[The maternal and fetal acid-base status during general or spinal anesthesia for elective cesarean section in the left tilt position].

Thirty one healthy parturients received spinal or general anesthesia for elective cesarean section. Maternal blood pressures, maternal and fetal acid-base values, induction to delivery intervals (I-DI) and Apgar scores were determined. On spinal anesthesia, acute hydration by 6% hydroxyethyl starch solution and intramuscular injection of ephedrine were enforced prior to the block and in the left tilt position (17 degrees) oxygen inhalation immediately after the block was begun (group OII: 16 cases). As to general anesthesia, the same left tilt position was applied before the anesthesia by thiopental-0.5% halothane with-50% nitrous oxide in oxygen (group G: 15 cases). No significant decrease in maternal blood pressure was noticed, and maternal and the fetal acid-base status and Apgar scores were excellent in both groups. A positive correlation between umbilical venous pH values and 1 or 5 minutes Apgar scores was confirmed in group OII, and a negative correlation between 1 minute Apgar scores and I-DI was noticed in group G. Fetal acid-base values were not correlated with I-DI in either group, and it was postulated that placental or fetal circulation was sufficiently maintained. Biochemical status and clinical conditions in mothers and their infants are very favorable in well-conducted general or spinal anesthesia for elective cesarean section.