Minimum Alveolar Concentration of Sevoflurane With Nitrous Oxide Inducing Isoelectric EEG

General Anesthesia Clinical Trial

Official title:

Minimum Alveolar Concentration of Sevoflurane With 60% Nitrous Oxide Inducing Isoelectric EEG in Mid-aged Adults

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01705743
• Other study ID #: TJMZK20120903
• Status: Completed
• Phase: Phase 4
• First received: October 10, 2012
• Last updated: February 3, 2014
• Start date: September 2012
• Est. completion date: October 2013

Study information

• Verified date: February 2014
• Source: Huazhong University of Science and Technology
• Contact: n/a
• Is FDA regulated: No
• Health authority: China: Ministry of Health
• Study type: Interventional

Clinical Trial Summary

In order to investigate the effect of a combination effect of sevoflurane and nitrous oxide on cerebral electrical activity, the investigators determined the MAC of sevoflurane combined with nitrous oxide inducing isoelectric electroencephalogram (EEG) in 50% of the subjects (MACie) in middle aged subjects.

Description:

Anaesthesia was induced by sevoflurane in oxygen. Cisatracurium 0.15 mg 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 of 2 L min-1. Anesthesia was maintained by sevoflurane or sevoflurane+60% nitrous oxide respectively. The surgical incision was performed at least 30 min after tracheal intubation, provided that the predetermined end-tidal sevoflurane concentration had been constant for at least 30 min and that the difference between inspired and end-tidal concentrations was less than 10%.

Brain electrical activity was measured using Narcotrend Monitor and S/5 Compact Anaesthesia Monitor, which displayed unprocessed EEG and burst suppression ratio, respectively. The design of the experiment is referred to the "Dixon up-and-down" method. To avid anaesthesia awareness, the first subject was designed to receive end-tidal sevoflurane concentration of 2.5 %. The presence or absence of isoelectric EEG (Entropy Module) of the preceding patient determined the end-tidal concentration of sevoflurane given to the next patient (with an increment size of 0.2%). The isoelectric EEG was considered as significant when the isoelectric state last for more than 1 min. The maximal burst suppression rate was recorded if isoelectric EEG was not reached.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 76
• Est. completion date: October 2013
• Est. primary completion date: September 2013
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 45 Years to 64 Years

Eligibility

Inclusion Criteria:

• between 45 to 64 years old

• ASA physical status class 1 or 2

• elective abdominal surgery

• Informed Consent

Exclusion Criteria:

• history of 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

• others judged inappropriate as subjects for the study by the Study Chair

Study Design

Allocation: Randomized, Endpoint Classification: Pharmacodynamics Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Outcomes Assessor), Primary Purpose: Treatment

Related Conditions & MeSH terms

• General Anesthesia
• Middle Aged Patients

Intervention

Drug:
• Sevoflurane+Nitrous oxide
60% nitrous oxide +40% oxygen+ Sevoflurane
• Sevoflurane
100% oxygen+ Sevoflurane

Locations

Country	Name	City	State
China	Department of Anaesthesiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology	Wuhan	Hubei

Sponsors (1)

Lead Sponsor	Collaborator
Huazhong University of Science and Technology

Country where clinical trial is conducted

China, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	MACie	Minimal Alveolar Concentration of sevoflurane and NO inducing isoelectric electroencephalogram (EEG) in 50% of the subjects (MACie)	30min	Yes