Dialysis

Dialysis is s biomedical procedure that stubstitutes the function of the kidneys by filttering waste products from the blood, balancing pH and equilibrating minerals. Since the filtering function of the kidneys is reduced, dialysis patients are required to carefully control their diets. Dialysis patients typically see excess storage of potassium and phosphorous, which can have deleterious effects on the patient if not controlled. Two standard methods to help control waste products are hemodialysis and peritoneal dialysis.

Kidneys
The function of the kidneys is the following:
 * 1) filtering of waste products from the blood
 * 2) balancing pH
 * 3) equilibrating minerals
 * 4) regulate excess fluids

Food is eaten by the mouth, flows down the esophogus and is broken down in the gut (stomach + intestines). Nutrients are absorbed principally by the cilia and liing of the instines. The nutrients and waste products enter the bloodstream through capillaries in the gut. These products are transported and circuilated through the blood. The kidneys, a part of the circulatory system, receive blood through arteries. Blood is transfered through various portions of the kidney through capilaries, including the critical nephrons that regulate minerals that provide nutrients to the body and control pH by osmosis. The waste products and excess fluids are filtered within the glomerulus in the form of urine, which is directly released into to the bladder via the ureter.

Hemodialysis
Hemodialysis substitutes the function of the kidney by filtering products in the blood. The arterial and venous blood is accessed by cathers, which are surgically placed by vaascular surgeons. The blood is passed through a dialyzer, which screens excess minerals and some proteins through a polymer filter, e.g. Polyflux. This process is suitable from patients having end-stage kidney disease. The patient can have hemodialysis treatment as often as 4 hours, 3 times per week at a dialysis center.

Peritoneal Dialysis
Peritoneal dialysis (PD) can complement the function of the kidney by removing waste products from the peritoneal fluid located in the cavity containing the gut. This fluid is accessed by a catheter inserted in the belly. The implant has holes through which body fluid is exchanged. In order to maintain patency of these holes, anti-thrombotic drugs are flushed in the cather, such as heparin. Since PD is longer, more frequent and less complicated that hemodialysis, patients can administer their own PD treatments which last approximately 8-10 hours each day, typically overnight.