Kidney dialysis (hemodialysis): what is it, indications, how long people live

It is known that life expectancy directly depends on the condition of the kidneys. But only the chronically ill really know what is renal failure.

His body works in the mode of ever-increasing poisoning by the wastes of its own metabolism, because the organs of purification and excretion cannot cope with their task.

Smells of acetone, vinegar and other poisons in the air he exhales. They are clearly read by others, among other unpleasant odors, but give only a distant idea of ​​what is going on inside the body at this time.

The skin connected to the evacuation of toxins also exudes a waste of no less strength.

And then extremely clogged biological filters fail. They refuse to serve, causing the sick person to despair.

But not with someone who already has experience in hemodialysis. Such a patient does not bring the matter to a critical point - he knows: it's time to visit the dialysis center.

What is kidney dialysis?

The term "artificial kidney" apparatus is widely known. But for those who have questions for the kidneys, the unit saves lives. Or extends it for years.

An artificial kidney machine is a construction (machine) that makes renal hemodialysis possible.

The literal translation of the term "dialysis" means: separation or fractionation. Therefore, the literal answer to the question: kidney dialysis, what is it - means a division into good and bad. Thanks to the machine, which takes over the function of failing kidneys, the good that the body needs is returned to it, the obscene is removed.

Kidney hemodialysis is an artificial purification of the blood from toxins. During the procedure, it leaves the body for a short time in order to return to it cleansed.

“Leaving” does not mean at all that it is merging from the bloodstream somewhere - it continues to circulate, driven by the heart.

But some interference is made in its movement - the "artificial kidney" apparatus, or hemodialyzer, is connected.

Blood comes into it from:

• punctured vein, or
• direct arteriovenous connections, or
• graft - a synthetic tube that mimics the saphenous vein.

Leaving it already cleansed, it returns to the bloodstream through punctured vein.

The entire volume of blood is passed through the apparatus many times. The process is carried out either in sessions at 4-5 o'clock, or runs around the clock constantly. Depending on the pathology option, needs (and financial capabilities) of the patient, constructions are used:

• stationary;
• portable, body-worn, weighing 4-7 kg.

All this time, the movement of blood does not stop for a moment - it moves forward by contractions of the heart, which continues to perform its function as a pump. The procedure is exactly the same as a natural process. Only in the middle of the blood path from heart to heart there is a kidney constructed by man.

A short excursion into chemistry and physics

An illustration of the process is the purification of smoking smoke in a hookah, where it is passed through water and then consumed.

Kidney hemodialysis uses 3 physical and chemical laws, which the diffuser allows to realize - filter apparatus, which is a membrane with selective permeability.

Process diffusion happens through a membrane between the hemodialysis solution and the patient's blood. It allows you to extract compounds with given molecular weights from the blood.

In accordance with the pore diameter and other clear parameters of the filter membrane, these are electrolyte ions and proteins of the β2-microglobulin category.

But in parallel there is (possible) and the reverse process - the transition from the solution for hemodialysis into the blood of electrolytes and high molecular weight compounds. Considering this fact, a given concentration of electrolytes is maintained in the dialysate solution, which allows maintaining the salt balance in the patient's blood. To prevent the penetration of microbial poisons and other toxins into the patient's blood, the working solution is systematically cleaned.

Insufficient perfection of filtering membranes does not yet allow extraction from blood toxins, chemically associated with proteins, as well as their hydrophobic fractions.

Removal of hydrophobic fractions of toxins occurs using the same filter due to the process convection, possible due to the presence of osmotic pressure. It arises due to the difference in the concentration of solutions on different sides of the membrane.

The blood pathway during hemodialysis is lengthened and difficult. Therefore, to facilitate filtration through the membrane, the hemodialyzer has its own pump. Due to its work, pressure is created by blood on the surface of the membrane, and the process is started ultrafiltration - removal of excess water from the body.

The rest of the design is:

• blood pipeline;
• a dialysate solution propulsion system and
• control system for multiple parameters of both environments.

To prevent blood clotting, it is used anticoagulant (most often heparin).

Summary: since each chemical compound has a certain electric charge, specific gravity, chemical and spatial structure, kidney hemodialysis is electrochemical sorting on the beneficial and harmful to the body with the regular removal of the harmful with the help of the apparatus.

As a result of using a hemodialyzer, the following occurs:

• extraction from the blood of most nitrogenous compounds that are not chemically bonded to proteins;
• ridding the body of edematous fluid.

When and to whom is hemodialysis of the kidneys indicated?

If recently intravenous injection was equivalent to surgery, then hemodialysis of the kidneys is essentially an operation.

Therefore, before starting hemodialysis, not only the indication for the procedure is taken into account, but also factors that can complicate (make it impossible) the course of the operation - contraindications.

The main testimony for the hemodialysis procedure there are options:

• acute renal failure;
• chronic renal failure;
• poisoning with medicines or poisons (subject to their ability to pass through the membrane of the hemodialyzer);
• severe disorders of the electrolyte balance of the blood;
• alcohol intoxication;
• life-threatening overhydration (category of pulmonary edema, brain), which cannot be eliminated by other (conservative) methods. In the latter version, to improve the condition, we use the method isolated ultrafiltration.

