The Effects of Anesthesia Depth Monitoring on Postoperative Recovery and Cognitive Functions in the Geriatric Patient Population

Geriatrik Hasta Grubunda Anestezi Derinliği Monitörizasyonlarının Postoperatif Derlenme Ve Bilişsel Fonksiyonlara Etkileri

This study will be conducted on patients aged 65 and older scheduled for surgery due to lumbar or cervical disc herniation. General anesthesia is routinely used for these types of surgeries in the hospital. In patients receiving general anesthesia, anesthesia depth monitoring is performed.

As part of the study, a preoperative anesthesia evaluation will be conducted, which will include age, weight, height, comorbidities, regularly used medications, previous surgical or anesthesia experiences, nutritional habits, mental status, and daily activity levels.

On the day of surgery, upon arrival in the operating room, the following will be measured and recorded:

• Blood pressure using a non-invasive blood pressure monitor
• Heart rate and rhythm via electrocardiogram (ECG)
• Blood oxygen level with a pulse oximeter
• Anesthesia depth using a forehead-applied sensor

All monitoring procedures are non-invasive and painless. Following the placement of these monitoring devices and initial measurements, anesthesia induction and surgery will commence. Throughout surgery, blood pressure, heart rate, and brain activity will be continuously recorded. After the surgical procedure, anesthesia emergence and mental status will be assessed. Preoperative evaluation data and intraoperative recordings will be used solely for research purposes, with patient identity information remaining confidential.

Study Overview

• Status: Recruiting
• Conditions: Postoperative Delirium (POD); Burst Suppression; Geriatric Patient Care Improvement
• Intervention / Treatment: Other: Control Group: Standard Hemodynamic Monitoring; Device: Processed Electroencephalogram (BIS Index); Device: Processed Electroencephalogram (DSA Mode)

Detailed Description

Perioperative cognitive decline and delirium occur more frequently in the geriatric population undergoing surgery. International guidelines recommend monitoring anesthesia depth to reduce the risk of postoperative cognitive dysfunction. Anesthesia depth is commonly measured using non-invasive electroencephalography (EEG)-based methods, such as the Bispectral Index (BIS).

Previous studies have predominantly utilized processed EEG monitors that generate numerical values for tracking anesthesia depth. However, in this study, anesthesia depth will be monitored using both the standard numerical BIS index and the Density Spectral Array (DSA) mode, an advanced feature of the BIS device. To date, no studies have simultaneously examined BIS and DSA modes in relation to cognitive function and the recovery process.

The use of advanced monitoring techniques may serve as a valuable resource for future research, particularly in optimizing anesthetic management for geriatric patients with reduced cognitive reserve. This study aims to evaluate the effects of different intraoperative anesthesia depth monitoring approaches, including hemodynamic monitoring, numerical BIS values, and DSA functions. The primary objective is to determine the optimal anesthesia monitoring strategy that minimizes intraoperative hypotension, burst suppression, and postoperative delirium.

• Study Type: Interventional
• Enrollment (Estimated): 75
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Aslihan Gulec Kilic, MD; Phone Number: +905072709000; Email: aslihangulec@gazi.edu.tr
• Study Contact Backup: Name: Gozde Inan, Associate Professor; Phone Number: +905358105620; Email: inangozde@yahoo.com

Study Locations

• Turkey
  • Ankara, Turkey, 06560
    • Recruiting
    • Gazi University School of Medicine
    • Contact: Aslihan Gulec Kilic, MD; Phone Number: +905072709000; Email: aslihangulec@gazi.edu.tr
    • Contact: Gozde Inan, Associate Professor; Phone Number: +905358105620; Email: inangozde@yahoo.com
    • Contact: Aslihan Gulec Kilic, MD
    • Contact: Gozde Inan, Associate Professor
    • Contact: Zerrin Ozkose Satirlar, Professor

