Nitrous oxide in modern anaesthetic practice

Nitrous oxide is an N-methyl--aspartate receptor antagonist and may reduce the incidence of chronic post-surgical pain. • Nitrous oxide oxidizes Vitamin B12 and can precipitate sub-acute combined degeneration of the cord with chronic use or in patients with folate/B12 deficiency. • Nitrous oxide expands air spaces and is contraindicated in patients with pneumothorax or recent (up to 4–6 weeks) ocular surgery using intraocular gas. • Nitrous oxide has global warming and ozone depletion potential and its concentration in the theatre environment is regulated. • The ENIGMA-II trial showed that nitrous oxide does not increase the risk of death or cardiovascular complications