Use of bispectral index monitoring for a patient with hepatic encephalopathy requiring living donor liver transplantation: a case report.

We report the use of perioperative bispectral index (BIS) monitoring in a patient who underwent living donor liver transplantation (LDLT). Hepatic encephalopathy featuring extreme excitement developed in a 42-year-old male and was diagnosed as acute hepatitis. Sedation with continuous infusion of midazolam was necessary. BIS value gradually decreased and reached 0 17 h after commencement of continuous infusion of midazolam. Midazolam infusion was stopped but BIS value remained 0. Brain CT scan revealed an almost normal image. Multi-lead electroencephalogram was recorded revealing almost no electrical activity. Administration of flumazenil did not improve his consciousness and BIS value. Adequate spontaneous respiration was maintained and the possibility of brain death was excluded. LDLT was performed on the 5th ICU day. BIS value remained 0 throughout surgery. BIS value suddenly increased 2 h after surgery and reached 60 11 h after surgery. It became possible to communicate with the patient and his trachea was extubated on the 4th postoperative day. We believe that, with BIS, we were able to follow preoperative exacerbation of the "pathological" process of hepatic encephalopathy, and predict postoperative emergence from general anesthesia, suggesting normal graft function.