British journal of anaesthesia
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We have estimated the effect of omitting antagonism of neuromuscular block on postoperative nausea and vomiting. A systematic search (MEDLINE, EMBASE, Biological Abstracts, Cochrane library, reference lists and hand searching; no language restriction, up to March 1998) was performed for relevant randomized controlled trials. In eight studies (1134 patients), antagonism with neostigmine or edrophonium was compared with spontaneous recovery after general anesthesia with pancuronium, vecuronium, mivacurium or tubocurarine. ⋯ In two studies, three patients with spontaneous recovery after mivacurium or vecuronium needed rescue anticholinesterase drugs because of clinically relevant muscle weakness (number-needed-to-harm, 30). Omitting neostigmine may have a clinically relevant antiemetic effect when high doses are used. Omitting antagonism, however, introduces a non-negligent risk of residual paralysis even with short-acting neuromuscular blocking agents.
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Randomized Controlled Trial Comparative Study Clinical Trial
Relative potencies of bupivacaine and ropivacaine for analgesia in labour.
We have used the technique of randomized, double-blind sequential allocation to compare the minimum local analgesic concentrations (MLAC) of epidural bupivacaine and ropivacaine for women in the first stage of labour. The test bolus was 20 ml of local anaesthetic solution. The concentration was determined by the response of the previous woman to a higher or lower concentration of local anaesthetic, according to up-down sequential allocation. ⋯ For bupivacaine, MLAC was 0.093 (95% CI 0.076-0.110)% w/v, and for ropivacaine, 0.156 (95% CI 0.136-0.176)%w/v (P < 0.0001, 95% CI difference 0.036-0.090). The analgesic potency of ropivacaine was 0.60 (0.47-0.75) relative to bupivacaine. Claims for reduced toxicity and motor block must be considered with differences in analgesic potency in mind.
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Randomized Controlled Trial Clinical Trial
Management of opioid-induced pruritus: a role for 5-HT3 antagonists?
We have evaluated the efficacy of ondansetron in the prevention of opioid-induced pruritus in a prospective, randomized, double-blind, placebo-controlled study. Using a 'human model' of opioid-induced pruritus, 80 ASA I-II patients about to undergo routine surgery were given either ondansetron 4 mg i.v. or 0.9% saline i.v. (40 in each group), 30 min before alfentanil 10 mg kg-1 i.v. During the following 5 min, patients were observed for signs of perinasal scratching and at 5 min were asked about symptoms of pruritus. ⋯ There was a significant reduction in the incidence of scratching in patients receiving ondansetron compared with placebo (42.5% vs 70%, respectively, P = 0.013). The incidence of itching in the ondansetron group was less than that in the placebo group but this was not statistically significant (30% vs 42.5%, respectively, P = 0.245). We conclude that the 5-HT3 antagonist ondansetron may have a role in the management of opioid-induced pruritus.
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Randomized Controlled Trial Clinical Trial
Effect of nitrous oxide on myogenic motor potentials evoked by a six pulse train of transcranial electrical stimuli: a possible monitor for aortic surgery.
Intraoperative recording of myogenic motor potentials evoked by transcranial electrical stimulation (tcMEP) is a method of monitoring the integrity of the vulnerable motor pathways during thoracoabdominal aortic aneurysm (TAAA) surgery. Deflation of the left lung during TAAA surgery may result in impairment of arterial oxygenation. Ventilation with nitrous oxide may cause further desaturation. ⋯ There was no significant difference in the coefficients of variation for tcMEP between the three nitrous oxide anaesthetic regimens. Our results suggest that increasing doses of nitrous oxide reduce the MEP waveform to six pulse transcranial electrical stimulation, but even with 60% nitrous oxide in oxygen, the tcMEP were recordable and as reproducible as with 20% and 40% nitrous oxide regimens. The method is sufficiently robust for use in aortic surgery.
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Clinical Trial Controlled Clinical Trial
Electromyographic assessment of neuromuscular block at the gastrocnemius muscle.
We have assessed neuromuscular block electromyographically at the gastrocnemius muscle and compared it with that at the abductor digiti minimi muscle in 60 adult patients undergoing cervical spine surgery under general anaesthesia. All patients were in the prone position. ⋯ Times to return of the first response of the train-of-four (TOF) at the gastrocnemius and abductor digiti minimi muscles were 41.0 (9.1) and 49.9 (8.7) min, respectively (P = 0.01). Recovery of PTC, T1/T0 and TOF ratio at the gastrocnemius muscle were significantly faster than at the abductor digiti minimi muscle.