British journal of anaesthesia
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Bupivacaine induces fatal arrhythmia when accidentally injected i.v. or overdosed, whereas lidocaine is used as an anti-arrhythmic agent. We have suggested recently that the anti-arrhythmic effect of lidocaine may be explained by suppression of ATP-sensitive potassium (KATP) channels. Therefore, it could be argued that different sensitivities of KATP channels to both drugs could be a reason for their different arrhythmic and anti-arrhythmic properties. ⋯ Binding of bupivacaine influenced the gating of this channel, but did not reduce the conductance of the open channel. Bupivacaine and lidocaine were equipotent in blocking KATP channels. However, because of its excessive block of the sodium channel in the inactivated state, block of KATP channels by bupivacaine will only enhance its cardiotoxicity.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of midwife top-ups, continuous infusion and patient-controlled epidural analgesia for maintaining mobility after a low-dose combined spinal-epidural.
We studied 133 women given a combined spinal-epidural for analgesia in labour. The initial intrathecal dose contained bupivacaine 2.5 mg with fentanyl 25 micrograms. When the mothers were comfortable, they were allocated randomly to one of three groups: continuous infusion (group Cl, n = 46), midwife top-ups (group MW, n = 43) or patient-controlled epidural analgesia (group PCEA, n = 44), to maintain analgesia throughout labour. ⋯ Four hours after combined spinal-epidural analgesia, 88.1% of women could SLR in group MW, 83.7% in group PCEA and 57.8% in group Cl (P = 0.002). Total use of bupivacaine was highest in group Cl (mean 11.3 (SD 3.3) mg h-1) compared with group MW (7.5 (3.1) mg h-1) and group PCEA (9.1 (2.1) mg h-1) (P < 0.001). Analgesia was similar between groups and overall satisfaction was equally high.
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Randomized Controlled Trial Comparative Study Clinical Trial
Respiratory effects of low-dose bupivacaine interscalene block.
In this double-blind study, interscalene brachial plexus (ISBP) block was performed in 11 volunteers using 10 ml of either 0.25% (n = 6) or 0.5% (n = 5) bupivacaine with epinephrine 1:200,000. Diaphragmatic excursion, respiratory function and neural function were assessed for 90 min. ⋯ Sensory anaesthesia in the upper limb was found consistently in both groups, although biceps paralysis occurred earlier after 0.5% bupivacaine. We conclude that ISBP block using 10 ml of 0.25% bupivacaine provided upper limb anaesthesia to pinprick in C5-6 dermatomes with only occasional interference with respiratory function.