Anesthesiology
-
Local anesthetics block nerve conduction by preventing the increase in membrane permeability to sodium ions that normally leads to a nerve impulse. Among anesthetics containing tertiary amine groups, the cationic, protonated form appears to be more active than the neutral form. However, the neutral forms, as well as uncharged molecules like benzocaine and the aliphatic alcohols, also depress sodium permeability. ⋯ The channel has a higher affinity for larger anesthetic molecules, but this may result from their greater hydrophobicity as well as from their size. The binding site favors molecules that contain more polar linkages between the amine group and the aromatic residue. Binding of amine anesthetics is weakly stereospecific and, surprisingly, shows no absolute requirement for the terminal alkyl ammonium moiety present in most local anesthetics...
-
Comparative Study
Neurobehavioral responses and drug concentrations in newborns after maternal epidural anesthesia with bupivacaine.
The neurobehavioral status of 20 newborn infants was evaluated after two to four hours of life following maternal epidural anesthesia with bupivacaine for labor and vaginal delivery. All infants were normal products of uncomplicated full-term gestations. The 20 infants, whose mothers had received continuous lumbar epidural anesthesia with bupivacaine, demonstrated no measurable difference from control infants and did not have the decrease in muscle tone and strength observed in infants whose mothers had received continuous lumbar epidural anesthesia with lidocaine or mepivacaine in a previous study.