A randomized comparison between midazolam and thiopental for elective cesarean section anesthesia: III. Placental transfer and elimination in neonates.

Forty neonates delivered by cesarean section were studied, half being delivered of mothers in whom anesthesia was induced with midazolam (0.3 mg/kg intravenously) and half of mothers given thiopental (4 mg/kg). At delivery, blood samples from mother and the umbilical vein were drawn for determination of plasma concentrations of thiopental, midazolam, and alpha-hydroxymidazolam. Over the next 60 hours, three blood samples were drawn using a randomized procedure of two blood samples at 30 different times. Placental transfer, expressed as the umbilical/maternal concentration ratio, was 0.96, 0.66, and 0.28, respectively, for thiopental, midazolam, and alpha-hydroxymidazolam. The transfer of thiopental was significantly more rapid than the transfer of midazolam and alpha-hydroxymidazolam. The population average of elimination half-life in neonates was 6.3 hours for midazolam and 14.7 hours for thiopental. Both values are substantially larger than those found in previous studies in adults.

RCT Entities:   Population Interventions Outcomes