Vestibular and cochlear ototoxicity of topical antiseptics assessed by evoked potentials.
OBJECTIVE
To evaluate and compare the effect of chlorhexidine gluconate, povidoneiodine, and alcohol-three antiseptics used before ear surgery-on the function of the vestibular and cochlear parts of the sand rat's inner ear. The assessment of damage is based on the recording of vestibular evoked potentials (VsEPs) and auditory brainstem response (ABR).


METHODS
Prospective controlled animal study.


METHODS
Fat sand rats were randomly assigned to five different groups, each receiving topical application of a different agent: saline (control), gentamicin (ototoxic control), chlorhexidine, povidone-iodine, and alcohol. Right-side total labyrinthectomy was performed, and a polyethylene tube was inserted into the left (contralateral) middle ear. After baseline recordings were taken of VsEPs and ABR, each animal received five consecutive daily applications of the specific agent into the left middle ear. Three days after the fifth application, evoked potential recordings (VsEPs and ABRs) were repeated and compared with baseline measurements.


RESULTS
Administration of saline affected neither VsEPs nor ABR. In contrast, as expected, neither of these responses could be recorded after gentamicin application. After application of chlorhexidine all waves disappeared in all sand rats. Alcohol caused the waves to disappear in some of the animals only. Povidone-iodine did not affect VsEP recordings and had only a small effect on ABR.


CONCLUSIONS
Chlorhexidine and alcohol had a clear toxic effect on the vestibular and cochlear function of the inner ear of the sand rat, whereas povidone-iodine did not. Thus, taking into consideration that this is an animal study, it appears that povidone-iodine might be preferable to the other agents tested in disinfecting ears with a perforated tympanic membrane.
Perez
R
R
Department of Otolaryngology and Head and Neck Surgery, Shaare Zedek Medical Center, Hadassah University Hospital, Jerusalem, Israel.
Freeman
S
S
Sohmer
H
H
Sichel
J Y
JY
D000287:Administration, Topical; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects*; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000009:adverse effects*; D002710:Chlorhexidine / Q000008:administration & dosage / Q000009:adverse effects*; D003051:Cochlea / Q000187:drug effects* / Q000503:physiopathology; D000431:Ethanol / Q000008:administration & dosage / Q000009:adverse effects*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005839:Gentamicins / Q000008:administration & dosage / Q000009:adverse effects*; D005849:Gerbillinae; D011446:Prospective Studies; D011897:Random Allocation; D051381:Rats; D013997:Time Factors; D014722:Vestibule, Labyrinth / Q000187:drug effects* / Q000503:physiopathology
D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local; D005839:Gentamicins; D000431:Ethanol; D002710:Chlorhexidine