British journal of anaesthesia
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Comparative Study Clinical Trial Controlled Clinical Trial
Comparison of the neuromuscular block induced by mivacurium, suxamethonium or atracurium during nitrous oxide-fentanyl anaesthesia.
We compared the neuromuscular and cardiovascular changes following administration of mivacurium 0.15, 0.20 and 0.25 mg kg-1, suxamethonium 1.0 mg kg-1 or atracurium 0.5 mg kg-1 i.v. in 41 (ASA physical status I or II) patients during nitrous oxide-fentanyl anaesthesia. Mean onset times for total ablation of twitch response for mivacurium 0.15, 0.20 and 0.25 mg kg-1, were 2.5, 2.4 and 2.7 min, respectively, similar to that for atracurium (2.5 min), but longer than for suxamethonium (1.1 min) (P less than 0.05). ⋯ Following neostigmine 0.045 mg kg-1, mean times for twitch tension to recover from 10% to 90% of control were similar for mivacurium (9.7 min) and atracurium (10.5 min). Transient decreases in mean arterial pressure (greater than 20%) were observed in seven of 15 patients who received the two higher doses of mivacurium.
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Randomized Controlled Trial Clinical Trial
Postoperative analgesia with extradural clonidine.
The analgesic effect of extradural clonidine was evaluated in a double-blind study. In the recovery room, following orthopaedic or perineal surgery 20 ASA I and II patients were allocated randomly to two groups. The extradural clonidine (EC) group received clonidine 2 micrograms kg-1 in isotonic saline solution 15 micrograms ml-1. ⋯ In the EC group, the mean (SD) maximum pain relief was 68.2 (24.1)% of the initial VAS score, but it was only 14.7 (25.2)% in the ES group. The mean duration of analgesia, before injection of morphine, was significantly longer in the EC group (210 (87) min) compared with the ES group (45 (27) min) (P less than 0.001). Drowsiness and moderate hypotension were observed in the EC group.
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In a laboratory model, humidity output was investigated in relation to the design of a circle absorber system. A 70-kg subject was simulated with fresh gas flows of 0.5, 2 or 5 litre min-1. Different circle systems, absorption canisters and tubings were studied. ⋯ Coaxial tubing only moderately increased the humidity. If a fresh gas flow of 0.5 liter min-1 was used, optimum moisture contents were attained, irrespective of the circle system tested. Low fresh gas flows, a small canister and an Eger A type circle system, were factors which increased humidification.
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Randomized Controlled Trial Clinical Trial
Haemodynamic changes after induction of anaesthesia and tracheal intubation following propofol or thiopentone in patients of ASA grade I and III.
Thirty-six ASA I patients received either propofol 2.25 (0.07) mg kg-1 (mean (SEM] or thiopentone 4.8 (0.18) mg kg-1, for induction of general anaesthesia together with fentanyl and a neuromuscular blocking drug. This technique was repeated in 12 ASA III patients, using propofol 1.8 (0.18) mg kg-1 or thiopentone 4.7 (0.37) mg kg-1. There was a significant decrease in systolic arterial pressure following induction of anaesthesia with both drugs; this was more pronounced after propofol, and in ASA III patients. Plasma noradrenaline concentrations increased after tracheal intubation only in the thiopentone group, but the pressor response to tracheal intubation was not attenuated by the use of propofol.
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The effects of Org 9426 (the 2-morpholino, 3-hydroxy, 16N-allyl pyrrolidino analogue of vecuronium) were studied in anaesthetized cats and pigs and in isolated nerve--muscle preparations using tension and intracellular recording techniques. In isolated preparations, the effects of Org 9426 were antagonized by neostigmine. No contracture of the chick muscle preparation occurred. ⋯ Ganglion block was seen only at doses several times those producing vagal block. In general the effects of Org 9426 on the cardiovascular system were slight, a small depressor effect occurring at high doses in the cat. The 17-hydroxy analogue, the potential metabolite of Org 9426, was approximately 20 times less potent than Org 9426 and is thus unlikely to contribute to the neuromuscular block produced by the parent compound.