Cardiogenic shock

Cardiogenic shock is a severe disruption of the body's main pump, that is, of the heart, due to problems in it or blood vessels that supply blood to the heart. From such a seemingly simple definition, those levels of damage are immediately visible, in which cardiogenic shock can occur. Significant damage directly to the heart( to consider this topic, it is enough to take its pump function as a basis), - the blood ceases to move along the vessels, and hence to be delivered to the most important organs, such as the brain and kidneys. On the other hand, losing their tone, the vessels also will not be able to deliver oxygen to these organs and to the heart. Of course, this looks rather simplistic. In fact, deep mechanisms and close relations between the bodies are involved in this process.

In the aorta, for one its contraction, the heart pushes out a certain amount of blood, denoted as the shock volume. For a minute, cutting an average of 70 times, it pumps the so-called minute volume. These are the main indicators of such a function of the heart muscle, as a pumping. When there is any catastrophe in the body, the need for oxygen sharply increases. This can be provided in three ways: breathing more often, raising blood pressure and increasing the frequency of heart contractions. With the described imbalance, either the heart itself is not able to maintain the required volume of ejected blood with an increased frequency of contractions and the minute volume and the shock volume of blood fall, or the vessels can not maintain their blood pressure at the required level due to their elasticity, and it falls. Why all this happens, we will consider in more detail.

Cardiogenic shock of the cause of

The heart has its own power plant called the conductive heart system. If at any level a complete block of this system arises, the impulses cease freely and with a certain frequency excite the cells of the heart, it ceases to work. Violation of the rhythm of heart excitement or impulses, passing through additional paths, excite the cells "wrong", not in their rhythm. On the graphical display of the work of the heart, there will be an arrhythmia in this case.

If the heart itself is damaged, the ability to fully contract the muscle is impaired. This leads to a violation of nutrition of the heart cells or death of approximately 40% of cardiomyocytes( necrosis, infarction).The larger the zone of necrosis, the higher the probability of shock in the first hours of the catastrophe. If the closure of the artery is gradual, then the zone of its blood supply will suffer not so quickly, and the shock may develop delayed. Naturally, if the heart muscle is torn( a heart attack in the area of ​​the interventricular septum or a heart injury), the heart will not adequately decrease either.

Violation of the full operation of cardiomyocytes can occur due to their inflammation - this condition is called myocarditis( cardiogenic shock rarely develops).

The next reason for cardiogenic shock is the situation in which the heart can contract and the impulses are carried out regularly and correctly, but they are not allowed to reduce obstacles from the outside. That is, grasping the heart from all sides and clamping it, you can achieve a violation of its pumping function. This happens when the liquid accumulates in the so-called heart bag.

I must say that the structure of the heart is not uniform, and there are at least three layers in it. Endo-, myo-, and pericardium. Between the myo- and pericardium there is space. It is small and contains a certain amount of liquid. This fluid makes it possible to freely move the heart, contract without strong friction about the pericardium. When there is inflammation( pericarditis), this fluid becomes larger. In some cases, a lot is critical. A sharp increase in this volume in a confined space interferes with the work of the heart, a tamponade arises.

Another mechanism for the onset of cardiogenic shock is of course pulmonary embolism. A thrombus that flies, in most cases, from the veins of the lower extremities, clogs the pulmonary artery and blocks the work of the right ventricle of the heart. This pathogenesis of the onset of cardiogenic shock, in contrast to the above reasons, blocks the work of the right ventricle.

Cardiogenic shock due to the appearance of blockages in the conduction system of the heart or rhythm disturbances, the development of pericarditis, necrosis of the heart muscle( infarction) occurs due to disruption of the left ventricle.

Four main valves can be distinguished in the heart. If there is any acute situation with their damage - it can also lead to cardiogenic shock( for example, developed acute stenosis or insufficiency of the mitral or aortic valves).

Cardiogenic shock classification

- True;

- Peripheral vessels expand, blood pressure drops without a serious damage to the myocardium itself - cardiogenic shock, its reflex form( complicates the course of a posterior myocardial infarction with a very strong pain syndrome);

- If there is no response to ongoing therapy in cardiogenic shock - talk about its areactive form;

- The presence of such rhythm disturbances as paraxism of ventricular tachycardia or paroxysm of atrial flutter, as well as conduction disturbances such as the distal full A-V blockade and the cardiogenic shock itself-indicates its arrhythmic form( both stroke volume and cardiac output sharply decrease);

- The rupture of the heart muscle is accompanied by a drop in the blood pressure of the reflex, due to the discharge of blood into the heart bag and irritation of these receptors by the pericardium, the development of cardiac tamponade, and the drop in cardiac output - suggest a form of cardiogenic shock due to rupture of the myocardium.

Cardiogenic shock can be graded according to severity:

- I degree. The duration of the shock state is less than five hours. The clinic is not bright. The fall in blood pressure is insignificant( 90 mm Hg lower limit of systolic blood pressure).Slightly expressed tachycardia( 100-110 per minute heart rate).It lends itself well to therapy.

