Electroencephalographic prediction of anoxic brain damage after resuscitation from cardiac arrest in patients with acute myocardial infarction.

The short-term prognostic value of routine electroencephalography (EEG), carried out on the days after cardiac arrest, was evaluated in a consecutive study of 185 patients with acute myocardial infarction together with an episode of clinical cardiac arrest. The individual EEGs were classified on a 5-grade scale. Of the 89 patients who survived, 18 had signs of anoxic brain damage; 96 patients died, 76 as a result of cerebral anoxia. Only 2 patients survived out of the total of 72 for whom the first EEG was classified as grades III--V. The EEGs of both these patients were recorded within a few hours after the cardiac arrest. None of the patients with an EEG of grade I died of cerebral anoxia, while all degrees of brain damage were otherwise observed in connection with EEGs of both grades I and II. It is concluded that an EEG of grades III--V indicates a fatal outcome, provided it has been recorded more than 24 hours after the cardiac arrest. A grade III--V EEG that is recorded within 24 hours after a cardiac arrest should be repeated some days later. It is not possible, on the basis of a single EEG, to predict the extent of the anoxic brain damage.