| In advanced life support, an ECG is obtained to characterize arrhythmias, followed by drug administration or defibrillation as indicated. The purpose is to reestablish electrical and myocardial activity of the heart. Five major arrhythmias are frequently associated with cardiac arrest: ventricular flutter, ventricular fibrillation, asystole, pulseless idioventricular rhythm, and electromechanical dissociation. Drugs are selected based on the arrhythmia and can be administered by
intravenous, intraosseous, intratracheal, intracardiac, or sublingual routes (Table:
Drugs Used in Cardiopulmonary-cerebral Resuscitation, Dosages, and Indications). |
| Isotonic balanced electrolyte crystalloid solutions should be rapidly infused to restore volume and promote perfusion. Synthetic colloids such as hetastarch or dextran 70 or stroma-free hemoglobin rapidly expand the intravascular volume with a much smaller volume required. Overzealous fluid administration can result in fulminant pulmonary edema due to poor myocardial contractility or arrhythmias. |
| If the basic life support is unsuccessful (determined by failure of spontaneous respiration or inability to generate detectable forward blood flow) after 5-10 min, open-chest cardiopulmonary resuscitation (CPR, see
Open-chest Cardiopulmonary Resuscitation) is indicated. There are instances when open-chest CPR is indicated during initial basic life support, such as severe trauma with blood loss or in a large dog in which external compressions are unlikely to generate an adequate forward blood flow. |
