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Sunday, June 14, 2009 | When someone is struck by cardiac arrest in El Cajon or Chula Vista or Santee, paramedics will likely perform the internationally recommended kind of CPR. They’ll pump the person’s chest 30 times, breathe into the person twice, and repeat several times before using a defibrillator.

But not in the city of San Diego.

Paramedics here break from the CPR guidelines established in 2005, by breathing once every 10 chest pumps. It’s an unusual approach, and a retired chief of San Diego lifeguards says it’s potentially dangerous.

“The theories of a doctor or doctors and a few paramedics are being substituted for the international consensus of experts on the best practice for CPR,” said B. Chris Brewster. “It’s fair to say it’s an experiment that could turn out to be very wrong, and many people who might otherwise have been resuscitated might in fact might not be.”

Dr. Jim Dunford, the city of San Diego’s medical director, said Brewster’s claims are “much ado about nothing,” and contends the technique used by San Diego paramedics is “99.99 percent within the guidelines.”

“Everything we’re doing is safe,” he said.

As things stand now, it is hard to know who’s right. There are surprisingly little data on CPR beyond the sad fact that, whatever method is used, it usually doesn’t work. Currently, only about 12 percent of patients who receive CPR in San Diego are resuscitated, and many of those don’t survive.

The number of people being resuscitated in San Diego has improved since the new guidelines were implemented, but there’s no way to know whether San Diego’s divergence from the guidelines is responsible.

However, clarity regarding CPR methods may be on the horizon.

Both the city and the rest of county are taking part in an unusual, little-publicized study that requires paramedics to alternate between different strategies regarding when they stop CPR and try to shock a patient in cardiac arrest.

Meanwhile, a research project is on the drawing board, this one aiming to gather data for the first time on what ultimately happens to a local patient when different CPR methods are used.

For now, however, the kind of CPR patients get will continue to depend on where in the county they are.

Rebooting the Heart

Although they’re often confused, a heart attack and cardiac arrest are not the same. A heart attack occurs when part of the heart muscle dies because a blocked blood vessel prevents it from getting enough oxygen; it can lead to cardiac arrest in some cases.

In cardiac arrest, the heart starts quivering “like a bag of earthworms. If you let that person lie there, that heart will run out of oxygen and just stop,” said Dr. John Blenko, an anesthesiologist at the University of Maryland.

An immediate electric shock from a defibrillator is the best way to reboot the heart. But CPR can keep blood flowing to the brain until paramedics arrive.

“You’re pushing blood out from the heart into the brain, providing some oxygen to the brain,” Blenko said. “That’s just a holding measure when what you need to do is get that heart restarted again.”

If the person has been in cardiac arrest for several minutes, paramedics typically perform CPR first to prime the patient for a shock. One consensus that has emerged in recent years is that people who are administering CPR should not spend much of those early minutes on mouth-to-mouth breathing.

Guidelines issued in 2005 by the American Heart Association recommend that paramedics or bystanders devote most of their efforts to chest compressions, rather than getting oxygen into the body through mouth-to-mouth.

“The focus is to stay on the chest as much as you can,” said Dr. Bruce Haynes, medical director of emergency medical services for San Diego County. “Every time you interrupt the compressions, you fall back in trying to keep the heart alive.”

30:2 or 10:1

The 2005 guidelines suggest that rescuers compress the chest 30 times in quick succession and then breathe twice into the patient’s mouth. They’re to repeat the process repeatedly before turning to a defibrillator. Previous guidelines from 2000 suggested 15 compressions then two breaths.

Paramedics in the county outside of the city of San Diego use the recommended method in the guidelines, Haynes said. But in 2006, the city began instructing paramedics and firemen to compress the chest 10 times, breathe once, then keep repeating the procedure.

Dunford, the city medical director, said the technique — known by the ratio 10:1 — makes sense because “there’s no advantage” to following the 30:2 ratio recommendation. He said he and colleagues settled on the 10:1 ratio after experimenting with a mannequin and coming to a “common sense” conclusion.

