Minimal Alveolar Concentration of Sevoflurane Inducing Isoelectric Electroencephalogram

• Sponsor: Huazhong University of Science and Technology (Other)
• Overall Status: Completed
• CT.gov ID: NCT01662622
• Collaborator: Ministry of Health, China (Other), National Natural Science Foundation of China (Other)
• Enrollment: 31
• Location: 1
• Arm: 1
• Duration (Months): 4
• Patients Per Site Per Month: 7.7

Study Details

Study Description

Brief Summary

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 or Disease	Intervention/Treatment	Phase
Middle Aged Patients; Sevoflurane; General Anesthesia	Drug: Sevoflurane	Phase 4

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.

Study Design

• Study Type: Interventional
• Actual Enrollment: 31 participants
• Allocation: N/A
• Intervention Model: Single Group Assignment
• Masking: None (Open Label)
• Primary Purpose: Treatment
• Official Title: Minimal Alveolar Concentration of Sevoflurane Inducing Isoelectric Electroencephalogram
• Study Start Date: Mar 1, 2012
• Actual Primary Completion Date: May 1, 2012
• Actual Study Completion Date: Jul 1, 2012

Arms and Interventions

Arm

Intervention/Treatment

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.

Outcome Measures

Primary Outcome Measures

1. MACie [30min]

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

Secondary Outcome Measures

1. MACbs [30 min]

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

Other Outcome Measures

1. Hemodynamic parameters [3 min]

   Hemodynamic parameters 2 min before and 3 min after skin incision

2. Use of phenylephrine [30 min]

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

Eligibility Criteria

Criteria

• Ages Eligible for Study: 45 Years to 65 Years
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

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

Locations

	Site	City	State	Country	Postal Code
1	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

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• Responsible Party: Wei Mei, AssociateProfessor, Huazhong University of Science and Technology
• ClinicalTrials.gov Identifier: NCT01662622
• Other Study ID Numbers: TJMZK20120301
• First Posted: Aug 10, 2012
• Last Update Posted: Aug 14, 2012
• Last Verified: Aug 1, 2012

• Keywords provided by Wei Mei, AssociateProfessor, Huazhong University of Science and Technology: anaesthesia; middle aged; minimal alveolar concentration; sevoflurane; isoelectric EEG
• Additional relevant MeSH terms: Sevoflurane

Study Results

No Results Posted as of Aug 14, 2012