HEMODIALYSIS (haemodialysis; grech, haima blood + dialysis decomposition, department; synonym extracorporal hemodialysis) — a method of release of blood from low - and middlemolecular substances by means of selective diffusion by means of an artificial kidney.
— the main form of a vivodializ, i.e. intravital clarification of blood by means of different types of dialysis (peritoneal, pleural, etc.).
On an animal Abel, Rauntri and Turner (I. I. Abel for the first time made, L. G. Rountree, V. V. of Turner) in 1913 also called this method vividiffusion. They established that salicylates, bromides, urea can be removed from animal G.'s blood; they made the assumption of G.'s possibility at insufficient function of kidneys for removal of substances which accumulation in blood poses hazard to life. In a wedge, the practician G. began to apply widely after U. Kolff (1944) works, N. Alvall (1946). Is one of the most important achievements of modern medicine. For its carrying out various models of an artificial kidney are used.
Thanks to G. in some cases treatment acute and hron, a renal failure, acute poisonings is successfully performed. Frequency of these states defines the need for G. Ustanovleno that within a year on 1 million population also 20 — 25 G. at acute poisonings are required apprx. 150 G. for treatment of patients with an acute renal failure. The number of patients with hron, a renal failure is on average equal in various countries 50 on 1 million population a year. As each patient with hron, a renal failure demands apprx. 100 G. a year, during 1 year for treatment hron, it is necessary for a renal failure apprx. 5000 G. on 1 million population. It demands the organization of a large number of the centers G.
Indications for G. at acute and hron, a renal failure are defined a wedge, a current of a basic disease. The most often acute renal failure demanding G. develops at different types of shock (posttraumatic, postoperative, anaphylactic, posttransfusion, bacterial etc.); as a result of poisonings with exogenous poisons (inorganic and organic, poisons of an animal and plant origin), medicines; at the infectious diseases which are followed by damage of kidneys and their vessels (hemorrhagic fever with a renal syndrome, a hay fever); an acute glomerulonephritis, acute pyelonephritis, and sometimes and at obturation of uric ways when preoperative preparation is necessary. In cases of an acute renal failure after one or several G. usually there occurs recovery of functions of kidneys and recovery of the patient.
Indications to G. at an acute renal failure are defined as humoral disturbances, and a wedge, by manifestations uraemias (see). Most often G. is applied during the strengthening of urea of plasma to 300 mg of % (residual nitrogen apprx. 150 mg of %). Creatinemia to 15 mg of %, increase in potassium of plasma more than 6,5 mekv/l and decrease in an alkaline reserve to 12 mekv/l are also indications by. At a hyperpotassemia more than 7 mekv/l G. shall be carried out urgently. A hyperphrenia, drowsiness, coma, various disturbances of breath as a result of development of a metabolic acidosis, a spasm, paresthesia, pernicious vomiting — all this is the indication to G. even at rather low level of an azotemia and small expressiveness of humoral disturbances. G.'s carrying out in early stages of development of these changes is important.
If at acute or hron, a renal failure of G. is a measure of symptomatic therapy, then in cases of acute poisonings of G. — pathogenetic means since from an organism poisons are removed.
The most frequent indication is the end-stage hron, a renal failure. At this stage decrease in glomerular filtering to 5 ml/min., increase in content of urea of plasma to 120 — 150 mg of %, creatinine — to 12 — 15 mg of % is usually observed. However, as well as at an acute renal failure, a wedge, manifestations hron, uraemias force to apply G. and at less expressed humoral disturbances.
Contraindications — hematencephalons, not stopped bleeding, the cardiovascular insufficiency considerably expressed, a septic endocarditis.
G.'s Carrying out is based on laws dialysis (see). For G. use both the individual devices «artificial kidney», and the systems providing its carrying out at the same time at several patients (see. Artificial kidney ).
Connection of the patient with the device can be venovenozny and arteriovenous. At veno-venous G. make catheterization of the lower vena cava through a naked big saphena (see. Catheterization of veins puncture ). From a vein take away blood by means of the pump, force in the dialyzer, and then return blood in any peripheral vein. Connection by catheterization of the lower vena cava through a femoral vein by the method offered by S. Seldinger is less traumatic. Catheterization of a vein is made two catheters or one double-thread catheter. At arteriovenous G. blood sampling is carried out from a peripheral artery, and return — in a peripheral vein. Hron. Demands use of the arteriovenous shunt offered in 1960 to Skribnerom (V. N. of Scribner). The shunt consists of the teflon cannulas entered into an artery and a vein and the silastikovy tubes connecting vessels outside (fig. 1).
