Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Prevention of hypotension during spinal anaesthesia for caesarean section: ephedrine infusion versus fluid preload.
We compared the efficacy of prophylactic ephedrine infusion over fluid preloading in prevention of maternal hypotension during spinal anaesthesia for Caesarean section. Forty-six women undergoing elective Caesarean section at term were allocated randomly to receive either intravenous fluid preloading with Hartmann's solution 20 ml.kg-1 (fluid group) or prophylactic intravenous ephedrine 0.25 mg.kg-1 (ephedrine group). Moderate hypotension was defined as > or = 20% reduction in systolic blood pressure and severe hypotension as > or = 30% reduction in systolic blood pressure. ⋯ Mean umbilical venous pH was higher in the ephedrine group than in the fluid group (7.33 vs. 7.29, p = 0.02) and the number of patients shivering was lower in the ephedrine group (2 vs. 9, p = 0.02). No difference was found between pre- and postspinal uterine artery pulsatility indices in either group. We conclude that prophylactic ephedrine infusion alone is at least as good as fluid preload alone in combating the hypotension associated with spinal anaesthesia for Caesarean section.
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Comparative Study Clinical Trial Controlled Clinical Trial
A comparison of intercuff and single cuff techniques of intravenous regional anaesthesia using 0.5% prilocaine mixed with technetium 99m-labelled BRIDA.
Intravenous regional anaesthesia of the upper limb is a widely used technique first described by Bier in 1908. The exact site of action of injected local anaesthetic has not been determined. We have performed intravenous regional anaesthesia on volunteers using prilocaine mixed with technetium 99m-labelled 2,4,6 trimethyl-3-bromo iminodiacetic acid. ⋯ The onset of action was similar for both techniques. The local anaesthetic was mainly retained in the antecubital fossa in both techniques but in the 'normal' technique, the local anaesthetic subsequently showed some retrograde spread. This would suggest that the main site of action of local anaesthetic used for intravenous regional anaesthesia is the larger nerves in the vicinity of the antecubital fossa.
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison of the infusion pharmacokinetics and pharmacodynamics of cisatracurium, the 1R-cis 1'R-cis isomer of atracurium, with atracurium besylate in healthy patients.
We have compared the pharmacokinetics of cisatracurium with atracurium when given by bolus dose followed by continuous infusion. Twenty healthy patients were anaesthetised with thiopentone, midazolam, fentanyl and 70% nitrous oxide in oxygen. Ten patients (Group C) were randomly allocated to receive cisatracurium 0.1 mg.kg-1 and 10 patients (Group A) were given atracurium 0.5 mg.kg-1. ⋯ The different isomer groups of atracurium have different pharmacokinetics, the trans-trans group having the highest clearance (1440 ml.min-1) and the cis-cis group the lowest (499 ml.min-1). The clearance of cisatracurium (425 ml.min-1) is less than that of cis-cis atracurium and its elimination half-life is longer (34.9 min and 21.9 min, respectively). The plasma concentration of laudanosine after cisatracurium was one-fifth of that after atracurium.
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Randomized Controlled Trial Comparative Study Clinical Trial
The addition of opioids to local anaesthetics in brachial plexus block: the comparative effects of morphine, buprenorphine and sufentanil.
We compared the duration of analgesia produced by a mixture of lignocaine and bupivacaine, either alone or combined with morphine (75 micrograms.kg-1), buprenorphine (3 micrograms.kg-1) or sufentanil (0.2 microgram.kg-1) in 80 patients after brachial plexus block for orthopaedic surgery of the upper limb. The characteristics of analgesia were evaluated hourly using a visual analogue scale. ⋯ The median duration (range) of satisfactory analgesia was: 11.5 (8-15) h without an opioid, 21 (9-27) h with morphine, 20 (14-34) h with buprenorphine and 24.5 (11-38) h with sufentanil. We conclude that the addition of an opioid to a local anaesthetic mixture lengthens the duration of analgesia.
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The McCoy laryngoscope undoubtedly improves the view of the vocal cords during difficult tracheal intubation. An inherent design problem with the McCoy blade is the need to relax the grip on the laryngoscope handle at the point when stability is most necessary. A new hinged tip blade is described which is operated by a button mechanism on a secondary handle that runs adjacent to the standard handle. This modification offers the possibility of better stability and ease of manipulation whilst maintaining all the benefits of the McCoy blade.