Trial Outcomes & Findings for Addition of Nitrous Oxide and Its Effects on Depth of Anesthesia (NCT NCT00717574)

Last Updated: 2017-07-31

Results Overview

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.

Recruitment status

COMPLETED

Study phase

Target enrollment

32 participants

Primary outcome timeframe

From baseline to 20 minutes after the addition of 60% nitrous oxide

Results posted on

2017-07-31

Participant Flow

Study includes patients aged 18 to 55 years who were classified as ASA physical status ≤2 and scheduled to have surgery under general anesthesia . Only patients for which intraoperative Entropy or BIS monitoring was planned were enrolled by speaking to the attending anesthesiologists working at the OU Presbyterian hospital.

Patients were randomized into 2 groups that differ in the choice of the agent for the maintenance of general anesthesia: sevoflurane or propofol.

Participant milestones

Participant milestones
Measure	Sevoflurane Group Sevoflurane based general anesthesia Sevoflurane group: Addition of 60% nitrous oxide for 20 minutes duration, then back to 1:1 oxygen/air mixture.	Propofol Group Propofol based general anesthesia Propofol group: Addition of 60% nitrous oxide for 20 minutes duration, then back to 1:1 oxygen/air mixture.
Overall Study STARTED	16	16
Overall Study COMPLETED	14	14
Overall Study NOT COMPLETED	2	2

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Addition of Nitrous Oxide and Its Effects on Depth of Anesthesia

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Sevoflurane Group n=14 Participants Sevoflurane based general anesthesia Sevoflurane group: Addition of 60% nitrous oxide for 20 minutes duration, then back to 1:1 oxygen/air mixture.	Propofol Group n=14 Participants Propofol based general anesthesia Propofol group: Addition of 60% nitrous oxide for 20 minutes duration, then back to 1:1 oxygen/air mixture.	Total n=28 Participants Total of all reporting groups
Age, Continuous	39 years STANDARD_DEVIATION 10 • n=5 Participants	38 years STANDARD_DEVIATION 9.6 • n=7 Participants	38.7 years STANDARD_DEVIATION 9.7 • n=5 Participants
Sex: Female, Male Female	8 Participants n=5 Participants	10 Participants n=7 Participants	18 Participants n=5 Participants
Sex: Female, Male Male	6 Participants n=5 Participants	4 Participants n=7 Participants	10 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	1 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants
Race (NIH/OMB) Asian	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	2 Participants n=5 Participants	3 Participants n=7 Participants	5 Participants n=5 Participants
Race (NIH/OMB) White	9 Participants n=5 Participants	10 Participants n=7 Participants	19 Participants n=5 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	2 Participants n=5 Participants	1 Participants n=7 Participants	3 Participants n=5 Participants
Region of Enrollment United States	14 participants n=5 Participants	14 participants n=7 Participants	28 participants n=5 Participants
Body Mass Index (BMI)	31 kg/m^2 STANDARD_DEVIATION 6 • n=5 Participants	32 kg/m^2 STANDARD_DEVIATION 10 • n=7 Participants	31.5 kg/m^2 STANDARD_DEVIATION 8 • n=5 Participants

PRIMARY outcome

Timeframe: From baseline to 20 minutes after the addition of 60% nitrous oxide

Outcome measures

Outcome measures
Measure	Sevoflurane Group n=14 Participants Sevoflurane based general anesthesia Sevoflurane group: Addition of 60% nitrous oxide for 20 minutes duration, then back to 1:1 oxygen/air mixture.	Propofol Group n=14 Participants Propofol based general anesthesia Propofol group: Addition of 60% nitrous oxide for 20 minutes duration, then back to 1:1 oxygen/air mixture.
The Effect of Nitrous Oxide on Bispectral Index (BIS) and State Entropy Index (SE) Baseline BIS	36 units on a scale Standard Deviation 7	40 units on a scale Standard Deviation 10
The Effect of Nitrous Oxide on Bispectral Index (BIS) and State Entropy Index (SE) 60% Nitrous Oxide BIS	32 units on a scale Standard Deviation 7	39 units on a scale Standard Deviation 10
The Effect of Nitrous Oxide on Bispectral Index (BIS) and State Entropy Index (SE) Baseline SE	37 units on a scale Standard Deviation 10	43 units on a scale Standard Deviation 11
The Effect of Nitrous Oxide on Bispectral Index (BIS) and State Entropy Index (SE) 60% Nitrous Oxide SE	31 units on a scale Standard Deviation 11	43 units on a scale Standard Deviation 12

Adverse Events

Sevoflurane Group

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Propofol Group

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Dr. Mehmet Ozcan, MD

Department of Anesthesia. OUHSC

Phone: 405-271-4351

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place