It is estimated that 166 200 out-of-hospital cardiac events occur each year in the United States, with approximately 60% of these events treated by emergency medical services (EMS). 1 Reported rates of survival following outof-hospital cardiac arrest (OHCA) vary widely, from 0.2% (Detroit [2007]) 2 to 23% (London, England [2005]). 3 Nationwide, the median reported survival rate is 6.4%. 4 The vast majority of patients who survive OHCA are resuscitated at the scene of the cardiac arrest and subsequently transported to the hospital for definitive care. 5,6 Nevertheless, the practice of EMS systems in cases of refractory OHCA vary widely from agency to agency. Although most systems generally follow the basic life support (BLS) and advanced life support(ALS)generalresuscitationguidelines outlined by the American Heart Association, 7 there is widespread variability in their application. In one study, adherence to American Heart Association guidelines for the out-of-hospital care of cardiac arrest was only 40%. 8 During the past 30 years, several research teams have sought to define objective clinical criteria to identify patients who likely will not benefit from rapid transport to the hospital for further resuscitative efforts. 9-18 Despite this research, many EMS systems still urgently transport patients with refractory cardiac arrest to the hospital for continued resuscitative efforts. 19-21 Rapid transport with lights and siren may pose hazards for EMS personnel and the public and should occur only when the risks of high-speed trans-See also pp 1423 and 1462.