[EEG and bispectral analysis during inhalational anesthesia in children]

Bispectral index (BIS) is a parameter of the depth of anesthesia, but the use of it in children remains discussable. The study was carried out to compare EEG and BIS considering the age of patients during anesthesia with halotane, sevoflurane and consequent combination of sevoflurane and isoflurane. 60 children 3 to 17 years of age, who underwent urological surgeries, were divided into 3 groups (20 patients in each): 1st--halothane group, 2nd--sevoflurane group and 3rd--consequent combination of sevodlurane and isoflurane group. The oxygen: nitrous oxide 1:1 mixture was used in all the mentioned groups. EEG recording (6 channel computerised encephalograph) and BIS monitoring (XP version) was carried out through the whole duration of anesthesia. In the 1st group the gradual reduction of main rhythm was registered on EEG, with slow activity and restoration during awakening. The BIS index values changed from 95-98 to 39-47 with rise to 77-85 during awakening. In the 2nd and 3rd group where sevoflurane was used for anesthesia induction sharpened alpha rhythms, amplitude enlargement and rhythm synchronization were registered on EEG. BIS values changed from 96-99 to 13-38. During the maintenance of anesthesia in the 2nd group BIS values were 30-40 and 72-77 during awakening. In the stage of isoflurane anesthesia in the 3rd group EEG pattern changed towards the rhythm synchronization and slow oscillations in all the leads. The BIS index was 30-39 during maintenance and 70-76 during awakening. The parameters of EEG and BIS in all the investigated groups were proportional to the clinical stage and depth of anesthesia. Based on the clinical data and its comparison to EEG and BIS values it is determined that BIS index can be used for monitoring depth of anesthesia in children.