[Effect on fetal umbilical arterial blood of administration of vasopressors for hypotension after spinal anesthesia during cesarean section].

Spinal anesthesia was performed in 40 patients undergoing cesarean section. When systolic blood pressure dropped below 100 mmHg, phenylephrine 100-200 microg (P group) or ephedrine 5-10 mg (E group) was administered. The pH of the umbilical arterial blood was collected after delivery of the baby. Apgar scores, and maternal systolic blood pressure and heart rate before and after each drug administration were compared retrospectively. The umbilical arterial pH and Apgar scores tended to be slightly higher in the P group, but there was no significant difference between the two groups. The rate of blood pressure elevation was 27% in the P group and 41% in the E group. The heart rate decreased significantly in the P group. There was no significant difference in the systolic blood pressure before administration of each drug. Recently, it is reported that the umbilical arterial pH is higher in cases in which phenylephrine is used for hypotension after spinal anesthesia during a cesarean section. However, the optimal dose of phenylephrine is debatable and has not been established. More studies are necessary to determine which drugs should be selected according to the maternal condition.