Postanesthesia Deafness in Cats & Dogs

Incidence and prevalence of acquired deafness in dogs and cats after an anesthetic procedure have not been established. However, this condition is believed to exist according to client communication with veterinarians. This study investigated the prevalence of clinical deafness in animals after dental or ear-cleaning procedures or other use of general anesthesia. Thirty-nine cases of bilateral hearing loss were identified after a dental procedure or other procedure; other cases were identified via a survey. Although the study did not investigate the details of hearing loss, it is possible that deafness resulted from edema or fluid in the ear canal or middle ear. Five animals were discharged with ear ointment containing gentamicin or neomycin after an ear procedure; ototoxicity of these products could also have been implicated as a cause of deafness. Other proposed potential causes of deafness included anoxia or mechanical disruption of the blood supply to the middle ear.

Commentary: This study provided some empirical data that support anecdotal reports of postanesthetic deafness. The sample size in this study was small; however, because unilateral deafness would require the use of brainstem auditory evoked response (BAER) testing for confirmation, the incidence of hearing loss following a procedure might be higher. Further studies should include postprocedural BAER testing for ear cleanings and dental procedures performed under general anesthesia.

Post-anesthesia deafness in dogs and cats following dental and ear cleaning procedures. Stevens-Sparks CK, Strain GM. VET ANAESTH ANALG 37:347-351, 2010.