Many kidney conditions are treated by dialysis to remove toxins, mineral buildup and excess fluid from the body when the kidneys have failed. More than 2.5 million people rely on regular dialysis treatment to prevent the further damage of organs these toxins can cause when they accumulate in the blood. Dialysis is performed while you are an inpatient with a kidney-related illness, at dialysis clinics chosen by your nephrologist and insurance provider, and sometimes at home.
During dialysis, a special vascular access in your lower arm allows the dialyzer—the “artificial kidney” machine—to pump blood out of your body where it is filtered externally to remove the waste products and excess fluid. While the blood is “cleaned” in the dialyzer, the machine also monitors the circulation of your blood outside of your body and controls the composition of the dialysis fluid that is used to flush out the metabolic waste products before with the filtered blood is then returned to your body. Anticoagulants may also be added to the dialysis solution to prevent blood clotting. Hemodialysis is generally performed for at least four hours and three times a week, often in a dialysis unit. Although some people receive training to perform hemodialysis at home, often with the help of a partner.
The peritoneal cavity—the lining of your abdomen—acts as the filter for cleaning your blood since it has characteristics similar to those of the dialyzer machine. The pores in the peritoneal membrane allow certain substances through, while retaining others. During peritoneal dialysis, your blood is filter in your body through a tube or catheter that is inserted into the peritoneal cavity in your abdomen. The dialysis solution containing glucose is fed through the tube and left to absorb the impurities in your blood. Later, the fluid containing the impurities of toxins and excess water is removed through the tube and drained off into a bag and replaced with fresh solution. This process of filling and draining can be done manually during the day, or at home at night using a cycler. There are two types of peritoneal dialysis: continuous ambulatory peritoneal dialysis and automated peritoneal dialysis using a cycler.
Continuous renal replacement therapy
For people critically ill with acute renal failure or end stage renal disease and who cannot tolerate regular hemodialysis, continuous renal replacement therapy is appropriate. This is a slower form of blood filtration that gently removes extra fluid and waste products, that is better tolerated by people who may be unstable as a result of shock or severe fluid overload. Both average and smaller sized people can undergo continuous renal replacement therapy and it can be adapted to meet changing needs.