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[Sudden deafness in patients undergoing cardiac surgery with extracorporeal circulation]
J L Cervantes Escárcega1, J López Luciano, F Fernández
1Instituto Nacional de Cardiología Ignacio Chávez, México, D.F.
Insights
Sudden unilateral hearing loss is a rare complication following open heart surgery, affecting 1.8 per 1000 patients. Potential causes include microembolism, reduced cerebral blood flow, or inner ear microhemorrhage.
Area of Science:
- Cardiology
- Otolaryngology
- Neurosurgery
Context:
- Open heart surgery, specifically cardiopulmonary bypass, carries various risks.
- Sudden hearing loss is an uncommon but documented complication post-cardiac surgery.
Purpose:
- To investigate the incidence and characteristics of unilateral sudden hearing loss after cardiopulmonary bypass.
- To explore potential etiological factors linking auditory deficits to surgical procedures and patient conditions.
Summary:
- A retrospective review of 5,975 open heart surgeries identified 11 cases (1.8/1000) of unilateral sudden hearing loss post-cardiopulmonary bypass.
- Auditory assessments included pure tone audiograms, speech reception threshold, discrimination testing, tympanometry, and stapedius reflex testing.
- Possible causes explored were microembolism to cochlear arteries, decreased cerebral blood flow, or inner ear microhemorrhage; ototoxic drug effects were considered unlikely due to unilateral presentation.
Impact:
- Highlights unilateral sudden deafness as a rare, typically benign complication of cardiopulmonary bypass.
- Suggests the need for further research into the pathophysiology of hearing loss associated with cardiac surgery.
- Informs clinical awareness regarding potential auditory complications in patients undergoing open heart procedures.
Abstract:
Between January 1974 and December 1986, 5,975 patients underwent open heart surgery at National Institute of Cardiology "Ignacio Chávez". We reviewed all open heart cases carried out at this Center. Eleven patients (1.8/1000) presented unilateral sudden hearing loss following cardiopulmonary bypass surgery. Pure tone audiograms, speech reception threshold, discrimination testing, tympanometry and stapedius reflex testing were carried out. We then studied the relationship between the auditory deficit and the type of surgical procedure, length of time on the pump, preexisting ear disease, coexistence of diabetes, use of ototoxic drugs and occurrence of hemodynamic complications. There are 3 possible causes for hearing loss in cardiopulmonary bypass: 1) Microembolism from the cardiopulmonary bypass pump to the arteries that supply only the cochlea. 2) Decreasing cerebral flow, or 3) Microhemorrhage of the internal ear. Ototoxic drugs are used frequently, but the hallmark of these drugs is bilateral toxicity, and all the cases under discussion have been unilateral. Unilateral sudden deafness after open heart surgery constitutes another complication, fortunately rare and benign in most cases. Further studies should be undertaken to clarify the pathophysiology of this entity.