The BIS Change and Neonatal Effect during General Anesthesia for a Cesarean Section / 대한마취과학회지

ABSTRACT

BACKGROUND: The problem of psychological complications (trauma) by intraoperative awareness is a well discussed issue recently. The bispectral index (BIS) is reported to be closely related to the sedation and consciousness of anesthetics. This study was to observe the effects of ketamine injection and enflurane inhalation on the BIS, Apgar score of the neonate and blood gas analysis of umbilical cord artery and vein with general anesthesia for a Cesarean section. METHODS: The subjects of the study were 30 pregnant women who received a Cesarean section with general anesthesia. Before the delivery enflurane 1.0% inhalation group (group 1, n = 10), ketamine 20 mg injected group (group 2) and both ketamine 20 mg injected and enflurane 1.0% inhalation group (group 3) were assessed by BIS, blood pressure, heart rate, induction-delivery time, Apgar score of the neonate at 1, 5 minutes and blood gas analysis of the umbilical artery and vein. RESULTS: The BIS of all groups was over 70 after tracheal intubation and the ketamine injected group (group 2) was higher than the enflurane inhalation group (group 1) from 2 minutes after tracheal intubation. The BIS of the both ketamine 20 mg injected and enflurane 1.0% inhalation group (group 3) was lower than the ketamine injected group (group 2), 4 minutes after tracheal intubation. The Apgar score of neonates and blood gas analysis of the umbilical cord artery and vein had no significant differences between these groups. CONCLUSIONS: In the anesthetics injected before delivery in a cesarean section under general anesthetics, a small dose of ketamine can increase the BIS while a small dose of ketamine with 1.0% enflurane inhalation decreases the BIS, but in all groups the BIS was over 70 which can cause intraoperative awareness. Thus to avoid this problem, more studies are needed on the methods of anesthesia and multifactorial approaches to increase the utility of BIS monitoring.