Deafness post-GA

[Michael de Sousa]

Our department has had 2 reported instances (reported to our Morbidity and Mortality Review Committee) of sensori-neural deafness following general anesthesia. Both patients were otherwise well, having 1-2 hour procedures (peripheral limb surgery for one, and laparotomy for the other) with no hearing loss pre-op. They reported partial deafness both worse in one ear than the other. referal to ENT  - opinion was sensori-neural deafness (not simple conductive) of fairly high grade in one ear in each patient. So far, each has lasted 6 weeks with no signs of resolution.

Has anybody else come across this?

[Michael de Sousa]

I should add that no aminoglycosides were used on either patient.

[George Miklos]

Conductive deafness is common - probably much more common than we realise. Pressure changes within the middle ear due to nitrous oxide or simple auditory tube obstruction secondary to swelling are thought to be the cause. Usually mild and usually temporary.

A sensorineural deafness is a different kettle of cod.

Drugs are the most common cause: aminoglycazides and frusemide are most common and cytotoxic agents are also implicated.

Barotrauma can also cause sensorineural deafness. It is well-known is divers that a rapid ascent can cause bubbles of nitrogen in the cochlea, which can cause sensory deafness. Was nitrous oxide used in these cases? It is possible that an insignificant gas bubble within the inner ear could expand when nitrous is used and may cause deafness.

Ischemic injury has been shown to cause sensory deafness. Were either of these patients hypoxic or hypotensive at any time?

These are theoretical observations only. Otherwise I am at a loss.  ???