Nitrous Oxide

Nitrous oxide (N₂O) or laughing gas as it is commonly known as, was first synthesised by Joseph Priestley in 1772. It was used as a medical gas forty years after this as a dental analgesic. From about the late 1800’s to the present day N₂O has been used extensively for both analgesia and anaesthesia in a wide range of surgical procedures.

Uses

Nitrous oxide is predominately used as a background anaesthetic due to its weaker anaesthetic properties. Nitrous oxide is supplemented with either a potent volatile agent or an intravenous anaesthetic. When used in this way, it allows a much lower dosage of the other agents, usually by up to half. The use of Nitrous oxide allows for faster induction times when used with a volatile agent, due to its low blood/gas solubility.

Mode of action

Nitrous oxide suppresses spinal impulses and may supress supraspinal pathways. Nitrous oxide is thought to work on the N-methyl-d-aspartase receptors inhibiting pain. It is also thought to have an effect on the GABA cells increasing inhibition of nerve cells causing drowsiness and sleep.

Contra-indications / side effects

Nitrous oxide should not be used with any condition where air is entrapped within a body and where its expansion might be dangerous such as:

• Head injuries with impairment of consciousness
• Artificial, traumatic or spontaneous pneumothorax
• Air embolism
• Decompression sickness
• Following a recent dive
• Following air encephelography
• Severe bullous emphysema
• During myringoplasty
• ·Gross abdominal distension
• ·Maxillofacial injuries.

When using Nitrous oxide for more than 24 hours, monitoring of peripheral blood for signs of megablastic anaemia and leukopenia should be undertaken. Rarely, inactivation of vitamin B12 may occur which can then interfere with folate metabolism which can result in bone marrow changes. This is usually related to prolonged usage of the gas or where an existing deficiency is present.

More Information

For more information on Nitrous Oxide contact your local account manager to arrange a meeting or to order product related literature. Reference guides, brochures, and safety data sheets are avaialble.

You can also call our call centre on 0800 111 333

or e-mail BOC Medical Customer enquiries team.