The recommended ratio is designed for laypeople, he said, not trained paramedics. “I don’t have 10 studies that prove what I’m doing,” he said. “I’m just using my brain.”

Brewster, the former lifeguard chief, said that is not good enough. “You can’t base broad medical practices on ‘This sounds good to me,’” said Brewster, who’s retired from the city and serves as president of the Americas region of the International Life Saving Federation, a lifeguard group.

Brewster, who fought the city’s CPR policy when it was instituted in 2006, contacted voiceofsandiego.org after reading a story regarding aCPR research project that’s underway locally.

Paramedics in the city and county are taking part in a study that assigns them to perform CPR for 30 seconds or three minutes before trying to shock a patient. Normally, paramedics perform CPR for 30 seconds and then turn to a defibrillator.

The study is unusual, reflecting the challenge of getting any reliable research regarding CPR. For one thing, it’s difficult to experiment on CPR patients because they usually cannot give consent to medical research.

And very few patients actually survive cardiac arrest so they can’t provide data as to which method works best, making it difficult for researchers to come to any statistically valid conclusions, said Wake Forest University’s Dr. Howard Blumstein, vice president of the American Academy of Emergency Medicine.

Indeed, the internationally recommended ratio of compressions to breaths is based not on human studies but “theoretical” research and experiments on animals and mannequins, said Dr. Anthony Handley, a leading CPR specialist based in England, via email.

Blenko, the Maryland anesthesiologist, said the recommended CPR guidelines aren’t requirements, but an international panel of specialists approved them. “They’re clearly what the vast majority of people are doing,” he said.

The problem with the San Diego approach is that “if they’re stopping every 10 pumps as opposed to every 30 pumps to give a breath, the patient doesn’t get a lot of blood flow,” he said.

A Departure from Mouth-to-Mouth

In fact, Blenko said he’s not aware of agencies that have diverted from the guidelines outside San Diego and Arizona, which is experimenting with CPR that doesn’t require mouth-to-mouth breathing.

The Arizona approach represents a full move away from providing oxygen to people in cardiac arrest. The theory is that the chest compressions provide enough air to the lungs, so breaths aren’t needed.

Handley, the specialist in England, supported the current CPR guidelines, saying “it makes sense to follow these unless there is an overwhelming reason not to.”

A spokeswoman for the American Heart Association said it doesn’t know how frequently its guidelines are followed, although they’re considered the “gold standard” around the world.

However, Blumstein, the emergency medicine official, isn’t concerned that San Diego diverges from the recommended method. “I doubt that it makes any difference,” he said, adding that the big issue is we still don’t know the best way to perform CPR.

A new project in San Diego County may help change that. As soon as later this year, all hospitals in the county will begin tracking what happens to patients who suffer cardiac arrests outside their facilities. Only an estimated 6.5 percent of people who suffer from cardiac arrest outside the hospital actually survive.

Currently, there’s no way for local health officials to know whether cardiac-arrest patients ultimately live or die after paramedics treat them. “We don’t know whether they get to go home,” said Dunford, who’s spearheading the project.

City statistics say 8.2 percent of 1,873 cardiac arrest patients were resuscitated between January 2002 and February 2005. The percentage rose to 12.2 percent of 3,395 patients between May 1, 2006, and May 15, 2009, after city instituted the new CPR.

The numbers could have gone up because the city now follows the 2005 CPR guidelines with the exception of the ratio of chest compressions to breaths. Or there might be another factor at work.

For now, Dunford is confident that the city’s method is best. “I vet all this stuff all the time,” he said, “and it’s the right thing to do.”

Randy Dotinga is a San Diego-based freelance writer. Please contact him directly at rdotinga@aol.com with your thoughts, ideas, personal stories or tips. Or set the tone of the debate with a letter to the editor.

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