Authors: Zhou L. et al.
Anesthesiology, September 25, 2025. DOI: 10.1097/ALN.0000000000005770
This large randomized multicenter trial investigated whether Bispectral Index (BIS)–guided anesthesia improves postoperative outcomes in older adults undergoing elective noncardiac surgery. Although BIS monitoring has been recommended in several perioperative guidelines to help maintain optimal anesthetic depth and potentially reduce complications, strong evidence supporting its clinical benefit has been limited.
The study enrolled 6,982 patients aged 65 years and older (mean age 71) across 21 tertiary hospitals in China between 2015 and 2022. Participants were randomized to BIS-guided anesthesia (target range 40–60) or routine anesthetic management without BIS feedback (the monitors were masked). The primary endpoint was 1-year all-cause mortality. Secondary outcomes included 30-day complications, postoperative functional independence, quality of life, ICU admissions, hospitalization duration, and total hospital costs.
Despite the large sample size and rigorous design, BIS-guided management did not improve outcomes. Mean BIS readings were nearly identical between groups (47 vs. 46), indicating that anesthesiologists titrated anesthetic depth effectively using standard clinical signs alone. One-year mortality was nearly identical between groups (10.2% vs. 10.0%; HR 1.02, P = 0.812). Likewise, moderate-to-severe complications within 30 days occurred in 10.4% vs. 10.6% (P = 0.938). There were no significant differences in functional independence, quality of life, or hospital utilization.
These findings suggest that while BIS monitoring provides objective data, experienced anesthesiologists achieve comparable anesthetic depth and outcomes without routine BIS use. BIS may still hold value for select high-risk cases or limited-responsiveness scenarios but does not appear to improve mortality or major morbidity for most older adults.
What You Should Know
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BIS-guided anesthesia did not reduce 1-year mortality or 30-day complications in older surgical patients.
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Mean BIS values were virtually identical between BIS-guided and routine-care groups.
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No improvements were seen in recovery, functional independence, or hospital cost.
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Routine BIS monitoring may not be necessary for most elderly noncardiac surgical cases.
Thank you to Anesthesiology for publishing this comprehensive multicenter trial clarifying that BIS-guided anesthesia offers no significant long-term outcome advantage in older adults.