Articles: nerve-block.
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Randomized Controlled Trial Clinical Trial
Edrophonium antagonism of intense mivacurium-induced neuromuscular block in children.
We have studied the time course of recovery after administration of edrophonium during intense mivacurium block in children aged 2-10 yr, using thumb acceleration in response to train-of-four (TOF) stimulation. Forty-three children receiving alfentanil, propofol, nitrous oxide, isoflurane anaesthesia and mivacurium 0.2 mg kg-1 were allocated randomly to one of three groups. Patients in group 1 (n = 15) received edrophonium 1 mg kg-1, 2 min after maximum block (intense block group). ⋯ The recovery index (time interval between T1 25% and 75%) was comparable in groups 1-3 (5.5 (2.0), 4.8 (2.1) and 5.7 (1.4) min respectively). Ten minutes after development of maximum block, the numbers of patients who recovered adequately (TOF ratio 70% or more) were, respectively, 12 (80%), 8 (53%) and 1 (8%) in groups 1-3. We conclude that edrophonium antagonized intense (no response to TOF stimulation) mivacurium-induced block in children, with significant reduction in the recovery times of T1 and TOF ratio compared with conventional reversal and spontaneous recovery.
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Anesthesia and analgesia · Feb 1996
Randomized Controlled Trial Comparative Study Clinical TrialCompound motor action potential recording distinguishes differential onset of motor block of the obturator nerve in response to etidocaine or bupivacaine.
The purpose of this investigation was to establish an objective (quantitative) method for determining onset time of motor block induced by different local anesthetics. Twenty-four consenting patients undergoing transurethral surgery during spinal anesthesia were randomized to receive direct obturator nerve block with 10 mL of plain bupivacaine 0.5% (n = 12) or 10 mL of plain etidocaine 1% (n = 12). Another 14 patients (control group) received obturator nerve "block" with saline. ⋯ While CMAP amplitudes in the control group returned to their initial (baseline) values after 3-6 min, the patients receiving etidocaine or bupivacaine achieved > or = 90% motor blockade after 6 and 13 min, respectively. In the present report, the time to > or = 90% block was significantly faster in patients given etidocaine compared with those given bupivacaine. We conclude that electromyographic recording of CMAPs can be used to compare the ability of different local anesthetics to induce motor block.
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We review the results of 312 cases of sciatic nerve blockade in the poplitea fossa for surgery of the dorsal foot. An atraumatic, insulated needle connected to a neurostimulator was used to make a single puncture using a posterior approach. The anesthetic was 1% mepivacaine (4-5 mg/kg-1). ⋯ Time of analgesia was 6 h 15 min (range 3-16 h). No complications or sequelae were recorded. We conclude that the technique is highly effective and comfortable for patients, as it requires only one puncture and gives good postoperative analgesia with no major side effects.
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Recent published data suggest that despite apparently satisfactory recovery from nondepolarising block (train-of-four ratios in excess of 0.90), even very small doses of additional relaxant may re-establish significant paralysis. We sought to verify this observation and quantify its magnitude. Twelve adult patients were studied under nitrous oxide-propofol-opioid anaesthesia and neuromuscular block was monitored electromyographically. ⋯ The control ED50 of mivacurium (calculated from the initial dose of mivacurium) averaged 43 micrograms.kg-1. When the same dose of drug was given at 95% recovery of the train-of-four ratio, the ED50 was reduced to 19 micrograms.kg-1 (p < 0.0001). Hence, there remains a considerable reduction in the neuromuscular margin of safety even at a train-of-four ratio of 0.95.