CARDIOGENIC SHOCK

From Big Medical Encyclopedia

CARDIOGENIC SHOCK (grech, kardia heart + gennao to create, make; shock) — one of the most terrible complications of a myocardial infarction which is characterized by disorganization of a hemodynamics, its nervous and humoral control and disturbance of life activity of an organism. It is shown by disorders of consciousness, the expressed arterial hypotension, peripheral vasoconstriction with heavy disorders of microcirculation and an oliguria.

The term «cardiogenic shock» at a myocardial infarction is entered by Fishberg (A. Fishberg, 1940). As a synonym To. highways quite often use the term «cardiogenic collapse», however some authors distinguish these concepts, designating the term «cardiogenic collapse» only reversible cardiovascular insufficiency with short-term decrease in the ABP and without essential disorders of microcirculation. Most often at To. highway systolic the ABP happens lower than 90 mm of mercury., and the diuresis falls lower than 30 ml an hour.

To. highway develops in the acute period myocardial infarction (see), at Krom it often is a cause of death of patients. Frequency To. highway at a myocardial infarction, according to various authors, fluctuates from 4,5 to 44,3%. So big difference of the given indicators, apparently, is explained by heterogeneity of the applied diagnostic criteria To. highway and the unequal number of the inspected patients. Epidemiol, the researches conducted according to the program of WHO among big population of the population with standard diagnostic criteria showed that at the patients with a myocardial infarction aged up to 64 years To. highway develops in 4 — 5% of cases.

The pathogeny

the Pathogeny is extremely difficult and up to the end is not studied. E. I. Chazov (1971) suggested to allocate the following four forms K. highways having pathogenetic features: 1) reflex shock, in a pathogeny to-rogo lies generally painful irritant; clinically this type of shock proceeds rather easily; 2) «true» To. highway, in development to-rogo an important role plays disturbance of sokratitelny function of the affected myocardium; proceeds with a classical picture of peripheral signs of shock and falling of a diuresis; 3) areactive To. highway — the most severe form with a difficult multifactorial pathogeny which is almost not giving in to lay down. to actions; 4) arhythmic To. highway; at the heart of a pathogeny of this form K. highway both at a takhisistoliya, and at a bradisistoliya (in connection with a total atrioventricular block) lies decrease in minute volume of heart; in the first case it happens because of sharp increase of cordial reductions, reduction of time of diastolic filling and falling of systolic emission, in the second — owing to a considerable urezheniye of number of cordial reductions.

As To. highway arises most often at the heavy hours-long anginous status, many authors consider the main reason for its development pain. However sometimes To. highway is observed at small subjective pain, in some cases it arises at bezbolevy option of a myocardial infarction, usually repeated.

According to most of researchers, the major factor causing emergence To. highway, is falloff of cordial emission owing to falling of sokratitelny function of a myocardium of a left ventricle. In this regard great value in development To. highway is given to the volume of damage of a myocardium. Direct correlation between this indicator and a functional condition of a left ventricle is revealed: at the patients who died from To. highway, only the fresh centers of a necrosis or a combination of the fresh centers to old cicatricial changes appears the mass of a myocardium of a left ventricle captured more than 50% while at the patients with an acute heart attack who died because of disturbance of a heart rhythm without To. highway, appears the mass of a myocardium of a left ventricle struck no more than 23%.

Decrease in contractility of heart at a myocardial infarction is confirmed, in particular, with endocardiac X-ray contrast methods of a research using a two-plane film cardiography. In a zone of a heart attack various forms of a regional asynergia were revealed: the hypokinesia, an akineziya, is more often dyskinesia (paradoxic movement, i.e. protrusion in the period of a systole of the struck part of a left ventricle). The specified forms of an asynergia are observed separately and in various combinations; at the same time the functioning part of a muscle is in conditions of the raised loading, replacing function of an affected area and in addition overcoming the damping effect of the sticking-out zone of a necrosis. Function of a left ventricle suffers both at the expense of the center of a necrosis, and due to education in a myocardium of an ischemic perinekrotichesky zone.

Owing to functional insufficiency of a myocardium the speed of rise in pressure in a left ventricle decreases, and end diastolic pressure increases in his cavity. The tachycardia which is usually arising in response to falling of shock emission does not provide preservation of minute volume on datum level. Decrease in minute volume and, therefore, arterial perfused pressure leads to reduction of coronary perfusion, a cut, in turn, causes decrease in functional capacity of an ischemic myocardium. The vicious circle leading to distribution of the initial center of defeat and progressing of kontraktilny insufficiency is created.

