Nitrous oxide, N2O, is a nonirritating gas with a slightly sweet odor that patients breathe in to help reduce pain. It was discovered in 1772 by Humphrey Davy when he used it to help lessen the pain of a toothache and gum infection he was suffering from. In his journal, he wrote,
“On the day when the inflammation was the most troublesome, I breathed three large doses of nitrous oxide. The pain always diminished after the first four or five inspirations; the thrilling came on as usual, and uneasiness was for a few minutes swallowed up in pleasure."
Davy’s description of nitrous oxide is accurate. It kills pain and induces a pleasurable feeling in the patient. Prior to a dental procedure, a patient spends five minutes breathing the gas. In that time, the patient will begin to feel euphoric and perhaps a bit light-headed. Nitrous oxide is nicknamed ‘laughing gas’ because some patients will begin giggling. Patients who use nitrous oxide for anesthetic do not lose consciousness.
Modern analgesia machines are used to deliver a precise dose of the gas, mixed with oxygen, to the patient. The gas is breathed in by the patient through the nose only.
Nitrous oxide is metabolized by the human body at a rate of 0.004%, so when the patient breathes out, almost all the nitrous oxide is released into the room. Clinic staff will ensure the treatment room is properly ventilated or that a nitrous oxide scavenger system is used to prevent their exposure.
How does Nitrous Oxide (laughing gas) works?
There are four levels of nitrous oxide sedation, after the first feeling of light headedness.
- Tingling of the arms and legs and a feeling of internal vibration
- Warm sensations
- Feeling of well-being, euphoria, and floating. At this point, patients may hear a constant, electric-like throbbing.
- Sleepiness, difficulty keeping eyes open or speaking. If the patient is nauseous, he is over sedated.
Are there any contraindications?
People who suffer from multiple sclerosis, emphysema and a few very rare chest problems should not use nitrous oxide.
Pregnant women should not use nitrous oxide because it has not been proven safe for pregnant women.
People with upper respiratory issues such as colds or allergies should not rely on nitrous oxide because they cannot effectively breathe through their noses. Check with your dentist before agreeing to using nitrous oxide if you have any breathing issues.
Nitrous oxide is safe to use if you have epilepsy, liver or heart disease, diabetes or a cerebrovascular disease. You cannot be allergic to N2O, either.