critical care medicine
Cardiopulmonary Resuscitation (CPR) in Adults
Arrhythmia Treatment
VF or pulseless VTis treated with one direct-current shock, preferably with biphasic waveform, as soon as possible after those rhythms are identified. Despite some laboratory evidence to the contrary, it is not recommended to delay defibrillation to administer a period of chest compressions. Chest compression should be interrupted as little as possible and for no more than 10 seconds at a time for defibrillation. Recommended energy levels for defibrillation vary: 120 to 200 joules for biphasic defibrillators 360 joules for monophasic defibrillators If this treatment is unsuccessful after 2 attempts,epinephrine1 mg IV is administered and repeated every 3 to 5 minutes. Defibrillation at the same energy level or higher is attempted 1 to 2 minutes after each drug administration. If VF persists,amiodarone300 mg IV is given. Then, if VF/VT recurs, 150 mg is given followed by infusion of 1 mg/minute for 6 hours, then 0.5 mg/minute. Current versions of automatic external defibrillators (AEDs) provide a pediatric cable that effectively reduces the energy delivered to children. (For pediatric energy levels, see Defibrillation ; for drug doses, see table Asystole can be mimicked by a loose or disconnected monitor lead; thus, monitor connections should be checked and the rhythm viewed in an alternative lead. If asystole is confirmed, the patient is givenepinephrine1 mg IV repeated every 3 to 5 minutes. Defibrillation of apparent asystole (because it “might be fine VF”) is discouraged because electrical shocks may injure the nonperfused heart. 1.0 mg IV repeated every 3 to 5 minutes, followed by 500- to 1000-mL (20 mL/kg for children) infusion of 0.9% saline if hypovolemia is suspected. Cardiac tamponade can cause pulseless electrical activity, but this disorder usually occurs in patients after thoracotomy and in patients with known pericardial effusion or major chest trauma. In such settings, immediate pericardiocentesis or thoracotomy is done (see figure Treatment ). Tamponade is rarely an occult cause of cardiac arrest but, if suspected, can be confirmed by ultrasonography or, if ultrasonography is unavailable, pericardiocentesis. 