Unanticipated ventilation obstruction due to a defective reinforced endotracheal tube.

Wire-reinforced endotracheal tubes are used to prevent obstruction. Risk factors related to reinforced endotracheal tube obstruction were believed to be repeatedly used tube and in presence of N2O. In our case, even in free of these risk factors, a delayed tube obstruction occurred with the progress of surgical duration. This delay suggests that the obstruction was caused by diffusion of warm air/oxygen into an initially small defect, especially as the duration of surgery progresses.