In 1967 Mr. of Chimino and Brescia (J. E. Cimino, M. of J. Brescia) developed a new way for carrying out hron. Which consists in imposing of a hypodermic anastomosis between an artery and a vein. Most often the fistula is imposed on vessels of a forearm therefore there is an expansion of saphenas that facilitates their repeated punctures (fig. 2). Such technique has advantages in front of the shunt: at it there are no restrictions of movements of a hand, infection is less dangerous, however with a small diameter of vessels this method is inapplicable. At an arteriovenous fistula usually take away blood through one needle, and return through another. The method of carrying out G. by means of one needle is offered, at Krom blood alternately at first is forced in the device, and then through the same needle is returned. During the carrying out hron. For the patient this essential simplification. For the same G. the method of transplantation of a big saphena under skin of a forearm or a shin where its ends connect to an artery and a vein is recommended. Connection of the device is carried out as well as at an arteriovenous fistula. G.'s technique is so well developed that in the presence of the corresponding equipment G. can be carried out also in house conditions (house G.).
For G. at an acute renal failure prepare the dialyzing solution Depending on the qualitative and quantitative characteristic of humoral disturbances at the patient. Concentration of magnesium in it (0 — 1 mekv/l) and potassium (0 — 4 mekv/l) is selected individually, administration of sodium (140 mekv/l) and calcium (4,5 mekv/l) there corresponds fiziol, to their concentration in plasma, and concentration of chlorine in the dialyzing solution — above fiziol, norms (to 117 mekv/l); concentration of glucose usually 200 mg of %.
During the carrying out hron. Use the solution containing 130 mekv/l sodium, 3 mekv/l potassium, 103 mekv/l chlorine, 5 mekv/l calcium, 36,5 mekv/l acetate, 1,5 mekv/l magnesium and 200 mg of % of glucose. For the purpose of prevention of a blood coagulation in the device before dialysis enter heparin into a vein of the patient (the general geparinization at the rate of 2 mg/kg of weight) or constantly small doses in the device Dosed, an infusional geparinization). At danger of bleeding the heparin entered into blood on an entrance to the device during the escaping it is neutralized protamin in equivalent quantities (a regional geparinization).
As a result of 6-hour G. it is possible to reduce concentration of urea by 70 — 75% (residual nitrogen for 50%). Less intensively concentration of creatinine, uric to - you, sulfates and phosphates decreases. During G. it is possible to bring usually potassium concentration of plasma to norm, and to bring closer the level of sodium, chlorine and calcium to norm. From an organism of the patient also other middlemolecular substances which nature and a role in a pathogeny of uraemia remain not found out so far are removed.
Character and frequency of complications depend on many factors. The technical reasons of complications are observed quite often, but by means of devices of their observation it is possible to notice and prevent timely. The break of a membrane and leak of blood in the dialyzing solution concerns to them. In that case the detector of leak of blood can timely give an alarm signal. An air embolism during G. — extremely rare complication, but nevertheless inclusion in kroveprovodyashchy system of the detector of air traps in blood is reasonable. Hemolysis can arise at an overheat and the wrong preparation of the dialyzing solution therefore, except reliable control of temperature, in systems G. turning on of the saline tester which is constantly controlling correctness of preparation of dialyzate is obligatory.
Clinically complications are characterized by a variety and often limit rehabilitation of patients. At hron. Cardiovascular insufficiency is observed at 25,3% of patients, cerebrovascular complications — at 13,5%, ischemia and a myocardial infarction — at 5,6% of patients. A specific place is held by hepatitis. According to the European association of dialysis and transplantation (PIECE of T A), in 1971 hepatitis was noted in 47% of the centers G., got sick with hepatitis and sotr. these centers. Bleedings are possible from went. - kish. a path or from the shunt which can sometimes have the menacing character.
Hit of pathogenic microorganisms and the pyrogenic substances in kroveprovodyashchy system of an artificial kidney therefore in many-placed devices sterilization of all channels filled by the dialyzing solution periodically shall be made is the cornerstone of the pyrogenic reactions. Sometimes during G. there is a headache, convulsive twitchings, confusion of consciousness (demanding symptomatic therapy). These complications are caused by bystry decrease in content of urea in blood and slower — in cerebrospinal liquid. Thereof the difference of osmotic pressure between two environments is created and there is a movement of water from plasma in cerebrospinal liquid — the syndrome of the broken balance develops. Sometimes there is a so-called syndrome of insufficient dialysis developing within weeks and months at insufficiently effective treatment of patients. It is characterized by lack of appetite, weight loss, weakness, a skin itch, increase of anemia, a polyneuritis, a pericardis. At the patients who are exposed hron., thrombosis of the shunt, phlebitis, suppuration of a wound, sometimes an osteodystrophy is quite often observed.