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• 65 years and older
• Elective spinal surgeries
• ASA status I-III

Exclusion Criteria:

• Emergent surgeries
• ASA status IV-V
• Prediagnosed delirium and or dementia
• Inability to give consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Hemodynamic-Guided Group; Anesthesia depth monitoring will be managed according to hemodynamic parameters, primarily avoiding hypotension.	Other: Control Group: Standard Hemodynamic Monitoring; Anesthesia depth monitoring based on hemodynamic values without additional processed EEG guidance.
Active Comparator: BIS-Guided Group; Anaesthesia depth monitoring according to numeric BIS index values	Device: Processed Electroencephalogram (BIS Index); Anaesthesia depth monitoring according to numeric BIS index values.
Active Comparator: DSA-Guided Group; Anesthesia depth monitoring using the Density Spectral Array (DSA) function of the BIS monitor.	Device: Processed Electroencephalogram (DSA Mode); Anaesthesia depth monitoring according to density spectral array functions

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ratio of Burst Suppression	The burst suppression ratio (BSR) will be calculated as the percentage of total anesthesia time spent in burst suppression, as measured by processed electroencephalography (EEG). A higher BSR has been associated with worse postoperative cognitive outcomes.	Intraoperative (continuously recorded from anesthesia induction to emergence)
Time of Burst Suppression	Anesthesia time spent in burst suppression (BS), as measured by processed electroencephalography (EEG). A higher BS time has been associated with worse postoperative cognitive outcomes.	Intraoperative (continuously recorded from anesthesia induction to emergence)
Intraoperative Hypotension Incidence	Intraoperative hypotension will be measured in 5-minute intervals. Hypotension is a mean arterial pressure (MAP) below 60 mmHg. The episodes of hypotension at any point during surgery will be recorded.	Intraoperative (assessed continuously throughout surgery)
Alpha Band Preservation or Loss	Alpha band activity (8-12 Hz) in the frontal lobe will be evaluated to determine whether it is preserved or lost during general anesthesia. Alpha band preservation is associated with optimal anesthesia depth and cognitive function preservation, while loss of alpha band activity is linked to increased postoperative cognitive impairment.	Intraoperative (measured continuously from anesthesia induction to emergence)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Postoperative Delirium Assessed via CAM Scale	Postoperative delirium will be assessed using the Confusion Assessment Method (CAM) tool. The number of participants meeting the criteria for delirium within the first 48 hours postoperatively will be recorded.	Postoperative (assessed at 6, 24, and 48 hours after surgery)
Total Intraoperative Propofol Consumption	The total dose of propofol administered intraoperatively will be recorded. Data will be reported as mg/kg.	Intraoperative
Total Intraoperative Sevoflurane Consumption	The total dose of Sevoflurane administered intraoperatively will be recorded. Data will be reported as ml.	Intraoperative
Total Intraoperative Remifentanil Consumption	The total dose of Remifentanil administered intraoperatively will be recorded. Data will be reported as mcg/kg.	Intraoperative
Total Intraoperative Vasopressor Consumption	The total dose of vasopressors (noradrenaline, adrenaline, dopamine) administered intraoperatively will be recorded. Data will be reported as mcg/kg.	Intraoperative

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Frailty Score Assessed via Clinical Frailty Scale (CFS)	Frailty will be assessed preoperatively using the Clinical Frailty Scale (CFS), which ranges from 1 (very fit) to 9 (terminally ill). Higher scores indicate worse frailty status. The proportion of participants classified as frail (CFS ≥ 5) will be reported.	Preoperative (assessed on the day of surgery)

Collaborators and Investigators

• Sponsor: Aslıhan Güleç
• Investigators: Study Director: Zerrin Ozkose Satirlar, Professor, Gazi University

