The oxygen tension in transudate of the middle ear

The pO2 of transudate in the middle ear was measured in situ by a small pO2-electrode introduced through the tympanic membrane. Errors involved in some previous methods using aspiration of gas from the middle ear were avoided by the present method since contamination by air from outside of the drum was almost completely eliminated. Seventeen patients, of whom the majority had a naso-pharyngeal carcinoma or chronic otosalpingitis, were investigated. The mean pO2 of the middle ear transudate was 46 mmHg or 6.5% with a pO2 range between 10 and 108 mmHg. Investigations of the function of the Eustachian tube by the aspiration-deflation method after application of a transmyringeal tube was performed in 10 of the patients, revealing no passage through the Eustachian tube. Among these 10 patients only 4 had a passage of air on Politzer, and these had a higher pO2 in the middle ear transudate than the remaining 6 patients in whom Politzer was performed with a negative result.