Overview
The study examines the concentrations of nitrous oxide that are achieved in blood, exhaled air, and urine after three different exposures to nitrous oxide:
inhalation of three or four cartridges of nitrous oxide released in a car cabin in a switched-off car, consumption of 100 g of whipped cream in which nitrous oxide is used as a propellant, and exposure through work as a midwife in a delivery room.
The concentrations in blood and exhaled air are measured for up to 1 hour after exposure, and in urine for up to 2 hours after exposure. The concentrations in blood and urine are measued with gas chromatography and mass spectrometry, while the concentration in exhaled air is measured by a sensor using an NDIR sensor (Olythe, France).
Eligibility
For arm 1, 2, and 3:
Inclusion Criteria:
- Age 18-65 years
- Able to understand Danish
- Willing to use effective contraception for 24 hours after the end of exposure (oral contraceptives, contraceptive implant, transdermal patch, vaginal ring, or injectable contraceptives)
- Written informed consent
Exclusion Criteria:
- Current or past abuse of drugs, nitrous oxide (N₂O), or alcohol
- A psychiatric disorder requiring medical treatment, including severe depression
- A diagnosis of epilepsy
- Symptoms of peripheral neuropathy
- Significant cardiac or pulmonary disease
- Previous allergic or adverse reaction to N₂O
- Diving within the past 2 days
- Inability to refrain from diving for 2 days after the study
- Occupational exposure to N₂O
- Use of N₂O within the past 3 months
- Treatment with methotrexate, benzodiazepines, opioids, or other centrally depressant drugs
- Recent intraocular gas injection
- Known impaired liver or kidney function
- Pregnant or breastfeeding women (fertile women, defined as amenorrhea for less than 12 months, must have a negative hCG pregnancy test prior to receiving the study intervention)
