kidney and urinary tract disorders
Dialysis
Types of Dialysis
There are two types of dialysis: Hemodialysis Peritoneal dialysis In hemodialysis, blood is removed from the body and pumped by a machine outside the body into a dialyzer (artificial kidney). The dialyzer filters metabolic waste products from the blood and then returns the purified blood to the person. The total amount of fluid returned can be adjusted, in particular the excess fluid that builds up during kidney failure can be removed. Hemodialysis requires repeated access to the bloodstream. Although doctors can achieve temporary access by inserting a large intravenous catheter in a big vein, usually an artificial connection between an artery and a vein (an Arteriovenous Fistula ) is surgically created to make long-term access easier. In this procedure, typically the radial artery in the forearm is joined with the cephalic vein in the forearm. As a result, the cephalic vein subsequently enlarges and blood flow through the vein increases, making the vein suitable for repeated puncture with a needle. Fistulas are created by vascular surgeons. When a fistula cannot be created, an artery and a vein may be surgically connected to each other using a synthetic connector (graft). Grafts are often placed in the person's arm. In hemodialysis, a technician places needles into the person's fistula or graft to allow the blood to be removed for cleaning. , a drug that prevents clotting, is given during hemodialysis to prevent blood from clotting in the dialyzer. Inside the dialyzer, a porous artificial membrane separates the blood from a fluid (the dialysate). Fluid, waste products, and Overview of Electrolytes in the blood filter through the membrane into the dialysate. Blood cells and large proteins are unable to filter through the small pores of the membrane and so remain in the blood. The dialyzed (purified) blood is then returned to the person’s body. Dialyzers have different sizes and degrees of efficiency. Dialysis treatment time is usually about 3 to 5 hours. Most people who have Chronic Kidney Disease need hemodialysis three times a week. The most common complication of hemodialysis is low blood pressure during or shortly after dialysis. Blood pressure usually increases during the period between treatments. People, particularly when starting hemodialysis, may have muscle cramps, itching, nausea and vomiting, headache, restless legs syndrome, and pain in the chest and back. Less often, they can have confusion, restlessness, blurred vision, and/or seizures. Complications can also involve the graft or fistula, such as infection, blood clots, bleeding, and bulging ( Aortic Aneurysms formation). People should promptly notify their doctors if any of the following occurs: Pain Redness or warmth Breaks in nearby skin Bruising Prolonged bleeding from the fistula site Rapidly enlarging (over a few days or less) bulge over the graft or fistula Loss of the pulse or vibratory feeling that the graft or fistula site normally has Swelling (edema) The abdominal organs, such as the stomach and intestines, are inside a large hollow space called the abdominal cavity. The peritoneum is a membrane that lines the abdominal cavity and covers the abdominal organs. In peritoneal dialysis, that membrane acts as a filter. This membrane has a large surface area and a rich network of blood vessels. Substances from the blood can easily pass through the peritoneum into the abdominal (peritoneal) cavity. A fluid (dialysate) is infused through a catheter inserted through the abdominal wall into the peritoneal space within the abdomen. The dialysate must be left in the abdomen for a sufficient time to allow waste products from the bloodstream to pass slowly into it. Then the dialysate is drained out, discarded, and replaced with fresh dialysate. A soft silicone rubber or porous polyurethane catheter allows the dialysate to flow smoothly and is unlikely to cause damage. A catheter can be put in place temporarily at the person’s bedside, or it may be surgically put in place permanently. One type of permanent catheter eventually forms a seal with the skin and can be capped when not in use. Peritoneal dialysis can be done using a machine (called automated peritoneal dialysis) or without one (using manual techniques). Manual peritoneal dialysis, generally done using continuous ambulatory peritoneal dialysis, techniques are the simplest. No machine is used. The dialysate is usually drained and replenished 4 or 5 times per day. Generally, 3 of these dialysate exchanges are done during the day, with dwell times of 4 hours or longer. An exchange is done at night with a long dwell time of 8 to 12 hours during sleep. Automated peritoneal dialysistechniques are becoming the most commonly used forms of peritoneal dialysis. In automated peritoneal dialysis, an automated device does multiple exchanges during the night while the person sleeps. These techniques minimize the number of exchanges during the day but prevent mobility at night because of cumbersome equipment. Sometimes a daytime exchange time is used. Automated peritoneal dialysis techniques are further divided into three subcategories: Continuous cyclic peritoneal dialysis uses a long (12- to 15-hour) daytime dwell period and 3 to 6 nighttime exchanges done with an automated cycler. Nocturnal intermittent peritoneal dialysis uses exchanges done with a cycler at night while the person's peritoneal cavity is left without dialysate fluid during the day. Tidal peritoneal dialysis is a modification in which some of the dialysate fluid is left in the peritoneal cavity from one exchange to the next. This technique may be more comfortable for the person. Tidal peritoneal dialysis may be done with or without a daytime dwell period. Some people require a combination of continuous ambulatory peritoneal dialysis and continuous cyclic peritoneal dialysis to achieve adequate removal of waste products from their blood. Many factors, including lifestyle, must be considered in determining which type of dialysis is best for a person. Doctors recommend hemodialysis for people with recent abdominal wounds or abdominal surgery or defects in the abdominal wall that make peritoneal dialysis difficult. Peritoneal dialysis is better tolerated than hemodialysis in people whose blood pressure fluctuates frequently between periods of high or normal pressure and periods of low blood pressure. People typically undergo hemodialysis at a dialysis center3 times a week for 3 to 5 hours at a time, usually outside of a hospital. The main advantage of in-center dialysis is that the dialysis staff manages the treatment. In-center nocturnal hemodialysisis a good choice for people who experience certain difficulties (for example, high fluid gains, low blood pressure, or difficult-to-control phosphorus levels). Although this variation of dialysis is also done 3 times a week, the sessions are longer, lasting from 6 to 8 hours each. Home hemodialysiscan also be done on a conventional schedule (3 times per week during the daytime), or at night. Most home hemodialysis programs require a care partner who is able to help with the treatments if needed. People treated with home dialysis may have longer lives and better quality of life than people treated with conventional hemodialysis. Peritoneal dialysiscan also be done at home, eliminating the need for travel to a hemodialysis center. The most common and troublesome complications of peritoneal dialysis are infection of the peritoneal fluid (causing inflammation of the peritoneum, called Peritonitis ) and infection of the area where the catheter enters the skin (insertion site). Peritonitis may cause constant, sharp, severe pain throughout the abdomen, but sometimes causes little pain. Infection at the insertion site causes redness of the skin and pain at the insertion site. Such infections can be treated with antibiotics and careful wound care. When the kidneys fail, waste products and excess water can be removed from the blood by hemodialysis or peritoneal dialysis. In hemodialysis, blood is removed from the body into a dialyzer (called an artificial kidney), which filters the blood. An artificial connection between an artery and a vein (arteriovenous fistula) is made to facilitate the removal of blood. In peritoneal dialysis, the peritoneum is used as a filter. The peritoneum is a membrane that lines the abdomen and covers the abdominal organs, creating a space within the abdomen called the peritoneal space or abdominal cavity. 