Dialysis

 

Dialysis is the process of artificially removing waste products and excess fluid from the body. This process is necessary when the kidneys are unable to perform their function.

There are many indications for dialysis, but the most common reason for dialysis is when the kidneys fail to properly filter waste products from the blood (renal failure). Kidney function may deteriorate rapidly (called acute kidney injury or acute kidney failure) or the kidneys may lose their ability to filter waste products slowly (called chronic kidney disease or chronic kidney failure).

In people with kidney failure, many doctors recommend dialysis if blood tests show that the kidneys are no longer able to filter waste products well and the accumulation of waste products is causing problems. For acute kidney injury, doctors continue dialysis until blood test results show that kidney function has returned. For patients with chronic kidney disease, dialysis may be given as long-term therapy or as a temporary measure until the patient has a kidney transplant. Dialysis treatment may be given as a short-term emergency or intensive care treatment to remove fluids, drugs, or poisons from the body.

 

Kidney Failure: Dialysis

The decision to start long-term dialysis is not easy, as it involves significant lifestyle changes, including dependence on medical equipment. However, for most people, a successful dialysis program provides an acceptable quality of life. Most people on dialysis can eat normal meals, have normal blood pressure, and avoid progression of nerve damage, severe anemia (a decrease in the number of red blood cells that carry oxygen to the body's cells), and other serious complications.

 

Dialysis usually involves a whole group of people:

The doctor prescribes a dialysis regimen, monitors complications and provides medical care.

The nurse monitors the general condition of the patient, teaches him about dialysis, explains to him what to do to maintain health, monitors the dialysis procedure, administers the drugs necessary for dialysis, and also supervises the work of the technical staff serving the dialysis.

Typically, a social worker assesses mental health, arranges transportation, arranges for dialysis at another location (when the patient is traveling), and provides home care if necessary.

The nutritionist selects a suitable diet and monitors the patient's response to changes in diet.

When dialysis is planned to be done temporarily (before a kidney transplant), this group of people also includes a transplant surgeon.

During a hemodialysis procedure, when blood is filtered outside the body through an "artificial kidney" machine:

 

●     a technical specialist is present from the very beginning of the procedure and monitors the dialysis machine throughout the entire dialysis procedure;

●     Doctors, such as a vascular surgeon and often an interventional radiologist, prepare blood vessels so that blood can be easily taken from the body and passed through a dialysis machine.

Sometimes another method (such as hemofiltration or hem perfusion) is used to temporarily filter the blood, which performs the same tasks as dialysis. These methods are most commonly used to remove poisons from the blood or to remove large amounts of fluid in people with acute kidney injury when dialysis is not possible.

 

Indications for dialysis in renal failure

●     Doctors decide on dialysis when a patient has certain conditions due to kidney failure:

●     impaired brain function (uremic encephalopathy);

●     some other serious symptoms (loss of appetite, vomiting, or weight loss);

●     inflammation of the heart sac ( pericarditis );

●     high levels of acidity in the blood ( acidosis ) that do not go down despite treatment

●     heart failure;

●     general hypervolemia;

●     hypervolemia in the lungs (pulmonary edema), not amenable to other treatment;

●     too high levels of potassium in the blood ( hyperkalemia );

●     high levels of calcium in the blood ( hyperkalemia );

●     Significant decrease in kidney function.

 

Types of dialysis

There are two main types of dialysis:

 

1. Hemodialysis
2. Peritoneal dialysis
3. Hemodialysis

During hemodialysis, blood is taken from the patient's body and pumped using an external device into the dialyzer ("artificial kidney"). The dialyzer filters metabolic products from the blood, and then the purified blood is returned to the body. It is possible to correct the total amount of fluid returned, in particular the excess fluid that accumulates during kidney failure.

 

Hemodialysis requires multiple access to the circulatory system. Although doctors can provide temporary access with a large intravenous catheter placed in a large vein, it is common to create an artificial connection between an artery and a vein ( arteriovenous fistula) to facilitate permanent vascular access.) surgically. Usually, a fistula is formed on the forearm, connecting the radial artery of the forearm with the cephalic vein of the forearm. As a result, the diameter of the cephalic vein increases, and the flow of blood through it also increases. Thus, the vein is prepared for multiple punctures. Fistulas are created by vascular surgeons. If it is impossible to create a fistula, then the artery and vein are surgically connected to each other using a synthetic connector (graft). A synthetic hemodialysis prosthesis is usually formed on the arm. To enable blood purification outside the body, during hemodialysis, a technician inserts needles into an arteriovenous fistula or vascular prosthesis of the patient.

 

To prevent blood clotting in the dialyzer, heparin, a drug that prevents blood clotting, is given during hemodialysis. In a dialyzer, a thin porous artificial membrane separates blood from fluid (dialysate). Fluid, waste products and electrolytes contained in the blood pass through the membrane and enter the dialysate. Blood cells and large proteins cannot pass through the small pores of the membrane and therefore remain in the blood. The dialyzed (purified) blood is then returned to the patient's body.

 

Dialyzers vary in size and efficiency. The dialysis procedure on average lasts about 3-5 hours. Most patients with chronic kidney disease need to undergo hemodialysis three times a week.

 

The most common complication of hemodialysis is a decrease in blood pressure during or shortly after dialysis. Blood pressure usually recovers between treatments. Patients (especially those starting hemodialysis treatment) may suffer from muscle cramps, itching, nausea and vomiting, headache, restless leg syndrome, and chest and back pain. Sometimes there is confusion, restlessness, blurred vision and/or convulsive states.

 

A fistula or synthetic prosthesis can also cause complications such as infection, blood clots, bleeding, and bulging of the vessel wall ( aneurysm formation ). Patients should inform their doctor immediately if the following symptoms occur:

 

●     pain;

●     redness or fever;

●     ruptures of adjacent tissues;

●     bruising;

●     prolonged bleeding in the area of ​​the fistula;

●     a sharp increase in blood vessels (for several days) near the prosthesis or fistula;

●     loss of pulse or a feeling of vibration, which is usually present in the area of ​​the prosthesis or fistula;

●     dropsy (edema).