Lead to reduction of cordial emission also the disturbances of a cordial rhythm caused by electric instability of a myocardium in the acute period of a heart attack, in particular a supraventricular or ventricular Bouveret's disease, frequent premature ventricular contraction, especially polytopic.

Decrease in cordial emission and speed of rise in pressure in a left ventricle activates baroreceptors of a carotid sine and an aorta owing to what the tone of peripheral vessels increases and the general peripheric resistance increases. However even extensive peripheral vasoconstriction at To. highway does not compensate falloff of cordial emission, and the acute circulatory unefficiency with the expressed arterial hypotension as a result develops. At a part of patients with To. highway the general peripheric resistance does not increase, and sometimes even goes down.

The arterial hypovolemia and hypotension lead to decrease in an effective blood-groove in various bodies and fabrics — in skin, abdominal organs, kidneys, in heart and, at last, in a brain. Fabric hypoxia (see) activates anaerobic glycolysis, causes accumulation of acid products of exchange, and the metabolic acidosis develops. Accumulation in blood of a large number milk, pyroracemic and others to - t has negative inotropic effect on a myocardium and supports conditions for development of heart failure and acute disorders of a cordial rhythm.

In process of progressing To. highways arise the secondary disturbances which are leading preferential to vascular insufficiency and negatively influencing a functional condition of a myocardium. The fabric hypoxia and a metabolic acidosis increase vascular permeability, favoring to an ekstravazalny exit of a liquid part of blood. Expansion of precapillary arterioles and narrowing of post-capillary venules under the influence of acidosis cause sharp increase in capillary volume of blood and its sequestration with development of a hypovolemia and decrease in the central venous pressure. Since the affected myocardium needs more high pressure of filling for maintenance of adequate cordial emission, the pressure decrease of filling connected with a hypovolemia can lead to development of shock even at those patients who have a volume of damage of a myocardium less than 50%.

In insufficiently bodies and fabrics supplied by blood the expressed disturbances of microcirculation are noted (an intravascular hemostasis, «monetary columns» from erythrocytes, aggregation of thrombocytes and leukocytes, adjournment of fibrin).

The hypoxia and disorders of microcirculation in abdominal organs, especially in a pancreas, lead to disintegration of intracellular proteins with formation of the peptides exerting negative inotropic impact on a myocardium and aggravating frustration of the central and peripheral hemodynamics.

Clinical manifestations and a current

One of the leading objective symptoms To. highway is the expressed and long arterial hypotension. As a rule, falling of systolic pressure below 90 mm of mercury is noted., it is frequent is not defined auskultativno. However To. highway can develop also at the ABP «normal» values, in particular at patients with an idiopathic hypertensia with steadily high level of the ABP before developing of a myocardial infarction. On the other hand, the ABP is lower than 90 mm of mercury. in some cases the myocardial infarction is not followed by development To. highway. More exact indicator of development To. highway serves the size of pulse pressure: its reduction to 20 mm of mercury. below is always followed by peripheral signs of shock irrespective of the ABP level to a disease. Extent of decrease in the systolic, diastolic and pulse ABP in most cases corresponds to severity of shock.

Important for recognition K.sh. its peripheral signs are: pallor of integuments, it is frequent with an ash-gray or tsianotichesky shade, the cyanosis of extremities sometimes expressed, cold sweat, the fallen-down veins, small frequent pulse. Cyanosis of mucous membranes is expressed to those stronger, than shock is heavier. The marble drawing of integuments with pale impregnations on a tsianotichesky background appears at very heavy shock with the adverse vital forecast.

Due to the falling of blood pressure at To. highway decreases an effective renal blood stream and arises oliguria (see) or (at a long current heavy To. highway) anury (see) with increase in level of residual nitrogen in blood. Extent of functional disturbances of kidneys is proportional to severity To.

Odin Highway from frequent signs To. highway is sinus tachycardia, however at early stages To. highway can take place and a sinus bradycardia owing to oppression of function of automatism of a sinus node. Emergence of a partial or total atrioventricular block, disturbances of intra ventricular conductivity, and also acute frustration of a cordial rhythm (premature ventricular contraction, blinking and an atrial flutter, a Bouveret's disease) is possible. All these frustration of a rhythm and conductivity (see. Arrhythmias of heart , Heart block ) in a bigger degree aggravate a current To. highway.

Along with disturbance of blood circulation at To. highways are observed symptoms of various dysfunctions of the central and peripheral nervous system — psychomotor arousing or an adynamia, confusion of consciousness or its temporary loss, changes of tendon jerks, disorders of skin sensitivity. However at To. highway, unlike traumatic, sharp block is observed infrequently.

