Background: Many patients who suffer an out-of-hospital cardiac arrest are found in electromechanical dissociation at the time the Emergency Medical Service (EMS) arrives. Since they have a poor prognosis, less attention has been paid to them.
Aim: To describe a consecutive population of patients with out-of-hospital cardiac arrest found in electromechanical dissociation and to try to define indicators for an increased chance of survival in this patient population.
Setting: The municipality of Göteborg.
Patients: All the patients who suffered an out-of-hospital cardiac arrest between 1981-1992 and were reached by our EMS system and in whom cardiopulmonary resuscitation (CPR) was attempted.
Results: In all, there were 3434 patients with cardiac arrest of whom 748 (22%) were found in electromechanical dissociation. They differed from patients found in ventricular fibrillation as there were more women, a higher frequency of cardiac arrest during the night, a lower frequency of witnessed cardiac arrest and consequently a lower frequency of bystander-initiated CPR. In all, 96 patients (13%) were hospitalized alive and only 16(2%) could be discharged from hospital. In a multivariate analysis relating to age, sex, time of cardiac arrest, interval between collapse and the arrival of the first ambulance, bystander-initiated CPR and treatment with adrenaline, atropine and tribonate, no independent predictor of survival was found.
Conclusion: Of all the patients with out-of hospital cardiac arrest in whom CPR was attempted by our EMS, 22% were found in electromechanical dissociation. Of these, 13% were hospitalized alive and 2% could be discharged from the hospital. No independent predictor of an increased chance of survival was found.