British journal of anaesthesia
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Clinical Trial Controlled Clinical Trial
Midazolam acts synergistically with fentanyl for induction of anaesthesia.
The induction dose-response of midazolam was compared with the dose-response of its combination with fentanyl and with that of fentanyl alone in three groups of 60 unpremedicated, ASA physical status I or II women undergoing minor gynaecological surgery. The end-point of induction of anaesthesia was inability to open eyes upon command. ⋯ Twenty-five percent of the ED50 of fentanyl was required in combination with 23% of the ED50 for midazolam to achieve the ED50 of the combination. This degree of synergism may explain mutual potentiation between opioids and benzodiazepines reported previously.
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Multicenter Study Clinical Trial Controlled Clinical Trial
An open study of ropivacaine in extradural anaesthesia.
Ropivacaine 0.5%, 0.75% and 1.0% was investigated in an open study of extradural anaesthesia in three groups of 15 patients undergoing urological or orthopaedic surgery. Following a test dose of 3 ml of 1.0% lignocaine with 1:200,000 adrenaline, ropivacaine 20 ml was given in incremental doses over 4 min via a lumbar extradural catheter. The onset time for analgesia was short in all groups: T12 was blocked 4-6 min after the end of the injection of ropivacaine. ⋯ Bradycardia occurred in seven patients and was associated with hypotension in five. Backache was experienced after operation by four patients, and three patients complained of a brief mild headache. No late adverse events were seen.
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We have measured plasma concentrations of local anaesthetics, and the substance fraction of methaemoglobin (MetHb), in infants less than 3 months of age, after application of a lignocaine-prilocaine cream (EMLA). A total of EMLA 2 g was applied over four different skin areas, totalling 16 cm2, for 4 h before anaesthesia for a minor surgical procedure. Sampling was carried out before and 4, 8 and 12 h after application. ⋯ It showed a good inverse correlation with the maximum MetHb values after application of EMLA. Although the MetHb concentrations in the infants younger than 3 months were small, the enzyme capacity may be overloaded when EMLA is administered at the same time as other MetHb-inducing agents. It is concluded that the use of EMLA should be restricted in this age group.
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Randomized Controlled Trial Clinical Trial
Modification by fentanyl and alfentanil of the intraocular pressure response to suxamethonium and tracheal intubation.
We have measured in a double-blind study the changes in intraocular pressure (IOP) in 40 consecutive patients (pretreated with fentanyl or alfentanil) who received suxamethonium and tracheal intubation. Although IOP increased significantly following administration of suxamethonium, mean IOP in both groups remained significantly less than control values (P less than 0.002). ⋯ There were no significant differences in mean IOP between the fentanyl and alfentanil groups. Both opioids reduced, but did not abolish the haemodynamic responses to tracheal intubation.
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Randomized Controlled Trial Clinical Trial
Effect of fluid preloading on cardiovascular variables after spinal anaesthesia with glucose-free 0.75% bupivacaine.
We studied the effect on systemic arterial pressure of fluid preloading with 1 litre of crystalloid fluid before spinal anaesthesia in 40 patients undergoing minor lower abdominal or lower limb surgery. Fluid was given at a rate of either 1 ml min-1 (no preload group), or 1000 ml in the 15 min (preload group) immediately before induction of spinal anaesthesia with 3 ml of 0.75% glucose-free bupivacaine. There was no difference between the groups in the character of anaesthesia or motor block in the lower limbs. ⋯ The group not given a fluid preload had significantly lower arterial pressures (P less than 0.05) when anaesthesia extended above the T5 dermatome. The mean time before the lowest arterial pressure was recorded was twice as long in the preloaded group as in the non-preloaded group. Glucose-free 0.75% bupivacaine did not give a reliable extent of anaesthesia for lower abdominal surgery.