povidone-iodine and Hearing-Loss

Povidone-Iodine preparation is used as a disinfectant in otological surgeries. The ototoxicity of Povidone-Iodine preparation was evaluated using infant, young and adult guinea pigs. The effects of different concentrations and of different exposure durations on compound action potentials were also studied.. Povidone-Iodine was used to fill one middle ear cavity of the guinea pig, and the compound action potential (CAP) was measured from the round window membrane at 24h, 7 days, and 28 days. The contralateral side was filled with saline as control. Test sounds used were clicks and tone bursts of 2, 4, and 8 kHz.. At 24h, Povidone-Iodine solution showed a significant toxic effect in the infant group. In the young animal group, no toxic effect was seen. In the adult group, a mild degree of deafness for 2 kHz was found. At 7 days, the young group showed significant hearing loss for all frequencies, but the adult group did not show any hearing loss. With a half strength solution, both young and adult group did not show hearing loss. At 28 days, with a full strength solution, hearing loss became prominent for all sound stimulation. With 1/8th dilution, the young group showed a moderate hearing loss, but the adult group did not.. The thicker round window membrane in human is expected to provide more protection to the human cochlea than in the guinea pig model that we have studied. Mild hearing loss at 24h and 7 days using 10% solution, but no hearing loss with 5% solution at 7 days may indicate that rinsing of the middle ear cavity with saline during surgery should minimize the ototoxic effect of this product. The age of the animals does influence the outcome of the ototoxicity experiment. From this experiment, Povidone-Iodine preparations in the infant should be used with caution. Povidone scrub should not be used for otologic surgery.

Topics: Administration, Topical; Age Factors; Animals; Animals, Newborn; Anti-Infective Agents, Local; Deafness; Disease Models, Animal; Ear, Middle; Guinea Pigs; Hearing Loss; Hearing Tests; Incidence; Povidone-Iodine; Random Allocation; Reference Values; Risk Assessment

The ototoxic effect of povidone-iodine antiseptics topically applied to the chinchilla round window was examined with particular emphasis on the action potential (AP) input-output function at 2 and 4 kHz. A group of chinchillas exhibited a marked elevation of AP threshold at 8 and 12 kHz, with only a slight threshold elevation at 2 and 4 kHz. A distinct decruitment (less than normal growth of response with increasing sound intensity) of the AP input-output function was, however, found at the lower frequencies. There are implications of an ototoxically induced high-frequency hearing loss on speech frequencies.

Topics: Action Potentials; Animals; Chinchilla; Cochlea; Electrophysiology; Hearing Loss; Hearing Loss, High-Frequency; Hyperacusis; Povidone; Povidone-Iodine; Round Window, Ear