COVID-19 is an emerging, rapidly evolving situation.
Get the latest public health information from CDC:

Get the latest research information from NIH: Menu

Reduction of Intraoperative EEG Burst Suppression (BsR)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT03775356
Recruitment Status : Recruiting
First Posted : December 13, 2018
Last Update Posted : September 18, 2020
Information provided by (Responsible Party):
Technische Universität München

Brief Summary:
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.

Condition or disease Intervention/treatment Phase
Burst Suppression EEG With Abnormally Slow Frequencies Postoperative Delirium Other: Treatment of hypotension and/or reduction of anesthetics Not Applicable

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.

Layout table for study information
Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 66 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Care Provider, Investigator)
Masking Description: Single masked. The entropy and EEG module will be masked for the responsible anesthetist as well as the study team during the entire investigation.
Primary Purpose: Prevention
Official Title: Reduction of Intraoperative EEG Burst Suppression - Test of Efficacy
Actual Study Start Date : December 15, 2018
Estimated Primary Completion Date : February 1, 2021
Estimated Study Completion Date : March 31, 2021

Resource links provided by the National Library of Medicine

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.

Primary Outcome Measures :
  1. Chance of the total, cumulative burst suppression rate. [ Time Frame: During general anesthesia and within the intervention ]
    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).

Secondary Outcome Measures :
  1. Burst suppression rate during induction. [ Time Frame: During induction within the intervention ]
    Rate of change of the burst suppression rate during induction.

  2. Burst suppression rate during maintenance. [ Time Frame: During maintenance within the intervention ]
    Rate of change of the burst suppression ratio during maintenance.

  3. Mean arterial blood pressure. [ Time Frame: During burst suppression within general anesthesia ]
    Evaluation of the mean arterial blood pressure with positive burst suppression rate.

  4. Endtidal anesthetic concentration (ETAC) and infusion rate of propofol. [ Time Frame: During burst suppression within the intervention ]
    Evaluation of the mean ETAC and infusion rate of propofol.

  5. Specific characteristics of the EEG frequency spectrum during burst suppression [ Time Frame: During burst suppression within general anesthesia ]
    Evaluation of specific EEG frequencies differentiating BSR caused by hypotension or oversedation of anesthetics.

  6. Postoperative delirium. [ Time Frame: Within the first three postoperative days ]
    Screening of the patients regarding a postoperative delirium by a brief confession assessment method (bCAM).

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

Layout table for eligibility information
Ages Eligible for Study:   60 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03775356

Layout table for location contacts
Contact: Gerhard Schneider, Prof. Dr. 0049-89-4140-4291
Contact: Stefanie Pilge, PD Dr. 0049-89-4140-4291

Layout table for location information
Klinikum rechts der Isar - Klinik fuer Anaesthesiologie und Intensivmedizin Recruiting
München, Bayern, Germany, 81675
Contact: Gerhad Schneider, Prof. Dr.    0049-89-4140-4291   
Sponsors and Collaborators
Technische Universität München
Layout table for investigator information
Principal Investigator: Gerhard Schneider, Prof. Dr. Clinic director - Department of anesthesiology and intensive care
Layout table for additonal information
Responsible Party: Technische Universität München Identifier: NCT03775356    
Other Study ID Numbers: BsR
First Posted: December 13, 2018    Key Record Dates
Last Update Posted: September 18, 2020
Last Verified: September 2020
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Layout table for additional information
Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Technische Universität München:
Intraoperative EEG based monitoring
Level of hypnosis
Burst suppression
Postoperative delirium
EEG-signal characteristics
Additional relevant MeSH terms:
Layout table for MeSH terms
Vision Disorders
Neurobehavioral Manifestations
Neurologic Manifestations
Nervous System Diseases
Neurocognitive Disorders
Mental Disorders
Sensation Disorders
Eye Diseases
Central Nervous System Depressants
Physiological Effects of Drugs