Hearing loss after cardiopulmonary bypass surgery.

Hearing loss (HL) is a rare complication following cardiac surgery with extracorporal circulation (CSWEC) or other non-otologic surgery under general anesthesia, as is HL caused by loss of cerebrospinal fluid during neurosurgery or spinal anesthesia. The incidence of HL after CSWEC is not known since preoperative hearing testing is not commonly done and a perioperative HL may occur unnoticed. We present four cases of profound sensorineural hearing loss following CSWEC for coronary artery bypass or cardiac valve surgery. The hearing loss was noticed immediately on waking from anesthesia in three of the patients, whereas the fourth patient noticed decreased hearing during the first postoperative week. In all patients audiological investigation suggested a cochlear etiology of the HL. The possible mechanisms for HL are discussed. HL after CSWEC is most likely caused by a microembolism generated by atheromatous material.