Closed-chest cardiac resuscitation in patients with acute myocardial infarction

Abstract

An experience with 60 patients who sustained cardiac arrest while convalescing from acute myocardial infarction has been described. Nearly one half of these patients were under 65 years of age, and recovering from their first coronary artery occlusion. Eighty-three per cent of the patients sustained their arrest within the first 5 days of hospitalization. In 38 of the 60 patients, some warning of the impending event occurred in the form of recurrent chest pain, cardiac arrhythmias, or hypotension, whereas in 22 patients no premonitory symptoms or signs were noted. The cardiac arrests presented as ventricular fibrillation in 58 per cent, ventricular standstill in 22 per cent, and some other arrhythmia in 20 per cent. Although cardiac action was restored in 47 patients, 26 of whom had sinus rhythm, only 13 patients were restored to their pre-arrest status and only 3 were discharged from the hospital. From observations made during these attempts at resuscitation, several conclusions appear justified: (1) All patients with acute myocardial infarction should be placed in a coronary-care unit, with continuous electronic monitoring for at least 5 days. (2) When cardiac arrest is recognized, immediate attention should be given to the artificial circulation. External cardiac massage should be performed continuously and with sufficient vigor by a house officer or nurse until the automatic pneumatic pump can be substituted. A rate of 40 compressions per minute is desirable, and should not be interrupted. (3) As soon as the artificial circulation has been instituted, mouth-to-mouth or mouth-to-airway ventilation should be started. Insufflation of the lungs can be achieved by this method between every other sternal compression. The change-over to endotracheal intubation and automatic respiration should be undertaken only when fully equipped and trained personnel are present. (4) Concern with the electrical characteristics of the arrhythmia should be demonstrated only at this point. Ventricular fibrillation is best treated by three countershocks, given at 1-second intervals. If the current derived from the lower voltage (350 or 450 volts) is not effective, no hesitancy should be displayed in switching to shocks of 750 volts. Ventricular standstill or other types of arrhythmia which do not yield an effective arterial pressure should be treated with intracardiac epinephrine. The standardization of the resuscitative technique in these broad terms is highly desirable. Unless thoroughly trained personnel are involved, it is not uncommon, under these stressful circumstances, for serious deviations in procedure to occur. The usual result is delay in the institution of artificial circulation. This loss of time, as well as that which results from failure to recognize immediately the onset of the arrest, is believed to be responsible for many unsuccessful resuscitations. The potential rate of success in treating these patients has not been approximated by us or by any other workers in this field. Such approximation will occur only after more knowledge is obtained about the correct details of the resuscitative procedure, and the proper use of adjunct measures to support the circulation during the recovery period.