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Updated: May 19, 2026
08:23
Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
Published on: February 16, 2022
Direct measurement of nitrous oxide kinetics
G B Drummond1, L Fisher, O Pumphrey
1Department of Anaesthesia and Pain Medicine, University of Edinburgh, Royal Infirmary, 51 Little France Crescent, Edinburgh, UK. g.b.drummond@ed.ac.uk
British Journal of Anaesthesia
|August 31, 2012
Summary
Nitrous oxide rapidly impairs cognitive function, specifically the digit symbol substitution test (DSST). This effect on cerebral function occurs quickly, aligning with blood flow to active brain tissues.
Area of Science:
- Anesthesiology
- Neuroscience
- Pharmacokinetics
Background:
- Measuring anesthetic effects in conscious subjects requires rapid tests of cerebral function.
- Estimating anesthetic agent dynamics (onset/offset) and kinetic values is crucial.
Purpose of the Study:
- To assess the rapid effects of nitrous oxide on cognitive function using a validated test.
- To correlate nitrous oxide concentrations with cognitive impairment and estimate kinetic parameters.
Main Methods:
- A shortened Digit Symbol Substitution Test (DSST) was used for frequent cognitive assessments.
- Volunteers inhaled 5% and 30% nitrous oxide in oxygen, with a control group breathing only oxygen.
- End-tidal nitrous oxide concentrations were used to predict central compartment concentrations based on T(1/2) values.
Main Results:
- Only 30% nitrous oxide significantly decreased DSST scores.
- A T(1/2) of 37 seconds showed the best dose-effect relationship, correlating with cerebral blood flow of approximately 120 ml/100g/min.
- Nineteen volunteers participated in the study.
Conclusions:
- Nitrous oxide's impact on the DSST is rapid, reflecting perfusion of metabolically active cerebral cortical tissues.
- The observed onset rate is faster than previously reported using motor tests involving subcortical structures.
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