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Minimal Alveolar Concentration of Sevoflurane Inducing Isoelectric Electroencephalogram

This study has been completed.
Sponsor:
Collaborators:
Ministry of Health, China
National Natural Science Foundation of China
Information provided by (Responsible Party):
Wei Mei, Huazhong University of Science and Technology
ClinicalTrials.gov Identifier:
NCT01662622
First received: August 8, 2012
Last updated: August 12, 2012
Last verified: August 2012
  Purpose

Sevoflurane can abolish movement or adrenergic response to noxious stimulus. In order to investigate the effect of sevoflurane on cerebral electrical activity, we determined the MAC of sevoflurane inducing isoelectric electroencephalogram (EEG) in 50% of the subjects (MACie) in middle aged subjects.


Condition Intervention Phase
Middle Aged Patients
Sevoflurane
General Anesthesia
Drug: Sevoflurane
Phase 4

Study Type: Interventional
Study Design: Endpoint Classification: Pharmacodynamics Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Minimal Alveolar Concentration of Sevoflurane Inducing Isoelectric Electroencephalogram

Resource links provided by NLM:


Further study details as provided by Huazhong University of Science and Technology:

Primary Outcome Measures:
  • MACie [ Time Frame: 30min ] [ Designated as safety issue: Yes ]
    Minimal Alveolar Concentration of sevoflurane inducing isoelectric electroencephalogram (EEG) in 50% of the subjects (MACie)


Secondary Outcome Measures:
  • MACbs [ Time Frame: 30 min ] [ Designated as safety issue: Yes ]
    Minimal Alveolar Concentration of sevoflurane inducing inducing burst suppression EEG (MACbs) in middle aged adults.


Other Outcome Measures:
  • Hemodynamic parameters [ Time Frame: 3 min ] [ Designated as safety issue: Yes ]
    Hemodynamic parameters 2 min before and 3 min after skin incision

  • Use of phenylephrine [ Time Frame: 30 min ] [ Designated as safety issue: Yes ]
    Use of phenylephrine during induction and maintenance of anesthesia with sevoflurane.


Enrollment: 31
Study Start Date: March 2012
Study Completion Date: July 2012
Primary Completion Date: May 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Sevoflurane
Anaesthesia was induced by 8% sevoflurane. Cisatracurium 0.15mg kg-1 was administered after loss of the lash reflex, then ventilated manually until the amplitude of T1 decreased to 0. Intubation was performed and switched to mechanical ventilation with a fresh gas flow 2L min-1. Gas concentrations were analysed using a gas analyser.The end-tidal concentration of carbon dioxide was maintained at 4.7kPa; an esophageal temperature probe was inserted and a warming unit was used if necessary to maintain normothermia (35.5°-38.5°). The surgical incision was performed at least 30min after tracheal intubation. When arterial blood pressure (MAP) decrease exceeding 20% of baseline values. Phenylephrine 0.1mg was administered intravenously if necessary to maintained MAP and recorded.
Drug: Sevoflurane
The design of experiment is referred to the "Dixon up-and-down" method. The first subject was designed to receive end-tidal sevoflurane concentration of 1.7%. For each subject, 30 min interval time was given. The isoelectric EEG was considered as significant when the isoelectric state last for more than 1min. The maximal burst suppression rate was recorded if isoelectric EEG was not reached. Heart rate and MAP, were recorded 2 and 1min before and 3 min after skin incision. Adrenergic reflexes positive cases were counted.

Detailed Description:

Patients received sevoflurane for anesthesia induction and maintenance at preselected concentrations according to an 'up and down' design, with 0.2% as a stepsize. General anesthesia was induced and maintained with sevoflurane, tracheal intubation was facilitated with cisatracurium. After a steady-state period of 30min without surgical stimulation, the state of isoelectric EEG was considered as significant when a burst suppression ratio of 100% last for more than 1 min. The haemodynamic responses to skin incision and the vasopressor requirement to maintain cardiovascular system were also analysed according to the EEG state.

  Eligibility

Ages Eligible for Study:   45 Years to 65 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • 45-65yr
  • upper abdominal surgery in general anaesthesia
  • ASA physical status classification of I or II

Exclusion Criteria:

  • neurological disease
  • received central nervous system-active drugs
  • cardiac ejection fraction less than 40%
  • history of difficult intubation or anticipated difficult intubation
  • daily alcohol consumption
  • obesity, defined as a body-mass index of more than 30
  • without informed consent
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT01662622

Locations
China, Hubei
Department of Anaesthesiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology
Wuhan, Hubei, China, 430030
Sponsors and Collaborators
Huazhong University of Science and Technology
Ministry of Health, China
National Natural Science Foundation of China
Investigators
Study Chair: Yuke Tian, MD. Department of Anaesthesiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology
  More Information

No publications provided

Responsible Party: Wei Mei, AssociateProfessor, Huazhong University of Science and Technology
ClinicalTrials.gov Identifier: NCT01662622     History of Changes
Other Study ID Numbers: TJMZK20120301
Study First Received: August 8, 2012
Last Updated: August 12, 2012
Health Authority: China: Ministry of Health

Keywords provided by Huazhong University of Science and Technology:
anaesthesia
middle aged
minimal alveolar concentration
sevoflurane
isoelectric EEG

Additional relevant MeSH terms:
Sevoflurane
Anesthetics
Anesthetics, General
Anesthetics, Inhalation
Central Nervous System Agents
Central Nervous System Depressants
Hematologic Agents
Pharmacologic Actions
Physiological Effects of Drugs
Platelet Aggregation Inhibitors
Therapeutic Uses

ClinicalTrials.gov processed this record on November 20, 2014