Effects of nitrous oxide on volume and pressure of endotracheal tube cuffs

Abstract

The effects of nitrous oxide on endotracheal tube cuff gas volumes and pressures were determined with 50 size 32 to 40 Fr Foregger endotracheal tubes fitted with fluted latex rubber cuffs. The cuffs were inflated with 5, 10, or 15 ml of air and then exposed to 100, 75, 50, or 25% nitrous oxide in oxygen for one to four hours. Nitrous oxide increased cuff gas volumes in a concentration and time related fashion. The increases were significant (P < .001) after one hour of exposure and often dramatic after four hours. Intracuff pressures also increased after nitrous oxide, with pressures frequently reaching 70 and occasionally 100 mm Hg. These findings demonstrate that nitrous oxide has the capacity to diffuse into latex rubber endotracheal tube cuffs in significant volumes and suggest that such diffusion may result in overexpansion of the cuffs and cause upper airway obstruction and trauma in the intubated patient.