| Renal dialysis is a mechanical method of removing waste products and excess fluid from the blood when the kidneys are unable to do so (renal failure). The two forms of dialysis are hemodialysis and peritoneal dialysis. Hemodialysis cycles blood through a machine that filters the blood and returns it to the body cleaned of waste. Peritoneal dialysis cycles fluid into and out of the abdomen using the individual's own abdominal membrane (peritoneum) as a filter.
In acute renal failure, which is a sudden, severe decrease in the blood filtering function of the kidneys, dialysis is carried out intensively over a period of days or weeks until the kidneys work normally again. Chronic renal failure usually involves progressive kidney dysfunction and may require hemodialysis several times a week for the rest of the individual's life or until a kidney becomes available for transplant.
Acute renal failure may be caused by pre-existing renal disease (end-stage renal disease or ESDR) or liver disease (cirrhosis), toxic reactions to allergens or drugs, surgery, trauma, reduction of blood flow to the kidneys, acute fluid loss and dehydration, or obstruction of urine flow. It results in harmful accumulation of protein wastes (urea and creatinine) that are normally filtered out of the blood by the kidneys and excreted in urine. Acute renal failure occurs in approximately 7.2% of all hospitalized individuals (Liano 811) and in 30% of all individuals treated in intensive care units (Smith).
Chronic renal failure stems from conditions or diseases causing progressive damage to the internal structures of the kidneys. It may be caused by factors present at birth (congenital), a defect of the immune system (immunological cause), inflammatory diseases, infectious diseases, anti-inflammatory medications, diabetes, multiple myeloma, high blood pressure (hypertension), obstruction in the urinary tract, or trauma to the kidneys. |
Source: Medical Disability Advisor
| Renal dialysis is a method of mechanically removing protein waste products (urea and creatinine) and excess fluid from the blood when damaged or dysfunctional kidneys are unable to perform this essential function (renal failure).
Healthy kidneys filter approximately 150 liters of blood daily. From this blood, the kidneys reabsorb important elements such as sodium, potassium, calcium, amino acids, glucose, and water. In turn, the kidneys excrete waste products such as excess minerals, toxins, and drugs in the form of urine. In damaged kidneys, this process may fail, either suddenly (acute renal failure) or gradually (chronic renal failure). Wastes begin to accumulate in the blood (uremia) causing harmful or even life-threatening effects such as systemic poisoning (sepsis). Dialysis removes wastes and excess fluid from the body when damaged kidneys cannot perform this function. |
Source: Medical Disability Advisor
| Hemodialysis may be done in the hospital or a dialysis clinic. Approximately 5% of individuals undergoing dialysis in the US perform the procedure themselves with a home kidney dialysis machine. Some individuals have technicians come to their homes to perform hemodialysis using a portable dialysis machine.
Prior to the first course of hemodialysis, a surgical procedure is performed to join an artery to a vein forming an external shunt or arteriovenous fistula. The shunt or fistula provides an accessible site through which the individual's blood can be drawn into the dialysis machine and then returned when it has been filtered. The shunt or fistula is left in place for each subsequent dialysis procedure. A small dose of anticoagulant (heparin) may be instilled into the shunt between dialysis procedures to prevent blood clots from forming and obstructing the shunt.
The procedure requires no anesthesia. A needle connected to the shunt passes blood from the individual through plastic tubes into the machine. The machine consists of many layers of special membrane. This membrane separates the blood from the dialysing solution called dialysate. Urea and creatinine, the nitrogen end-products of protein metabolism (amino acid metabolism), along with excess fluid from the blood pass through the membrane and into the dialysate, which is then discarded. The purified blood is then returned to the individual. Each dialysis session lasts 2 to 6 hours. The individual's heart rate, blood pressure, and respiration are monitored throughout the procedure. Blood chemistries may be drawn before, during, and after the procedure to monitor changes in circulating levels of blood constituents that occur in response to treatment.
Although peritoneal dialysis is usually performed in the hospital, an increasing number of individuals now dialyse themselves at home through continuous ambulatory peritoneal dialysis. This portable self-dialysis technique allows an individual to have control over his or her own care. It requires a simple surgical procedure, but no medical equipment and usually little assistance.
Prior to the first ambulatory dialysis, a flexible synthetic catheter is inserted through a small incision into the abdominal cavity (insertion of a peritoneal catheter). The catheter is left in place indefinitely. The peritoneum is a smooth piece of tissue covering the abdominal contents like an apron. The peritoneum serves as a filter in the dialysis procedure. A special solution (dialysate) is instilled via the peritoneal catheter into the abdominal cavity. The dialysate remains in the abdominal cavity for a prescribed period of time (approximately 30 to 60 minutes). The dialysate attracts excess fluid, electrolytes, and some toxins from the blood vessels in the peritoneum. The dialysate and the excess fluid, electrolytes, and toxins are then allowed to flow out of the peritoneal catheter into a collection bag. The individual is usually weighed prior to and following the procedure. A record is kept of the amount of fluid instilled and the amount withdrawn. |
Source: Medical Disability Advisor
| Outcome with dialysis procedures is dependent on the underlying disease process and physical condition of the individual. Acute renal failure is often reversible while chronic renal failure is not. In general, those undergoing dialysis therapy have an average life expectancy of 4 years although many survive as long as 25 years on dialysis therapy. |
Source: Medical Disability Advisor
| Complications of the hemodialysis procedure include dehydration, bleeding, and electrolyte imbalance, which can affect the heart rate. Complications associated with the hemodialysis shunt are infection, blood clot (thrombosis), and weakening of the shunt arterial wall (aneurysm). Common complications of peritoneal dialysis are infection and inflammation of the abdominal covering (peritonitis). |
Source: Medical Disability Advisor
| Individuals on either form of renal dialysis should be restricted from any work such as lifting heavy objects or wearing restrictive belts or harnesses that could dislodge or contaminate an indwelling catheter or shunt.
Individuals on continuous ambulatory dialysis may require an additional break for approximately 1 hour to perform a dialysis exchange during the day. Special accommodations may be needed to perform the dialysis procedure at work. Hemodialysis treatments are most often carried out 3 times weekly with treatments lasting 3 to 5 hours each time. The procedure should be performed in a clean environment. Accommodations should be made to allow the individual to be seated and hang the sealed dialysis bag during the procedure. |
Source: Medical Disability Advisor
| Clochesy, John M., et al., eds. Critical Care Nursing. 2nd ed. Philadelphia: W.B. Saunders, 1996.Liano, F., et al. "Epidemiology of Acute Renal Failure: A Prospective, Multicenter, Community-Based Study." Kidney International 50 3 (1996): 811-818. National Center for Biotechnology Information. National Library of Medicine. 8 Dec. 2004 <PMID: 8872955>. Mangram, A. J., et al. "Outbreak of Sterile Peritonitis Among Continuous Cycling Peritoneal Dialysis Patients." Kidney International 54 4 (1998): 1367-1371. National Center for Biotechnology Information. National Library of Medicine. 8 Dec. 2004 <PMID: 9767557>. |
Source: Medical Disability Advisor
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