A prospective study was done to determine changes in hearing which might be related to microembolism occurring during perfusion by the extracorporeal cardiopulmonary bypass apparatus. In the 50 patients examined both preoperatively and postoperatively no significant change in hearing was documented which could be attributed to microembolism.
Brownson RJ, Stroud MH, Carver WF. Extracorporeal Cardiopulmonary Bypass and Hearing. Arch Otolaryngol. 1971;93(2):179–182. doi:10.1001/archotol.1971.00770060265012