Mouth-to-mouth ventilation: Help or hindrance in CPR?

By John Easton
Medical Center Public Affairs

A blue-ribbon panel of experts assembled by the American Heart Association and chaired by Lance Becker, Associate Professor in Medicine, has called into question the role of mouth-to-mouth ventilation as an integral part of cardiopulmonary resuscitation (CPR).

The panel's analysis, published as a "Special Report" in the Sept. 16 issue of the AHA's journal, Circulation, will also appear in coming issues of the journals Annals of Emergency Medicine, Journal of Respiratory Care and Resuscitation.

Although they are not yet ready to change the current AHA guidelines for performance of CPR, the Ventilation Working Group's consensus statement suggests that in many cases of adult cardiac arrest, mouth-to-mouth ventilation as a part of CPR rarely helps and may even harm the patient.

The experts believe that mouth-to-mouth ventilation can interfere with the rescuer's efforts to perform chest compressions and cause significant adverse effects. It makes CPR more difficult to teach, learn and perform, and dissuades bystanders from initiating therapy.

More than 350,000 people die from cardiac arrest each year in the United States. Nationally, only a little more than 30 percent receive any form of CPR. In Chicago, that rate falls to 22 percent.

"Early CPR using chest compression clearly saves lives," Becker said, "but in part because of the complications, complexity and concern associated with mouth-to-mouth ventilation, CPR is not performed for the majority of those who need it. A simpler technique might lead to more widespread performance, which would improve survival rates."

More research needs to be done, the panel insists, to prepare new guidelines for the year 2000.

Although it has a long history -- the first references to mouth-to-mouth resuscitation involve the prophets Elijah and Elisha in the Old Testament -- recent studies have cast doubt on the effectiveness of mouth-to-mouth ventilation in the setting of adult cardiac arrest, where the key determinant of survival is the time from arrest until defibrillation, when the heart is shocked back into a normal rhythm.

Unlike victims of near drowning or choking where mouth-to-mouth ventilation can quickly improve oxygen levels, low blood flow is the primary disorder for those who suffer a cardiac arrest. Without significant blood flow, forcing air into the lungs will not make much difference.

Besides, when the heart stops, oxygen levels in the blood decline gradually. Many patients continue to gasp for air and chest compressions induce some air exchange. Assisted ventilation appears to become important only after four to 10 minutes of CPR.

"It may be time to reshuffle the cardiac-arrest survival alphabet," suggests Becker, "from the old ABC [for Airway, Breathing and Circulation] to CAB [Circulation, Airway, Breathing], as they have already done in the Netherlands."

Until new guidelines are formulated, Becker advises those who witness a cardiac arrest: "Just do it. First, call 911. Then, if mouth-to-mouth ventilation bothers you, skip it and concentrate on chest compressions. That is far, far better than doing nothing."

The panel also emphasized that immediate mouth-to-mouth ventilation remains critically important for children and for adults where cardiopulmonary arrest results from airway obstruction, drowning, or respiratory problems.