Clinical evaluation of the augmented delta quotient monitor for intraoperative electroencephalographic monitoring of children during surgery and cardiopulmonary bypass for repair of congenital cardiac defects.

To assess the augmented delta quotient (ADQ) monitor as a monitor of cerebral function during cardiac surgery, we monitored during operation the electroencephalograms of 48 young subjects (aged 2 weeks to 19 yr). We found ADQ patterns produced by cardiopulmonary bypass, hypothermia and general anaesthetic agents correlated with those obtained from a compressed spectral array (CSA) monitor and could be differentiated from changes caused by cerebral ischaemia, except in the youngest group of patients (less than or equal to 18 months) undergoing deep hypothermia (19.4 (SD 0.8) degrees C nasopharyngeal). In all other age groups the ADQ proved to be a simple monitor of the adequacy of cerebral perfusion. Neurological deficit occurred only if the ADQ was abnormal during hypotension for a period exceeding 7 min. ADQ evaluation of cerebral function was limited by events which produced artificially normal ADQ readings such as low amplitude EEG activity and the described isoflurane effect that was demonstrated to occur in some cardiac patients. The results obtained by the ADQ were comparable to those obtained by compressed spectral array and the ADQ was easier to use and interpret.