[Gas-diffusion induced pressure kinetics in low pressure cuffs. Continuous pressure measurement in vivo and in vitro (author's transl)].

The main cause for the rise in cuff-pressure during anesthesia is the diffusion of nitrous oxide into the tube cuff. Gas-diffusion induced pressure changes in low pressure-high volume cuffs are registered continuously. Exposure of an air-filled cuff into an anaesthetic gas atmosphere in vitro shows, that there is an increase in cuff-pressure up to 150 mm Hg within 8 hours. This pressure-plateau remains for several hours. In intubated patients cuff-pressure increases even more. During anesthesia lasting 4--5 hours we recorded pressures up to 150 mm Hg, too. To prevent these high pressures we recommend the reducing of cuff-volume within defined times of anesthesia or, alternatively, the use of the anesthetic gas mixture as cuff inflating gas.