Cardiopulmonary Arrest : Pathophysiology, Diagnosis And Treatment
Cardiopulmonary arrest is the abrupt cessation of spontaneous and effective ventilation and circulation after a cardiac or respiratory event. Cardiopulmonary resuscitation (CPR) provides artificial ventilation and circulation until it is possible to provide advanced cardiac life support (ACLS) and reestablish spontaneous circulation.
Cardiopulmonary arrest in adults usually results from arrhythmias. The most common arrhythmias are ventricular fibrillation (VF) and pulseless ventricular tachycardia (PVT). In children, cardiopulmonary arrest is often the terminal event of progressive shock or respiratory failure.
Diagnosis of Cardiopulmonary Arrest :
Rapid diagnosis is vital to the success of CPR. Patients must receive early intervention to prevent cardiac rhythms from degenerating into less treatable arrhythmias.
Cardiac arrest is diagnosed initially by observation of clinical manifestations consistent with cardiac arrest. The diagnosis is confirmed by evaluating vital signs, especially heart rate and respirations.
Electrocardiography (ECG) is useful for determining the cardiac rhythm, which in turn determines drug therapy.
The goal of CPR is to return effective ventilation and circulation as quickly as possible to minimize hypoxic damage to vital organs.
The treatment of CPR :
Persons in VF or PVT should receive electrical defibrillation with at least three shocks using 200 J with the first attempt and 200 to 360 J for the second and third attempts. After three unsuccessful attempts of defibrillation, the patient should receive about 1 minute of CPR. Endotracheal intubation and IV access should be obtained at this time. Once an airway is ensured, patients should be ventilated with 100% oxygen. Pharmacologic agents play a secondary role and are not recommended until an airway has been established and IV access attempted.
Hypothermia can protect from cerebral injury by suppressing chemical reactions that occur after restoration of blood flow following cardiac arrest. On the basis of the results of two clinical trials, the Advanced Life Support Task Force of the International Liaison Committee on Resuscitation recommends that unconscious adult patients with spontaneous circulation after out-of-hospital cardiac arrest be cooled to 32 to 34Â°C for 12 to 24 hours if the initial rhythm was VF. Cooling may also benefit other rhythms or in-hospital cardiac arrest in adults; there is insufficient evidence to recommend therapeutic hypothermia in children.