Retention of auditory information presented during anaesthesia. A study of children who received light general anaesthesia.

Surgical procedures that involve a local anaesthetic block are often accompanied by light general anaesthesia. It is possible that under these circumstances, the patients are more likely to register auditory events while apparently unconscious. Two groups of children were exposed to auditory stimuli during surgery; one group received a lighter level of anaesthesia than the other. Retention of the stimuli was tested using a cued recall technique, and the performance of the two experimental groups was compared with a control group which had not been exposed to the material but was tested in the same way. The light anaesthesia group retained more items than did the other two groups but this difference was significant (p less than 0.05) only when compared with the other experimental group. This is not very strong evidence of auditory registration, but a greater effect might be found with exposure to emotionally significant material. It is suggested that patients should be protected from unfortunate theatre conversation.