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Study Evaluating Whether the Bispectral Index Prevents Patients at Higher Risk From Being Awake During Surgery and Anesthesia (BAG-RECALL)

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ClinicalTrials.gov Identifier: NCT00682825
Recruitment Status : Completed
First Posted : May 22, 2008
Last Update Posted : January 4, 2011
Foundation for Anesthesia Education and Research
American Society of Anesthesiologists
University of Chicago
University of Manitoba
University of Michigan
Information provided by:
Washington University School of Medicine

Brief Summary:
The overall purpose of this study is to see if a Bispectral Index (BIS) monitor, a Food and Drug Administration (FDA) approved brain monitoring device, will help to reduce the risk of patients remembering being awake during surgery. The BIS monitor may be able to measure how asleep a patient is during surgery. Using the BIS monitor to guide anesthesia will be compared with using the concentration of anesthetic gas to guide anesthesia.

Condition or disease Intervention/treatment Phase
Explicit Recall of Intra-Operative Events Behavioral: Bispectral index protocol Behavioral: End tidal anesthetic gas-guided Phase 4

Detailed Description:

The incidence of anesthesia awareness (AA) is 0.1-0.2% and may result in post traumatic stress disorders. For some patients, owing to illness, medications, substance misuse or surgery, the risk approaches 1%. The B-AWARE Study by Myles et al. suggested that the bispectral index (BIS) monitor, which reportedly reflects anesthetic depth, may decrease the incidence of AA in higher risk patients by 82%. The American Society of Anesthesiologists has published a practice advisory on AA, which does not recommend the routine use of cerebral function monitors. We propose to test the hypothesis that an anesthetic protocol based on BIS decreases the incidence of AA among higher risk patients compared with an anesthetic protocol based on the end-tidal anesthetic gas (ETAG) concentration. We have completed a randomized, single-blinded prospective feasibility study (The B-Unaware Trial) which enrolled 2000 patients at higher risk for AA. Four patients (0.21%; 95% CI=0.06% to 0.57%) had definite AA, of whom two were in the BIS-guided group and two in the ETAG-guided group. Nine patients (0.46%; 95% CI=0.22% to 0.91%) had definite or possible AA, of whom six were in the BIS-guided group and three in the ETAG-guided group. The BAG RECALL study will be a multi-center, prospective, single-blinded, randomized study enrolling 6000 patients at higher risk for AA. The BAG RECALL study is adequately powered and rigorously designed to answer with a reasonable degree of scientific probability whether BIS guidance results in clinically relevant reduction in anesthesia awareness among higher risk patients undergoing general anesthesia.

At the University of Michigan, a parallel study will be conducted - Michigan Awareness Control Study, MACS (NCT00689091) - enrolling 30,000 patients to assess whether the BIS monitor decreases the likelihood of anesthesia awareness among all patients undergoing general anesthesia, regardless of their risk profile. The investigators of this study and the BAG-RECALL study have collaborated in designing these studies and are pre-specifying that common outcome measures will be examined collaboratively including data from both studies.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 6000 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: BAG-RECALL Study: BIS or Anesthesia Gas to Reduce Explicit Recall
Study Start Date : March 2008
Actual Primary Completion Date : December 2010

Arm Intervention/treatment
Experimental: 1
Bispectral index-guided protocol
Behavioral: Bispectral index protocol
Aim to titrate anesthesia to maintain BIS between 40 and 60.

Active Comparator: 2
End-tidal anesthetic gas-guided protocol
Behavioral: End tidal anesthetic gas-guided
Aim to maintain anesthetic gas between 0.7 and 1.3 MAC equivalents

Primary Outcome Measures :
  1. The incidence of explicit recall of events during the surgical and anesthetic periods. [ Time Frame: Three years ]

