Journal of Anesthesia

, Volume 30, Issue 2, pp 345–348 | Cite as

Limitation in monitoring depth of anesthesia: a case report

  • Marco CascellaEmail author
  • Francesca Bifulco
  • Daniela Viscardi
  • Maura C. Tracey
  • Domenico Carbone
  • Arturo Cuomo
Clinical Report


Although we describe a clinical situation that most likely occurs in hundreds of operatory rooms in the world, we report this case as provocation. It concerns an unexpected awakening from an appropriate depth of anesthesia, although the BIS monitor showed a BIS index of less than 50 for a prolonged period before and after the event. Approximately 30 min after induction of anesthesia, the patient had a hypothetic sudden arousal of consciousness, with spontaneous movements, facial muscle activation, intolerance to the tracheal tube, and tearing. After immediate intravenous administration of midazolam (4 mg), the patient returned to a depth of anesthesia status, and surgery was completed uneventfully. The patient had no recall of the event when questioned during the episode, at emergence, or at 24 h, 36 h, and 7 days after surgery. Were these events spinal reflexes to pain or stimulation although the cortex was still anesthetized? Maybe this is the more rational explanation. Was the patient awake but not aware? Is it possible that our patient experienced only a transient arousal from consciousness, and that he did not have recall because the arousal time was short and we blocked memory consolidation? The latter hypothesis provides an opportunity to discuss the evidence that at the moment there is no device to assess the depth of anesthesia. We also focus on the possibility of interfering with memory processing under anesthesia.


Anesthesia awareness Bispectral index (BIS) Benzodiazepines Memory consolidation 


Compliance with ethical standards

Conflict of interest

The authors have no conflicts of interest.

Financial support

The study had no financial support.