The basis data are used to prescribe hemodialysis procedures laboratory and instrumental diagnostics:

• indicators of the level of urea, creatinine, uric acid in blood;
• Ultrasound, MRI of the kidneys.

Contraindications

Kidney hemodialysis has contraindications both relative and absolute.

The first category includes:

• pulmonary tuberculosis;
• conditions with the possibility of massive bleeding (stomach ulcer and KDP, fibroma of the uterus).

The second is the options:

• mental disorders and pathologies (epilepsy, schizophrenia, psychosis);
• malignant neoplasms in an incurable stage (for example: colon cancer, throat cancer at stage 4);
• blood diseases (anemia, leukemia, Werlhof disease, multiple myeloma);
• severe neurological pathologies;
• diabetes in patients over 70 years old or senile (over 80 years old) age;
• a combination of two (or more) significant pathologies such as advanced atherosclerosis, cirrhosis of the liver, diseases with respiratory failure;
• drug addiction and alcoholism without the likelihood of rehabilitation.

About security guarantees

In addition to the emergence of a number of social and financial issues in front of the patient (the cost of one course reaches 1.5 million rubles, because for 1 session the volume of dialysate is about 120 liters), one should not discount the possibility for him complications during this mini-operation.

Since the kidneys not only participate in the cleansing of the internal environment of the body, but are also complex hormone-producing formations, risk of occurrence complications as:

• arterial hyper- or hypotension;
• hyper- or hyponatremia;
• convulsive syndrome or seizure of epilepsy;
• air embolism or thrombus formation;
• weakness, dizziness, nausea, vomiting, or heart rhythm disturbances due to changes in intracranial pressure;
• an allergic response to the components of the dialysate solution.

In the age of disposable catheters and syringes, a natural question arises: is it not dangerous to use a device that simulates the work of the kidneys? Could any infection of the hepatitis or HIV-AIDS category be transmitted through the device?

Unintentional infection the patient during the preparation of the procedure is unlikely, but it is also possible - it all depends on the state of immunity and the general status of the body. Indeed, with the loss of kidney function up to 85% (which is the basis for treatment), the state of the internal "climate" often changes irreversibly.

"Artificial kidney" - the only method of blood purification?

After receiving an answer to the question: kidney dialysis, what is it - it would be unfair not to get acquainted with alternative methods of blood purification.

In addition to cleansing with an artificially constructed kidney, there are other methods based on the same principle of a restricted membrane.

At peritoneal dialysis the role of the filter is performed by its own peritoneum the patient to be cleaned when intestinal dialysis the same function is performed by colon wall.

Although both methods are less effective, they make it possible to achieve a satisfactory result when hemodialysis is contraindicated.

In addition, they differ in the lower cost of ingredients and equipment.

The method of detoxification hemosorption is somewhat different. It offers the purification of the patient's blood by its perfusion through a detoxifier - a special column-filter made of activated carbon or another type of sorbent.

Used in a specialized hospital, the technique, which is also cheaper in terms of compared with hemodialysis, has its own field of application in the removal of a number of toxic substances from organism.

After solving a number of technical issues (such as replacing a sorbent of a simple composition with ion-exchange resins), this method promises great prospects.

In the case when all options for detoxification have been exhausted, the patient has the last chance to survive - kidney transplantation.

On the need for a regimen and diet for hemodialysis

Due to the load on the body, which increases as with all options renal failure, and in the process of its hardware treatment, there is a need for therapeutic nutrition.

• Due to the forced circulation of blood and aggressive intervention in the existing balance of metabolism, part of the amino acids, minerals and vitamins, the supply of which should be replenished by the consumption of high-grade protein foods, predominantly of animal origin.
• In the presence of arterial hypertension, it is prescribed completely salt-free diet.
• Due to a sharp decrease in the volume of diuresis (oliguria of any genesis: with cardiac, renal, hepatic insufficiency), consumption water is also sharply limited.
• Due to a disorder of excretion in the urine potassium it is necessary to reduce the consumption of foods rich in this substance in order to avoid its overabundance in the body.
• Balance disorder phosphorus and calcium - minerals working in close conjunction with potassium, there is a need for forced correction of their content in the blood.
• Renal failure causes greater caution about compounds aluminum. This microelement, which gets inside when using aluminum dishes or is part of complexes of multivitamins, becomes very toxic under the changed new conditions. Therefore, rash behavior and non-compliance with a diet can become cause of anemia, bone tissue damage and neurological pathology.

For drug correction of the level of all the listed trace elements, repeated laboratory diagnostics are required.

Forecast and conclusion

Deciding on certain measures for the diet and lifestyle of the patient remains the prerogative of the attending physician or physician consultation, the patient is obliged to coordinate all his actions with a doctor - a specialized specialist (nephrologist or urologist).

Not only the patient's condition at the moment depends on compliance with medical recommendations, but also the possible the future duration of his life, which, thanks to this method, can be increased by a period from 15 to 25 years.

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