Investigations on the critical perilymphatic pressure value causing round window membrane rupture in anesthetized cats.

Increasing perilymphatic fluid pressure was found to be an important factor in the etiology of round window membrane rupture. The critical pressure, causing membrane rupture was determined in anesthetized cats. Its value was found to be in the range 10--30 mmHg (x+/-S.E.M.=23.4+/-17.1). This value was compared with the pressure increases caused by thoracic and abdominal compression, cervical strangulation, forced Trendelenburg position, coughing and sneezing.