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

OBJECTIVE: Some clinicians use hydrogen pet-oxide (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. (C) 2007 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.