Sharp transients in the EEGs of non-epileptic adult patients receiving sevoflurane.

[OBJECTIVE] In this article unexpected EEG findings are described which were observed during EEG monitoring under sevoflurane anesthesia.

[METHOD] In seven non-epileptic adult patients sevoflurane was administered as inhalation anesthetic during routinely performed surgical operations. The EEG was recorded continuously as part of the standard monitoring process and served mainly as a dosage guide for anesthetics/narcotics.

[MAIN OUTCOME MEASURE] Occurrence of sharp transients in the EEG resembling distinctive waves which can be seen in epileptic disorders.

[RESULTS] In six of the seven patients under 8.0% sevoflurane, sharp transients were observed which appeared in very deep EEG stages, mostly with endtidal sevoflurane concentrations of 4.8-5.9%. The findings are in accordance with observations in non-epileptic children from our clinic.

[CONCLUSIONS] The clinical significance of the observed EEG pattern under sevoflurane anesthesia is still unclear. Taking into consideration that convulsive and nonconvulsive status epilepticus can be followed by signs of brain damage, it would appear to be important to further investigate the phenomenon.