BIS-guided deep anesthesia decreases short-term postoperative cognitive dysfunction and peripheral inflammation in elderly patients undergoing abdominal surgery

Objectives Postoperative cognitive dysfunction (POCD) is a common clinical complication, with an underlying pathophysiology linked to heightened levels of neuroinflammation. However, it requires clarification as to whether the depth of anesthesia modulates postoperative cognitive dysfunction. This study investigated the association between depth of anesthesia and POCD in elderly patients undergoing abdominal surgery. Methods A total of 120 patients aged 60 years or older who were planned for abdominal surgery under total intravenous anesthesia were included in this study. The depth of anesthesia was guided by monitoring Bispectral Index (BIS) data. All study participants completed a battery of nine neuropsychological tests before surgery and at 7 days and 3 months after surgery. POCD was calculated by using the reliable change index. Plasma concentration of C-reactive protein (CRP), interleukin (IL)-1 beta, IL-10, S-100 beta, and norepinephrine (NE) were measured. Results The incidence of POCD at 7 days after surgery in the deep anesthesia group was 19.2% (10/52), which was significantly lower (p = 0.032) than the light anesthesia group 39.6% (21/53). The depth of anesthesia had no effect on POCD at 3 months after surgery (10.3% vs 14.6%, respectively, p = 0.558). Similarly, plasma levels of CRP and IL-1 beta in deep anesthesia group were lower than that in light anesthesia group at 7 days after surgery (p < 0.05), but not at 3 months after surgery (p > 0.05). There were no significant differences in the plasma concentration of IL-10, S-100 beta, and NE between the groups (p > 0.05). Conclusions Deep anesthesia under total intravenous anesthesia could decrease the occurrence of short-term POCD and inhibit postoperative peripheral inflammation in elderly patients undergoing abdominal surgery, compared with light anesthesia.