Boston — No medical degree? No job on an ambulance? No sweat!

A study suggests you can still operate the simplified defibrillators that many heart specialists want to spread around public places to revive people who go into cardiac arrest.

The first-of-a-kind research project found that ordinary passers-by, without any training, were willing and able to come to the rescue with defibrillators stationed like fire extinguishers in glass cabinets around three Chicago airports.

"It was extraordinary," said Sherry Caffrey, the paramedic who ran the city-sponsored project. "We never imagined we were going to have the results we had."

The study was published Thursday in the New England Journal of Medicine. Although several previous studies have examined the effectiveness of automated defibrillators in the hands of trained and designated staff members at casinos and other public places, this is the first to evaluate their use by untrained passers-by in real medical crises.

Dr. Lance Becker, an emergency doctor at the University of Chicago who acted as an advisor and helped write the study, predicted that it will force large organizations "to truly reconsider how to set up a system to save people's lives with these devices."

"Our entire paradigm until now is: You must train every person who is going to touch the device, and this study says it's not true."

Sudden cardiac arrest — from heart attacks, heart disease, accidents or other causes — strikes about 250,000 American adults every year outside hospitals. About 95 per cent die before reaching the hospital.

People stand a much better chance of surviving if they undergo defibrillation, which restores a normal beat to a helplessly quivering heart, within the first few minutes of cardiac arrest. Ambulances often fail to arrive with their rescue equipment within 10 minutes.

Small, easy-to-operate defibrillators that automatically detect the heart's rhythm and decide whether it needs a shock have been developed over the past 20 years.

The Chicago study's four-pound defibrillators were distributed in labelled cabinets around O'Hare, Midway and Meigs Field airports. About the size of a toaster, they carried both written and oral instructions.

During the two-year study, someone tried to use one in each of 18 witnessed cases of fibrillating cardiac arrest. Eleven people were revived.

Although some airport personnel were trained on the defibrillators, six of the primary rescuers in the 11 successful efforts were passers-by, usually travellers, with no connection to the program or experience with the machines.

Three were doctors, however, and in each case someone helped by applying cardiopulmonary resuscitation, a manual technique for temporarily restoring some blood flow.

Still, the research gave momentum to the drive to install automated defibrillators in airports, shopping malls, casinos, stadiums, schools and other public places.

"I think there's enough evidence that these devices should be in every public place, and ultimately they ought to be in every home," Dr. W. Douglas Weaver of the Henry Ford Heart Institute in Detroit said.

Patrice Duker, a spokeswoman for the International Council of Shopping Centers, said many shopping centres are rolling out such programs — but with designated operators, usually security staffers. "The biggest issue is liability and making sure people who use the equipment know how to do it properly," she said.

Illinois and many other states have adopted Good Samaritan laws, which offer varying protection from lawsuits for well-meaning rescuers. No one was sued during the Chicago airport study.

One of the 53 defibrillators was, however, stolen. They typically cost about $2,500 each.

Actress and motivational speaker Tracey Conway, 46, of Seattle, said the devices are well worth spreading around. Her brother died when his heart gave out at home in 1989 and help arrived too late. Six years later, she went into arrest in front of an audience, and emergency personnel arrived in time with an automated defibrillator.

"I made it because my personal heart event happened later, it was a public setting, the technology was available," she said.

American Heart Association: http://www.americanheart.org