Changes in hearing during extracorporeal cardiopulmonary bypass

ABSTRACT

Sudden sensory-neural hearing loss has been reported after the use of the extracorporeal cardiopulmonary bypass apparatus. This study was conducted on 50 patients who underwent surgery requiring the use of apparatus. Preoperative, postoperative and long term follow-up audiologic assessments were performed together with recording of all possible contributing factors such as the bypass time, aortic clamp time, peri and postoperative medications in an attempt to cover all possible aspects of this problem. A bilateral 10 dB increase of threshold including most frequencies occurred in only 4 patients. Although an embolic etiology has been suggested in most previously published reports, doubt is cast on this causation which is discussed in detail. The very mild bilateral hearing loss in our series can. be explained more likely on the basis of perfusion failure theory in addition to the possibility of ototoxicity