An emergency room doctor is hailing the use of automatic external defibrillator (AED), which he used to save a fellow passenger's life on a Winnipeg Transit bus.

Dr. Doug Eyolfson was on the bus on Portage Avenue on Feb. 6 when the other passenger's heart stopped.

Eyolfson told the driver to call 911 and then jumped in to perform CPR. He also asked a friend to run to a nearby hotel to borrow the defibrillator.

The portable devices, which are becoming more common in public places, automatically diagnose the cardiac arrhythmias of a patient and direct the user on how to operate the machine.

Eyolfson, who used the AED to shock the man and correct the arrhythmias, says the machine can be used by anyone.

"It will tell you to do CPR, it will tell you to stop, and tell you if a shock is indicated. It won't shock if it's not indicated," he said.

"You can't shock someone by mistake."

Eyolfson says the sooner you use the device, the greater the chance of survival.