Cardiogenic shock

Description:

Cardiogenic shock is the acute left ventricular failure of extreme severity developing at a myocardial infarction. Allocate three forms of cardiogenic shock: reflex, true cardiogenic and arhythmic.

Symptoms of Cardiogenic shock:

Reflex shock (collapse)  is the easiest form and is, as a rule, caused not by heavy injury of a myocardium, but a lowering of arterial pressure in response to the expressed pain syndrome arising at a heart attack. At timely stopping of pain proceeds it is good-quality, arterial pressure quickly increases, however in the absence of adequate treatment transition of reflex shock to true cardiogenic is possible.

True cardiogenic shock arises, as a rule, at extensive myocardial infarctions. It is caused by sharp decrease in pumping function of a left ventricle. If the mass of a nekrotizirovanny myocardium makes 40 - 50% and more, then areactive cardiogenic shock at which administration of sympathomimetic amines does not give effect develops. The lethality in this group of patients approaches 100%.

Cardiogenic shock leads to deep disturbances of blood supply of all bodies and fabrics, causing disorders of microcirculation and formation of microblood clots (IDCS). As a result functions of a brain are broken, the phenomena of an acute renal and liver failure develop, in the digestive channel acute trophic ulcers can be formed. Disturbance of blood circulation is aggravated bad blood of oksigenization in lungs owing to sharp decrease in a pulmonary blood-groove and shunting of blood in a small circle of blood circulation, the metabolic acidosis develops.

Characteristic of cardiogenic shock is formation of a so-called vicious circle. It is known that with a systolic pressure in an aorta lower than 80 mm hg coronary perfusion becomes inefficient. The lowering of arterial pressure sharply worsens a coronary blood stream, leads to increase in a zone of a necrosis of a myocardium, further deterioration in pumping function of a left ventricle and aggravation of shock.

Arhythmic shock (collapse) develops owing to a tachycardia paroxysm (a thicket ventricular) or sharply arisen bradyarrhythmia against the background of a total atrioventricular block. Disturbances of a hemodynamics at this form of shock are caused by change of frequency of reduction of ventricles. After normalization of a heart rhythm pumping function of a left ventricle is usually quickly recovered and the phenomena of shock disappear.

The standard criteria on the basis of which diagnose cardiogenic shock at a myocardial infarction are low indicators systolic (80 mm hg) and pulse pressure (20-25 mm hg), an oliguria (less than 20 ml). Besides, existence of peripheral signs very much is important: pallor, cold clammy sweat, cold snap of extremities. Superficial veins are fallen down, pulse on beam arteries is threadlike, nail beds pale, cyanosis of mucous membranes is observed. The consciousness, as a rule, confused and the patient is not capable to estimate adequately weight the condition.

Reasons of Cardiogenic shock:

Cardiogenic shock develops at a myocardial infarction. Reduction of stroke and minute output of blood at shock is so expressed that is not compensated by increase in vascular resistance owing to what the arterial pressure and a system blood stream sharply decrease, blood supply of all vitals is broken.

Treatment of Cardiogenic shock:

Treatment of cardiogenic shock. Cardiogenic shock - a terrible complication of a myocardial infarction at which lethality reaches 80% and more. Treatment represents it a complex challenge and includes a complex of the actions directed to protection of an ischemic myocardium and recovery of its functions, elimination to microcircus of lyatorny disturbances, compensation of the broken functions of parenchymatous bodies. Efficiency of medical actions at the same time in many respects depends on time of their beginning. The early initiation of treatment of cardiogenic shock is the key to success. The main task which needs to be solved as soon as possible is a stabilization of arterial pressure at the level providing adequate perfusion of vitals (90-100 mm hg).

The sequence of medical actions at cardiogenic shock:

  1. Stopping of a pain syndrome. As the intensive pain syndrome arising at a myocardial infarction is one of the reasons of a lowering of arterial pressure, it is necessary to take all measures for its bystry and full stopping. Most effective use of a neyroleptanalgeziya.
  2. Normalization of a heart rhythm. Stabilization of a hemodynamics is impossible without elimination of disturbances of a heart rhythm as sharply arisen attack of tachycardia or bradycardia in the conditions of ischemia of a myocardium leads to sharp decrease in shock and minute emission. The most effective and safe way of stopping of tachycardia with a low arterial pressure is the countershock. If the situation allows to carry out drug treatment, the choice of antiarrhytmic drug depends on a type of arrhythmia. At bradycardia which is, as a rule, caused by sharply arisen atrioventricular block almost only effective remedy is endocardial cardiostimulation. Atropini sulfas injections most often do not give essential and lasting effect.
  3. Strengthening of inotronny function of a myocardium. If after elimination of a pain syndrome and normalization of frequency of reduction of ventricles arterial pressure is not stabilized, then it demonstrates development of true cardiogenic shock. In this situation it is necessary to increase sokratitelny activity of a left ventricle, stimulating the myocardium which remained viable. For this purpose use sympathomimetic amines: a dopamine (dopamine) and Dobutaminum (добутрекс) which are selectively operating on beta 1 - heart adrenoceptors. Dopamine is entered intravenously kapelno. For this purpose 200 mg (1 ampoule) of drug dissolve 5% of solution of glucose in 250-500 ml. The dose in each case is selected by practical consideration depending on dynamics of arterial pressure. Usually begin with 2-5 mkg/kg in 1 min. (5-10 drops in 1 min.), gradually increasing rate of administering before stabilization of systolic arterial pressure at the level of 100-110 mm hg Dobutreks is issued in bottles on 25 ml containing 250 mg of Dobutaminum of a hydrochloride in the lyophilized form. Before the use dry matter in a bottle is dissolved, adding 10 ml of solvent, and then dissolve 5% of solution of glucose in 250-500 ml. Intravenous infusion begin with a dose 5 mkg/kg in 1 min., increasing it before emergence of clinical effect. Optimum rate of administering is selected individually. It seldom exceeds 40 mkg/kg in 1 min., effect of drug begins in 1-2 min. after introduction and very quickly stops after its termination in connection with short (2 min.) half-life.
  4. Nonspecific antishock actions. Along with administration of sympathomimetic amines for the purpose of impact on various links of a pathogeny of shock use the following drugs:
        1.glyukokortikoidy: Prednisolonum - on 100-120 mg intravenously struyno;
        2.geparin - on 10 000 PIECES intravenously struyno;
        3.natriya a hydrocarbonate - on 100-120 ml of 7,5% of solution;
        4.reopoliglyukin - 200-400 ml if introduction of large amounts of liquid is not contraindicated (for example, at a shock combination to a fluid lungs); besides, carry out oxygen inhalations.

Despite development of new approaches to therapy of cardiogenic shock, a lethality at this complication of a myocardial infarction makes from 85 to 100%. Therefore best "treatment" of shock is its prevention which consists in bystry and full stopping of a pain syndrome, disturbances of a heart rhythm and restriction of a zone of a heart attack.