We describe a case of a 14-year-old boy with
congenital insensitivity to pain and
anhidrosis (
CIPA) who underwent tarsal tunnel release for
tarsal tunnel syndrome. Because of abnormal pain perception, the patient's response to normally painful surgical stimuli is severely impaired and not adequately reflected in a corresponding rise in blood pressure or heart rate. This lack of autonomic feedback to
pain stimuli may make it more difficult to assess whether
anesthetic depth is adequate to prevent
intraoperative awareness and thus to safely conduct
anesthesia, especially if muscle
paralysis is required for surgical indications. We describe for the first time the use of processed EEG monitoring with a BIS A-2000 monitor to gauge
anesthetic depth in a patient with
CIPA. Initial forehead bispectral index (BIS) values prior to induction were normal (98) and then ranged between 23 and 79 during the whole
surgical procedure.
Propofol and
lidocaine were used for induction and deep extubation;
isoflurane was used as the sole
anesthetic for maintenance with concentrations ranging from 0.21% to 0.92% to maintain a target BIS of 40-60. Volatile
anesthetic requirements remained low throughout the procedure and no
narcotics were necessary during surgery. The BIS monitor served as an adequate tool to help avoid excessive use of volatile
anesthetic while assuring a processed EEG consistent with unconsciousness and
amnesia. After the patient had recovered and was oriented to place and time in the recovery room, he was asked whether he remembered anything about the surgery and the presence of a breathing tube in his mouth. He denied any recall of such events.