CARDIOPLEGIA

From Big Medical Encyclopedia

CARDIOPLEGIA (Greek kardia heart + plege blow; synonym artificial cardiac standstill) — temporary switching off of heart from blood circulation for creation of a bloodless («dry») surgery field at operations on open cardial cavities in the conditions of artificial circulation.

The idea To. belongs to the Soviet surgeon of H. To N. Terebinsky who in 1940 in an experiment for receiving a «dry» surgery field and a cardiac standstill squeezed it a hand, pressed an aorta and the right auricle, made a tamponade forcing of air in a pericardium.

Only in 1955 there were D. G. Melrose's messages et al., Lem (Page R. Lam) with soavt, about use of various chemical drugs for achievement To., Deterlinga (To. A. Deterling) — about a technique of an ischemic cardiac standstill, N. E. Shumway et al. — about coronary perfusion by the cooled heparinized blood in clinic at open heart operations. In 1956 Mr. Lillekhey (S. of Lillehei) with soavt, Shamuey with soavt reported about the technique of retrograde perfusion of coronal arteries developed by them oxygenic blood with various chemical drugs for K. V 1959, developed and applied in clinic a technique To. irrigation of an epicardium of cold 5% solution of glucose or 1% solution of sodium chloride. The first of the Soviet surgeons To. at open heart operations A. A. Vishnevsky applied (1957).

Distinguish ischemic, chemical and cold To.

The ischemic Cardioplegia

the Ischemic Cardioplegia is reached by the termination of a coronary blood-groove by overlapping of an aorta at once after an otkhozhdeniye of coronal arteries. It leads to disappearance of ATP and change of potential of intercellular membranes. As a result of ischemia the glycoclastic pathway becomes the only way of maintenance of resynthesis of ATP, edges goes first of all for the active processes happening in a plasma membrane and membrane cellular organoids. Potassium leaves a cell, sodium and chlorine direct in a cell, calcium comes out a sarcoplasmic reticulum; lizosomalny the enzymes which appeared in cytoplasm begin an autolysis. Catabolic processes prevail over anabolic. It leads to increase in intracellular osmolarity, intracellular hypostasis.

These changes develop in various terms of the ischemic period, however danger of their emergence in the post-ischemic period comes after 30 min. ischemic

K. Ishemicheskaya K. is shown when it is required to switch off heart from blood circulation for the short period (10 — 15 min.).

The chemical Cardioplegia

the Chemical Cardioplegia is reached by administration of solution of various chemical drugs causing a cardiac standstill, directly in coronal arteries. After the termination chemical. To. the used drug is washed away by a blood flow.

Mechanism chemical. To. it is based on blocking of consumption by a myocardium of oxygen. It allows to extend the term of ischemia of heart up to 40 — 60 min.

As chemical drugs for To. are offered: potassium citrate, potassium chloride, acetylcholine, magnesium sulfate in combination with potassium citrate, a citrated blood, mekholit with addition of atropine, neostigmin, citrate of lithium, sodium citrate, etc.

Use chemical. To. in clinic showed that the cardiac standstill by means of chemical drugs in the doses necessary for long operation, causes heavy oppression of sokratitelny function of a myocardium that is shown by an unstable hemodynamics in the course of recovery of cordial activity. In the postoperative period disturbance of a tone of a myocardium can lead to emergence of fibrillation. The last managed to be overcome coronary perfusion by the solution offered Bret-shnayderom in 1964. It contains 12 mekv/l sodium, 7 mekv/l potassium, 2 mekv/l magnesium, 28 mekv/l chlorine, 7 mekv/l novocaine, 263 mekv/l a mannitol. However and this technique did not meet requirements of clinic since at increase in hydrostatic pressure in system of coronal vessels (it is higher than 40 mm of mercury.) perfusion of heart leads to hypostasis of a myocardium.

Developing a method chemical. To., Kirsch in 1972 offered for continuous coronary perfusion the solution containing ions of magnesium, Procainum, ions of sodium, potassium, calcium, etc. in the doses close to minimum efficient concentration. This solution with oxygen and nutrient medium reaches the selection interruption of sokratitelny ability of a myocardium without impact on other processes necessary for preservation of a metabolism at rest.

Chemical. To. on Bretshnaydera and to Kirsch it is shown at the operations demanding a cardiac standstill to 1,5 — 2 hours

the Cold Cardioplegia

the classical experiences of A. A. Kulyabko (1902) showed that heart well keeps the funkts, properties at contents it in cold to 2 — 3 days. As supportive application in a heart surgery the hypothermia was offered W. Bigelow in 1950.

