For a witnessed cardiac arrest, you immediately apply AED and attempt to defibrillate. For an unwitnessed cardiac arrest you do five cycles of CPR and then apply AED and attempt to defibrillate. Are these 2005 or 2010 AHA CPR guidelines?
The section entitled "Shock First Versus CPR First"
"When any rescuer witnesses an out-of-hospital arrest and an AED is immediately available on-site, the rescuer should use the AED as soon as possible. [...] When an out-of-hospital cardiac arrest is not witnessed by EMS personnel, they may give about 5 cycles of CPR before checking the ECG rhythm and attempting defibrillation (Class IIb)."
Edit: I believe it's still the same for the witnessed and the un-witnessed arrests in the new 2010 AHA Guidelines.
National EMS Certification exams will reflect the 2010 AHA Guidelines for CPR and Emergency Cardiovascular Care on the dates below - these dates allow ample time for implementation plans, instructor updates, and anticipated publication of all related AHA educational support materials.
November 1, 2011 EMT-Paramedic
January 1, 2012
Emergency Medical Responder (EMR)
Emergency Medical Technician (EMT)
Advanced Emergency Medical Technician (AEMT)