The 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care, which were published online November 24 by Circulation, include substantial changes to cardiopulmonary resuscitation with an emphasis on chest compressions.

Topics in the new guidelines include use of automated external defibrillators and recommendations for advanced cardiovascular life support and pediatric advanced life support. The revision emphasizes that high-quality cardiopulmonary resuscitation, particularly effective chest compressions, contributes significantly to successful resuscitation after cardiac arrest.

Robert Hickey, MD, Chair of the Emergency Cardiovascular Care program, characterized the updated guidelines as a ‘back to basics’ approach to resuscitation.

The most significant change to cardiopulmonary resuscitation is a change in radio of compressions to breaths from 15 compressions to 2 breaths (2000 guidelines) to 30 compressions to 2 rescue breaths. The 30-to-2 ratio is given to adults, children and infants, excluding newborns.

The change resulted from studies showing that blood circulation increases with each chest compression in a series and must be built back up after interruptions. The only exception to the new ratio is when two healthcare providers resuscitate a child or infant (except newborns), in which case they should provide 15 compressions for every 2 rescue breaths.

Another change involves cardiopulmonary resuscitation when using automated external defibrillators. Previously, when defibrillator pads were applied to the chest, the device analyzed rhythm, delivered a shock if necessary, and analyzed rhythm again to determine whether the shock successfully stopped the abnormal rhythm. The cycle of analysis, shock and re-analysis could be repeated three times before manual resuscitation was recommended, resulting in delays of 37 seconds or more.

Now, after one shock, the new guidelines recommend that rescuers provide about two minutes of cardiopulmonary resuscitation, beginning with chest compressions, before activating the defibrillator to re-analyze rhythm and attempt another shock.

Studies have shown that the first shock stops the abnormal cardiac arrest rhythm more than 85 percent of the time and that a brief period of chest compressions between shocks can deliver oxygen to the heart, increasing the likelihood of successful defibrillation.

The guidelines also recommend that healthcare providers minimize interruptions to chest compressions by doing heart rhythm checks, inserting airway devices, and administering drugs without delaying resuscitation.

The guidelines are based on the Consensus on Science and Treatment Recommendations, a document developed by the International Liaison Committee on Resuscitation. This group includes the American Heart Association and leading international resuscitation councils. The review of resuscitation literature is the largest ever published.

It took more than 36 months and includes input from 380 international experts; the document serves as the scientific basis for many countries' resuscitation treatment guidelines.