Secondary Outcome Measures :
  1. Meta-analysis for anesthesia awareness incorporating higher risk patients from the completed B-Unaware Trial (NCT00281489), the BAG-RECALL Trial, and the Michigan Awareness Control Study (MACS)(NCT00689091). [ Time Frame: Three years ]
  2. Incidence of post-traumatic stress disorder (PTSD). [ Time Frame: Five years ]
  3. Association between type of awareness event and PTSD, and whether the PTSD is associated with late reporting (30 days) of awareness. [ Time Frame: 5 years ]
  4. Types of dreams and their relationship to BIS and ETAG. [ Time Frame: Three years ]
  5. The relationship between deep hypnotic time, anesthetic dose (MAC), mean arterial pressure, and end tidal carbon dioxide, and early (one-month) and late (one-year) mortality. [ Time Frame: Four years ]
  6. Relationship between BIS, heart rate and blood pressure. [ Time Frame: Three years ]
  7. Relationship between BIS and anesthesia dose and concentration. [ Time Frame: Three years ]
  8. Association between baseline BIS values, patient health and early (one-month) and late (one-year) mortality. [ Time Frame: Four years ]
  9. Interaction between hemispheric dominance and BIS. [ Time Frame: Three years ]
  10. Effect of red hair phenotypes on the relationship between ETAG and BIS. [ Time Frame: Three years ]
  11. Refinement of risk factors for anesthesia awareness. [ Time Frame: Three years ]
  12. Relationship between rising BIS in the PACU and first memory after surgery. [ Time Frame: Three years ]
  13. Postoperative delirium. [ Time Frame: Three years ]
  14. BIS and mixed venous saturation. [ Time Frame: Three years ]
  15. Induction of anesthesia and hypotension. [ Time Frame: Three years ]
  16. Incidence of postoperative nausea and vomiting. [ Time Frame: Three years ]
  17. Incidence of and severity of postoperative pain. [ Time Frame: Three years ]
  18. Effect of BIS and ETAG protocols on time to open eyes, time to extubation, and time spent in the postoperative recovery unit. [ Time Frame: Three years ]
  19. Effect of a defasciculating dose of a non-depolarizing muscle relaxant on BIS. [ Time Frame: Three years ]
  20. The effect of patient temperature on BIS. [ Time Frame: Three years ]
  21. Incidence of recall of traveling to the OR among patients who receive midazolam in the holding area and whose initial BIS reading in the OR is > 60. [ Time Frame: Three years ]
  22. Relationship between BIS, ETAG and EEG parameters. [ Time Frame: Three years ]
  23. Annual assessment of practitioners' abilities to interpret BIS tracings and to identify artefacts. [ Time Frame: Three years ]
  24. Differences in anesthesia practice among four institutions in the USA and Canada as judged by anesthetic doses and BIS readings. [ Time Frame: Three years ]
  25. Effect of BIS and ETAG protocols on anesthetic dose administration and on BIS readings. [ Time Frame: Three years ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:


General Anesthesia with volatile anesthetic


Major Criteria (Must have any 1 of the following:)

  1. Planned open heart surgery
  2. Medications - anticonvulsants, abuse of opiates, benzodiazepines, cocaine
  3. EF<40%
  4. Prior history of awareness (recall)
  5. History of difficult intubation or anticipated difficult intubation
  6. ASA IV or V status
  7. Aortic stenosis
  8. End stage lung disease
  9. Marginal exercise tolerance not secondary to musculoskeletal dysfunction
  10. Pulmonary hypertension
  11. Daily alcohol consumption

Exclusion Criteria:

  1. Surgical procedure that prevents the use of the BIS (e.g. surgery of forehead)
  2. Patient positioning prevents use of the BIS
  3. Surgery with wake-up test.
  4. Less than 18 years of age
  5. Vulnerable populations, such as those with dementia and those unable to provide informed consent.
  6. Stroke with residual neurological deficits


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 ClinicalTrials.gov identifier (NCT number): NCT00682825

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United States, Illinois
University of Chicago
Chicago, Illinois, United States
United States, Missouri
Washington University
St Louis, Missouri, United States, 63110
Canada, Manitoba
University of Manitoba
Winnipeg, Manitoba, Canada
Sponsors and Collaborators
Washington University School of Medicine
Foundation for Anesthesia Education and Research
American Society of Anesthesiologists
University of Chicago
University of Manitoba
University of Michigan
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Principal Investigator: Michael S Avidan, MBBCh FCA Washington University School of Medicine
Study Director: David Glick, MD University of Chicago
Study Chair: Eric Jacobsohn, MBChB University of Manitoba
Study Director: Michael O'Connor, MD University of Chicago
Study Chair: Alex S Evers, MD Washington University School of Medicine
Additional Information:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
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Responsible Party: Michael Avidan, Washington University
ClinicalTrials.gov Identifier: NCT00682825    
Other Study ID Numbers: 07-1253
First Posted: May 22, 2008    Key Record Dates
Last Update Posted: January 4, 2011
Last Verified: January 2011
Keywords provided by Washington University School of Medicine:
Additional relevant MeSH terms:
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Anesthetics, Inhalation
Central Nervous System Depressants
Physiological Effects of Drugs
Anesthetics, General