Systematic review of ototoxic pre-surgical antiseptic preparations – what is the evidence?

Abstract

ObjectiveThere is uncertainty regarding the safety of surgical antiseptic preparations in the ear. A systematic review of the literature was conducted to assess the evidence regarding ototoxicity of surgical antiseptic preparations.MethodsA literature search was conducted using the PRISMA methods. Key words included “ototoxicity” “hearing loss”, “antiseptic”, “surgical preparation”, “tympanoplasty”, “vestibular dysfunction”, “chlorhexidine”, “iodine”, “povidone”, “ethanol”, and “hydrogen peroxide” using Medline, Embase, Cochrane Library, Scopus and Web of Science. We included peer-reviewed papers that 1) objectively measured ototoxicity in humans or animals through hearing, vestibular function or histologic examination, 2) studied topically applied surgical antiseptic preparations, 3) were either in English or had an English abstract. We excluded papers that were 1) in vitro studies, 2) ear trauma studies, 3) studies of ototoxic ear drops intended for therapy, or 4) case reports. Studies included in the final review were screened using the PRISMA method.Current systematic review registration number pending: 83,675.ResultsFifty-six papers were identified as using PRISMA criteria. After applying our exclusion criteria, 13 papers met overall study criteria. Of these, six papers reported ototoxicity of iodine based solutions, five papers reported ototoxicity of chlorhexidine and ethanol and two papers assessed hydrogen peroxide. All papers reviewed were animal studies. Iodine based solutions show least harm overall, while chlorhexidine and high concentrations of alcohol based solutions showed most harm. The evidence on hydrogen based solutions was inconclusive.ConclusionsThe overall evidence for anyone antiseptic solution is weak. There is some evidence that iodine, chlorhexidine, hydrogen peroxide and alcohol based antiseptics have ototoxicity. Conclusive evidence for human ototoxicity from any solution is not strong.

Drug‐Induced Ototoxicity: A Comprehensive Review and Reference Guide

“…Although the evidence for ototoxicity is weak, it is largely accepted that iodine and non-alcohol-based and nondetergent solutions are the safest to use before ear surgery. 53 Two recent Cochrane database reviews studied the efficacy of topical antiseptic in the treatment of chronic suppurative otitis media. 54,55 The studies evaluated boric acid, acetic acid, aluminum acetate, and povidone iodine.…”

“…Chlorhexidine, povidone‐iodine, and alcohol are commonly used presurgical antiseptics. Although the evidence for ototoxicity is weak, it is largely accepted that iodine and non–alcohol‐based and nondetergent solutions are the safest to use before ear surgery 53 . Two recent Cochrane database reviews studied the efficacy of topical antiseptic in the treatment of chronic suppurative otitis media 54, 55 .…”

Topical preparations to reduce SARS‐CoV‐2 aerosolization in head and neck mucosal surgery

“…Other studies have examined the effect of PVP‐I in varying concentrations from 0.5% to 5% on the sinonasal mucosa without detrimental effect to the nasal epithelium; however, one recent in vitro study found that iodine preparations of 5% to 10% demonstrated ciliotoxicity 27‐30 . Fortunately, PVP‐I also exhibits the least ototoxicity of topical preparation solutions and is safe to use as an ophthalmic preparation agent (1%‐5%), which is relevant to head and neck procedure that involves or exposes the skull base otologic or orbital apparatuses 31,32 . Unlike alcohol‐based preparations, it is not flammable which is relevant when using electrocautery in the airway 33…”

“…In isolation, chlorhexidine has been found to be less effective against coronaviruses than PVP‐I in both in vitro studies and studies of disinfection of inanimate surfaces 15,39 . Overall, there are limited data demonstrating the activity of chlorhexidine against coronaviruses and it is also associated with high levels of ototoxicity and can be flammable when utilized in commercial preparations that commonly include alcohol 31,33 …”

Efficacy of common reagents for killing ticks in the ear canal

“…Furthermore, ethanol has been shown to cause erythema and mild edema in the mucosa of the middle ear cavities of sand rats treated with 70% ethanol as antiseptic, while 90% to 95% isopropyl alcohol used as a prophylaxis for otitis externa dries the ear canal, and can cause stinging and local irritation . Both ethanol and isopropyl alcohol have the potential for ototoxicity . Again, due to potential perforation of the tympanic membrane by the tick bite, the ototoxicity of these reagents must be weighed against their benefits.…”