ABSTRACT
Awareness of intraoperative events in patients under general anesthesia is rare, but awareness during anesthesia is a serious complication that leads to anxiety and post-traumatic stress disorder. The Bispectral Index (BIS) has generally been accepted as a measurement of hypnosis under anesthesia. It is derived from a processed electroencephalogram and computer algorithm that assigns a numerical value based on the probability of consciousness. A 46-year-old, 65-kg male without underlying disease underwent elective surgery for ventral hernia. The patient in this case was administered an anesthetic that we frequently use and then average BIS value are 35. But he experienced awake during general anesthesia. We describe the first case of intraoperation awake under BIS 40 using desflurane.