Hydrogen peroxide ototoxicity in unblocking ventilation tubes: A chinchilla pilot study

Objective: Some clinicians use hydrogen peroxide (H₂O₂) to clear the lumen of ventilation tubes that become blocked postoperatively. The ototoxicity associated with H₂O₂ has been controversial. Study design: We designed an experiment to test if H₂O₂ damages the cochlear hair cells using a Chinchilla laniger animal model. Methods: Nine chinchillas (18 ears) were included in this study. Each animal was used as its own control. Following the insertion of ventilation tubes in both ears and baseline recordings of the auditory brain stem responses (ABR), we instilled 2 ml of 3 percent H₂O₂ into their right external auditory canals (experimental ears). H₂O₂ was left in the external auditory canal for a total of 5 minutes and then was drained. We instilled a normal saline control solution in their left ears (control ears) in a similar fashion. ABR recordings were performed 1 day after the last instillation of H₂O₂ and 5 days later. Results: There was no statistically significant difference in the ABR thresholds of the experimental and control ears. Conclusion: H₂O₂ did not appear to cause ototoxicity in chinchilla ears with tympanostomy tubes exposed to H₂O₂ instillation using a standard clinical protocol.