The ABC’s of AED’s
April 07, 2011
Ian McGregor, Ph.D.
McGregor & Associates
Background: Sudden Cardiac Arrest and AED’s
- Sudden cardiac arrest (SCA) is one of the leading causes of death in North America. It strikes more that 200,000 Americans each year, nearly one death every two minutes.
- SCA is caused by ventricular fibrillation, a condition in which the heart’s electrical impulses suddenly become chaotic, causing the heart to cease pumping blood effectively. Many victims of SCA have no prior symptoms. SCA can strike anyone at any time. Victims of SCA will quickly loose consciousness, often without warning, and unless there is quick intervention, death will occur within a few minutes.
- SCA is treatable using an AED (Automated External Defibrillator).
Every Minute Counts!
- There is a direct linkage between the ‘call-to-shock’ time and the rate of survival:
Time from Call to Shock Survival Rate
Immediate defibrillation (1-2 mins) 90%
Early defibrillation (6 mins) 45%
Early defibrillation (7 mins) 30%
Delayed defibrillation (>10 mins) <5%
The Problem: Ineffective Planning
- Although defibrillator technology to save lives is readily available, survival rates remain low — because organizations do not have an effective defibrillator plan in place.
The Solution: The ‘Chain of Survival’
- The American Heart Association (AHA) and other organizations have adopted a simple action plan to improve survival from sudden cardiac arrest — called the ‘Chain of Survival’:
Early Advanced Care
* The Chain of Survival
- Recognize the emergency
- Decide to help
- Establish unresponsiveness
- Call 911
- Provide rescue breathing
- Provide chest compressions if pulse absent and AED not yet available
- Attempt to defibrillate as soon as AED available
Early Advanced Care
- Give advanced cardiac life support, including airway and breathing support and medications
How does an AED work?
- An AED is a device that analyses the heart’s rhythm for abnormalities and, if necessary, delivers an electric shock (called defibrillation) which may help re-establish a normal rhythm. (Note: an AED will not deliver a shock to a person who is in asystole (flatline) where the heart has no electrical activity)
- AED’s require little training to use. The machine automatically diagnoses the heart rhythm and determines if a shock is needed. Automatic models will administer the shock without the user’s command. Semi automatic models will tell the user that a shock is needed but the user must activate the shock. In most situations, the user cannot override a ‘no shock’ advisory by an AED.
- AED’s can even be used on children — all that is required is the use of pediatric pads. The American Heart Association recommends that if pediatric pads are not available, adult pads should be used to determine if the child is in a shockable rhythm. There is insufficient evidence to suggest that a child, in a shockable cardiac arrest, can be hurt by an adult defibrillation energy setting.
AED Equipment: Types, Selection, Cost and Maintenance
- Two sub-types of AED’s are currently available — monophasic and biphasic. Older defibrillators use a monophasic high energy electrical impulse, while newer AED’s deliver two lower energy shocks, one from the chest pad, and one from the back or rib pad. Earlier models have caused cardiac injury in some situations, while use of the newer model results in fewer complications and reduced recovery time.
- There are several AED manufactures to choose from — research them well and choose based on your particular needs. Major manufacturers include:
Laerdal Medical Corporation
Medtronic, Emergency Response Systems
Philips Medical Systems
Zoll Medical Corporation
Detailed information on these and other AED Manufacturers can be obtained on the National Center for Early Defibrillation website.
- Costs for AED machines are currently in the $1500 – $2000 range.
- It is important to keep AED’s in a state of readiness. A regular AED inspection and maintenance program is required to determine whether machine(s) are readily availability, in good working order and there are adequate supplies on hand.
Implementing an AED Plan in your Department
- A critical first step for departments developing a comprehensive AED plan is assessment. This involves reviewing issues such as location(s), training, equipment selection, and funding. Consult the article by Lari Bangert in this issue of the Newsletter (‘Framework for Developing a Departmental AED Plan’) for an in-depth account of a comprehensive planning process.
Legal Issues and State Legislation Issues:
- Concern from individuals about being sued for improper use of an AED.
Good Samaritan laws exist in all states. This means that no one can be held liable for the harm of a victim by providing improper or inadequate care if the harm was not intentional. There are no known cases of persons being sued trying to help – although there have been cases where people have been sued for not helping when they could.
- Use of AED’s by trained non-EMT first responders (EMT: Emergency Medical Technician)
While most states require EMT’s (e.g. firefighters and police) to know how to use AED’s as part of their job description, these states also permit the use of AED’s by non-EMT first responders and laypersons under certain conditions.
- Check with your local or state emergency medical services (EMS) department about current state AED legislation.
For more information on AED’s, consult the following excellent resources:
National Center for Early Defibrillation
American Red Cross: Saving a Life is as easy as A-E-D:
FDA Heart Health Online: AED
National Safety Council
http://www.nsc.org (search for AED)
New England Journal of Medicine
http://content.nejm.org (search for AED)