To evaluate the relationship between nasal obstruction and otitis media, 10
ferrets were studied before and after either unilateral (n = 5) or bilater
al (n = 5) nasal obstruction. Observations included otomicroscopic assessme
nts of middle ear status, tympanometric recordings of middle ear pressure a
nd forced-response, inflation-deflation and continuous monitoring tests of
Eustachian tube function. During the 6-8 week post-obstruction follow-up pe
riod no animal developed evidence of otitis media. Abnormal positive middle
ear pressures lasting for the period of follow-up occurred only in the ani
mals with bilateral nasal obstruction. Eustachian tube function test result
s showed these pressures to be generated during swallowing. No changes in t
he passive function of the tube were documented in either group, but change
s in active function consistent with alterations in the pressure gradient b
etween the middle ear and the nasopharynx were observed in both groups.