Newswise — On TV medical shows, doctors yell "clear!" and revive patients who are struck with cardiac arrest. But what happens when there's no doctor nearby?
Cardiac arrest can strike with frightening speed. The patient may descend from apparently good health to unconsciousness, without warning and within seconds.
Ideally, an ambulance could arrive in time. But since emergency personnel often need eight or nine minutes to reach a patient, a device called an in-home defibrillator might help save some of the 450,000 people who die each year from cardiac arrest, says Aman Chugh, M.D.
He notes that unlike a heart attack, which typically occurs when there is a sudden blockage in an artery supplying blood to a heart, cardiac arrest is more of an electrical problem, in which the heart goes into a fast and chaotic rhythm called ventricular fibrillation. Blood pressure and blood flow to vital organs drop suddenly. And unlike a heart attack, cardiac arrest offers no advance warning.
"There's a very narrow time window in which you can act before there's permanent brain damage or permanent damage to other vital organs," says Chugh, assistant professor, Division of Cardiology, department of Internal Medicine at the University of Michigan Medical School. "Each minute that a shock is delayed decreases the chance for survival by approximately 10 percent."
Having an external defibrillator at the home of a patient who is at risk "would be ideal," he says, since 80 percent of cardiac arrests occur at home.
In September, the U.S. Food and Drug Administration approved the over-the-counter sale of automatic external defibrillators, or AEDs. With training and by following the straightforward instructions that come with the device, a family member or friend could use the AED, which administers an external electric shock through the chest wall to the heart. A recorded voice prompts the person using the AED.
An AED collects information through electrodes to analyze a patient's heart rhythm and instructs the rescuer whether or not to shock the patient's heart. If it is needed, a defibrillating shock interrupts the potentially lethal rhythm and gives it the chance to start beating normally. The device costs about $2,000.
The best-case scenario is that the delivery of a shock from a defibrillator occurs within five minutes after a cardiac arrest starts, Chugh says, noting that studies show that less than 10 percent of people who wait eight or nine minutes for help will survive.
Chugh says patients should talk to their doctors about whether they should have an at-home defibrillator. Risk factors for sudden cardiac arrest include pre-existing heart disease, including prior history of a heart attack or heart failure, he says.
Training is vital for people who may need to use an AED, says Susan Housholder, RN, MSN, APRN, BC; nurse practitioner/Clinical Director, Coronary Heart Disease Management. The AED will provide instructions, such as "apply pads to patient's bare chest" and "deliver shock now." But the rescuer still must be able to assess the patient in case the AED analyzes a non-shockable rhythm, she says. Training in CPR also is necessary, she says, since it often is used in conjunction with a defibrillator.
Housholder was the first chair of the American Heart Association's Operation Heartbeat for Washtenaw County. Her committee worked hard to educate the community on the value of AEDs and helped organizations get AEDs for their facilities, she says. She also is a basic and advanced life support instructor, which means she teaches professional and lay people how to resuscitate individuals of sudden cardiac death.
"One of the things that must be stressed is that people that have this in their home must be trained in basic life support," Housholder says.
Facts about cardiac arrest and over-the-counter home defibrillators:
"¢The 450,000 deaths each year from cardiac arrest (also called sudden cardiac death) account for more than the deaths from AIDS, breast cancer, lung cancer and stroke combined."¢The signs of cardiac arrest include sudden loss of responsiveness, no normal breathing, and no signs of circulation."¢There are many manufacturers of home AEDs, which received approval for use in September 2004. No matter which one you choose, make sure you, your family and your neighbors know how to use it. "¢In addition to home use, AEDs are available to churches, shopping malls, schools, airports and other busy places. For these public locations, it makes sense to purchase an AED if it might get used on a cardiac arrest victim every seven years, according to a study by researchers from the University of Iowa and the University of Michigan Health System (http://www.med.umich.edu/opm/newspage/2003/aed.htm).
For more information, visit these web sites: U-M Health Topics A-Z: Warning signs of heart disease http://www.med.umich.edu/1libr/aha/aha_warning_sha.htmAmerican Heart Association: Heart attack, stroke & cardiac arrest warning signs http://www.americanheart.org/presenter.jhtml?identifier=3053Heart Rhythm Society: Sudden cardiac death http://www.hrspatients.org/patients/heart_disorders/cardiac_arrest/default.aspFDA: Automated external defibrillator http://www.fda.gov/hearthealth/treatments/medicaldevices/aed.html
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