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| Automated External Defibrillators Save Lives | |
| By Karyn Holm PhD RN and Susie McNulty BSN RN | |
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A 73 year old male collapses leaving a fitness center. A fitness instructor sees him, determines he is unresponsive, calls cardiac arrest and initiates CPR. She calls to a colleague to get the automated external defibrillator (AED). The colleague takes the AED down from its mount on the wall, opens it, and follows the audio and the corresponding written instructions on the lid of its container. She turns on the AED and places the electrode pads on his chest. Incorporating algorithms to analyze the ECG, the AED is programmed to determine whether a shock is necessary and does this in a few seconds. In the present situation, defibrillation was necessary and a low voltage shock was delivered. Regaining consciousness almost immediately, this man, who was / is a regular at the fitness center, is transported via ambulance to the nearest hospital.1 A well functioning heart pumps oxygenated blood from the left ventricle through the aorta to all organs and tissues of the body. This well orchestrated process is a consequence of electrical impulses generated by the cardiac conduction system preceding cardiac contraction. A cardiac arrest that evolves into sudden cardiac death happens when the electrical impulses to the heart are too rapid (ventricular tachycardia) or chaotic (ventricular fibrillation) or both. In the advent of either, ventricular tachycardia or ventricular fibrillation, rapid or chaotic electrical impulses interrupt cardiac contractions with consequent fall in blood pressure. Today’s AEDs can be used successfully by almost any responder with minimal training. Many have both audio and visual prompts which instruct the operator to press the power button; place the pads on the victim’s chest (once the pads are on the chest, the device automatically analyses the heart’s rhythm to determine whether a shock is needed); if needed the operator is instructed to press the shock button and stand clear. In the... |
...event that the ECG does not warrant the need for an electrical shock, but the operator mistakenly goes ahead and pushes the shock button, no shock will be delivered. This built in safety check has been instrumental in addressing the primary criticism associated with making AEDs available for public use.2 Current estimates are that 95% of cardiac arrest victims die before reaching the hospital. However in those places where AEDs are available for use by first responders, the survival rate is markedly improved by as much as 49%. According to the American Heart Association (AHA), 40,000 more lives could be saved if every community achieved even a 20% cardiac arrest survival rate.3 Further, according to Community Lay Rescuer AED Programs Writing Group for the AHA, on any given day, up to 20% of the combined United States adult and child population can be found in school.2 While sudden cardiac death is much less common in children than in adults, it can and does occur in children and adolescents. Parents of children who have died from sudden cardiac arrest have started a grassroots movement to insure that AED programs are available in schools. As a consequence the AHA has issued a scientific statement that recommends that schools develop a medical emergency response plan to deal with life-threatening conditions including sudden cardiac arrest. 1. Trelber R. Code Blue. Daily Southtown, March 8, 2006; Local: B1-B8. 2. Aufderheide T, Hazinski MF, Nichol G. et al Community Lay Rescuer Automated External Defibrillation Programs. Circulation. 2006;113:1-13. 3. AHA. Cardiac Arrest. Accessed April 15, 2006. |
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