First Responder EMS Curriculum for Training Centers in Eurasia

hythms, the AED delivers an electrical shock that stops the abnormal rhythm.Defibrillation, using the AED, is considered the highest priority in adult patients in cardiacarrest, even before CPR is started. Early defibrillation makes the greatest difference in thechance for survival in adult cardiac arrest patients. The AED is not used in patients underthe age of 12 or those weighing less than 41 kg (90 lb).The AED works by placing two conductive electrode patches on the patient’s chest andturning on the battery-operated machine. The AED analyzes the patient’s cardiac rhythm.If the computer (AED) detects a life-threatening electrical rhythm, it automatically deliversan electrical shock that stops the chaotic rhythm, hopefully resulting in a non-chaoticrhythm that produces a pulse. If a life-threatening rhythm is not detected by the AED, itwill not shock the patient.The AED delivers electrical shocks when a patient has either ventricular fibrillation orventricular tachycardia. Ventricular fibrillation is a chaotic dysrhythmia causing the heartto quiver, without any effective pumping action. Ventricular tachycardia is anotherdysrhythmia that may or may not produce a pulse. It is vitally important that the FirstResponder attach the AED to a patient who is pulseless and not breathing. However,providing an electrical shock with an AED to a patient who has ventricular tachycardia anda pulse may cause the rhythm to deteriorate to ventricular fibrillation or an unshockablerhythm known as asystole. Asystole is a condition of no detectable electrical rhythm. Donot attach an AED to a patient unless he/she is unresponsive with no pulse and nobreathing.There are two types of AEDs: fully automatic and semiautomatic. The fully automaticAED simply requires the First Responder to attach the two electrode patches to thepatient’s chest, connect the two lead wires, and turn on the AED. The semiautomatic AEDrequires the First Responder to attach the two electrode patches to the patient’s chest,connect the two lead wires, turn on the AED, and press a button on the AED to analyze therhythm. The AED’s computer-synthesized voice then advises you whether or not to pressthe shock button. Both machines deliver up to three shocks in a row. The fully automaticAED requires fewer steps, but both are equally effective. Both AEDs will automaticallydeliver electrical shocks of increasing energy until the abnormal rhythm stops (first 200joules, then 200 to 300 joules, and then 360 joules).You must follow important general rules when using an AED. First, never attach an AED to apatient who is responsive, breathing, or has a pulse. Your primary concern is determiningthe presence or absence of a pulse, then using the AED if the patient is pulseless and notbreathing. The AED’s batteries should always be properly charged. CPR should be stoppedwhen the AED is analyzing the patient’s heart rhythm. People and objects in contact withthe patient may also receive an electrical shock. Therefore, do not touch the patient while theAED is analyzing a patient’s rhythm. The AED also should not be used in a moving vehicle.The unstable movement may cause improper analysis of the cardiac rhythm.Remember, early defibrillation is the life-saving intervention of first priority. The earlierthe heart is defibrillated, the more likely abnormal rhythms can be successfully convertedto life-sustaining rhythms. Therefore, it is beneficial to stop CPR to use the AED. CPRmay be stopped for up to 90 seconds when three consecutive shocks are delivered. ResumeCPR only after the first three shocks are delivered, or when the AED indicates a “noshock” situation.110 First Responder EMS Curriculum/AIHA, July 2002