British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Dexmedetomidine reduces intraocular pressure, intubation responses and anaesthetic requirements in patients undergoing ophthalmic surgery.
We studied the effects of a single i.v. dose of dexmedetomidine, a highly selective and specific alpha 2 adrenoceptor agonist, on intraocular pressure (IOP), haemodynamic and sympathoadrenal responses to laryngoscopy and tracheal intubation, and on anaesthetic requirements in ophthalmic surgery. Thirty ASA I-II patients undergoing cataract surgery were allocated randomly to receive either dexmedetomidine 0.6 microgram kg-1 or saline placebo i.v. 10 min before induction of anaesthesia in a double-blind design. After dexmedetomidine there was a 34% (95% confidence interval (CI) 27-43%) reduction in IOP (P less than 0.001) and 62% (CI 57-68%) decrease in plasma noradrenaline concentrations (P less than 0.001). ⋯ The induction dose of thiopentone was smaller (23% (CI 20-26%) P = 0.012), and the use of isoflurane or fentanyl supplements during anaesthesia was less frequent in the dexmedetomidine group. The patients premedicated with dexmedetomidine recovered faster from anaesthesia (P = 0.042). These results suggest that dexmedetomidine may be a useful anaesthetic adjunct in ophthalmic surgery.
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Randomized Controlled Trial Comparative Study Clinical Trial
Continuous extradural analgesia: comparison of midwife top-ups, continuous infusions and patient controlled administration.
We have compared three techniques used to provide extradural analgesia during the first stage of labour: 0.25% plain bupivacaine 10 ml demand top-ups delivered by the midwife; continuous infusion of 0.125% plain bupivacaine 10 ml h-1; and patient-controlled extradural analgesia (PCEA) delivering 3-ml boluses of 0.25% bupivacaine. Each technique produced comparable analgesia achieving equivalent maternal satisfaction, with no difference in mode of delivery and no complications. This regimen for PCEA proved a viable alternative for continuous extradural analgesia and was popular with the mothers, midwives and anaesthetists.
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Comparative Study
Spinal anaesthesia for caesarean section: 0.125% plain bupivacaine 12 ml compared with 0.5% plain bupivacaine 3 ml.
Forty women had elective Caesarean section under spinal anaesthesia with either 0.5% bupivacaine 3 ml or 0.125% bupivacaine 12 ml, injected at a rate of 1 ml/5 s. For 30 min after the spinal injection, each patient lay on her right side. Compared with the patients given 3 ml, in those given bupivacaine 12 ml there was a significantly greater spread of block (P less than 0.02 for analgesia; P less than 0.002 for touch) and significantly less variation in levels of block (P less than 0.02 for analgesia; P less than 0.04 for touch). However, within 5 min of placing the women in a supine, tilted (right hip up) position, there were no clinically or statistically significant differences in the levels of block between the two groups.