[The potentialities of EEG analysis using the Lifescan in anesthesiology]

In 87 patients a new computerized EEG monitor was used in clinical anesthesia. Following aperiodic analysis, the Lifescan shows the computerized EEG in a striking color visualization allowing recognition of changes in the course of the EEG and of interhemispheric differences. The computerized EEG can be read after a brief training period. The changes caused by different clinical situations are visualized in detail. Different changes were observed with the anesthetics used. During induction with thiopentone a sudden increase in activity was obvious. During a lighter level of anesthesia with thiopentone beta activity was easily recognizable. During induction with high-dose fentanyl frequency was slowed over a long period and activity was increased. The monitor shows the changes in the lower frequency range in detail. A bimodal pattern occurred with a higher dosage of enflurane. During lightening of anesthesia with enflurane a typical pattern indicated return to consciousness. When nitrous oxide was administered during anesthesia with halothane, and to a lesser degree during anesthesia with enflurane or isoflurane, remarkable slowing and decrease in activity occurred. The monitor allowed detailed recognition of the different patterns obtained with the various anesthetics. In some cases it was possible to say what dosage of the anesthetic used had been given or what depth of anesthesia had been achieved. The effect of combined anesthesia, however, was difficult to judge. In carotid artery surgery a quick unilateral decrease in activity and slowing of frequency indicated cerebral ischemia and quickly disappeared after insertion of a shunt. This change was particularly obvious with the new monitor.(ABSTRACT TRUNCATED AT 250 WORDS)