Publications and helpful links

General Publications

• Fritz BA, Kalarickal PL, Maybrier HR, Muench MR, Dearth D, Chen Y, Escallier KE, Ben Abdallah A, Lin N, Avidan MS. Intraoperative Electroencephalogram Suppression Predicts Postoperative Delirium. Anesth Analg. 2016 Jan;122(1):234-42. doi: 10.1213/ANE.0000000000000989.
• Monk TG, Weldon BC, Garvan CW, Dede DE, van der Aa MT, Heilman KM, Gravenstein JS. Predictors of cognitive dysfunction after major noncardiac surgery. Anesthesiology. 2008 Jan;108(1):18-30. doi: 10.1097/01.anes.0000296071.19434.1e.
• Purdon PL, Sampson A, Pavone KJ, Brown EN. Clinical Electroencephalography for Anesthesiologists: Part I: Background and Basic Signatures. Anesthesiology. 2015 Oct;123(4):937-60. doi: 10.1097/ALN.0000000000000841.
• Wildes TS, Mickle AM, Ben Abdallah A, Maybrier HR, Oberhaus J, Budelier TP, Kronzer A, McKinnon SL, Park D, Torres BA, Graetz TJ, Emmert DA, Palanca BJ, Goswami S, Jordan K, Lin N, Fritz BA, Stevens TW, Jacobsohn E, Schmitt EM, Inouye SK, Stark S, Lenze EJ, Avidan MS; ENGAGES Research Group. Effect of Electroencephalography-Guided Anesthetic Administration on Postoperative Delirium Among Older Adults Undergoing Major Surgery: The ENGAGES Randomized Clinical Trial. JAMA. 2019 Feb 5;321(5):473-483. doi: 10.1001/jama.2018.22005.
• Shao YR, Kahali P, Houle TT, Deng H, Colvin C, Dickerson BC, Brown EN, Purdon PL. Low Frontal Alpha Power Is Associated With the Propensity for Burst Suppression: An Electroencephalogram Phenotype for a "Vulnerable Brain". Anesth Analg. 2020 Nov;131(5):1529-1539. doi: 10.1213/ANE.0000000000004781.
• Aldecoa C, Bettelli G, Bilotta F, Sanders RD, Audisio R, Borozdina A, Cherubini A, Jones C, Kehlet H, MacLullich A, Radtke F, Riese F, Slooter AJ, Veyckemans F, Kramer S, Neuner B, Weiss B, Spies CD. European Society of Anaesthesiology evidence-based and consensus-based guideline on postoperative delirium. Eur J Anaesthesiol. 2017 Apr;34(4):192-214. doi: 10.1097/EJA.0000000000000594. Erratum In: Eur J Anaesthesiol. 2018 Sep;35(9):718-719. doi: 10.1097/EJA.0000000000000872.
• Chen YC, Hung IY, Hung KC, Chang YJ, Chu CC, Chen JY, Ho CH, Yu CH. Incidence change of postoperative delirium after implementation of processed electroencephalography monitoring during surgery: a retrospective evaluation study. BMC Anesthesiol. 2023 Oct 4;23(1):330. doi: 10.1186/s12871-023-02293-9.

Study record dates

Study Major Dates

• Study Start (Actual): January 10, 2025
• Primary Completion (Estimated): March 15, 2025
• Study Completion (Estimated): April 1, 2025

Study Registration Dates

• First Submitted: February 9, 2025
• First Submitted That Met QC Criteria: February 19, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 26, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Keywords: geriatric; bispectral index; postoperative delirium; anaesthesia depth monitoring; density spectral array; burst supression
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Postoperative Complications; Pathologic Processes; Confusion; Neurobehavioral Manifestations; Neurocognitive Disorders; Emergence Delirium; Delirium
• Other Study ID Numbers: Gazi-2024 -1816

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All IPD that underlie results in the publication
• IPD Sharing Time Frame: Beginning 3 months and ending one year after the publication
• IPD Sharing Access Criteria: Access to study protocol upon request, contact with one of the sub-investigators.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: Yes