Specialists revamp CPR guidelines

In an effort to reduce the number of deaths from cardiac arrest, heart specialists yesterday announced a significant shift in their recommendations regarding cardiopulmonary resuscitation, stressing the importance of pumping on the chest while reducing emphasis on mouth-to-mouth to revive victims.

Heart attacks and other forms of sudden cardiac arrest happening outside of hospitals kill about 250,000 people each year in the United States, and attempts to increase the use of CPR have achieved only modest success.

Studies have shown that successfully performing resuscitation can more than double the chances of surviving cardiac arrest, among the leading causes of death.

The guidelines released by the American Heart Association mark the latest and most sweeping change in a back-to-basics movement in recent years that has framed CPR.

For example, since May 2003, emergency response operators in Boston and other cities have told callers who were untrained in CPR to perform chest compressions only, an acknowledgement that mouth-to-mouth can be difficult to perform.

The association's rules, the first update since less significant revisions five years ago, aim to make CPR easier to administer -- and to establish a more consistent flow of blood to the heart and brain in the minutes after a heart attack.

The guidelines represent the work of 380 international heart specialists who reviewed thousands of medical studies on cardiac arrest and resuscitation.

The biggest shift involves changing the ratio between heart compressions and mouth-to-mouth resuscitation.

Old guidelines called for rescuers to pump the chest 15 times and then blow into the mouth of the victim twice.

The new recommendations call for 30 chest compressions for every two breaths.

But the guidelines state that in the case of 911 calls placed by CPR novices, it is acceptable for emergency operators to provide instructions for chest compressions only.

The recommendations emerge even as hospitals are expanding their capacity to fix ailing hearts with elaborate, expensive repair jobs.

''But we're very much emphasizing the basics, something that any person can do," said Dr. Monica Kleinman, chairwoman of the Emergency Cardiovascular Care Committee of the American Heart Association's Massachusetts and Rhode Island region. ''Anybody can learn how to do CPR, and it turns out to be really important to the outcome of these patients."

Dr. Peter Moyer, medical director for the city of Boston's emergency service agencies, said the new guidelines show that restoring blood flow with chest compressions is the most important component when attempting to manually resuscitate someone who has collapsed from cardiac arrest.

''To interrupt compressions for too long is very deleterious to the heart, which you're trying to revive, as well as the head," Moyer said. ''This is a better balance. I'm happy it's happening."

To make sure the guidelines become part of standard practice, representatives of the heart association will visit CPR training sites across New England starting in February to explain the recommendations.

Healthcare workers, including paramedics, will receive updated guidance on performing the technique.

Members of the public who previously trained in CPR are advised to take refresher courses every two years, and the new guidelines will be incorporated into those classes.

''These guidelines are a very important first step," said Dr. Mark Pearlmutter, who is on the national faculty of the American Heart Association and chief of emergency medicine for Caritas Christi Health Care System in Boston. ''We believe we can actually significantly improve cardiac survival. Ultimately, that's what it boils down to."

The recommendations represent a continuing effort to simplify the practice of CPR.

Once, the rules varied according to the age of the victim. And the guidelines used to call for rescuers to perform more difficult tasks, such as finding and reading a pulse.

Now the rules standardize guidelines on chest compression and ventilation for adults and children alike, and abandon practices such as taking a pulse.

The guidelines also alter the use of automated external defibrillators, devices that restore heart rhythm when someone has cardiac arrest because of a condition called ventricular fibrillation.

Those machines, which come equipped with a recorded voice to guide users, analyze the victim's heart functions and tell rescuers whether the person needs a shock.

Previously, specialists had recommended up to three jolts in succession.

Now the guidelines advise giving one shock, then resuming CPR for two minutes before giving another shock if necessary.

That decision was supported by studies showing that a single shock followed by manual resuscitation enhances the chances additional jolts will help.

More than anything, the recommendations demonstrate the importance of rapidly and continually restoring blood flow after a heart has stopped beating.

Recent studies have shown that deeper compressions work best, a finding that inspired the recommendation to ''push hard, push fast."

Evidence in humans and laboratory animals has shown that stopping chest compressions too soon to begin mouth-to-mouth resuscitation can fail to adequately restore blood flow, specialists said.

And that, in turn, lowers chances for survival.

About 95 percent of cardiac arrest victims die before reaching a medical center.

''It's the hands-off time we were having a problem with," said Dr. Robert O'Connor, vice chairman of a heart association committee that approved the new guidelines. ''We need to maximize the proportion of time we're doing chest compressions."

Researchers have also come to recognize that oxygen remains in the lungs and blood even after the heart stops working.

That means frequent mouth-to-mouth resuscitation isn't as necessary as once believed.

''We also know there's some air movement that occurs with just the compression and the recoil of the chest itself," said Dr. Charles Pozner, a specialist in resuscitation at Brigham and Women's Hospital.

Beyond the scientific reasons for the alteration in CPR guidelines, real-world experience helped shape the rules.

Emergency rescue specialists said it has long been clear that bystanders, especially if they're not related to the person suffering cardiac arrest, are reluctant to perform mouth-to-mouth resuscitation.

To address that concern, Boston's 911 operators now tell untrained rescuers to perform chest compressions only.

Since that policy was adopted, the number of callers following through with CPR has risen from 15 percent to 60 percent.

''Let's face it," Moyer said. ''If it's a stranger, people aren't crazy about doing mouth-to-mouth resuscitation."

Stephen Smith can be reached at stsmith@globe.com.