Direct-current countershock

For ventricular fibrillation, immediately apply direct-current countershock at 3-5 J/kg. Repeat twice if no response. Continue CPR if the patient is still without a pulse, and administer epinephrine, repeated countershocks, amiodarone, and/or lidocaine as recommended in advanced cardiac life support (ACLS) guidelines. 

For ventricular tachycardia in patients without a pulse, immediately give a precordial thump or apply synchronized direct-current countershock at 1-3 J/kg. If this is not successful, begin CPR and apply countershock at 3-5 J/kg administer amiodarone and/or lidocaine and repeated counter-shocks as recommended in ACLS guidelines. 

For patients in cardiac arrest, usual antiarrhythmic agents and direct-current countershock are frequently ineffective until the core temperature is above 32-35°C (90-95°F). Provide gastric or peritoneal lavage with warmed fluids and perfonn CPR. For ventricular fibrillation, bretylium, 5-10 mg/kg IV (see p 421), may be effective. 

Dahl CF, Ewy GA, Warner ED, Thomas ED. Myocardial necrosis from direct current countershock effect of paddle electrode size and time interval between discharges. Circulation 1974 50 956-960. 

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