The widespread use of nitrous oxide (N2O) in paediatric anaesthesia raises another issue. Nitrous oxide diffuses easily into the ET tube cuffs, raising the pressure within them. Various interventions have been trialled in adult studies to address this. Inflating ET tube cuffs with a mixture of air and N2O may be beneficial, but varying concentrations of N2O during anaesthesia limit the benefits. Filling the cuff with saline instead of air has been shown to prevent increases in cuff pressures in the adult population without any adverse safety issues, but it is still not standard practice.