Changes in middle ear pressure in daily life.

The present study was performed to estimate changes of middle ear pressure (ME-P) during actions of daily life such as nose blowing and sniffing. ME-P was measured in 18 patients with perforation of the eardrum. They were asked to perform actions which included nose blowing and sniffing. Eustachian catheterization and politzerization were also applied. Change of ME-P before and after these actions was recorded using a pressure monitor. Results showed that changes of ME-P after nose blowing with both nostrils closed were large and rapid. The mean value of ME-P after nose blowing was 252 mmH2O. In our previous study, the mean value of cerebrospinal fluid pressure (CSF-P) after nose blowing was 388 mmH2O. Therefore, the pressure gradient across the cochlear windows is about 130 mmH2O during nose blowing. The cochlear windows may have been pressed toward the middle ear side. After sniffing, ME-P was unchanged. These results suggest that nose blowing may be an important cause of perilymphatic fistula (PLF) via the "explosive route", while sniffing is not likely to cause PLF.