British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Magnesium sulphate enhances residual neuromuscular block induced by vecuronium.
Magnesium sulphate (MgSO4) is currently used for haemodynamic control during anaesthesia and the early postoperative period. We have investigated the effect of this treatment on residual neuromuscular block after administration of vecuronium. ⋯ MgSO4 caused rapid and profound recurarization in all 20 patients. MgSO4 decreased the amount of acetylcholine released at the motor nerve terminal and thus may lead to recurarization in patients previously exposed to neuromuscular blocking agents.
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Randomized Controlled Trial Clinical Trial
Postoperative analgesia by continuous extradural infusion of ropivacaine after upper abdominal surgery.
Ropivacaine is a new local anaesthetic with advantages that suggest an important role in the provision of postoperative analgesia. The main aim of this study was to investigate the dose-response relationship of extradural infusion of ropivacaine. We studied 36 ASA I-III patients undergoing upper abdominal surgery during general anaesthesia and extradural block (catheter insertion at T6-9) using 0.5% ropivacaine in a randomized, double-blind study. ⋯ Pain on coughing was significantly less in all ropivacaine groups than in the saline group after 4 h infusion (medians: saline 67 mm; 0.1% ropivacaine 44 mm; 0.2% ropivacaine 33 mm; 0.3% ropivacaine 0 mm) and for 0.2% and 0.3% ropivacaine at later times. Motor block was negligible throughout the infusion. Patient satisfaction was higher in the 0.2% and 0.3% ropivacaine groups than in the two other groups.
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We have examined the effects of sedation with midazolam 0.1 mg kg-1 and reversal with flumazenil 0.5 mg on beat-to-beat heart rate (HR) variability (HRV), systolic arterial pressure (SAP), finger photoplethysmograph amplitude (PLA) and impedence pneumography in eight volunteers. With the onset of sedation there was a small decrease in SAP and increase in HR (ns). ⋯ These were thought to be secondary to activity of coupled cardiorespiratory neurones within the brain stem and the ventilatory periodicity appeared similar to that observed during the early stages of sleep. The diminished high frequency and increased low frequency oscillations induced by midazolam sedation were reversed by administration of flumazenil.
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Propofol is used widely during general anaesthesia but there has been concern that it may be implicated in provoking seizure activity. We have investigated the effects of low-dose propofol on the electrocorticogram of anaesthetized patients undergoing surgery for medically intractable epilepsy. During continuous peroperative recording of the electrocorticogram, propofol was administered in 25 mg increments until burst suppression occurred. ⋯ There was an increase in mean spike frequency in 16, extension of spike distribution in 15 and polyphasia in 13 patients. The mean dose of propofol required to cause burst suppression was 88.2 (range 25-175) mg. We conclude that at low doses, propofol caused activation of the electrocorticogram in epileptic patients but at higher doses burst suppression was induced.
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Randomized Controlled Trial Comparative Study Clinical Trial
Rocuronium pretreatment reduces suxamethonium-induced myalgia: comparison with vecuronium.
We have studied, in 150 patients undergoing elective oral surgery, the effectiveness and sequelae of pretreatment with rocuronium for reducing myalgia after suxamethonium. Patients were allocated randomly to one of three groups: anaesthesia was induced with propofol and fentanyl, and group V received vecuronium 1 mg, group R rocuronium 6 mg and group P placebo pretreatment. Suxamethonium 1.5 mg kg-1 was given 60 s after the pretreatment agent. ⋯ The incidence of postoperative myalgia on day 1 after rocuronium (20%) was significantly less than after vecuronium (42%) (P < 0.05) or placebo (70%) (P < 0.01). By day 4 the incidence of myalgia was 28.6% in the rocuronium group, 46.3% in the vecuronium group and 95% in the placebo group. Intubating conditions were not affected adversely by any pretreatment regimen.