EARLY DEFIBRAILIATION FOR ADVANCED CARDIAC LIFE SUPPORT
(Photo courtesy of Physio-Control Corparation)
Each clay approximately 1,000 Americans die of heart attacks before reaching a hospital. Many others die from heart failure resulting from accidents such as drowning, electrocution, and suffocation. About 85 percent of these patients suffer ventricular fibrillation [rapid, irregular twitchings that replace the normal contractions of the muscular walls of the ventricles] immediately after circulation stops. Left untreated, ventricular fibrillation rapidly deteriorates into asystole |absence of muscular contractions!, which essentially is a dead heart. While early cardiopulmonary resuscitation (CPR) can help maintain fibrillation over a period of time, only defibrillation offers individuals suffering ventricular fibrillation a chance for survival.
By adopting an early defibrillation program, the fire service could save thousands of additional lives each year. This program is the next logical step for the fire service, whose responsibilities have expanded to accommodate the growing complexity of society and have expanded from strictly fighting fires to include rescue, extrication, emergency medical services, and hazardous materials.
AUTOMATED EXTERNAL DEFIBRILLATORS
Defibrillation, the use of equipment capable of delivering an electric shock to the heart to arrest ventricular fibrillation, once was a procedure whose use was restricted to advanced cardiac-life-support professionals such as paramedics, nurses, and physicians. The availability of automated external defibrillators (AEI)s), however, now makes it possible for all basic-life-support personnel to employ defibrillation.
AEDs comprise a heart rhythm analysis system and a defibrillator. Automatic and semiautomatic versions are available. Connecting cables and two adhesive pads attach the AED to the patient’s chest.
When using an automatic defibrillator, the operator attaches the pads to the victim’s chest and turns on the device. The defibrillator analyzes the heart’s rhythm, and if ventricular fibrillation is indicated, the device automatically charges and delivers a shock. Semiautomatic defibrillators require that the operator press the “analyze” control to initiate rhythm analysis after attaching the pads to the victim. If the device identifies ventricular fibrillation, the operator presses the “shock” control to deliver the electric shock. The AED’s accuracy in analyzing heart rhythm has been fairly consistent; errors rarely have been noted.
SURVIVAL RATES INCREASED
Early defibrillation has improved the survival rate of individuals who have experienced cardiac arrest. Its success has been documented by numerous controlled and published studies involving suburban, rural, and urban settings—with and without paramedic backup. These studies have confirmed that prehospital basic-life-support personnel can be trained to provide early defibrillation. When this training is combined with other EMS-system components, the chances for survival always have improved Few elements of emergency care have been subjected to such scrutiny.
All rescuers who respond to victims in cardiac arrest should be trained, equipped with, and permitted to operate a defibrillator.’ These rescuers include firefighters, EM I’s, non-EMT first responders, and others who routinely arrive first on the scene.
The sooner defibrillation is undertaken. the greater the chances of successful resuscitation. Survival rates are highest for patients whose ventricular fibrillation is detected and treated as quickly as possible. Up to 89 percent of patients [who are continuously monitored for abnormal heart rhythm] enrolled in cardiac-rehabilitation programs have been successfully resuscitated, according to “ACI.S Alert” (May 1991).
Emergency personnel have a few precious minutes to reestablish a sustained perfusing heart rhythm in a victim who has collapsed and is in ventricular fibrillation. Statistics show that only 50 percent of patients who experienced fibrillation after cardiac arrest had any heart rhythm at all after eight minutes. Although, as alreadynoted, CPR can buy a fewextra minutes, only defibrillation can restore the heart’s rhythm. Since the AED makes it possible for a greater number of people to operate a defibrillator, the time between a patient’s collapse and defibrillation can be shortened.
A thorough knowledge of the AED and its proper use is vital. Typical training courses for early defibrillation range from four to 12 hours and usually include an evaluation of CPR skills, an overview of cardiac physiology and arrhythmias, familiarization with the AED, practice of defibrillation procedures, and written and practical examinations. Because the AED itself determines the cardiacrhythm, the student does not have to be trained in rhythm recognition.
The American Heart Association (AHA) developed the first nationallystandardized curriculum for early defibrillation—a four-hour course for basic-life-support personnel. The module can be taken alone or as part of an advanced life support training course.
EMS providers and other training sites can supplement the AHA fourhour module w ith additional material to tailor the course to a variety of experience levels or state law-. Additional training, for example, might include reevaluation of CPR skills, interaction with ALS providers, or medico-legal documentation.