  1. 1.
    Kurata J, Hemmings Jr. HC. Memory and awareness in anaesthesia. Br J Anaesth. 2015;115(suppl 1):i1–3.CrossRefPubMedGoogle Scholar
  2. 2.
    Ekman A, Lindholm ML, Lennmarken C, Sandin R. Reduction in the incidence of awareness using BIS monitoring. Acta Anaesthesiol Scand. 2004;48:20–6.CrossRefPubMedGoogle Scholar
  3. 3.
    Avidan MS, Zhang L, Burnside BA, Finkel KJ, Searleman AC, Selvidge JA, Saager L, Turner MS, Rao S, Bottros M, Hantler C, Jacobsohn E, Evers AS. Anesthesia awareness and the bispectral index. N Engl J Med. 2008;358:1097–108.CrossRefPubMedGoogle Scholar
  4. 4.
    Sanders RD, Tononi G, Laureys S, Sleigh JW. Unresponsiveness not equal unconsciousness. Anesthesiology. 2012;116:946–59.CrossRefPubMedPubMedCentralGoogle Scholar
  5. 5.
    Brice DD, Hetherington RR, Utting JE. A simple study of awareness and dreaming during anaesthesia. Br J Anaesth. 1970;42:535–42.CrossRefPubMedGoogle Scholar
  6. 6.
    Mashour GA, Orser BA, Avidan MS. Intraoperative awareness: from neurobiology to clinical practice. Anesthesiology. 2011;114(5):1218–33.CrossRefPubMedGoogle Scholar
  7. 7.
    Watanabe A, Namiki A, Ujike Y, Watanabe H, Aoki M. Wakefulness during the induction with high-dose fentanyl and oxygen anesthesia. J Anesth. 1988;2(2):165–9.CrossRefPubMedGoogle Scholar
  8. 8.
    Heyse B, Proost JH, Schumacher PM, Bouillon TW, Vereecke HE, Eleveld DJ, Luginbühl M, Struys MM. Sevoflurane–remifentanil interaction: comparison of different response surface models. Anesthesiology. 2012;116(2):311–23.CrossRefPubMedGoogle Scholar
  9. 9.
    Shafer SL. All models are wrong. Anesthesiology. 2012;116(2):240–1.CrossRefPubMedGoogle Scholar
  10. 10.
    Perouansky M, Pearce RA. How we recall (or don’t): the hippocampal memory machine and anesthetic amnesia. Can J Anaesth. 2010;57:157–66.Google Scholar
  11. 11.
    Mashour GA, Esaki RK, Tremper KK, Glick DB, O’Connor M, Avidan MS. A novel classification instrument for intraoperative awareness events. Anesth Analg. 2010;110:813–5.CrossRefPubMedGoogle Scholar
  12. 12.
    Tononi G. Integrated information theory of consciousness: an updated account. Arch Ital Biol. 2012;150(4):293–329.PubMedGoogle Scholar
  13. 13.
    Dutton RC, Smith WD, Smith NT. Brief wakeful response to command indicates wakefulness with suppression of memory formation during surgical anesthesia. J Clin Monit. 1995;11:41–6.CrossRefPubMedGoogle Scholar
  14. 14.
    Dutton RC, Smith WD, Smith NT. Wakeful response to command indicates memory potential during emergence from general anesthesia. J Clin Monit. 1995;11:35–40.CrossRefPubMedGoogle Scholar
  15. 15.
    Timić T, Joksimović S, Milić M, Divljaković J, Batinić B, Savić MM. Midazolam impairs acquisition and retrieval, but not consolidation of reference memory in the Morris water maze. Behav Brain Res. 2013;15(241):198–200.Google Scholar
  16. 16.
    Semba K, Adachi N, Arai T. Facilitation of serotoninergic activity and amnesia in rats caused by intravenous anesthetics. Anesthesiology. 2005;102(3):616–23.CrossRefPubMedGoogle Scholar
  17. 17.
    Ishitobi S, Ayuse T, Yoshida H, Oi K, Toda K, Miyamoto T. Effects of midazolam on acquisition and extinction of conditioned taste aversion memory in rats. Neurosci Lett. 2009;450(3):270–4.CrossRefPubMedGoogle Scholar
  18. 18.
    Fiebig F, Lansner A. Memory consolidation from seconds to weeks: a three-stage neural network model with autonomous reinstatement dynamics. Front Comput Neurosci. 2014;1(8):64.Google Scholar
  19. 19.
    Fisher J, Hirshman E, Henthorn T, Arndt J, Passannante A. Midazolam amnesia and short-term/working memory processes. Conscious Cogn. 2006;15(1):54–63.CrossRefPubMedGoogle Scholar
  20. 20.
    Roehrs T, McLenaghan A, Koshorek G, Zorick F, Roth T. Amnesic effects of lormetazepam. Psychopharmacology. 1984;1:165–72.PubMedGoogle Scholar
  21. 21.
    Fiebig F, Lansner A. Memory consolidation from seconds to weeks: a three-stage neural network model with autonomous reinstatement dynamics. Front Comput Neurosci. 2014;1(8):64.Google Scholar
  22. 22.
    Veselis RA, Reinsel RA, Feshchenko VA, Wroński M. The comparative amnestic effects of midazolam, propofol, thiopental, and fentanyl at equisedative concentrations. Anesthesiology. 1997;87:749–64.CrossRefPubMedGoogle Scholar

Copyright information

© Japanese Society of Anesthesiologists 2015

Authors and Affiliations

  • Marco Cascella
    • 1
    Email author
  • Francesca Bifulco
    • 1
  • Daniela Viscardi
    • 4
  • Maura C. Tracey
    • 2
  • Domenico Carbone
    • 3
  • Arturo Cuomo
    • 1
  1. 1.Division of Anesthesia, Department of Anesthesia, Endoscopy and CardiologyIstituto Nazionale Tumori “Fondazione G. Pascale”-IRCCSNaplesItaly
  2. 2.Division of Thoracic Surgery, Department of Thoracic Surgery and OncologyIstituto Nazionale Tumori “Fondazione G. Pascale”–IRCCSNaplesItaly
  3. 3.Department of Emergency MedicineUmberto I HospitalNocera Inferiore, SalernoItaly
  4. 4.Intensive Care Unit, Department of Surgical and Anesthesiological SciencesUniversity Federico IINaplesItaly

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