The new, minimally interrupted cardiac resuscitation approach results in a higher survival rate for out-of-hospital arrests than standard treatments, according to an article in the March 12 issue of the Journal of the American Medical Association.

"Out-of-hospital cardiac arrest is a major public health problem and a leading cause of death," the authors wrote. "Although early defibrillation with automated external defibrillators improves survival, early defibrillation is rare and few patients with out-of-hospital cardiac arrest survive. In 2004, the average survival of patients with out-of-hospital cardiac arrest was 3 percent in the state of Arizona."

The new technique, previously referred to as cardiocerebral resuscitation, is a new approach to out-of-hospital cardiac arrest for emergency medical services personnel. It focuses on maximizing blood flow to the heart and brain through a series of coordinated interventions and includes an initial series of 200 uninterrupted chest compressions, rhythm analysis with a single shock, 200 immediate post-shock chest compressions before pulse check or rhythm re-analysis, early administration of epinephrine, and delayed endotracheal intubation.

Bentley J. Bobrow, MD, of Mayo Clinic, Scottsdale, Arizona, and colleagues investigated whether the new technique would improve survival from out-of-hospital cardiac arrest. Patients with out-of-hospital cardiac arrests in two metropolitan cities in Arizona before and after training of fire department emergency medical personnel were assessed. In a second analysis of protocol compliance, patients from the two metropolitan cities and 60 additional fire departments in Arizona who actually received the resuscitation were compared with patients who did not receive the new procedure but instead received standard advanced life support.

Among the 886 patients with cardiac arrest, survival-to-hospital discharge increased from 4 of 218 patients (1.8 percent) before training in minimally interrupted resuscitation to 36 of 668 patients (5.4 percent) after the same first responders were trained in the new technique. In the subgroup of 174 patients with witnessed cardiac arrest and ventricular fibrillation, survival increased from 2 of 43 patients (4.7 percent) in before training to 23 of 131 patients (17.6 percent) after training.

For protocol compliance analysis, overall survival-to-hospital discharge occurred in 69 of 1,799 patients (3.8 percent) who did not receive the new technique and in 60 of 661 (9.1 percent) who received it. Survival with witnessed ventricular fibrillation and cardiac arrest occurred in 46 of 387 patients (11.9 percent) who did not receive the new technique and in 40 of 141 patients (28.4 percent) who received it.

"Why should MICR be associated with improved outcomes after out-of-hospital cardiac arrest- One major contributor to the poor survival rates of patients with out-of-hospital cardiac arrest is prolonged inadequate myocardial and cerebral perfusion. During resuscitation efforts, the forward blood flow produced by chest compressions is so marginal that any interruption of chest compressions is extremely [harmful], especially for favorable neurological outcomes. Excessive interruptions of chest compressions by pre-hospital personnel are common. Therefore, MICR emphasizes uninterrupted chest compressions," the authors concluded.

In an accompanying editorial, Mary Ann Peberdy, MD, and Joseph P. Ornato, MD, of Virginia Commonwealth University, Richmond, commented on the findings of Bobrow and colleagues.

"Although the concept of MICR needs further scientific evaluation, perhaps in the form of a randomized, controlled, clinical trial with precise documentation of protocol compliance, these details are likely not important factors to the numerous additional survivors who are back home with their families after the implementation of this new protocol. Progress in improving survival after cardiac arrest is most commonly made by a gradual evolution of science and its translation into clinical medicine rather than single, earth-shattering revolutions. This study ... represents confirmation that the quality of CPR, particularly the need for minimally interrupted chest compression and the lesser importance of positive pressure ventilation, is a meaningful development in the evolution of resuscitation science."