http://www.ProCPR.org - If the patient is a witnessed cardiac arrest, first check to assure the scene is safe. Check for patient responsiveness, contact emergency services, and check for breathing. Perform two rescue breaths, check for a pulse, and turn on the AED if the patient has no pulse and is not breathing. Attach the AED pads to the patient, and do not touch the patient while the AED analyzes. After a shock is delivered, begin CPR for about 5 cycles or two minutes. The AED will interrupt after two minutes and reanalyze the patient. Continue to follow the AED's instructions until advanced life support arrives.