Quantitative EEG analysis during cardiac surgery in a case of spontaneous recall

A case of spontaneous postoperative recall of intraoperative events during tricuspid valvuloplasty is presented. In this case, EEG activity was continuously monitored and quantitatively processed to detect brain dysfunction during the procedure. Anesthetic maintenance was provided by fentanyl, isoflurane and midazolam. A retrospective analysis of the relative power distribution, median frequency and fast/slow ratio was conducted to characterize the recall and non-recall periods during the surgery. Analysis of the quantitative descriptors suggested that no specific EEG pattern was associated with the periods of recall. The use of several anesthetics with different effects on the EEG precludes the establishment of a single relationship between descriptors and changes in vigilance during episodes of recall.