Results of a hemodialysis depend not only on clarification of blood, but also on the managed extraction of excess of water by its ultrafiltration through a membrane of an artificial kidney as pressure of blood positive, and the movement of dialyzate happens with an adjustable negative pressure.
G.'s progress is obvious, despite possibility of complications. Considerably the lethality from an acute renal failure decreased and results of treatment of acute poisonings improved. Hron. Along with renal transplantation is method of effective treatment of an end-stage hron, a renal failure, a condition of the patient, but also to return it to public life and the work allowing not only to improve. Rehabilitation of the patient can be reached as a result of carrying out long dialysises in optimal conditions that is possible only in the conditions of the corresponding organizational system G.
Carrying out this method in the conditions of G.'s (fig. 3) departments is most widespread. Some of them are organized at the centers of transplantation of a kidney, others exist independently (see. Renal center .) In these departments of G. it is carried out as the patient who is in a hospital and it is out-patient (out-patient G.). The organization of departments satellites on the basis of peripheral hospitals enters practice. In some countries (e.g., in England) house G.
the Hemodialysis at children
the Hemodialysis at children for the first time is eurysynusic executed in 1957 Matir (F. M of Mateer) with sotr. Resistance of a children's organism to uraemic intoxication, disturbances of water and electrolytic exchange is lowered therefore at children it is desirable for G. to apply in earlier terms. At an acute renal failure the indication to G. is 3 — a 5-day anury, the accruing azotemia (urea of 150 — 200 mg of %, creatinine of 10 — 12 mg of %), a hyperpotassemia (potassium 7 mekv/l and more) with characteristic changes on an ECG, a metabolic decompensated acidosis, an overhydratation; at hron, a renal failure — a resistant azotemia (urea of blood of 100 — 150 mg of %, creatinine of blood of 8 — 12 mg of %), the progressing anemia, hypertensia, an overhydratation.
Technology of connection with the device «artificial kidney» in many respects depends on the weight, age and physical. development of the child. So, G. weighing child more than 30 kg carry out by the same technique, as at adults. Weighing from 15 to 30 kg it is possible to impose the arteriovenous shunt on beam or back tibial arteries. Weighing child less than 15 kg the arteriovenous shunt is imposed on humeral or femoral, arteries or carry out catheterization of the lower or upper venas cava by two catheters.
G. at children, since several months of life is carried out. The age is younger, the more difficultly the organism of the child adapts to difficult influences of. For small children the devices «Artificial Kidney» of special designs with the reduced speed of dialysis are offered. The device «Artificial Kidney» before G. depending on the capacity of the dialyzer, a state and age of the child is filled with blood of the patient or donor, a dextran, albumine. G.'s speed depends on age of the child. For small children G.'s duration no more than 3 — 4 hour.
At G.'s carrying out to children, especially the first two years of life, quite often there are complications from cardiovascular system (decrease or sharp increase in the ABP, disturbance of a cordial rhythm) and breath. The close check behind electrolytes of blood of the patient and their concentration in the dialyzing solution is necessary for their prevention. Individual selection of composition of the dialyzing solution reduces a possibility of various complications at small children.
See also Peritoneal dialysis .
Bibliography: Deryabin I. I. and Lisa N e of c of M. N. Artificial kidney, M., 1973, bibliogr.; L about p and t to and N. A. N and the Heap not a cue of I. N. Treatment of an acute and chronic renal failure, M., 1972; Pytel A. Ya. igoligor-with to and y S. D. Acute renal failure, Chisinau, 1963; Pytel a. I. and Kuchinsky I. N. About treatment of an acute renal failure at children, Pediatrics, No. 7, page 3, 1966; And b e 1 J. J., Rowntree L. G. a. Turner B. B. The removal of diffusible substances from the circulating blood by means of dialysis, Trans. Ass. Amer. Physic., v. 28, p. 51, 1913; Alwall N. Therapeutic and diagnostic problems in severe renal failure, Lund, 1964; B of e s with i and M. J. and. lake of Chronic hemodialysis using venipuncture and a surgically created arteriovenous fistula, New Engl. J. Med., v. 275, p. 1089, 1966; D i t t r i with h P. ul a. Hamodialyse und Peritonealdialyse, B., 1969; Praxis der Dialysebehandlung, hrsg. v. H. E. Franz, Stuttgart, 1973; Quinton W. o. Possible improvements in the technique of longterm cannulation of blood vessels, Trans. Amer.Soc.artif. intern. Org., v. 7, p. 60,1961.
G. P. Kulakov; B. D. Verkhovsky (ped.).