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The Neural Mechanisms of Anesthesia and Human Consciousness (LOC-2013)

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ClinicalTrials.gov Identifier: NCT01889004
Recruitment Status : Completed
First Posted : June 28, 2013
Last Update Posted : January 11, 2016
Sponsor:
Collaborators:
Academy of Finland
Hospital District of Southwestern Finland
Information provided by (Responsible Party):
Harry Scheinin, University of Turku

Tracking Information
First Submitted Date  ICMJE June 23, 2013
First Posted Date  ICMJE June 28, 2013
Last Update Posted Date January 11, 2016
Study Start Date  ICMJE February 2014
Actual Primary Completion Date January 2016   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: June 27, 2013)
Regional cerebral blood flow [ Time Frame: Several measurements during two separate days within 2 months ]
Altogether 14 PET scans during two separate study days. Cerebral blood flow changes will be used as surrogates for changes in regional brain activity.
Original Primary Outcome Measures  ICMJE Same as current
Change History
Current Secondary Outcome Measures  ICMJE
 (submitted: June 27, 2013)
  • EEG [ Time Frame: Continuous data collection during five separate days within 2 months ]
  • Functional magnetic resonance imaging (fMRI) [ Time Frame: Several measurements during one day ]
  • Event related potentials [ Time Frame: Several time points during five separate days within 2 months ]
Original Secondary Outcome Measures  ICMJE Same as current
Current Other Pre-specified Outcome Measures
 (submitted: June 27, 2013)
Drug concentration in plasma [ Time Frame: Several times points during two or three separate days within 2 months ]
Original Other Pre-specified Outcome Measures Same as current
 
Descriptive Information
Brief Title  ICMJE The Neural Mechanisms of Anesthesia and Human Consciousness
Official Title  ICMJE The Neural Mechanisms of Anesthesia and Human Consciousness (LOC-2013)
Brief Summary

The explanation of consciousness poses one of the greatest challenges to science and philosophy in the 21st century. It remains unclear what consciousness is and how it emerges from brain activity. By studying anesthesia and sleep, the investigators aim to reveal what happens in the brain when consciousness is lost and when it returns. During the study, a series of Positron Emission Tomography (PET), Magnetic Resonance Imaging (MRI) and electroencephalography (EEG) studies will be carried out on healthy male subjects to reveal the neural correlates of consciousness. Consciousness of the subjects will be manipulated with normal sleep and anesthetic agents dexmedetomidine and propofol.

First, various neurophysiological tools to separate consciousness, connectedness and responsiveness during normal sleep will be tested. The most suitable methods and subjects will be selected and then tested during anesthetic-induced sedation and loss of responsiveness (LOR). The anesthetics (dexmedetomidine or propofol) will be administered as target-controlled infusions (TCI) with step-wise concentration-increments until LOR is detected. Then, TCIs are repeated in the same subjects but adjusted according to the individual drug target concentrations sufficient for LOR, and a series of PET perfusion imaging measurements will be performed to obtain the brain activity information in various states of consciousness. The same subjects will then be imaged with PET for brain activity after sleep deprivation (awake), during various sleep stages and immediately after awakening. Finally, ten dexmedetomidine subjects will be given the drug once more, and functional MRI (fMRI) data will be collected at various states of consciousness before and during verbal and nonverbal vocalizations. EEG will be continuously collected in all sessions. The depth of anesthesia will be measured using quantitative EEG and bispectral index (BIS) monitoring.

The results may lead to the discovery of new and better objective indicators of the depth of anesthesia and consciousness, and new insights into the understanding of neural mechanisms behind drug-induced loss of consciousness and ultimately the mechanisms of action of (general) anesthetics as well as consciousness itself.

Detailed Description (not needed)
Study Type  ICMJE Interventional
Study Phase  ICMJE Phase 4
Study Design  ICMJE Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Condition  ICMJE Consciousness, Level Altered
Intervention  ICMJE
  • Drug: Dexmedetomidine
    Escalating concentrations until loss of responsiveness
    Other Name: Dexdor
  • Drug: Propofol
    Escalating concentrations until loss of responsiveness
    Other Name: Propofol-Lipuro
Study Arms  ICMJE
  • Experimental: Dexmedetomidine
    Intravenous dexmedetomidine using target controlled infusion
    Intervention: Drug: Dexmedetomidine
  • Experimental: Propofol
    Intravenous propofol using target controlled infusion
    Intervention: Drug: Propofol
Publications *

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status  ICMJE Completed
Actual Enrollment  ICMJE
 (submitted: January 8, 2016)
47
Original Estimated Enrollment  ICMJE
 (submitted: June 27, 2013)
40
Actual Study Completion Date  ICMJE January 2016
Actual Primary Completion Date January 2016   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

Inclusion Criteria:

  • Male
  • Age 20-30 years
  • Good general health i.e. American Society of Anesthesiologists (ASA) physical status I
  • Fluent in Finnish language
  • Right handedness
  • Written informed consent
  • Good sleep quality

Exclusion Criteria:

  • Chronic medication
  • History of alcohol and/or drug abuse
  • Strong susceptibility for allergic reactions
  • Serious nausea in connection with previous anesthesia
  • Strong susceptibility for nausea
  • Any use of drugs or alcohol during the 48 hours preceding anesthesia
  • Use of caffeine products 10-12 hours prior the study, 24 hours before sleep studies
  • Smoking
  • Clinically significant previous cardiac arrhythmia / cardiac conduction impairment
  • Clinically significant abnormality in prestudy laboratory tests
  • Positive result in the drug screening test
  • Blood donation within 90 days prior to the study
  • Participation in any medical study with an experimental drug or device during the preceding 60 days
  • The study subject has undergone a prior PET or SPECT study
  • Any contraindication to magnetic resonance imaging (MRI)
  • Hearing impairment
  • Detected unsuitability based on initial electrophysiological measurements
  • Detected unsuitability based on MRI scanning results
  • Sleep disorder or severe sleep problem
Sex/Gender  ICMJE
Sexes Eligible for Study: Male
Ages  ICMJE 20 Years to 30 Years   (Adult)
Accepts Healthy Volunteers  ICMJE Yes
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE Finland
Removed Location Countries  
 
Administrative Information
NCT Number  ICMJE NCT01889004
Other Study ID Numbers  ICMJE LOC-2013
266467 ( Other Grant/Funding Number: Academy of Finland )
2013-001496-21 ( EudraCT Number )
KLnro 72/2013 ( Registry Identifier: Finnish Medicines Agency (Fimea) )
Has Data Monitoring Committee No
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement  ICMJE Not Provided
Responsible Party Harry Scheinin, University of Turku
Study Sponsor  ICMJE University of Turku
Collaborators  ICMJE
  • Academy of Finland
  • Hospital District of Southwestern Finland
Investigators  ICMJE
Principal Investigator: Harry Scheinin, MD University of Turku
PRS Account University of Turku
Verification Date January 2016

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP