Minimal Alveolar Concentration of Sevoflurane Inducing Isoelectric Electroencephalogram

This study has been completed.

Sponsor:

Collaborators:

China: Ministry of Health

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

History of Changes

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:

Drug Information available for: Sevoflurane

U.S. FDA Resources

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.

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

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

China: Ministry of Health

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
Platelet Aggregation Inhibitors
Hematologic Agents
Therapeutic Uses
Pharmacologic Actions
Anesthetics, Inhalation

Anesthetics, General
Anesthetics
Central Nervous System Depressants
Physiological Effects of Drugs
Central Nervous System Agents

ClinicalTrials.gov processed this record on May 21, 2013

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