Reduction of Intraoperative EEG Burst Suppression (BsR)

Reduction of Intraoperative EEG Burst Suppression - Test of Efficacy

Burst suppression (BS) is a not physiological pattern in the electroencephalogram (EEG). BS during general anesthesia is mainly seen as a sign for too deep hypnosis and may increase the risk of postoperative delirium (POD), a disturbance of consciousness arising within 24 hours after surgery. This monocentric, simple masked randomized study aims primarily to investigate, whether particular anesthesiological interventions reduce the occurrence of intraoperative burst suppression. The investigator initiated trial includes 66 patients (male and female) aged ≥ 60 years in two groups (intervention and control group). Secondary aims will be the correlation of burst suppression and mean arterial pressure, concentration of anesthetics and postoperative delirium.

Study Overview

• Status: Completed
• Conditions: Postoperative Delirium; Burst Suppression; EEG With Abnormally Slow Frequencies
• Intervention / Treatment: Other: Treatment of hypotension and/or reduction of anesthetics

Detailed Description

Intraoperative burst suppression represents a non physiological EEG pattern. According to the literature and scientific knowledge, intraoperative burst suppression patterns might be caused either by hypotension resulting in a reduced cerebral circulation or by an oversedation of anesthetics correlating with a very deep level of hypnosis.

Some publications exist that discuss the occurrence of intraoperative burst suppression especially in elderly people (aged ≥ 60 years) as a predictor of postoperative delirium and postoperative cognitive dysfunction.

None of the studies however was able to prove a causal relationship between burst suppression and postoperative delirium. Contrary it might simply be an epiphenomenon.

Conducting this interventional trail primarily aims to prove whether specific anesthesiological interventions, such as the treatment of intraoperative hypotension in first line and/or the reduction of the concentration of anesthetics in second line, reduce intraoperative burst suppression. Hence it might be possible to investigate a possible casualty between burst suppression and postoperative delirium in a second trial.

• Study Type: Interventional
• Enrollment (Actual): 106
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Germany
  • Bayern
    • München, Bayern, Germany, 81675
      • Klinikum rechts der Isar - Klinik fuer Anaesthesiologie und Intensivmedizin

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 60 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age ≥ 60 years
• Surgical interventions in general anesthesia (volatile or total intravenous anesthesia)
• expected surgery duration ≥ 1h
• American Society of Anesthesiologists (ASA) 1-4
• written informed consent prior to study participation

Exclusion Criteria:

• Neurological or psychiatric disorders
• hearing difficulty
• deafness
• neurosurgical (intra)cranial surgery
• pregnancy
• expected continuous mandatory ventilation after surgery

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: 1 - Blinded; EEG and Entropy will be blinded. The anesthesiological management will be performed by the anesthetist according to clinical standard operations.
Active Comparator: 2 - Unblinded; EEG and Entropy will be unblinded. The intervention starts with the start of a positive burst suppression rate. In the case of a concurrent hypotension the anesthetist treats the hypotension according to clinical standard operations in the first step. Hypotension means blood pressure values blow the baseline value which is defined by the lowest, preoperatively measured value. If after this treatment and a reevaluation of the BSR, BSR remains positive, the anesthetist is going to reduce the concentration of anesthetics in a second step. In case of positive BSR and a blood pressure value ≥ the baseline value, the concentration of anesthetics will be reduced as a first measure. The aim is to figure out whether one or both of these interventions can reduce to total, cumulative BSR.	Other: Treatment of hypotension and/or reduction of anesthetics; The treatment of hypotension can be done by the responsible anesthetist according to the clinical standard operations including any accepted drug typically used in this hospital. The reduction of anesthetics can be done either by reducing the volatile end tidal anesthetics concentration (ETAC) or the infusion rate of propofol.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Chance of the total, cumulative burst suppression rate.	The total, cumulative burst suppression rate (BSR) corresponds to area under the curve and is defined by the BSR (%) and the absolute duration of BSR (t).	During general anesthesia and within the intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Burst suppression rate during induction.	Rate of change of the burst suppression rate during induction.	During induction within the intervention
Burst suppression rate during maintenance.	Rate of change of the burst suppression ratio during maintenance.	During maintenance within the intervention
Mean arterial blood pressure.	Evaluation of the mean arterial blood pressure with positive burst suppression rate.	During burst suppression within general anesthesia
Endtidal anesthetic concentration (ETAC) and infusion rate of propofol.	Evaluation of the mean ETAC and infusion rate of propofol.	During burst suppression within the intervention
Specific characteristics of the EEG frequency spectrum during burst suppression	Evaluation of specific EEG frequencies differentiating BSR caused by hypotension or oversedation of anesthetics.	During burst suppression within general anesthesia
Postoperative delirium.	Screening of the patients regarding a postoperative delirium by a brief confession assessment method (bCAM).	Within the first three postoperative days

Collaborators and Investigators

• Sponsor: Technical University of Munich
• Investigators: Principal Investigator: Gerhard Schneider, Prof. Dr., Clinic director - Department of anesthesiology and intensive care

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.
• Radtke FM, Franck M, Lendner J, Kruger S, Wernecke KD, Spies CD. Monitoring depth of anaesthesia in a randomized trial decreases the rate of postoperative delirium but not postoperative cognitive dysfunction. Br J Anaesth. 2013 Jun;110 Suppl 1:i98-105. doi: 10.1093/bja/aet055. Epub 2013 Mar 28.
• Soehle M, Dittmann A, Ellerkmann RK, Baumgarten G, Putensen C, Guenther U. Intraoperative burst suppression is associated with postoperative delirium following cardiac surgery: a prospective, observational study. BMC Anesthesiol. 2015 Apr 28;15:61. doi: 10.1186/s12871-015-0051-7.
• Sessler DI, Sigl JC, Kelley SD, Chamoun NG, Manberg PJ, Saager L, Kurz A, Greenwald S. Hospital stay and mortality are increased in patients having a "triple low" of low blood pressure, low bispectral index, and low minimum alveolar concentration of volatile anesthesia. Anesthesiology. 2012 Jun;116(6):1195-203. doi: 10.1097/ALN.0b013e31825683dc.
• Georgii MT, Kreuzer M, Fleischmann A, Schuessler J, Schneider G, Pilge S. Targeted Interventions to Increase Blood Pressure and Decrease Anaesthetic Concentrations Reduce Intraoperative Burst Suppression: A Randomised, Interventional Clinical Trial. Front Syst Neurosci. 2022 Mar 4;16:786816. doi: 10.3389/fnsys.2022.786816. eCollection 2022.

Study record dates

Study Major Dates

• Study Start (Actual): January 8, 2019
• Primary Completion (Actual): December 19, 2020
• Study Completion (Actual): December 19, 2020

Study Registration Dates

• First Submitted: November 22, 2018
• First Submitted That Met QC Criteria: December 12, 2018
• First Posted (Actual): December 13, 2018

Study Record Updates

• Last Update Posted (Actual): May 11, 2021
• Last Update Submitted That Met QC Criteria: May 10, 2021
• Last Verified: September 1, 2020

More Information

Terms related to this study

• Keywords: Postoperative delirium; Burst suppression; Intraoperative EEG based monitoring; Level of hypnosis; EEG-signal characteristics; Entropy
• Additional Relevant MeSH Terms: Mental Disorders; Nervous System Diseases; Eye Diseases; Neurologic Manifestations; Confusion; Neurobehavioral Manifestations; Neurocognitive Disorders; Sensation Disorders; Delirium; Vision Disorders; Physiological Effects of Drugs; Central Nervous System Depressants; Anesthetics
• Other Study ID Numbers: BSR

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

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