Automated external defibrillators at home
As you read this, someone somewhere in the United States is collapsing from a cardiac arrest. The odds are poor that she or he will survive this sudden disruption of the heart's normal rhythm. Most of the 1,000 or so people who go into cardiac arrest each day die because they don't get the treatment they need — an electric shock to the heart — fast enough.
Heart-shocking devices were once found only in hospitals and ambulances. Now they're popping up in airports, movie theaters, fitness centers, casinos, malls, office buildings, and other places. These public versions, called automated external defibrillators (dee-FIB-rih-lay-tors), are so easy to use that sixth graders who have never seen one before can master their use in a minute or so, as shown in a 2002 study. This ease of use, combined with the fact that 3 in 4 cardiac arrests happen at home, have opened a national debate over whether it's a good idea to have a defibrillator at home.The chances of surviving a cardiac arrest fall about 10% for each minute the heart stays in ventricular fibrillation. Shock the heart back into a normal rhythm within two minutes, and the victim has an 80% chance of surviving. Deliver that shock after seven minutes — the average time it takes an emergency medical team to arrive in many cities — and the odds are less than 30%. If someone near you goes into cardiac arrest, calling 911 is a must. Even if there's a defibrillator nearby, you'll need professional help as soon as possible. CPR is also important because it keeps blood flowing to the brain and other vital organs. Still, a home defibrillator could let you restore a healthy heart rhythm several crucial minutes sooner than emergency medical technicians.
Can home defibrillators help?
With a prescription from a doctor and $2,500 or so, you can buy a defibrillator for your home, office, or car at many large pharmacies or medical supply companies. The question is, should you? Experts in the areas of sudden cardiac arrest, emergency medicine, and public health don't see eye-to-eye on this issue. Some argue that people who want to buy defibrillators for their homes should be able to do so without needing a prescription from a doctor. Others argue that people won't maintain the devices so they will be ready when needed, or that most people would be better off spending some of the money on a health club membership and donating the rest to their local emergency response team.
Researchers have collected relatively little evidence on the benefits and risks of wider access to defibrillators. A few studies have examined their use in public places. One, published in the October 17, 2002, Journal of the American Medical Association, showed that 11 of 18 people who collapsed with ventricular fibrillation over a two-year period in Chicago's three airports were revived, mostly by passers-by who used highly visible and well-marked defibrillators.
But their use at home is uncharted territory. One project, Neighborhood Heart Watch, is putting automated defibrillators in volunteers' homes in Indianapolis neighborhoods. When there's a call to 911 about a cardiac arrest in that neighborhood, it's routed to both the emergency services and the nearest home with a defibrillator.
Another study, the Home Automatic External Defibrillator Trial, sponsored in part by the National Institutes of Health, aims to map out the benefits and risks. It will give home defibrillators to 3,500 heart patients and train their partners to use the devices. The partners of another 3,500 heart patients will get training in CPR, but no home defibrillator. The results aren't expected until 2007.
Who should have one?
A home defibrillator would probably be a good investment for anyone who has survived a sudden cardiac arrest but who does not have a pacemaker capable of shocking the heart (an implantable cardioverter/defibrillator, or ICD). Owning this device might also make sense for someone with severe heart failure, unstable angina, or other severe forms of heart disease. So far, though, there's no good evidence that home defibrillators will save lives in this group of people.
Training is a must
If you decide to buy a defibrillator for your home, or if you just want to be prepared for the chance you'll someday need to use one in a public venue, make the time now to take a class on using this device.
Why bother to go through training when these machines have been designed for virtually mistake-free use? Several reasons. A class can help you use the defibrillator with confidence and speed. It can help you deal with unusual situations, such as where to apply the pads on someone with an implanted pacemaker, a medication patch, or a hairy chest. It will also teach you how to do CPR, an important part of the process.
The American Heart Association has developed a 3 1/2-hour course called "HeartSaver AED for Lay Rescuers and First Responders." To find the closest training center that offers this course, call the AHA at 800-242-8721.
January 2003 Update
Cardiopulmonary Resuscitation Is Mouth-to-Mouth Ventilation Necessary?
Studies show that cardiopulmonary resuscitation (CPR) improves the survival rate of people suffering from cardiac arrest. However, in a survey of 975 people who knew basic CPR, only 15% said they would definitely perform CPR with mouth-to-mouth on a stranger. Of those surveyed, 68% said they would definitely perform CPR if only chest compressions were required. Fear of infection and mouth-to-mouth contact with a stranger were the primary reasons people were hesitant to perform the assisted breathing part of the procedure.
Studies on animals and humans suggest that chest compressions alone may be just as effective as chest compressions plus ventilation. Researchers in Seattle decided to test this theory by conducting a study involving emergency dispatchers. Callers seeking help from dispatchers in an emergency involving cardiac arrest were randomly assigned to receive either of two sets of instructions: CPR involving chest compressions alone or standard CPR involving chest compressions plus mouth-to-mouth ventilation. Callers were told to continue CPR until paramedics arrived. Dispatchers completed providing instruction in 81% of the chest compression cases and in 62% of the standard cases. Arrival of emergency personnel was the primary reason instructions were stopped before completion. The researchers followed the cases to discharge from the hospital. The survival rates for patients receiving the two sets of instructions were similar; 14.6% for chest compression alone and 10.4% for standard CPR.
These results suggest that, at least when performed by untrained bystanders, CPR involving chest compressions alone is just as effective as chest compressions and mouth-to-mouth ventilation. In addition, dispatchers are able to provide instruction for chest compressions alone more quickly than the standard instructions. Chest compression alone may become the preferred method of performing CPR for inexperienced bystanders. This may increase the chances that a person suffering from cardiac arrest will receive needed CPR from a stranger.
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