Relationship Between Induction Burst Suppression and Bispectral Index

The Relationship Between Burst Suppression Observed During Anesthesia Induction and the Bispectral Index Value During the Maintenance Phase of Anesthesia

The purpose of this study is to understand whether certain brain activity patterns that can appear at the beginning of anesthesia are related to how deep anesthesia remains during the operation.

The main question of the study is:

Do patients who show a pattern called burst suppression during the start of anesthesia experience deeper anesthesia during surgery?

Patients who are scheduled for elective surgery under total intravenous anesthesia (TIVA) may take part in this study. During the operation, brain activity will be monitored using a sensor placed on the forehead (Bispectral Index, BIS monitor), which is already commonly used during anesthesia. Information such as BIS values and the doses of anesthesia medications given during the operation will be recorded.

Participation in this study will not change the type of anesthesia or the routine care that patients receive during surgery. The study only involves recording and analyzing information collected during standard anesthesia monitoring.

Study Overview

• Status: Not yet recruiting
• Conditions: Total Intravenous Anesthesia; Bispectral Index Monitoring; Burst Suppression

• Study Type: Observational
• Enrollment (Estimated): 200

Contacts and Locations

• Study Contact: Name: Bülent Meriç Çam, MD; Phone Number: +90 (534) 815 6011; Email: bulentmericcam@gmail.com

Study Locations

• Turkey (Türkiye)
  • Amasya
    • Amasya, Amasya, Turkey (Türkiye), 05200
      • Amasya University Sabuncuoglu Serefeddin Training and Research Hospital
      • Contact: Bülent Meriç Çam, MD; Phone Number: +90 (534) 8156011; Email: bulentmericcam@gmail.com
  • İzmir
    • Izmir, İzmir, Turkey (Türkiye), 35360
      • Izmir Katip Celebi University Ataturk Training and Research Hospital
      • Contact: Ahmet Salih Tüzen, MD; Phone Number: +90 (535) 3915577; Email: astuzen@icloud.com

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

A tertiary care center in Amasya, Turkey

Description

Inclusion Criteria:

• Age between 18 and 75 years
• American Society of Anesthesiologists (ASA) physical status I-III
• Scheduled for elective surgery
• Surgery planned to be performed under total intravenous anesthesia (TIVA)

Exclusion Criteria:

• Presence of neurological disease
• Chronic use of sedative medications or antiepileptic drugs
• Severe hepatic or renal dysfunction
• Intraoperative administration of ketamine or dexmedetomidine

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Burst Suppression Group; Patients who exhibited burst suppression during the anesthesia induction period, defined as a burst suppression ratio of ≥10% lasting for at least 1 minute
Non-Burst Suppression Group; Patients who did not exhibit burst suppression during the anesthesia induction period, defined as the absence of burst suppression with a burst suppression ratio ≥10% lasting for at least 1 minute

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
TBIS<40	Total duration during the maintenance phase of anesthesia in which the BIS remains below 40, expressed as a proportion of total surgical time, compared between patients with and without burst suppression during induction	During intraoperative period

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
TBIS40-60	Duration during maintenance anesthesia in which BIS values remain between 40 and 60, expressed as a proportion of total surgical time.	During intraoperative period
TBIS>60	Duration during maintenance anesthesia in which BIS remains above 60, expressed as a proportion of total surgical time.	During intraoperative period
TLOC	Time to loss of consciousness :Time from induction agent administration to loss of consciousness. Loss of consciousness is defined as the moment when both the eyelash and corneal reflexes are abolished, and the time was recorded in seconds.	During induction of anesthesia
BIS-LOC	Bispectral Index (BIS) value at the time of loss of consciousness following induction of anesthesia. Loss of consciousness is defined as the moment when both the eyelash and corneal reflexes are abolished	At the exact time of loss of consciousness (LOC)
TROC	Time to return of consciousness:Time from discontinuation of anesthetic agents during the maintenance phase of anesthesia to return of consciousness. Return of consciousness was defined as the moment when the patient regained consciousness, demonstrated by eye opening and/or response to verbal commands, and the time was recorded in seconds	During emergence from anesthesia
BIS-ROC	Bispectral Index (BIS) value at the timeof return of consciousness. Return of consciousness was defined as the moment when the patient responded to verbal commands.	At the moment of response to verbal commands during emergence from anesthesia
Propofol infusion rate during anesthesia	Propofol administration will be recorded at 1-minute intervals throughout the intraoperative period. Additionally, total drug consumption during the procedure will be obtained from infusion pump records. Values recorded at 1-minute intervals will be used for time-based correlation analyses, while infusion pump data will be used to calculate mean infusion rates. The total amount of propofol administered during the entire surgical procedure will be calculated and expressed as mg/kg/hour.	During the intraoperative period
Remifentanil infusion rate during anesthesia	Remifentanil administration will be recorded at 1-minute intervals throughout the intraoperative period. Additionally, total drug consumption during the procedure will be obtained from infusion pump records. Values recorded at 1-minute intervals will be used for time-based correlation analyses, while infusion pump data will be used to calculate mean infusion rates. The total amount of remifentanil administered during the entire surgical procedure will be calculated and expressed as µg/kg/min	During the intraoperative period

Collaborators and Investigators

• Sponsor: Amasya University

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): August 1, 2027

Study Registration Dates

• First Submitted: April 23, 2026
• First Submitted That Met QC Criteria: April 23, 2026
• First Posted (Actual): April 29, 2026

Study Record Updates

• Last Update Posted (Actual): April 29, 2026
• Last Update Submitted That Met QC Criteria: April 23, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 2026-82

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No