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.
Bach
V
V
Department of Anesthesiology, Esbjerg Central Hospital, Denmark.
Carl
P
P
Ravlo
O
O
Crawford
M E
ME
Jensen
A G
AG
Mikkelsen
B O
BO
Crevoisier
C
C
Heizmann
P
P
Fattinger
K
K
D000773:Anesthesia, Obstetrical / Q000379:methods*; D002585:Cesarean Section; D005260:Female; D006207:Half-Life; D006801:Humans; D007231:Infant, Newborn / Q000378:metabolism*; D008431:Maternal-Fetal Exchange; D008874:Midazolam / Q000493:pharmacokinetics*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011897:Random Allocation; D013874:Thiopental / Q000493:pharmacokinetics*
D013874:Thiopental; D008874:Midazolam