal port at the right times while the person sleeps. It is usually necessary for the person to leave the fluid from the last exchange of the night in the abdomen during the day.