Evaluation of ear function after cardiopulmonary bypass with otoacoustic emissions: A pilot study

Objectives: During extracor- poreal circulation (ECC) there is a great hemody- namic stress with possible impact on the micro- circulation, including cochlear one. Previous studies have evaluated the effect of ECC on in- ner ear with contrasting results. The aim of this study is to evaluate possible modifications of the outer hair cells (OHC) function after open heart surgery (OHS) under ECC with transient evoked (TEOAEs) and distortion product otoa- coustic emissions (DPOAEs). Methods: Ten patients (5 F and 5 M), under- going OHS with ECC, were subjected to an audi- ological assessment pre- and postoperatively. We compared the pre-operative and post-opera- tive mean auditory thresholds, mean TEOAEs re- producibility and amplitude, and mean DPOAEs amplitude. Student's t-test was used to compare different values. Results: No significant differences were found between pre- and post-operative audiolog- ical assessment both in hearing level and in otoacoustic emissions. Conclusion: OHC function seems to be not affected by hemodynamic stress induced by ECC. Further studies on a larger scale will be necessary to confirm our preliminary data.