Study: Some Rescuers Give Too Many Breaths During CPR

An American Heart Association study suggests that paramedics could be incorrectly administering cardiopulmonary resuscitation, or CPR, during rescues.

Researchers found that some crews were exceeding the AHA's recommendation to give 12 to 15 breaths per minute to heart attack victims.

The study's lead author, Tom Aufderheide, said that finding could be linked to the overall heart attack survival rate in the United States, which is about 5 percent.

"Excessive ventilation may be contributing to that poor outcome," he said.

Researchers observed 13 cardiac arrest victims and found in the first seven patients that the average maximum ventilation rate was 37 breaths a minute, roughly 250 to 300 percent more than the recommendations. When the researchers started a CPR retraining program, the average ventilation rate for the next six patients dropped to 22 breaths per minute.

Aufderheide suggested one solution might include using a system that flashes a light every five seconds to let a rescuer know when to deliver another breath of oxygen.

During CPR, the chest compresses and expands, creating a slight vacuum for blood in the veins to return to the heart. But when that does not happen, not as much blood returns to the heart.

"The decreased return of blood to the heart reduces the blood going out of the heart, and that may decrease the effectiveness of CPR," Aufderheide said.

Although the small study focused on cardiac arrests in only one city, the researchers strongly believe that hyperventilation could occur nationwide.

As a result of their findings, published in the journal Circulation, the researchers urge all hospitals and emergency medical services to assess whether hyperventilation is a problem in their units. If it is, they suggest reducing ventilation during CPR to 12 breaths a minute.

Meanwhile, emergency medical groups across the country are starting to have 911 dispatchers skip the mouth-to-mouth part of the emergency instructions when someone calls to get help for heart attack victims.

That's because precious time might be wasted trying to explain mouth-to-mouth resuscitation to someone who's reluctant to get that close to a stranger. Some doctors say it's easier to tell a bystander how to do chest compressions.

Some big cities have already made the change in CPR instructions, and 17 communities are testing the new instructions from the National Academies of Emergency Dispatch.

The changes are only for victims older than 18 whose hearts have suddenly stopped. Children and those who have stopped breathing because of such things as drug overdoses, drowning, carbon monoxide poisoning or allergic reactions still require mouth-to-mouth resuscitation.