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Addition of Nitrous Oxide and Its Effects on Depth of Anesthesia (N20)

This study has been completed.
Information provided by (Responsible Party):
University of Oklahoma Identifier:
First received: July 9, 2008
Last updated: June 29, 2017
Last verified: June 2017
The study hypothesizes that adding 60% nitrous oxide to a steady state sevoflurance or propofol anesthetic will lead to a decrease in both BIS and Entropy indices during a constant level of surgical stimulus

Condition Intervention
Deep Sedation Anesthesia, General Drug: Sevoflurane group Drug: Propofol group

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Health Services Research
Official Title: Addition of Nitrous Oxide to a Sevoflurane or Propofol Based Anesthetic and Its Effects on Depth of Anesthesia Indices (N20)

Resource links provided by NLM:

Further study details as provided by University of Oklahoma:

Primary Outcome Measures:
  • The Effect of Nitrous Oxide on Bispectral Index (BIS) and State Entropy Index (SE) [ Time Frame: From baseline to 20 minutes after the addition of 60% nitrous oxide ]

    We planned this study to compare the effect of adding N2O on BIS and SE during an intravenous or an inhalation anesthetic. We hypothesized that neither BIS nor SE would decrease in response to the addition of N2O to a Propofol anesthetic. We also hypothesized that neither BIS nor SE would decrease in participants under Sevoflurane anesthesia if the inspired concentration of Sevoflurane were carefully and continuously adjusted to maintain a constant end-tidal concentration during the addition and discontinuation of N2O.

    BIS (0-100) and SE (0-92) are unitless, ordinal indices of anesthetic depth. Both indices are decreased when the depth of anesthesia is increased.

Enrollment: 32
Study Start Date: March 2008
Study Completion Date: October 2010
Primary Completion Date: October 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Sevoflurane group
Sevoflurane based general anesthesia
Drug: Sevoflurane group
Addition of 60% nitrous oxide for 20 minutes duration, then back to 1:1 oxygen/air mixture.
Other Name: nitrous oxide
Active Comparator: Propofol group
Propofol based general anesthesia
Drug: Propofol group
Addition of 60% nitrous oxide for 20 minutes duration, then back to 1:1 oxygen/air mixture.
Other Name: nitrous oxide

Detailed Description:
Nitrous oxide is a widely used general anesthetic pas. It is often used in addition to a second, more potent agent. BIS and Entropy are depth of anesthesia monitors in clinical use. There are conflicting reports about the usefulness of these monitors when nitrous oxide is used as a part of the anesthetic regimen. While some studies demonstrate a decrease in BIS and Entropy, this study aims to investigate the effects of adding nitrous oxide to a sevoflurane or a propofol based anesthetic on BIS and Entropy indices.

Ages Eligible for Study:   18 Years to 55 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Ages 18 to 55yrs
  • ASA status less than and equal to 2

Exclusion Criteria:

  • Surgery on head and neck
  • ASA greater than 3
  • Contraindication to nitrous oxide
  • Pregnant women
  • History of dementia and stroke, or other organic brain disorder
  • Prisoner
  • Ear surgery
  Contacts and Locations
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Please refer to this study by its identifier: NCT00717574

United States, Oklahoma
University of Oklahoma Health Sciences Center
Oklahoma City, Oklahoma, United States, 73152
Sponsors and Collaborators
University of Oklahoma
Principal Investigator: Mehmet S Ozcan, M.D. Univeristy of Illinois Chicago
  More Information

Responsible Party: University of Oklahoma Identifier: NCT00717574     History of Changes
Other Study ID Numbers: 13800
Study First Received: July 9, 2008
Results First Received: April 7, 2017
Last Updated: June 29, 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Keywords provided by University of Oklahoma:
depth of sedation
nitrous oxide
general anesthesia
anesthesia indices

Additional relevant MeSH terms:
Nitrous Oxide
Central Nervous System Depressants
Physiological Effects of Drugs
Hypnotics and Sedatives
Anesthetics, Intravenous
Anesthetics, General
Platelet Aggregation Inhibitors
Anesthetics, Inhalation
Analgesics, Non-Narcotic
Sensory System Agents
Peripheral Nervous System Agents processed this record on September 21, 2017