Effect of adrenaline on the distribution of bupivacaine in the rabbit fetus.
Adrenaline may decrease uterine blood flow and influence transplacental distribution of bupivacaine. Sixteen pregnant rabbits received an i.v. infusion of 0.125% bupivacaine either plain (n = 8) or with adrenaline 1.25 microgram ml-1. At 15-min intervals following the start of the infusion, rabbit fetuses were removed serially and bupivacaine concentrations measured in maternal arterial plasma, fetal plasma and brain, amniotic fluid and placenta. The presence of adrenaline was associated with increased bupivacaine concentration in placenta; there was no other significant effect on fetal bupivacaine concentrations or ratios. Fetal:maternal plasma ratios increased (P less than 0.05), while fetal brain:fetal plasma ratios decreased (P less than 0.05) significantly with time.
Laishley
R S
RS
Anaesthetic Unit, St Thomas' Hospital, London.
Carson
R J
RJ
Reynolds
F
F
D000653:Amniotic Fluid / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism; D002045:Bupivacaine / Q000493:pharmacokinetics*; D004837:Epinephrine / Q000494:pharmacology*; D005260:Female; D005312:Fetal Blood / Q000032:analysis; D005333:Fetus / Q000187:drug effects / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D011817:Rabbits
D002045:Bupivacaine; D004837:Epinephrine