An assessment of a method of inflating cuffs with a nitrous oxide gas mixture to prevent an increase in intracuff pressure in five different tracheal tube designs apparatus.

We assessed the efficacy of inflating cuffs with a nitrous oxide gas mixture to minimise changes in intracuff pressure during anaesthesia. Patients were randomly assigned to one of five groups of 15 subjects each, and the trachea was intubated with the Profile Soft-Seal Cuff, Hi-Contour, Reinforced, Sheridan or Trachelon tracheal tubes. Cuffs were inflated with 40% nitrous oxide and cuff pressure was measured during anaesthesia with 67% nitrous oxide. Concentration of nitrous oxide in the cuff was measured at the end of anaesthesia. Cuff pressure increased slightly but significantly in the Reinforced and Trachelon groups. Nitrous oxide concentration in the Reinforced, Sheridan, or Trachelon groups was slightly but significantly higher than that in the Profile or Hi-Contour groups. Cuff pressure never exceeded 22 mmHg and there were no air leaks. Therefore, inflating cuffs with 40% N2O preserves stable cuff pressure in all five tracheal tubes, despite differences in cuff and pilot balloon design.