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Physiological Effects of Nitrous Oxide on Anaesthesia

NCT01092923 · Status: COMPLETED · Phase: PHASE4 · Type: INTERVENTIONAL · Enrollment: 20

Last updated 2012-10-12

Study results available
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Summary

Nitrous oxide is the oldest anaesthetic agent still in routine use today. Despite huge changes in the pharmacology of volatile anaesthetic agents and intravenous anaesthetics, the unique properties of nitrous oxide have maintained its place in modern practice, where it is used in combination with other, more powerful inhaled agents, such as sevoflurane. It has useful analgesic properties, unlike the other agents used today, and its inclusion reduces the concentration of other agents required to maintain an adequate depth of anaesthesia for surgery.

In particular, its low solubility in body tissues gives it a unique pharmacokinetic profile, with rapid washin and washout from the body. It has been shown to have a similar effect on the speed of uptake of accompanying agents like sevoflurane (the "second gas effect"), which have much slower pharmacokinetics. A recent study by us suggested that this promotes faster and smoother onset of anaesthesia, as measured using the standard monitor of depth of anaesthesia (the BIS monitor). This finding requires confirmation prospectively in a larger group of patients. The investigators further hypothesise that a similar effect also exists on washout of sevoflurane at the end of the procedure, promoting quicker recovery (emergence) from anaesthesia. This has never been previously demonstrated. This information will help better define the place of nitrous oxide in achieving optimal outcomes in modern anaesthetic practice. The investigators propose to conduct a simple study to measure the effects of nitrous oxide washin and washout on exhaled concentrations of accompanying sevoflurane during both induction of anaesthesia and emergence, and identify any accompanying effect on the rate of change in depth of anaesthesia using BIS. The investigators hypothesise that the rate of fall of exhaled sevoflurane concentration at the end of anaesthesia will be more rapid in the group of patients breathing a gas mixture containing nitrous oxide, and that the rate of fall of BIS on induction and the rate of rise of BIS on emergence will be faster in the nitrous oxide group.

Conditions

  • Anesthesia

Interventions

DRUG

sevoflurane on air/O2

sevoflurane on air/O2

DRUG

sevoflurane in N2O/O2

sevoflurane in N2O/O2

Sponsors & Collaborators

  • Austin Health

    lead OTHER_GOV

Principal Investigators

  • Phil Peyton, MBBS · Austin Health

Study Design

Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Model
PARALLEL

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2009-10-31
Primary Completion
2010-07-31
Completion
2010-10-31

Countries

  • Australia

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT01092923 on ClinicalTrials.gov