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NCT Number: NCT01662622

Minimal Alveolar Concentration of Sevoflurane Inducing Isoelectric Electroencephalogram

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.

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Key information

Conditions

Middle Aged Patients General Anesthesia Sevoflurane

Age range

45 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Department of Anaesthesiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology

Wuhan, Hubei, 430030, China

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Sevoflurane

Drug

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.

Primary outcomes

  1. MACie

    Time frame: 30min

    Minimal Alveolar Concentration of sevoflurane inducing isoelectric electroencephalogram (EEG) in 50% of the subjects (MACie)

Secondary outcomes

  1. MACbs

    Time frame: 30 min

    Minimal Alveolar Concentration of sevoflurane inducing inducing burst suppression EEG (MACbs) in middle aged adults.

Other outcomes

  1. Hemodynamic parameters

    Time frame: 3 min

    Hemodynamic parameters 2 min before and 3 min after skin incision

  2. Use of phenylephrine

    Time frame: 30 min

    Use of phenylephrine during induction and maintenance of anesthesia with sevoflurane.

Sponsors and collaborators

Lead sponsor

Huazhong University of Science and Technology

Other

Collaborators

  • Ministry of Health, China
  • National Natural Science Foundation of China

Registry information

Important dates

Study start
2012
Primary completion
2012
Study completion
2012
First posted
Aug 10, 2012
Registry last updated
Aug 14, 2012

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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