Ketamine anaesthesia for electrocochleography in children. Are psychic side effects really rare?

Retrospectively, we have studied the occurrence of psychic side effects in 121 children (median age 2.25 years) who have had ketamine anaesthesia for electrocochleography. For comparison, the same questionnaire was given to 66 children who had had ketamine for the surgery of squints. Early signs of psychic disturbance ( < 3 days) were equally frequent in the two groups, whereas late ( > 3 days) nightmare was most common in the patients undergoing cochleography (17% vs 5%). In several cases, signs of nightmare were reported by the parents to have lasted for months or even years. There was a significant (p = 0.00019) correlation between the occurrence of nightmare and the degree of hearing impairment. The frequency of late nightmare reported in the cochleography patients is unacceptably high, but as numerous possibilities of bias exist further investigations are necessary before conclusions can be safely drawn.