Articles: anesthetics.
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Acta Anaesthesiol Scand · Dec 1983
Clinical Trial Controlled Clinical TrialTopical anaesthesia with EMLA, a new lidocaine-prilocaine cream and the Cusum technique for detection of minimal application time.
The minimal effective onset time of the new topical anaesthetic formulation EMLA (a eutectic mixture of lidocaine and prilocaine), was evaluated by the double-blind technique in 53 female and 66 male patients (median age 40 and 36 years, respectively) subjected to intravenous cannulation. Conventional plotting and regression analysis failed to answer the question. The Cusum technique, originally designed for industrial production control, could successfully be applied to solve the problem. It demonstrated a minimal effective EMLA application time of 45 min in adults.
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Anesthesia and analgesia · Dec 1983
Comparative StudyDifferential sensitivities of mammalian nerve fibers during pregnancy.
The onset of conduction blockade in the vagus nerve of pregnant and nonpregnant rabbits was studied utilizing an in vitro sheath nerve preparation. The time required for 50% depression of the action potential (AP) of A, B, and C vagal fibers from five pregnant and six nonpregnant animals was determined after the application of bupivacaine (0.35 mM). The onset of conduction block occurred in 6.7-12.1 min in the A, B, and C fibers from pregnant animals compared to onset times of 17.9-31.6 min in nerves taken from nonpregnant rabbits. ⋯ The results suggest either an increased sensitivity of nerve fibers from pregnant animals to bupivacaine or an enhanced diffusion of the bupivacaine to the membrane receptor site. Mechanical factors are clearly not responsible for the observed results. Hormonal factors may play a role in the decreased anesthetic latency, because progesterone levels were significantly higher in the pregnant animals.
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Anesthesia and analgesia · Oct 1983
Clinical Trial Controlled Clinical TrialEpidural bupivacaine, chloroprocaine, or lidocaine for cesarean section--maternal and neonatal effects.
The effects of epidural anesthesia on maternal blood pressure, newborn Apgar scores, neonatal acid-base status, and the early neonatal neurobehavioral scale (ENNS) were studied in 54 pregnant women undergoing cesarean section. Maternal and neonatal blood levels of the local anesthetics were also determined. Group 1 (n = 16) received 0.75% bupivacaine, group 2 (n = 18) received 3% chloroprocaine, group 3 (n = 11) received 2% lidocaine, and group 4 (n = 9) received 2% lidocaine with 1:200,000 epinephrine. ⋯ At delivery, the fetal/maternal concentration ratio of bupivacaine was 0.27, that of lidocaine without epinephrine 0.48, and that of lidocaine with epinephrine 0.58. Chloroprocaine was detected in 12 maternal samples, in seven umbilical venous samples, and in six umbilical arterial samples. It is concluded that epidural anesthesia as administered in this study had no adverse effect on the newborn Apgar scores, cord acid-base status, or the ENNS.