Related articles: Cardiac arrest
Definition
Cardiac arrest is an event that can be traced to numerous causes.
Most often, it represents the terminal event of a disease that leads to a critical or terminal state, but it can also manifest itself suddenly, within 24 hours of symptom onset in a previously healthy subject.
Cardiac arrest produces a global ischemia of the body with effects at the cellular level that negatively affect the correct functioning of the various organs. The main consequences include direct cell damage (alterations in ion flux, loss of membrane integrity and release of harmful compounds) and the formation of oedemas (if located in the brain, can cause serious neurological damage).
In adults, cardiac arrest is often caused by various types of heart disease. Coronary heart disease is the most commonly documented cause, however cardiac arrest can also result from idiopathic dilated cardiomyopathy, hypertrophic cardiomyopathy, long QT syndrome, Brugada syndrome, left ventricular hypertrophy, myocarditis and congenital coronary anomalies.
Other causes include circulatory shock caused by respiratory disorders (pulmonary embolism, respiratory failure, airway obstruction and drowning), massive gastro-intestinal bleeding, trauma and metabolic disorders (including poisoning and drug intoxication).
Most common symptoms and signs *
- Arrhythmia
- palpitations
- Cyanosis
- Coma
- Convulsions
- Dyspnoea
- Chest pain
- Edema
- Brain edema
- Shortness of breath
- Ventricular fibrillation
- Hydrops Fetal
- Intracranial hypertension
- Hypoxia
- Hypotension
- Mydriasis
- Cerebral Death
- Pallor
- Memory loss
- presyncope
- Reduction of respiratory noise
- Sense of suffocation
- Vegetative state
- Confusional state
- Fainting
- Tachycardia
- tachypnoea
- Cardiac tamponade
- Dizziness
Further indications
In patients with terminal conditions, cardiac arrest is often preceded by a period of clinical deterioration characterized by rapid and shallow breathing ("gasping"), arterial hypotension and progressive alteration of the level of consciousness.
In the brain, edema causes an increase in intracranial pressure with reduced perfusion. This determines, in a significant percentage of patients successfully resuscitated, the presence of short-term or long-term brain dysfunctions, which manifest themselves with altered state of consciousness (from a slight confusion to coma), convulsions or both.
In other cases of cardiac arrest, there is a sudden collapse without prodrome, sometimes accompanied by short seizures (<5 seconds).
Diagnosis is established based on the presence of clinical signs of respiratory arrest, lack of pulse and loss of consciousness. Blood pressure is not measurable, while pupils dilate and become non-reactive to light after about 1-2 minutes.
The patient is evaluated with physical examination, thoracic ultrasound and chest X-rays in order to identify potentially treatable causes, such as hypoxia, severe hypovolemia, cardiac tamponade, hypertensive pneumothorax or massive pulmonary embolism. Unfortunately, many causes are not identified during cardiopulmonary resuscitation.
In the event of cardiac arrest a rapid intervention is essential, which uses cardiac massage and defibrillation to restore a perfusion rhythm and, when possible, the management of the triggering cause. If correctable conditions are not present, intravenous fluids and vasopressor drugs are administered (eg noradrenaline, adrenaline, dopamine and vasopressin).
Therapy following resuscitation typically includes methods to optimize oxygen supply, the administration of antiplatelet agents and therapeutic hypothermia.
