BIS-Guided Anesthesia and Early Cognitive Recovery in Elderly: A Controlled Trial

Saba Arif; Muhammad Abdullah Shakeel; Aqeel Ahmad; Hafiz Muhammad Fawaad Bilal; Muhammad Imran Anjum; Dure Shahwar

doi:10.61919/1vmafm03

Authors

Saba Arif Anesthetist, DHQ Hospital, Khanewal, Pakistan Author
Muhammad Abdullah Shakeel Post Graduate Trainee, Anaesthesia, KRL Hospital, Islamabad, Pakistan Author
Aqeel Ahmad Assistant Professor, Anesthesiology, PGMI, Quetta, Pakistan Author
Hafiz Muhammad Fawaad Bilal Consultant Anesthesiologist, MS Anaesthesia, Primary and Secondary Health Care Department, District Khanewal, Pakistan Author
Muhammad Imran Anjum Consultant Anesthetist, HOD Anesthesia/ICU, DHQ Hospital, Khanewal, Pakistan Author
Dure Shahwar Services Hospital, Lahore, Pakistan Author

DOI:

https://doi.org/10.61919/1vmafm03

Keywords:

Aged; Anesthesia; Bispectral Index; Cognitive Dysfunction; Delirium; Postoperative Complications; Randomized Controlled Trial

Abstract

Background: Elderly patients undergoing general anesthesia are vulnerable to delayed cognitive recovery and postoperative delirium, partly because age-related physiological changes may increase sensitivity to excessive anesthetic depth. Objective: To compare BIS-guided anesthesia with standard anesthesia management for early postoperative cognitive recovery, delirium incidence, anesthetic consumption, and immediate recovery outcomes in elderly patients undergoing elective non-cardiac surgery. Methods: This parallel-group randomized controlled trial was conducted at a tertiary care teaching hospital in Central Punjab, Pakistan, from August 2025 to January 2026. Eighty patients aged 65–80 years undergoing elective non-cardiac surgery under general anesthesia were randomized to BIS-guided anesthesia or standard anesthesia management. In the BIS-guided group, anesthetic depth was maintained within a BIS range of 40–60. Cognitive recovery was assessed using MMSE and MoCA at baseline, 24 hours, and 72 hours postoperatively, while delirium was assessed using the Confusion Assessment Method. Final complete-case analysis included 73 participants. Results: At 72 hours, the BIS-guided group had higher MMSE scores than the standard anesthesia group (27.1 ± 1.5 vs 25.4 ± 1.9; mean difference, 1.7; 95% CI, 0.90–2.50) and higher MoCA scores (25.0 ± 1.8 vs 22.9 ± 2.1; mean difference, 2.1; 95% CI, 1.19–3.01). BIS-guided anesthesia also reduced sevoflurane consumption, extubation time, and recovery-room stay. Delirium occurred in 8.1% and 25.0% of participants, respectively, with exact testing indicating a clinically relevant but statistically non-definitive difference. Conclusion: BIS-guided anesthesia was associated with better early postoperative cognitive recovery and improved immediate recovery efficiency in elderly surgical patients.

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