British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Cardiovascular changes in labour associated with extradural analgesia using bupivacaine.
Cardiovascular changes were monitored continuously in 13 women during stimulated labour conducted under extradural analgesia with bupivacaine. Three solutions of bupivacaine (0.5% plain, 0.25% with adrenaline and 0.5% with adrenaline) were administered in a random fashion. ⋯ These changes did not occur when solutions containing adrenaline were used. The small number of patients and the random administration of the bupivacaine solutions make it difficult to establish the exact significance of the cardiovascular changes observed and a further within-patient study is required.
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Randomized Controlled Trial Comparative Study Clinical Trial
A double-blind trial of bupivacaine (Marcain) and etidocaine (Duranest) in extradural block for surgical induction of labour.
A double-blind randomized trial was conducted to compare etidocaine, the new local anaesthetic agent, with bupivacaine. One hundred patients were each given a single dose of one of the drugs during the surgical induction of labour. The results showed that etidocaine had a quicker onset of action than bupivacaine, but that its duration of action was shorter, and that it produced a greater degree of muscle weakness. No differences were noted in the side effects of the two drugs.
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Comparative Study Clinical Trial Controlled Clinical Trial
Cardiovascular effects of extradural analgesia in labour: comparison of bupivacaine with lignocaine.
Two groups of patients who requested extradural analgesia were studied in a within-patient controlled trial and received either 0.5% bupivacaine with adrenaline 5 mug/ml or 0.5% bupivacaine plain as the analgesic agent (first group) or 0.5% bupivacaine or 2% lignocaine both with adrenaline 5 mug/ml (second group). Arterial pressure, central venous pressure (CVP), maternal and foetal heart rate and uterine contractions were monitored continuously. ⋯ The position of the patient did not affect the cardiovascular measurements in either group. Since the addition of adrenaline 5 mug/ml to bupivacaine solutions did not confer any apparent advantages, it is concluded that plain solutions of 0.5% bupivacaine should be used except in the longest labours.
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Comparative Study
Differential B and C fibre block by an amide- and an ester-linked local anaesthetic.
The relative sensitivity of sympathetic preganglionic and postganglionic axons, B and C fibres, respectively, to two structurally dissimilar local anaesthetics was examined. The concentration of amethocaine (ester-linked tertiary amine) or prilocaine (amide-linked secondary amine) required to reduce the B fibre compound action potential by 50% was one-third of the concentration required to depress the C fibre potential to a similar extent. Both local anaesthetic agents also showed the action potential propagation through B fibres more than through C fibres. Similar results have been reported previously for lignocaine (amide-linked tertiary amine).