On weight of a current V. N. Vinogradov, V. G. Popov and A.S. Smetnev suggested to allocate three degrees To. highway: rather easy (I degree), moderately severe (II degree) and extremely heavy (III degree).

Duration To. highway of the I degree does not exceed usually 3 — 5 hour. The ABP level fluctuates within 85/50 — 60/40 mm of mercury. At the most part of patients bystry steady pressor reaction is observed (in 30 — 60 min. after carrying out a complex to lay down. actions). In some cases, especially at elderly people, positive pressor reaction can be slowed a little down, sometimes with the subsequent short decrease in the ABP and resuming of peripheral signs To.

Dlitelnost Highway To. highway of the II degree from 5 to 10 hour. The ABP level — within 80/50 — 40/20 mm of mercury: Peripheral signs of shock are expressed considerably and are quite often combined with symptoms of an acute left ventricular failure (an asthma at rest, a Crocq's disease, congestive rattles in lungs, at 20% of patients — an alveolar fluid lungs). Pressor reaction to the carried-out complex therapy is slowed down and unstable, within the first days of a disease numerous decrease in the ABP with resuming of peripheral signs of shock is noted.

To. highway of the III degree differs in extremely heavy and long current with sharp falling of the ABP (to 80/50 mm of mercury. below) and pulse pressure (it is lower than 15 mm of mercury.), progressing of frustration of peripheric circulation and increase of the phenomena of an acute heart failure. At 70% of patients rapid development of an alveolar fluid lungs is observed. Use of adrenomimetichesky means does not give positive effect, pressor reaction is absent in most cases. Duration of such areactive shock fluctuates within 24 — 72 hours, sometimes - its current gains wavy and long character and usually comes to the end with a lethal outcome.

Current To. highway can be also aggravated in some cases with the gastralgichesky syndrome (persistent vomiting, a meteorism, paresis of intestines) connected with vasculomotor dysfunctions of digestive tract.

Treatment

Efficiency of therapy To. highway is defined first of all by urgency of its use as with increase in duration To. highway a lethality increases. Complex therapy To. highway assumes holding urgent actions for the following directions.

1. Stopping of the anginous status intravenous administration of opiates with exponential means, analgetics, neyroleptanalgetik (see. Myocardial infarction , Neyroleptanalgeziya ).

2. Increase in sokratitelny function of a myocardium use of cardiac glycosides (strophanthin of 0,5 — 0,75 ml of 0,05% of solution or Korglykonum of 1 ml of 0,06% of solution) which enter intravenously slowly into 20 ml of isotonic solution of sodium chloride or kapelno in combination with plasma substitutes. Expediency of use of cardiac glycosides at To. highway is discussed first of all in view of danger of increase in excitability of a myocardium. In this regard at the first introduction of glycosides recommend to be limited to a dose, a component 1/2 — 2/3 usual therapeutic doses, during the providing by means of plasma substitutes of adequate pressure of filling. Before glycosides the glucagon which exerts positive inotropic impact on a myocardium has advantages, without possessing aritmogenny action, and can be used at overdose of cardiac glycosides. Enter a glucagon intravenously struyno or kapelno. At single-step introduction the effect is shown as much as possible to the 10th min. and gradually decreases for the next 30 min. At the same time the temporary moderate hyperglycemia is possible (to 200 mg of % of sugar in blood); in rare instances after long infusion the hypoglycemia is noted. Introduction of a glucagon, as a rule, is followed by a hypopotassemia for which prevention additional administration of salts of potassium is shown.

3. Elimination of a hypovolemia administration of plasma substitutes. If the central venous pressure is lower than 10 cm w.g., administration of liquid shall be a preferential form of therapy. Usually enter plasma substituting means — reopoliglyukin, Polyglucinum in volume to 1000 ml with a speed of 50 ice in 1 min. Reopoliglyukin improves microcirculation and causes sloshing from fabrics in a circulatory bed. Polyglucinum having high osmotic pressure it is also long circulating in blood, promotes deduction of liquid in a vascular bed. In order to avoid a fluid lungs administration of plasma substitutes shall be carried out under control of the central venous pressure, level to-rogo is increased to 15 cm w.g. Administration of liquid under control of pressure in system of a pulmonary artery, in particular «getting jammed» in its capillaries, measured by a floating catheter with the inflated barrel on the end, and end diastolic pressure in a left ventricle is optimum.

