British journal of anaesthesia
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Plasma concentrations of methadone were measured by gas chromatography in 16 patients receiving extradural methadone by continuous infusion for relief of postoperative pain. Venous blood samples were taken after a loading dose of extradural methadone 2 mg and during infusion of 0.46 mg h-1 plus patient-controlled increments of 0.2-1 mg. Mean (SD) plasma concentration of methadone was 9.8 (2.1) ng ml-1 at 15 min; this did not change significantly during the first 2 h, after which it increased gradually to 32.2 (4.6) ng ml-1 (P less than 0.001) at the end of 24 h. ⋯ No adverse effects were detected during the 2-3 days of methadone therapy. Plasma concentration of methadone increased significantly during patient-controlled infusion of extradural methadone in the first 24 h after operation, suggesting rapid vascular uptake. Systemic activity of the drug contributes to the analgesic effect of extradural methadone.
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Randomized Controlled Trial Clinical Trial
Effect of flumazenil on midazolam-induced amnesia.
We have studied the effect of i.v. flumazenil 0.01 mg kg-1 on the amnesia and sedation caused by midazolam 2 mg and 5 mg i.v. in volunteers in order to determine the relationship between the actions of the antagonist on these two effects. Midazolam caused dose-dependent central neural depression as assessed by critical flicker fusion frequency, and dose-dependent amnesia for word cards. In subjects given flumazenil 5 min after administration of midazolam, fusion frequency readings and memory were restored to levels comparable to those before midazolam administration. ⋯ Flumazenil given alone had no effect on memory. The study has demonstrated anterograde amnesia following benzodiazepine administration and antagonism by flumazenil. There was neither retrograde amnesia nor retrograde antagonism of amnesia.
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Myocardial infarction is encountered rarely during pregnancy, but when it occurs the event is life-threatening to both mother and fetus. Data on maternal and fetal outcome are limited, but overall maternal mortality approaches 35%, and 40% of deaths occur during the third trimester. We present a case of myocardial infarction occurring at 38 weeks gestation, and discuss the anaesthetic management of the problems encountered during labour and delivery.
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Randomized Controlled Trial Comparative Study Clinical Trial
Double-blind comparison of topical lignocaine-prilocaine cream (EMLA) and lignocaine infiltration for arterial cannulation in adults.
In a double-blind, double-dummy study, the efficacy of topical 5% EMLA cream was compared with that of lignocaine infiltration in alleviating the pain of arterial cannulation. Forty unpremedicated adults were allocated randomly to four groups to receive EMLA cream alone, EMLA and 0.9% saline infiltration, EMLA and 1% lignocaine infiltration or placebo cream and 1% lignocaine infiltration. ⋯ Significantly lower pain scores were observed in all patients receiving EMLA compared with those receiving placebo cream and lignocaine infiltration by both patient (P less than 0.01) and observer (P less than 0.001) assessments. There were no significant differences between the three EMLA groups.