Methods For Heart Attack Treatments Challenged

New research shows shift in oxygen mask used by paramedics could significantly increase survival

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Recent research suggests Payson’s paramedics could save lives if they changed the way they give oxygen to people who have suffered a heart attack.

However, despite accumulating research favoring “passive ventilation” in conjunction with CPR significantly increases survival, the Payson Fire Department will continue to use existing methods until the American Heart Association changes its recommendations to paramedics nationwide, said Captain Dan Bramble, the department’s CPR training center coordinator.

“Our current recommendations are based on science that happened before 2005,” said Bramble. “The guidelines will be updated in 2010. Much of the more recent data supports the change,” he said.

The most recent study published in the Annals of Emergency Medicine seemed to contradict common sense.

Currently, paramedics trying to keep a heart attack victim alive long enough to reach the hospital often do chest compressions and provide supplemental oxygen through a mask connected to an oxygen tank.

The new research focuses on how the oxygen flows through the mask. Current guidelines prefer “bag-valve-mask” ventilation, which actively forces air into the lungs through the nose and mouth.

By contrast, “passive ventilation” simply lets air flow through the oxygen mask as paramedics continue chest compressions.

However, contrary to expectations the research shows that use of the passive oxygen flow significantly increases survival.

The researchers from the University of Arizona College of Medicine studied the records of 1,019 patients who had heart attacks and were treated by paramedics in the field. Of those, 459 received passive ventilation and 560 received bag-valve-mask ventilation.

Some 38 percent of the patients who who received passive ventilation recovered without any brain damage compared to 26 percent of those who received bag-valve-mask ventilation.

The results from the U of A study mirrored earlier findings in a similar study done in Wisconsin. In that case, survival rates rose from 15 percent to 38 percent with the passive oxygen flow.

Lead study author Dr. Bentley Bobrow, an emergency physician at the Maricopa Medical Center in Phoenix, said the findings cast doubt on the dominant current treatment — which involves both forced oxygen and use of breathing tubes.

U of A professor Gordon Ewy, a co-author of the study, said the findings demonstrate that continuous chest compressions have more to do with survival after the heart has stopped than forcing oxygen into the lungs. Bramble said the results make sense, especially since passive flow oxygen requires fewer interruptions in chest compressions.

“Compressions have taken a more important role,” said Bramble. “When you do compressions, you don’t do breathing. Because compressions are more important, ventilations are less important — so that ties into this research.”

Bramble said that he expects the American Heart Association will changes its recommendations next year, based on the most recent research.

If the national standards do change, the department already has all the equipment it needs to switch to passive ventilation, said Bramble.

In the meantime, a mounting pile of research demonstrates the importance of administering CPR in the field. That’s why the department has partnered with the Mogollon Health Alliance to provide CPR training to anyone who wants it.

In the past decade, the department has trained 800 Rim Country residents in how to perform CPR in the field, which can keep blood flowing to the brain during the critical minutes before paramedics arrive. Serious brain damage starts to occur as soon as four minutes after the heart stops beating.

In addition, the fire department has worked with businesses like the Mazatzal Casino to put portable defibrillators throughout the community and to train employees of those businesses in how to use the devices. The portable machines can deliver an electrical shock that can restart a stopped heart.

Bystanders who administer CPR “are buying time — and that’s really what’s going to save a person. It’s a vital link in that chain of survival.”

Anyone who wants to take a CPR class can call the Health Alliance at 474-2588.

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