Fig. 1. Electrocardiograms of the patients operated in the conditions of an outside cold cardioplegia: 1 — before operation (it is given for comparison); 2 — during crossclamping of an aorta and a cardiac standstill; 3 — during recovery of cordial activity: the picture of blockade of the left leg of a ventriculonector is visible (expansion of the QRS complex; in the I assignment — the wide and high tooth of R lowered by ST, T negative; in the III assignment — the wide and deep tooth of S, ST is raised, T — positive); 4 — at the end of operation: positive dynamics is noted.
Fig. 2. Dynamics of arteriovenous coronary distinctions on key parameters of acid-base equilibrium in the conditions of artificial circulation and a cold cardioplegia: VE — buffer system (in milliekvivalenta on liter), is shown to the full curve; pCO 2 — tension of CO 2 in blood (in millimeters of mercury), it is shown to a large discontinuous curve; pH — is shown to a small discontinuous curve; 1 — to artificial circulation: 2 — during crossclamping of an aorta and a cardiac standstill; 3 — after declamping from an aorta (a portion of washing away): 4 — before shutdown of the cardiopulmonary bypass.

Cold To. represents option ischemic, but differs from it in the fact that the hypothermia increases tolerance of fabrics to a hypoxia (see. Hypothermia artificial ). At a hypothermia electric (fig. 1) and mechanical activity of heart stops, consumption by a myocardium of oxygen (fig. 2) sharply goes down. As a result the damaging action of an anoxia decreases by a myocardium of the stopped heart.

Cold To. it is reached by the irrigation of the heart which is switched off from blood circulation cooled to t ° +4 — — 5 ° fiziol, solution. It allows to reduce and maintain temperature of a myocardium at the level of 17 — 20 °. The cooling solution from the surface of heart is deleted with a suction machine.

Outside cold To. it is shown at long (up to 60 min.) switching off of heart from blood circulation.

The method of coronary perfusion is reached by oxygenic blood by a direct kanyulyation of coronal arteries after an aortotomy. There are numerous models of coronary cannulas. Special schemes of the isolated coronary perfusion with various temperature schedules — normotermichesky and hypothermal are developed.

Coronary perfusion adequate to energy demands of a myocardium is the most physiologic method for maintenance of viability of heart. It provides great opportunities for carrying out difficult and long operations on open heart and is method of the choice in most cardiac clinics.

See also Heart, operation .


Bibliography: Burakovsky V. I., etc. Experience of a cardioplegia at operations with artificial circulation, Grudn. hir., No. 2, page 26, 1963; Vishnevsky A. A., etc. The isolated deep hypothermia of heart as a method of an artificial cardioplegia, Eksperim, hir. and anesteziol., No. 3, page 3, 1961; Pe t-rovsky B. V., Solovyov G. M. and Bunyatyan A. A. Hypothermal perfusion in surgeries of open heart, Yerevan, 1967, bibliogr.; The tailor V. F. Zashchita of a myocardium in a heart surgery and transplantology, Saturday. nauch. works Ying-that hir. of Vishnevsky, page 229, M., 1976; Terebinsky H. H. Materials on studying of open access to atrioventricular valves of heart, M. — L., 1940, bibliogr.; And gp u 1 f G. Resistance and tolerance of myocardium in ischemia, J. cardiovasc. Surg. (Torino), v. 16, p. 218, 1975; Bigelow W. GM Callaghan J. C. a. Hopps J. A. General hypothermia for experimental intracardiac surgery, Ann. Surg., v. 132, p. 531, 1950; Bjork V, O., H e n z e A. Szamosi A. Coronary ostial stenosis, Scand. J. thorac. cardiovasc. Surg., v. 10, p. 1, 1976; GonnJ. H. a. Colling J. Local cardiac hypothermia for myocardial protection, Ann. thorac. Surg., v. 17, p. 135, 1974; Kalmar P. o. Induced ischemic cardiac arrest, J. cardiovasc. Surg. (Torino), v. 16, p. 470, 1975; Lillehei C. W. a. o. The direct vision correction of calcific aortic stenosis by means of a pump-oxygenator and retrograde coronary sinus perfusion, Dis. Chest, v. 30, p. 123, 1956.

V. I. Burakovsky, A. A. Krakovsky.

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