Laughing gas, scientifically known as nitrous oxide (N2O), has been used as a sedation technique in many medical procedures. This colorless and odorless gas was discovered in 1772. One of the pioneers of N2O experimentation named Humphrey Davy described his personal experiences with nitrous oxide during self-administration for a toothache and gum infection:
“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.”
Laughing gas is usually administered via inhalation apparatus in a mixture with oxygen. Thus, the gaseous mixture is now called N2O-O2 because it must contain at least 30% oxygen (guidelines of the American Academy of Pediatric Dentistry) for safety reasons. Nitrous oxide on its own can only be used for a short amount of time because the lack of oxygen can lead to unconsciousness or even death.
The concentration and length of administration of laughing gas varies and can result in different levels of sedation. The patient can experience a tingling sensation in the arms and legs or parasthesia (feeling of vibration). Next, a warm sensation is felt, quickly followed by euphoria and a feeling of well-being. When deeper levels of sedation are reached, sleepiness and difficulty to keep the eyes open or speak can occur. If nausea should set in, then the patient has been unfortunately over-sedated. The actual mechanism of N2O is still unknown. However, extensive research have shown that nitrous oxide inhibits ionic currents and excitotoxic neurodegeneration mediated through NMDA receptors in the body’s nervous system.
Laughing gas carries many advantages over other sedation techniques. First of all, the effects settle in very rapidly; the gas reaches the brain within 20 seconds. Relaxation and pain-killing effects usually develop 2-3 minutes later. A major advantage for this technique is that there is no “hangover” effect. The body eliminates the gas within 5 minutes after the continuous administration ceases. For those fearing needles, no injection is required. Inhalation sedation is also very safe. There are very limited side effects and the treatment has no ill effects on the major organs of the body.