Eustachian tube function in the ferret

The role of viral upper respiratory tract infections (URI) in the pathogenesis of otitis media (OM) may be related to Eustachian tube (ET) dysfunction. Preliminary experimental evidence suggests that the ferret may be an appropriate animal for modeling of pathophysiologic process related to URI's and ET dysfunction. In an effort to determine the applicability of this animal model, normal ET function was evaluated in 10 ferrets using the inflation-deflation and forced-response testing protocols. The results indicate that the ET of the ferret functions as a small-scale version of its rhesus monkey and human couterparts. The ET-middle ear (ME) system could maintain applied positive and negative ME pressures in all instances. Nearly complete swallow-induced pressure equilibrations were demonstrated in all ears tested. Elevated passive function parameters suggested a small tubal lumen. The efficiency of the tubal dilatory mechanism as expressed by the normalizing calculation (R_O/R_A) was shown to be quite similar to that in primates and man. These finindings suggest that the ferret's ET functions in a manner similar to humans and is, therefore, an appropriate animal to study the pathogenesis of otitis media in the context of ET dysfunction.