4. Normalization of the ABP use of pressor sympathomimetic means — a phenylephine hydrochloride, noradrenaline. The last is entered intravenously kapelno at the rate of 4 — 8 mg (2 — 4 ml of 0,2% of solution) for 1 l of 5% of solution of glucose or isotonic solution of sodium chloride. Speed of injection (usually 20 — 60 drops in 1 min.) it is regulated on changes of the systolic ABP, a cut recommend to support at the level of 100 mm of mercury. Positive takes are yielded by use of a dopamine — the predecessor of noradrenaline activating both beta and alpha adrenoceptors. The dopamine, except pressor action, expands renal and mezenterialny vessels, promotes increase in minute volume of heart and a mocheotdeleniye. The dopamine is entered intravenously kapelno with a speed of 0,1 — 1,6 mg/min. under careful control of an ECG since against the background of introduction of a dopamine quite often there are ventricular disturbances of a heart rhythm. Apply also hypertensia, possessing sharply expressed pressor action; the drug is administered intravenously kapelno in an average single dose of 2,5 — 5 mg on 250 — 500 ml of 5% of solution of glucose with a speed from 4 — 6 to 20 thaws of 1 min. under obligatory control of changes of the ABP.

At unstable pressor effect in addition enter intravenously kapelno a hydrocortisone in a dose of 150 — 300 mg (to 1500 mg a day) or Prednisolonum in a dose of 90 — 150 mg (sometimes to 500 mg a day) in isotonic solution of sodium chloride or 5% solution of glucose.

5. Normalization of rheological properties of blood by means of administration of heparin, fibrinolitic drugs, low-molecular dextrans in the standard clinical doses.

6. Recovery of disturbances of a rhythm and conductivity of heart use antiarrhythmic means (see). At disorders of atrioventricular conductivity, especially at total cross block, the most effective is electric cardiac activation by means of the transvenous endocardial electrode entered into a right ventricle (see. Cardiostimulation ).

7. Correction of acid-base equilibrium (in connection with a metabolic acidosis) use of sodium bicarbonate, sodium lactate.

In cases of a heavy areactive current of shock sometimes use counterpulsation (see. Artificial circulatory support ), usually in the form of periodic inflation of an intra aortal barrel by means of a catheter that reduces work of a left ventricle at increase in a coronary blood-groove. Timely use of counterpulsation reduces a lethality at To. highway for 10 — 15%. Implementation in practice of treatment is new To. highway. hyperbaric oxygenation (see). Efficiency of a surgical method of treatment To. highway — the emergency aortocoronary shunting remains low (see. Myocardial infarction, surgical treatment ).

The forecast

At a complication of a myocardial infarction To. highway the forecast for life of the patient depends first of all on duration and weight of a depressed case. To some extent it can be determined by response of the ABP to carrying out a complex to lay down. actions. The last is the main criterion of weight To. highway for practical doctors, especially in the conditions of ambulance. At an arhythmic form K. highway usually leads elimination of arrhythmia to normalization of minute volume of heart and the ABP.

At «true» To. highway the vital forecast bad, and it considerably worsens at a combination To. highway with other complications of a myocardial infarction (disturbance of conductivity and a heart rhythm, a thromboembolism, a fluid lungs, etc.). Despite considerable achievements in therapy To. highway, a lethality still remains very high: in cases when the phenomena of shock remain several hours, it reaches 80 — 90%, and at a combination To. highway with a fluid lungs — nearly 100%.



Bibliography Vinogradov A. V. and d river. Myocardial infarction, M., 1971, bibliogr.; Ganelina I. E., Breaker V. N. and Volpert E. I. Acute period of a myocardial infarction, L., 1970, bibliogr.; A myocardial infarction, under the editorship of E. Kordeya and X. J. K. Svona, the lane with English, M., 1977; The Myocardial infarction, under the editorship of Ch. K. Fridberg, the lane with English, M., 1975; Moybenko A. A., Pov-zhitkov M. M. and Butenko G. M. Cytotoxic injuries of heart and cardiogenic shock, Kiev, 1977; P at-d and M, I. and 3 y with to about A. P. Myocardial infarction, M., 1977; Smetnev A. S. Cardiogenic shock at a myocardial infarction, M., 1971, bibliogr.; Smetnev A. S. and Petrova L. I. Medical emergencies in clinic of internal diseases, M., 1977, bibliogr.; F i s li fe erg A. M. Heart failure, Philadelphia, 1944, bibliogr.; H an u s s W. H. u. Koch R. Koronarsklerose und Herzin-farkt, Stuttgart, 1976; Pantridge I. P. a. o. The acute coronary attack, L., 1975.

A.S. Smetnev, T. E. Dobrotvorskaya.

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