Effects of Low Concentrations of Nitrous Oxide

Study Overview
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Brief Summary
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The aim of the study is to test the effects of low concentrations of nitrous oxide on cognitive functions and reaction time in human.

Detailed Description
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Nitrous oxide is a widely used gas in medicine, in standard concentrations above 50%. Its favourable physical properties and easy detectability by anaesthetic gas analysors predispose nitrous oxide to become a possible tracing gas for leak detection in experiments in which modified breathing system are in use. In these breathing experiments, the inspired concentrations of nitrous oxide would be well below the anaesthetic/analgesic concentrations. The aim of this study is to investigate the effects of these low concentrations of nitrous oxide (5, 7, 10, 12, 15, 20 %), compared to placebo (air, 0% nitrous oxide). The cognitive functions are tested using Digit Symbol Substitution Test, Reaction Time and Visual Analogue Scale.

Official Title
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Effects of Low Concentrations of Nitrous Oxide on Cognitive Functions and Reaction Time

Conditions
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Nitrous Oxide Poisoning

Intervention / Treatment
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* Drug: Nitrous Oxide
* Other: Placebo - air


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy volunteers from the Czech Technical University Exclusion Criteria: pregnancy allergy to nitrous oxide severe asthma or other severe respiratory conditions severe cardiovascular conditions

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: All participants go through all study arms, in random order.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Control group - air<br>Breathing air with 21 % of oxygen (0% nitrous oxide). Performing cognitive tests as per protocol. | Other: Placebo - air<br>* Breathing air with 21 % oxygen, no nitrous oxide.<br>|
| Experimental: Intervention Group - 5% nitrous oxide<br>Breathing 5% nitrous oxide in air with 21 % of oxygen. Performing cognitive tests as per protocol. | Drug: Nitrous Oxide<br>* Breathing nitrous oxide, concentrations 5, 7, 10, 12, 15, 20 % in air with 21 % oxygen, in random order.<br>|
| Experimental: Intervention Group - 7% nitrous oxide<br>Breathing 7% nitrous oxide in air with 21 % of oxygen. Performing cognitive tests as per protocol. | Drug: Nitrous Oxide<br>* Breathing nitrous oxide, concentrations 5, 7, 10, 12, 15, 20 % in air with 21 % oxygen, in random order.<br>|
| Experimental: Intervention Group - 10% nitrous oxide<br>Breathing 10% nitrous oxide in air with 21 % of oxygen. Performing cognitive tests as per protocol. | Drug: Nitrous Oxide<br>* Breathing nitrous oxide, concentrations 5, 7, 10, 12, 15, 20 % in air with 21 % oxygen, in random order.<br>|
| Experimental: Intervention Group - 12% nitrous oxide<br>Breathing 12% nitrous oxide in air with 21 % of oxygen. Performing cognitive tests as per protocol. | Drug: Nitrous Oxide<br>* Breathing nitrous oxide, concentrations 5, 7, 10, 12, 15, 20 % in air with 21 % oxygen, in random order.<br>|
| Experimental: Intervention Group - 15% nitrous oxide<br>Breathing 15% nitrous oxide in air with 21 % of oxygen. Performing cognitive tests as per protocol. | Drug: Nitrous Oxide<br>* Breathing nitrous oxide, concentrations 5, 7, 10, 12, 15, 20 % in air with 21 % oxygen, in random order.<br>|
| Experimental: Intervention Group - 20% nitrous oxide<br>Breathing 20% nitrous oxide in air with 21 % of oxygen. Performing cognitive tests as per protocol. | Drug: Nitrous Oxide<br>* Breathing nitrous oxide, concentrations 5, 7, 10, 12, 15, 20 % in air with 21 % oxygen, in random order.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cognitive test results | The results of cognitive test performed during inhalation of defined concentration of nitrous oxide. Cognitive tests: Digit Symbol Substitution Test (DSST). | Through study completion, an average of 1 year | 
| Reaction Time | The results of reaction time test performed during inhalation of defined concentration of nitrous oxide. Reaction Time (in seconds) using a computer-based test. | Through study completion, an average of 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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nitrous oxide, tracing gas, breathing experiments, cognitive tests