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Chlorhexidine ototoxicity in ear surgery, part 1: review of the literature.

OBJECTIVE
Chlorhexidine is a common antiseptic used to prevent surgical infection. However, its exposure to the middle ear may lead to deafness. The mechanisms of the ototoxicity of chlorhexidine are reviewed. The importance of recognizing its toxicity cannot be overstated in preventing injury to patients undergoing ear surgery.


METHODS
A systematic literature search was performed looking at data from human and animal studies. Search engines included MEDLINE, EMBASE, The Cochrane Library, CENTRAL, CINAHL, and Web of Science to November 1, 2010, for relevant studies published in all languages. Two independent reviewers (P.L. and D.D.P.) screened the references from published articles for additional relevant studies. Medical Subject Headings and key words including intervention (chlorhexidine, antiseptic), exposure (myringoplasty, intratympanic), and adverse effects (sensorineural hearing loss, ototoxicity, vestibular toxicity) were used.


RESULTS
Twelve studies were identified, two of which were non-English and were excluded. Only 2 articles on human subjects and 12 articles on animal models concerning chlorhexidine ototoxicity were identified.


CONCLUSIONS
Chlorhexidine in both human studies and animal models demonstrates ototoxicity if it reaches the inner ear. The toxicity of chlorhexidine appears to be related to its concentration and probable contact time with the round window membrane intraoperatively. It is conceivable that the incidence of chlorhexidine toxicity may be higher than stated if unrecognized or has resulted in subsequent medicolegal actions. From the evidence available, safer preparation solutions are available without clinical risks for ototoxicity should surgeons continue with this practice.