[Modifications in and prognostic value of the EEG in anoxic encephalopathy: 75 cases]

The use of new cardiopulmonary resuscitation techniques has considerably increased the possibility of survival after cardiopulmonary arrest. It is of considerable interest to evaluate the extent of any anoxic brain damage. The EEG has proven very informative in the assessment of cerebral function in patients with anoxic encephalopathy. Its role is unchanged despite advanced imaging techniques. In 75 patients, the value of EEG recorded on the days after the onset of disturbances has been compared with the initial Glasgow coma scale (GCS) as a predictor of short-term prognosis. The EEG patterns were classified into 6 major grades and 12 sub-grades which were defined on the basis of the morphology of dominant activities, distribution and reactivity to external stimuli. A favorable outcome occurred with grade I to IIB associated with a GCS of 5 above. A bad prognosis was suggested by grades IVA to VC, particularly when epileptiform discharges were present, and the GCS was always below 5 in these patients. With new EEG grading scales in anoxic encephalopathies, the accuracy for predicting survival (or death) is now 90%.