COLUMBUS, Ohio — A woman called 911 recently and told dispatchers that her grandmother wasn’t breathing.  The Columbus firefighter who took the call double-checked the address and phone number and then told the woman that they were going to start CPR together.

She hesitated but answered yes when Russell McGinnis asked whether she knew how to do cardiopulmonary resuscitation. Even if she hadn’t known the basics, McGinnis would have talked her through the procedure.

These days, instead of asking callers whether they want to do CPR, Columbus firefighters are telling callers they’re going to do it.

The American Heart Association changed its CPR guidelines last year to an option of compressions only — no more mouth-to-mouth — in an effort to get more bystanders to help people whose hearts have stopped. That prompted the Columbus Division of Fire to have its 911 staff be a little pushy with callers and not take no for an answer.

“We work with dispatchers to be as aggressive as they can and encouraging to callers to do CPR until the paramedics arrive,” said Dr. David Keseg, medical director of the Columbus Division of Fire.  The national survival rate of cardiac arrest is 6.4 percent. In Columbus, the survival rate is about 11 percent, Keseg said.

Several studies, including two published in 2010, in The New England Journal of Medicine and The Journal of the American Medical Association, found that people in cardiac arrest have a better chance of survival when chest compressions are started quickly.

Emergency dispatchers can play a pivotal role. Columbus dispatchers aim to get CPR started within 20 seconds of the call.

That was the case with the woman and her grandmother. McGinnis told the woman where to place her hands on her grandmother’s chest and how deep to push.

“Come on, you got to do this,” he told her. “Chest compressions, 1-2-3-4. Count. 1-2-3-4-5-6-7-8-9-10. Don’t stop, don’t stop, keep going. Come on.”

The woman cried, counted with McGinnis, and then cried some more. Through heavy breaths, she told him it wasn’t working.

“This is probably going to be the hardest thing you have to do your whole life,” he said. “Don’t stop until the paramedics walk through the door.”

Five minutes and 37 seconds after she called, paramedics arrived. Her grandmother survived that day but died a week later in a hospital.

Keseg said the stepped-up approach is making a difference, although he doesn’t have the data yet to show how many more lives have been saved.

Che Sitton called 911 in January after his mother, Nancy, collapsed in her room at their North Side home. He told the dispatcher that he knew CPR, but that was the last thing on his mind as he stared at his mom.

Sitton, 40, said of the dispatcher: “He could tell the stress of my voice, and he said, ‘You can do this,’ and I started the chest compressions.”

The dispatcher kept him motivated by counting compressions and reminding him to push deeply and fast even as his arms tired and his hope faded.

If Sitton hadn’t had that encouragement, “I would have given up,” he said.

His mom spent about a month in a hospital, had a pacemaker implanted and has recovered.

Other local dispatching agencies vary on how aggressive they are about getting callers to start CPR.

The Franklin County sheriff’s office asks callers whether they want to do CPR and leaves it up to them.

An official at the Metropolitan Emergency Consortium Communications Center, a consortium of townships on the east side of the county, said dispatchers there push callers to do compressions.

Dr. Michael Sayre, an associate professor of emergency medicine at Ohio State University who helped Columbus fire officials develop their protocol, said one-third of cardiac-arrest victims in Columbus get CPR before paramedics arrive.

A key is for dispatchers to help callers through difficult situations.

“You don’t have the luxury of a lot of time,” Sayre said. “There are a few effective methods, including taking control and getting the rescuer to get done what needs to be done.”

Columbus fire officials strive for a response time of zero.

“You don’t want to ask them if they want to do it,” said Rick Johnson, a Columbus firefighter who takes emergency calls. “You’re letting them know this is the best way we know for your loved one to survive.

“You need to be forceful, direct and respectful.”