Electromechanical dissociation: six years prehospital experience.

Electromechanical dissociation (EMD) is the presenting rhythm in approximately 17% of all prehospital cardiorespiratory arrests. Yet, we know comparatively little about the demographic profile of these patients. The purpose of this study was to review historical and resuscitative parameters to help create a demographic profile. For a 6-year period of time from January 1st, 1980 to December 31st, 1985, 503 adult patients presented to a prehospital system in non-traumatic, nonpoisoned, cardiorespiratory arrest with an initial rhythm of electromechanical dissociation. The overall average response time was 6.1 +/- 3.2 min. Sixty percent of the patients were witnessed arrests and 65% had bystander initiated CPR. Forty-six percent of the patients had a cardiac history: myocardial infarction 13%, CHF 11% and other 21%. Other pertinent past medical history included diabetes 15%, COPD 10% and seizures 3%. The average age was 69.8 +/- 13.7 years. Fifty-seven percent were male. Forty-three percent were on cardiac medication including: digoxin, 24%; nitroglycerin, 12%; potassium supplements, 9%; propranolol, 8%; isordil, 6%; quinidine, 3%; nitropaste, 3%; and other cardiac medications, 15%. One hundred forty-eight (29%) patients developed a pulse at some time during resuscitative efforts, of these 17 (3.4%) patients responded with a pulse immediately after intubation. The mean time of resuscitation to sustaining pulse was 20 +/- 11 min and the mean resuscitation time to sustaining pressure was 22 +/- 11 min. Nineteen percent were successfully resuscitated, defined as a conveyance of a patient with a pulse and a rhythm to an emergency department. Four point four percent were saved, defined as a patient discharged alive from the hospital. Approximately 53% of the successfully resuscitated patients and 45% of the save patients were determined to have a probable respiratory event as the primary etiology of their arrest. This study attempts to provide some insight into the demographic profile of the patients in EMD.