Addition of Nitrous Oxide and Its Effects on Depth of Anesthesia

Study Overview
=================
Brief Summary
-----------------
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

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.

Official Title
-----------------
Addition of Nitrous Oxide to a Sevoflurane or Propofol Based Anesthetic and Its Effects on Depth of Anesthesia Indices (N20)

Conditions
-----------------
Deep Sedation, Anesthesia, General

Intervention / Treatment
-----------------
* Drug: Sevoflurane group
* Drug: Propofol group


Participation Criteria
=================
Eligibility Criteria
-----------------
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

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Health Services Research
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Sevoflurane group<br>Sevoflurane based general anesthesia | Drug: Sevoflurane group<br>* Addition of 60% nitrous oxide for 20 minutes duration, then back to 1:1 oxygen/air mixture.<br>* Other names: nitrous oxide;|
| Active Comparator: Propofol group<br>Propofol based general anesthesia | Drug: Propofol group<br>* Addition of 60% nitrous oxide for 20 minutes duration, then back to 1:1 oxygen/air mixture.<br>* Other names: nitrous oxide;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Effect of Nitrous Oxide on Bispectral Index (BIS) and State Entropy Index (SE) | 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. | From baseline to 20 minutes after the addition of 60% nitrous oxide | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
depth of sedation, nitrous oxide, general anesthesia, anesthesia indices