BIS-guided light versus deep general anesthesia on postoperative cognitive dysfunction in older patients with...

Postoperative cognitive dysfunction (POCD) is a common and serious complication in older surgical patients. The impact of anesthetic depth on cognitive recovery, particularly when combined with regional analgesia, requires further elucidation. In this single-center, prospective, randomized, assessor-blinded trial, A total of 100 Older Patients (≥ 60 years) scheduled for elective lower limb orthopedic surgery were enrolled. All patients received an ultrasound-guided iliofascial block. They were then randomly assigned to receive either Bispectral index(BIS) guided light anesthesia (BIS 50-60, n = 50) or deep anesthesia (BIS < 45, n = 50)[1]. The primary outcome was the trajectory of cognitive function assessed by the Montreal Cognitive Assessment (MoCA) score preoperatively and on postoperative days 1, 3, and 7. Secondary outcomes included the incidence of POCD, postoperative nausea and vomiting (PONV), intraoperative burst suppression, and hospital length of stay. Compared with the deep anesthesia group, the light anesthesia group was associated with significantly better postoperative cognitive function. MoCA scores were higher in the light anesthesia group at all postoperative time points (all p < 0.01). The incidence of POCD on postoperative day 1 was markedly lower in the light anesthesia group (14.0% vs. 42.0%; p = 0.002). Patients receiving light anesthesia also had a lower incidence of PONV (16.0% vs. 40.0%; p = 0.008), a lower incidence of intraoperative burst suppression (20.0% vs. 48.0%; p = 0.003), and a significantly shorter median hospital stay (7.0 vs. 9.5 days; p = 0.01). In Older Patients undergoing lower limb surgery with regional nerve blockade, a BIS-guided light anesthesia strategy, compared with a deep anesthesia strategy, resulted in better early postoperative cognitive recovery, a lower risk of POCD, and improved quality of recovery, characterised by fewer complications and a shorter hospital stay.