Heart failure

Cardiac arrest, or sudden cardiac death, can occur suddenly (within 24 hours of the onset of the first signs of the disease in physically active individuals), this happens outside the hospital, approximately 400,000 people a year (USA), 90% of the cases of cardiac arrest is cause of death.

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Causes of cardiac arrest

In adults, sudden cardiac arrest usually occurs in the presence of heart disease, and is often the first manifestation of this pathology. Other causes of cardiac arrest include PE, trauma, ventilation and metabolic disorders (including drug overdose).

In children, the main causes are trauma, poisoning and various respiratory disorders (airway obstruction, smoke inhalation, drowning, infection, etc.).

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Pathophysiology of cardiac arrest

Cardiac arrest causes global ischemia, the main consequences of which are cell damage and edema formation. Edema is especially dangerous for the brain, since the rigidity of the bones of the skull leads to increased intracranial pressure and reduced perfusion of the brain. All safely resuscitated patients experience short-term or long-term cerebral disorders.

Decreased production of ATP leads to an increase in the permeability of the cell membrane. Potassium comes out of the cell, and sodium and calcium enter the cell. Excess sodium intake causes swelling of the cell. Calcium causes damage to mitochondria (decreases the formation of ATP), increases the production of nitric oxide (free radicals are formed) and in some cases activates proteases that cause cell damage.

In neurons, the abnormal ion current causes depolarization, the release of neurotransmitters. The most damaging effect is the neurotransmitter glutamate, which activates specific calcium channels and increases the calcium content in cells.

Isolation of mediators of inflammation leads to thrombosis of microvessels, increased permeability of the vascular wall and formation of edema. With prolonged ischemia, the processes of apoptosis are activated.

Symptoms of cardiac arrest

In severe patients, cardiac arrest is usually preceded by a worsening of the condition, frequent surface breathing, hypotension, and impaired mental functions.

In other cases, it is preceded by a collapse with a short seizure spasm (less than 5 seconds).

Treatment of cardiac arrest

Clinically, cardiac arrest manifests itself in apnea, lack of pulse and consciousness. The pressure is not determined. On the cardiomonitor may be ventricular fibrillation, ventricular tachycardia or asystole. In the case of electromechanical dissociation on the monitor, one can see a sinus bradycardia in the absence of a pulse.

In children, asystole is often preceded by bradyarrhythmia. 15-20% of children have ventricular tachycardia or fibrillation. Therefore, children need to have emergency defibrillation if sudden cardiac arrest is not preceded by respiratory distress.

It is necessary to immediately eliminate the potentially curable causes of cardiac arrest (hypoxia, cardiac tamponade, intense pneumothorax, massive hemorrhage or PE). However, not all reasons can be established during resuscitation. Clinical, X-ray and ultrasound studies help in establishing the cause of cardiac arrest. The most probable causes should be immediately eliminated. If the patient is in a state of severe shock and can not determine the cause of cardiac arrest, it is necessary to begin massive infusion therapy in combination with vasopressors.

Further treatment continues during cardiopulmonary resuscitation.