[Clinical studies on the use of ketalar in obstetric anesthesia (author's transl)]

26 healthy pregnant women at term were divided into 2 groups and anaesthetized with either 1 mg/kh or 2 mg/kg ketamine - N20/02 - for primary caesarean section. Maternal venous ketamine plasma levels, neonatal ketamine plasma levels (umbilical artery and umbilical vein) and blood gases were measured. Maternal venous ketamine plasma levels in group I exceeded those in group II by 2.8 (30-60 sec after injection) and 2.0 (at the time of delivery) respectively. Independent of the dose used, the plasma levels of ketamine in the umbilical artery or the umbilical vein were found to be identical in the two groups of newborn infants. Neonatal blood gases and acid base parameters did not significantly differ between the two groups, except for the oxygen tension in group II which slightly exceeded the PO2 values in group I 15, 60 and 120 min after delivery. pH and standard bicarbonate values were found to be higher (1 and 5 min) in both groups, compared to pH and standard bicarbonate levels in a group of newborns delivered spontaneously.--The results of this study show: 1. Independent of a low or high ketamine dosage, neonatal blood concentration of the drug remain low, probably due to a placental barrier effect.--2. The post partum recovery of the newborns was neither influenced by the ketamine anesthesia itself nor by different drug doses.