Study Design:To investigate the effect of xenon on the endotracheal tube cuff in comparison to that of nitrous oxide.Design:Prospective, randomized study.Setting:Laboratory in vitro testing of endotracheal tubes.Interventions:Exposure of air-filled endotracheal tube cuffs to xenon or nitrous oxide (79 vol%) mixed with a balance of oxygen (21 vol%) for 3 hours.Measurements:The intra-cuff pressure and gas volume in the cuff were measured for 3 hours.Main Results and Conclusion:Increase in pressure and gas volume was significantly less and slower with xenon than with nitrous oxide. More nitrous oxide passes into the cuff than xenon.