Effects of anaesthesia for caesarean section on the computerized EEG of the neonate.

The effects of anaesthetic techniques and drugs on 18 neonates born after elective Caesarean section were studied, employing computerized EEG. Three different groups, epidural, spinal and general anaesthesia, were compared with each other and with a control group after normal vaginal delivery. A new computerized EEG method, Zero Band Power Rate (ZBPR) analysis, was devised for this study and implemented together with conventional spectral EEG estimates of five frequency bands. ZBPR analysis was found to be much more sensitive than conventional spectral analyses for detecting differences between the study groups. Significant differences occurred between the general anaesthesia group and the epidural and control groups and also between the spinal group and the epidural and control groups. No significant difference was seen between the epidural group and the control group. Significant differences were attributed to the clinical use of two drugs: thiopentone in the general anaesthesia group and ephedrine in the spinal group. The effects of these drugs on the neonatal EEG were reflected in decreased ZBPR values, particularly during sleep.