Tracheostomy and endotracheal tube cuff volume and pressure changes during thoracic operations.

The effects of oxygen and 60% nitrous oxide and oxygen on the pressure and volume of Portex low-pressure (LP) and high-pressure (HP) endotracheal tube cuffs were determined in 120 intubated patients undergoing thoracic surgical procedures. Cuffs were filled with either room air or a sample of the inspired gases. All cuffs had sustained significant increases in cuff volume and pressure by the end of the procedure except those filled with inspired gases. LP cuffs had lower initial and final cuff pressures than HP cuffs, but pressure and volume changes were similar with both types. Cuff gas analysis revealed that cuff volume changes were due to diffusion of oxygen and nitrous oxide into the cuff and failure of nitrogen to diffuse out. These findings suggest that cuff overexpansion during anesthesia or prolonged ventilation may be an important cause of tracheal trauma.