People who have a cardiac arrest that can't be helped by a
defibrillator shock are more likely to survive if given
cardiopulmonary resuscitation (CPR) based on updated guidelines
that emphasize chest compressions, according to the American
Heart Association (AHA). AHA changed its CPR guidelines in 2005
to recommend more chest compressions with fewer interruptions.
The emphasis on chest compressions continued in the 2010
guidelines update. After the 2005 guidelines, several studies
showed improved survival from shockable cardiac arrest. However,
new evidence shows that most cardiac arrests—nearly 75%— are due
to conditions that don't respond to shocks. Researchers
identified 3,960 patients in King County, Washington, who had a
type of cardiac arrest that doesn't respond to shock from a
defibrillator, or nonshockable cardiac arrest. They compared
survival rates among patients who had nonshockable cardiac
arrests from 2000-2004—before the 2005 guidelines changes—to
those who had nonshockable arrests from 2005-20