Table of Contents
ISRN Otolaryngology
Volume 2013, Article ID 453920, 5 pages
http://dx.doi.org/10.1155/2013/453920
Research Article

Effects of Cardiopulmonary Bypass Surgery on Auditory Function: A Preliminary Study

1Speech and Hearing Unit, ENT Department, New OPD, Postgraduate Institute of Medical Education & Research, 4th floor, Chandigarh 160012, India
2Department of Otolaryngology, Postgraduate Institute of Medical Education & Research, Chandigarh 160012, India
3Department of Cardiothoracic and Vascular Surgery, Postgraduate Institute of Medical Education & Research, Chandigarh 160012, India

Received 6 June 2013; Accepted 31 July 2013

Academic Editors: M. V. Kirtane, K. Parham, M. Sone, and S. C. Winter

Copyright © 2013 Sanjay Kumar Munjal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Hearing loss has been reported as a complication following cardiac surgery with extracorporeal circulation. Preoperative hearing testing is not commonly done in these procedures, so preoperative and postoperative hearing loss, if any, may occur unnoticed. 30 subjects in the age range of 50–70 with a mean age of 60.16 years with myocardial infarction and scheduled to undergo cardiopulmonary bypass surgery underwent detailed audiological assessment comprising of pure tone audiometry with extended high frequency audiometry, speech audiometry and otoacoustic emissions (OAE) testing. The audiological testing was done preoperatively and at 2 weeks after the surgery. On pure tone audiometry, the difference between pre- and postsurgery mean values for both ears at 10, 12, and 16 KHz showed highly significant differences ( ). On OAE testing, a significant difference ( ) between pre- and postvalues of signal to noise ratio (SNR) was found. It is hypothesised that CPB surgery makes blood redistribution to other organs easy, deviating from internal ear, which is highly susceptible as it lacks collateral circulation and its cells have high energy metabolism. Epithelial damage on internal ear microcirculation causes reduction of the cochlear potentials and hence hearing loss.