- II degree. The duration of the shock is more than five, but less than ten hours. Symptoms of cardiogenic shock are expressed, acute left-ventricular failure predominates, accompanied by pulmonary edema. Arterial blood pressure is significantly reduced( systolic blood pressure is 80-60 mm Hg).Severe tachycardia( up to 120 per minute heart rate).The response to therapy is slowed down.

- III degree. The duration of the shock is more than ten hours. Symptoms are pronounced, the clinic is bright, and swollen pulmonary edema. Arterial pressure is reduced critically( less than 60 mm Hg systolic blood pressure).Tachycardia is preserved and intensified( more than 120 per minute heart rate).The response to therapy is short-term or absent.

Cardiogenic shock symptoms

The situation of cardiogenic shock is acute, almost instantaneous. The person pales, turns blue, sweating( cold, sticky, moist skin), loses consciousness.

The systolic pressure is reduced sharply( it is less than 90 mm Hg for at least 30 minutes), the pulse is weak, it can not be detected, with auscultation - heart sounds are deaf, heart beats very often, cold extremities, impaired blood circulation in the kidneys is manifested by sharp reduction of productionUrine - oliguria, in the lungs( in the presence of pulmonary edema) auscultatory - wet rales. The suffering of the brain can manifest itself with total loss of consciousness or only with stunning, matching.

The clinic of cardiogenic shock is similar to the clinic of other types of shock.

Cardiogenic shock diagnostics

To diagnose cardiogenic shock is very simple - at the clinic.
Diagnosis, or rather, even the prevention of cardiogenic shock is very important. The percentage of death from shock is 80 to 95%.

Patients with acute heart disease or a sudden complication of an already existing heart disease are included in the zone of increased risk of developing cardiogenic shock:

- with complicated course of myocardial infarction( 40% or even more cardiocytes died, cardiac remodeling occurred immediately or in the early days of myocardial infarction, There are violations of conduction and rhythm, the development of myocardial infarction repeatedly);

- patients with endocarditis and pericarditis;

- especially elderly patients;

- patients suffering in addition diabetes mellitus.

Cardiogenic shock Emergency care

All treatment for cardiogenic shock is a complex of urgent measures. Emergency treatment is the main and only method of removing the patient from cardiogenic shock. The main effort is to increase blood pressure.

Treatment of cardiogenic shock includes anesthesia, inhalation with oxygen, intravenous fluid administration, mandatory monitoring of hemodynamic parameters.

Drug therapy

The first goal of the whole treatment is to maintain systolic blood pressure values ​​of at least 90 mm Hg. This goal is achieved by the introduction of the following drugs, most commonly with syringe pumps:
Dobutrex( dosage 2.5-10 μg / kg / min) is a selective adrenomimetic, it has a positive inotropic effect and not a significant positive chronotropic effect, with minimalInfluence on the frequency of contractions of the heart. Dopamine( in small doses) has a pronounced chronotropic effect, increases the frequency of cardiac contractions, raises myocardial requirements for the delivery of oxygen, may enhance ischemia. Dosage of 2-10 μg / kg / min., Every 2-5 minutes the dose is increased and adjusted to 20-50 μg / kg / min.
Norepinephrine, an adrenomimetic, has a pronounced effect directly on the vascular tone, increasing the overall vascular resistance, and to a lesser extent increases myocardial contractility. Can aggravate already existing myocardial ischemia.

In cardiogenic shock, qualitative analgesic therapy is needed. It is provided as non-narcotic( using a group of non-steroidal anti-inflammatory drugs - Analgin, Ketorol, etc.) and narcotic analgesics( Tramodol, Promedol, Morphine, Fentanyl, Buprenorphine) administered intravenously. Well relieve pain syndrome preparations of a group of nitrates( nitroglycerin, nitroprusside, etc.) administered by the same intravenous cardiologic patient. It is important to remember when treating nitrates that they dilate the peripheral vessels and reduce the arterial pressure.

The dosage of injectable drugs in case of cardiogenic shock and their combination is introduced under constant monitoring of arterial pressure.

Oxygen cushion or portable oxygen tank must be in the arsenal of any ambulance. In the hospital, the patient must always wear an oxygen mask or inject oxygen moisturized through special nasal catheters.

Increased blood pressure, intravenous nitrates, oxygen therapy and the administration of intravenous diuretics( Lasix), with adequate analgesia, help to reverse pulmonary edema at grade II and III severity. It is important to remember again that diuretics also reduce blood pressure.

Surgical treatment of

When the effectiveness of drug therapy for cardiogenic shock is low, the intra-aortic balloon counterpulsation method is used, in which a balloon installed in the descending aortic arch section swells during diastole and increases blood flow to the coronary arteries. This method allows you to get additional time for examination of the patient and performing the operation - balloon coronary angioplasty, that is, expansion of the narrowed coronary arteries, introducing a balloon into them.

If angioplasty is ineffective, an emergency aortocoronary bypass is performed. With refractory shock, auxiliary blood circulation is used as a "bridge" before heart transplantation.