Abstract: Objective To observe the relationship of awake bispectral index (BISawake) and the postoperative cognitive dysfunction (POCD). Methods 100 patients aged 60~75 years with ASA status Ⅰ~Ⅱ, underwent elective lower abdominal surgery with intravenous anesthesia (propofol, remifentanyl and rocuronium). The BIS was adjusted in 40~60 during the surgery. Their cognitive function was assessed with the neuropsychological test battery commended by International study of postoperative cognitive dysfunction (ISPOCD). Results 8 patients withdrew for unwilling or serious complications. The BISawake was more than 65 in 68 patients (group A), and less than 65 in 24 patients (group B). The difference of the verbal learning immediate and delayed of Hopkins Verbal Learning Test-Revised was more in the group B than in the group A. Conclusion Lower BISawake may be associated with the decline of postoperative cognitive function.

Key words: bispectral index, postoperative cognitive dysfunction, awake, elderly