Dialysis or blood washing is the purification of blood, usually by means of an artificial kidney. It is used when kidney functions are impaired and the organs can no longer provide vital blood washing in the body. There are several procedures for dialysis, the most common being hemodialysis.
What is dialysis (blood washing)?
Dialysis is a blood purification procedure used as part of kidney replacement therapy. Dialysis is artificial blood washing. Normally, the kidneys do this work in the body. They clean the blood, filter out harmful metabolites, and remove excess water from the body. If the kidneys are sick or too weak and can no longer perform this function, the blood must be purified artificially. Dialysis is used in approximately 85-90% of all cases of loss of function. In dialysis, blood from the body’s vascular system is passed through a purification system that replaces the kidneys. It is filtered, cleansed of harmful substances and flows back into the bloodstream after the procedure. The purification of blood is vital; without it, the body would cease to function. If the kidneys fail, without dialysis harmful substances would accumulate in the organism and certain processes in the body would no longer be guaranteed.
Function, effect and goals
Dialysis is usually used for chronic kidney failure. However, it is also used in acute cases of poisoning, when the kidneys need to be helped to cleanse the blood, or when they fail for a short time due to trauma (acute renal failure). There are two main types of dialysis procedures used. One is hemodialysis, like which the cleansing takes place via an artificial kidney outside the body (extracorporeal dialysis). The second type is peritoneal dialysis, in which the blood is filtered through the peritoneum of the patient inside the body. Hemodialysis is the most commonly used method. For hemodialysis, a shunt is first placed in the patient during a minor surgical procedure. This is a connection between an artery and a vein and is used to dilate the vessels to increase blood flow. The blood is then directed into the artificial kidney via a tube system. There, it flows in a rinsing fluid (dialysate) across a special membrane that filters out harmful substances and water, and then flows back into the vascular system via the shunt. Dialysis lasts about four to five hours and is usually performed three times a week at a dialysis center. Peritoneal dialysis cleans the blood inside the body by using the peritoneum as a filter and the abdominal cavity as a container for the flushing fluid. The dialysate is filled into the abdominal cavity via a catheter and, after the cleansing process, is discharged again together with the now contained harmful substances. The patient can perform peritoneal dialysis independently at home. It is performed either several times a day or overnight, whereby the nocturnal procedure allows the patient more freedom and better mobility in everyday life. Other blood purification procedures include hemofiltration, hemodiafiltration and hemoperfusion. In hemofiltration, the blood plasma is drawn out of the blood through a membrane, removing the harmful substances. This is done without dialysate. Hemodiafiltration is a combination of dialysis and filtration. Hemoperfusion is used specifically for poisoning and is performed only in special clinics. In this method, the blood is passed over adsorbents. These are substances that, because of their surface structure, are able to bind other substances, such as poisons.
Side effects, risks and dangers
Dialysis cannot replace a kidney completely or permanently. Therefore, this procedure is helpful only for a certain period of time. In case of complete kidney failure, kidney transplantation must be sought in the long run. Dialysis is also very stressful for the patient psychologically and physically. If the artificial purification of the blood is carried out over a period of years, damage can occur to the vessels and joints or heart disease. Patients must also observe certain dietary rules.They should consume no more than one liter of fluid a day and they must avoid foods containing potassium, since the lack of kidney activity means that more potassium remains in the body than normal and this can damage the heart. Patients should also take vitamins in the form of medication, since certain vitamins essential for life are flushed out of the body by dialysis.
