Survival rates from out-of-hospital cardiac arrest continue to be low despite periodic updates in the Guidelines for Emergency Medical Services and periodic improvements such as the addition of automatic external defibrillators (AEDs). The low incidence of bystander cardiopulmonary resuscitation (CPR), substantial time without chest compressions throughout the resuscitation effort, and a lack of response to initial defibrillation after prolonged ventricular fibrillation contribute to these unacceptably poor results. Resuscitation guidelines are only revised every 5 to 7 years and can be difficult to change because of the lack of randomized controlled trials in humans. Such trials are rare because of a number of logistical difficulties, including the problem of obtaining informed consent. An alternative approach to advancing resuscitation science is for evidence-based demonstration projects in areas that have adequate records, so that one may determine whether the new approach improves survival. This is reasonable because the current guidelines make provisions for deviations under certain local circumstances or as directed by the emergency medical services medical director. A wealth of experimental evidence indicates that interruption of chest compressions for any reason in patients with cardiac arrest is deleterious. Accordingly, a new approach to out-of-hospital cardiac arrest called cardiocerebral resuscitation (CCR) was developed that places more emphasis on chest compressions for witnessed cardiac arrest in adults and de-emphasizes ventilation. There is also emphasis on chest compressions before defibrillation in circulatory phase of cardiac arrest. CCR was initiated in Tucson, Arizona, in November 2003, and in two rural Wisconsin counties in early 2004.