Middle ear pressure during and after prolonged nasotracheal and/or nasogastric intubation.

Changes in middle ear pressure during and after prolonged nasotracheal and/or nasogastric intubation were studied in 47 patients who had been intubated, for various reasons, during 1-24 days. All the patients had a negative middle ear pressure; in 84% of the ears the pressure was -200 mm of water or less. In most ears the pressure fell rapidly after the intubation, being most negative before extubation and during the first 2 days after. In all patients who could be followed the pressure returned to normal. The normalization was slow, depending upon the duration in intubation. Possible causes, such as abolished ventilation of the rhinopharynx, insufficient swallowing, mechanical occlusion of the tubal orifice, and the influence of anaesthetic gases are discussed. During the period after extubation the most probable cause is irritative and inflammatory reaction of the mucosa, leading to internal tubal occlusion.