Effects of Ketamine, Halothane and Enflurane on the Awareness Under N₂O for Cesarean Section

A major problem with general anesthesia for Cesarean section is the incidence of maternal awareness and unpleasant recall occasioned by the use small doses and low concentrations of anesthetics to minimize neonatal effect.

To reduce awareness, various measures have been attempted. The purpose of study is to assess the influence of ketamine, halothane and enflurane on the maternal awareness and neonatal depression under N₂O for Cesarean section. This study group consisted of 48 patients undergoing Cesarean section under general anesthesia.

Anesthesia was induced by thiopental, succinylcholine chloride injected, and maintained until baby delivery with according to divided group.

Group 1: thiopental, 50% N₂0

Group 2: thiopental, 50% N₂O and ketamine(0.25mg/kg)

Group 3: thiopental, 50% N₂O and 0.5% halothane

Group 4: thiopental, 50% N₂0 and 0.6% enflurane

The results were as follows :

1. The incidence of awareness of 50% N₂O group was 66.7%.

2. The incidence of awareness of ketamine, halothane and enflurane group was 8.3%.

3. When induction-delivery time is 8 minutes or less, there was no correlation between induction-delivery time and awareness.

4. There was no neonatal depression.

The use of ketamine, halothane and enflurane appears to be effective in preventing awareness when induction-delivery time is 8 minutes or less.