Non-medical Professionals can use Cardiac Defibrillator, Studies Show

      Anyone who has watched an episode or two of ER or another medical show has heard a doctor call "clear!" after he or she places two electric paddles against a patient''s chest. The doctor is using a device called a cardiac defibrillator to restart a recalci trant heart. Most would say that such machines are lifesaving devices that should only be used by doctors or other health professionals in a medical setting. But two studies published in the October 26 New England Journal of Medicine indicate that this is not necessarily true. Indeed, even when used by non-medical personnel in non-medical settings, cardiac defibrillators apparently can significantly increase the percentage of patients who survive cardiac arrest due to ventricular fibrillation-a severely d isordered heart rhythm.

      Defibrillators are used when the ventricles, the main pumping chambers of the heart, starts quivering, rather than contracting rhythmically. Ventricular fibrillation means that the heart can no longer pump blood to the head or body-if not corrected quickl y the patient will die. But when an appropriate electrical charge is transmitted to the heart soon after fibrillation begins, it may be "shocked" back into its normal rhythm. If the heart has not been too damaged, the patient can survive.

      Both New England Journal of Medicine studies examined the survival rate after defibrillation of patients who had suffered cardiac arrest in non-medical settings-one dealt with cardiac arrests in casinos, and the other with events in airline terminals and planes.

      A team of researchers led by Dr. Terence D. Valenzuela from the University of Arizona in Tucson, trained security officers in casinos in Nevada and Mississippi to use defibrillators. The officers also had current certification in traditional cardio-pulmon ary resuscitation, or CPR.

      When a casino patron suffered a collapse, the security officers evaluated whether electrical defibrillation would be an appropriate treatment, and if so, they administered it. The defibrillators themselves are programmed to check a person''s heart beat, an d to determine whether a shock is called for.

      These researchers found that in 148 cases of cardiac arrest, 105 were due to ventricular fibrillation, and 90 of these were actually witnessed so that early medical intervention could be applied. Of these 90 patients, 53, or 59 percent, survived and were discharged from hospital. In addition, the earlier the treatment was instituted, the better the outcome: 74 percent of those whose defibrillation was applied within 3 minutes of collapse survived, significantly more than the 49 percent of those whose defi brillation began more than 3 minutes post-collapse.

      Dr. Richard L. Page from the University of Texas Southwestern Medical Center in Dallas and colleagues reported on the use of cardiac defibrillators by airline flight attendants. The researchers trained the attendants, and then monitored the outcome of def ibrillator use in 13 air passengers with documented ventricular fibrillation.

      In these cases, shock was applied, and normal cardiac rhythm was restored. The researchers reported that six patients, 40 percent of those who received shocks, subsequently returned "home with full neurologic and functional recovery." In their discussion, the authors termed this survival rate "excellent", and said that it compared quite favorably to published out-of-hospital survival rates.

      In an editorial accompanying these studies, Dr. Rose Marie Robertson from the Vanderbilt Medical Center in Nashville noted that the results should encourage the use of cardiac defibrillators in some non-hospital settings. "Taken together, these studies pr ovide strong evidence that trained personnel can intervene effectively when witnessed cardiac arrest is due to ventricular fibrillation." She continued, "The increase in survival (from the national average of 5 percent) among all persons with cardiac arre st is extremely encouraging and should give new impetus to efforts to deploy these devices in the most effective manner."

    

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