Training programs must be designed in collaboration with your system’s medical director and adapted to local standards of care and state law. Since a variety of programs already exist, however, you do not have to reinvent the wheel when designing your program; you can draw from the established programs.
Periodic retraining should be an integral component of all early defibrillation programs. Most include refresher training sessions at least twice a year.
MEDICAL SUPERVISION REQUIRED
An early defibrillation program requires medical supervision. An EMT or first responder can operate a defibrillator only under direct orders from a physician, by way of standing orders or direct radio contact. An early defibrillation program, therefore, must have a medical director who will authorize under his or her license properly trained and certified emergency responders to defibril late cardiac arrest patients. The medical director selects the personnel, develops the training program, and reviews all cardiac arrest cases to ensure that responders adhere to established protocols.
Close medical control is maintained by the dual-channel tape recorder attached to the AED. The cassette tape records the electrocardiogram from the patient and on-scene voice reports provided by the responders. This system permits electronic reconstruction of each cardiac arrest to ensure that all aspects of the care were performed properly. Proper care includes verifying cardiac arrest, initiating CPR, setting up the portable defibrillator, assessing the cardiac rhythm, and delivering the electric shock if ventricular fibrillation is present.
Costs for establishing an early defibrillation program vary. Provisions must be made for training responders, equipping response vehicles with AEDs (S4,000 to S7,000 per unit), and providing necessary components such as medical supervision and follow-up case reviews. The King County, Washington, program, noted for its expertise in early defibrillation, estimates that training an EMT to defibrillate costs between S31 and S36. Funds also must be provided for EMTs’ wages (they must attend classes while on duty), a cassette tape demodulator, an event-documentation system (S 1,500 to S2,000), data base management software packages (S450 to S 1.200), and training equipment (S100 to S3,000). Most AED manufacturers include limited-period service in the price, but ongoing AED maintenance more than likely will become a budgetary item after the first year.
Audiovisual packages in video or slide format usually are provided at no charge. Costs of supplies such as electrodes, cassette tapes, replacement batteries, and so on also must be considered.
The number of early defibrillation programs in the United States has doubled over the past two years. ‘ This growth has been the result of a number of influences. The early defibrillation concept has been endorsed by an expanding list of organizations including the American Heart Association, the American College of Emergency Physicians, the National Association of EMS Physicians, the National Association of EMTs, the National Association of State EMS Directors, the National Council of State EMS Training Coordinators, and the National Registry’ of EMTs. The International Association of Fire Chiefs has initiated its “Rapid Zap” program to propagate the use of AEDs among the nation’s 32,000 fire departments.
Early defibrillation programs can fill the gaps that exist among EMS systems. By providing quicker response from more locations, for example, smaller EMS systems, which usually have less sophisticated equipment, can achieve the same survival rates as more expensively equipped paramedic systems.
Potential applications for the AEI) are vast. It successfully has been used by first responders and EMTs at world fairs, shopping centers, marinas, and country clubs. Community responders trained in its use include private security officers for buildings and large public assembly facilities, restaurant personnel, health club managers, recreation center managers, office supervisors, corporate administrators, line workers in industrial plants, recreational therapists in senior care centers, and public railroad conductors.
Studies underway are investigating the possibilities of placing AEDs in the homes of high-risk cardiac patients and training family members in their use. The AEI) also has been proposed for use by flight attendants on commercial airlines. There is some speculaton that during the 1990s, AEDs will be as widely accepted as fire extinguishers and smoke detectors. The reason for AED saturation is that the risk for a patient’s developing ventricular fibrillation is greater in an office building or senior citizen center than it is at a fire occurring in that same community.
If early defibrillation is to become more widely available, it must be adopted throughout the fire service. Moreover, since heart attacks cause nearly one-half of the on-duty deaths of both career and volunteer firefighters, early defibrillation benefits the fire service as well as the overall community.
The concept of early defibrillation and the use of the AED still is evolving. Although the AED is not a complete solution, it has solved a major problem in the management of cardiac arrest: It gets the defibrillator to patients quickly—-within the time period when chances for survival are greatest.
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- 2. Cummins, RO: “From concept to standard of care? Review of the clinical experience with automated external defibrillators.”Ann Etnerg Med. 1989; 18: 1269-1275.
3. Textbook of Advanced Cardiac Life Support, chap. 20, American Heart Association, 1990.
- 4. Newman, M: “Defibrillation shakes the nation.” JEMS. Jan. 1989.