People who suffer cardiac arrest outside of a hospital have a 33 percent better chance of survival if the emergency medical services responding bring a defibrillator to the scene within eight minutes, according to a Canadian study appearing in the April 7 Journal of the American Medical Association. 

   Defibrillators use an electric current to stop the uncoordinated series of contractions in the heart that can occur when a person suffers cardiac arrest.

   Researchers, led by Dr. Ian G. Stiell of the Ottawa Hospital Loeb Health Research Institute in Ontario, looked at the impact of a rapid defibrillation program on the survival rates of cardiac arrest victims.

   The rapid defibrillator program: reduced emergency services dispatch time; deployed ambulances more efficiently; and had firefighters perform defibrillation.

   These changes resulted in emergency services reaching cardiac arrest victims in less than eight minutes 92.5 percent of the time, which was an increase from 76.7 percent prior to the implementation of the program.

   The study, called the Ontario Pre-hospital Advanced Life Support (OPAL), consisted of two parts: Phase I focused on the 36 months prior to the implementation of the rapid defibrillation program. Phase II focused on the 12 months after the start of the program in communities with emergency services with basic life support and defibrillation capabilities.

   OPAL set out to look at the effectiveness of various pre-hospital interventions for patients with cardiac arrest, trauma and critical illnesses.

   The researchers followed cardiac arrest patients who were treated first by emergency medical personnel responding to the scene. The study was conducted in 19 urban and suburban Ontario communities.

   According to the authors, after the program was established 79.7 percent of those who were resuscitated, and lived at least a year, had "very good" cerebral performance scores and functional status.

   The researchers contend the expense of such a program is worth the gain in the number of lives saved.

   "We estimate the crude start-up cost of establishing the rapid defibrillation programs was approximately $36,500 per 100,000 residents and the annual cost would be small," the authors wrote. "Hence, we believe that this study has demonstrated that the implementation of a rapid defibrillation program is an effective and inexpensive approach to significantly improving out-of-hospital cardiac arrest survival."