911. CPR. AED.

If you ask Evanston Fire Department Captain and paramedic Alan Lermer, these letters and numbers are the first three links in the “chain of survival” — and they can save lives.

Lermer spoke to eight city employees Friday at a session certifying them in cardio-pulmonary resuscitation and in the use of automatic external defibrillators. He began by telling about a man who collapsed and was saved by a city employee mowing a nearby lawn. The employee administered CPR until paramedics arrived.

“We were able to deliver this guy to the hospital alive and breathing,” Lermer said. “This can make a difference, and it does make a difference.”

The voluntary four-hour training session, sponsored by the American Heart Association, came as part of the city’s plan to place more defibrillators in public buildings, according to an Evanston press release.

Lermer said calling 911 is the essential first step in the “chain of survival” to help someone suffering from cardiac arrest. An ambulance can transport patients to a hospital faster than a normal vehicle, and trained paramedics can give more advanced care than a rescuer, he said.

The next link in the chain is CPR. CPR mimics the heart’s action by pumping oxygenated blood through the body when the heart has stopped working. Without oxygen, the brain can be damaged, Lermer said.

“After four to six minutes, brain cells die, and they die rapidly,” he told the group. “CPR can buy time.”

Still, Lermer said CPR alone is not enough. Only an external source of electricity — such as an automatic external defibrillator — can stimulate the heart to pump under its own power.

“When I first got (CPR) certified, I got a sticker that said ‘CPR saves lives,’ and I put it on the back of my Pinto,” Lermer said. “(The sticker) is not really true … CPR without defibrillation is not going to bring them back.”

Inside the heart are cells that act as an internal pacemaker. The electricity generated by these cells forces the heart to beat in a regular pattern. During cardiac arrest, electricity is being generated but in an abnormal pattern — and the heart stops beating.

An automatic external defibrillator — a smaller version of the electrical paddles applied to patients’ chests in hospital emergency rooms — shocks the heart with enough power to stop it completely, cutting off any erratic electrical flow. The heart’s pacemaker can then restart on its own.

Participants in Friday’s session spent the majority of their time practicing CPR and learning to the use automatic external defibrillator replicas.

“I think it’s neat,” said participant Barbara Zdanowicz, who works in finance for the city. “I said as long as it isn’t too hard, I’ll try it.”

Evanston fireman and paramedic P.J. Casey, who co-lead the session, said the devices are relatively easy to use, and they even give vocal instructions to the rescuer through a speaker.

“Basically, you follow the commands that the AED tells you,” Casey said.

Casey said all of the participants in the seminar passed the training. Although they did take a written exam, he said the practical aspects learned during the day were more important.

“I don’t feel comfortable letting anyone go out of my class knowing that if I had a heart attack, I wouldn’t feel comfortable letting them use the AED on me,” Casey said. “That’s why we have these practicing sessions.”

Reach Lee S. Ettleman at [email protected].