Vestibular and Cochlear Ototoxicity of Topical Antiseptics Assessed by Evoked Potentials

Abstract

Objectives/Hypothesis: 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). Study Design: 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.

Ototoxicity of Different Concentrations Povidone-Iodine Solution Applied to the Middle Ear Cavity of Rats

“…Morizono and Sikora [17], studied the ototoxicity of povidone-iodine preparations in chinchilla, and found reduction in compound action potential at 120 min after middle ear application. Perez et al [8], studied povidone-iodine in rats and studied changes in both vestibular evoked potentials and auditory brainstem responses. They found no apparent changes in either the vestibular evoked potentials or auditory brainstem responses with applications of 5 consecutive days.…”

“…The resulting distortion product otoacoustic emissions were evaluated at 1.5, 2, 3, 4, 5, 6, 7, 8, 10 and 12 kHz. Statistically significant reductions in DP-gram amplitudes were noted at high frequencies (7,8,10, 12 kHz) in the group A at day 1 but this effect return at day 10. In group B and group C statistically significant differences were recorded for low and high frequencies (1.5,2,7,8,10, 12 kHz) according to the control group at day 1 and 10.…”

“…The suspicion arose as a result of reported sensorineural hearing losses following myringoplasty procedures when antiseptic chlorhexidine gluconate were used before surgery [7]. During the past 30 years, relatively little study has been directed to the potential ototoxicity of these commonly used agents [8].…”

Ototoxic effect of topical rifamycin SV applied in the middle ear of rats

“…[11,14] While the application of antiseptics chlorhexidine and alcohol (70%) to the middle ear showed vestibulotoxic and cochleotoxic effects in rats, they were not observed in povidone-iodine, and the results obtained from the control agent, saline, were similar. [15] While ototoxic effects were observed for Burow's solution (aluminum acetate of approximately 13% with a pH of 3.7), ear drops containing acetic acid and boric acid solutions prepared with 70% alcohol, they were not observed for boric acid solutions prepared with distilled water. [12,16,17] In addition, although ototoxic effects were observed during the topical application of antibiotics such as aminoglycosids, [18] chloramphenicol, [19] polymyxin B, [20] vancomycin, [21] and daptomycine, [22] they were not observed for the topical application of antibiotics such as ciprofloxacin, [23] ofloxacin, [24] mupirocine, [21] and vasocidine.…”

Case report: Epidural abscess in a parturient with pruritic urticarial papules and plaques of pregnancy (PUPPP)

“…This concentration difference may prove relevant to both concerns of efficacy and possible toxicity of CHG. There are only limited clinical data regarding the neurotoxicity of CHG. Two animal studies demonstrated both ototoxicity 13 and ocular toxicity 14 when applied directly to the target organs. No study, however, has addressed the potential toxicity of CHG used for skin preparation prior to neuraxial procedures.…”