Plasma lidocaine concentrations are higher in twin compared to singleton newborns following epidural anesthesia for Cesarean delivery.
OBJECTIVE
This study compares plasma lidocaine concentrations in 16-sets of twin neonates to 16-singleton neonates all of whom were delivered by Cesarean section under lumbar epidural anesthesia (LEA).


METHODS
Lidocaine 1.5% with epinephrine 5 microg x mL(-1) was used for activation of LEA. Upon delivery plasma lidocaine concentrations were measured from the maternal vein (MV), neonatal umbilical vein (UV) and umbilical artery (UA) using TDx fluorescence polarization immunoassay.


RESULTS
MV lidocaine concentrations were similar in both twin and singleton mothers. Both mean lidocaine UV and UA levels were 35% higher in twin A (first-delivered) compared to the singleton neonate, (P < 0.01, t test). Similarly, twin B mean UV and UA lidocaine levels were 35% and 53% higher than the singleton value (P < 0.01). Mean UV and UA lidocaine fetal/maternal ratios in both twins were at least 18% higher than the singleton value (P < 0.05).


CONCLUSIONS
Even though there were no differences in neonatal outcome, a potential does exist for high plasma lidocaine concentrations in twin fetuses, suggesting that the total maternal dose of lidocaine must be regulated carefully.
Department of Anesthesiology, Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA. vallejomc@anes.upmc.edu
Manuel C
MC
Vallejo
Sivam
S
Ramanathan
D000328:Adult; D000767:Anesthesia, Epidural; D000779:Anesthetics, Local / Q000097:blood*; D002585:Cesarean Section; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn / Q000097:blood*; D008012:Lidocaine / Q000097:blood*; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D014427:Twins
D000779:Anesthetics, Local; D008012:Lidocaine