Nitrous oxide and oxygen

Gas and air redirects here, for the 1923 film, see Gas and Air

A mix of nitrous oxide 50% and oxygen 50% is a medical anaesthesia gas, commonly known as Entonox (a registered trademark of BOC) or Nitronox, or colloquially as gas and air, and is frequently used in pre-hospital care, childbirth and emergency medicine situations by medical professionals such as doctors, nurses, midwives and paramedics.

History

Nitrous oxide as a single gas was first used as a medical analgesic in 1844 by American dentist Horace Wells, growing in popularity in the late 1800s. Negative side effects were found from the hypoxia caused by a lack of oxygen, and the requirement to have at least 21% oxygen content in the gas was discovered (the same percentage as in air).

In 1911, the anaesthetist Arthur Ernest Guedel first described the use of self-administration of a nitrous oxide and oxygen mix.

It was not until 1961 that the first paper was published by Michael Tunstall et al. describing the administration of a pre-mixed 50:50 nitrous oxide and oxygen mix, which led to the commercialisation of the product.

Composition

The gas is made of a mixture of fifty percent nitrous oxide (N₂O or laughing gas) and fifty percent oxygen (O₂).<ref...
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