British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Novel bioadhesive delivery system for percutaneous local anaesthesia.
We have assessed the efficacy of a novel bioadhesive amethocaine patch device, compared to Ametop gel, in a randomized, double-blinded trial. Patch and gel formulations, including placebos, were applied to the forearms of volunteers (n = 30) for 40 min. Once the formulations were removed from the skin, anaesthesia was assessed by volunteers using a conventional pinprick test. ⋯ Statistical analysis of the results indicated that both amethocaine gel and patch preparations were superior to placebo (P < 0.05). No significant difference was observed between amethocaine gel and patch formulations (P > 0.05) in either onset time or duration of action for percutaneous local anaesthesia. The results of this study indicate therefore that the novel bioadhesive patch provides clinically comparable anaesthesia to the established gel formulation in a more defined dosage form.
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Randomized Controlled Trial Clinical Trial
Randomized placebo-controlled trial to assess the effect of remifentanil and propofol on bispectral index and sedation.
The effect of the combination of opiates and hypnotics on bispectral index (BIS) is unclear. This double-blind placebo-controlled trial investigated the effect on BIS and sedation of different infusion doses of remifentanil combined with a steady infusion of propofol. Forty patients initially received a target-controlled infusion of propofol 2 micrograms ml-1 for 15 min. ⋯ We found a significant correlation between the dose of remifentanil and the change of BIS after 15 min of infusion. The correlation between all the sedation scores and their corresponding BIS was also significant. We concluded that remifentanil, in combination with propofol, reduces BIS when used for sedation.
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Comparative Study
Pharmacokinetics of inhaled anaesthetics in a clinical setting: comparison of desflurane, isoflurane and sevoflurane.
The pharmacokinetic characteristics of desflurane, isoflurane and sevoflurane (16 patients for each anaesthetic) were estimated from measurements of inspired and end-expired agent concentrations and ventilation, obtained during routine anaesthesia in patients undergoing maxillofacial surgery (mean age 38 yr, duration of anaesthesia approximately 2 h). A two-compartment model described the data adequately. Although isoflurane and sevoflurane have almost the same tissue/blood partition coefficients, significant differences between substances were observed for the peripheral volume of distribution (medians and ranges: desflurane, 612 (343-1850) mlvapour kgbw-1; isoflurane, 4112 (1472-9396) mlvapour kgbw-1; sevoflurane, 1634 (762-8843) mlvapour kgbw-1) and the transport clearance from the central to the peripheral compartment (desflurane, 7.0 (4.4-11.1) mlvapour kgbw-1 min-1; isoflurane, 30.7 (15.9-38.7) mlvapour kgbw-1 min-1; sevoflurane, 13.0 (9.8-22.4) mlvapour kgbw-1 min-1). Thus, during clinical anaesthesia the important characteristics of the compounds could be obtained and compared between substances from simple data.
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Comparative Study
Epidural top-up solutions for emergency caesarean section: a comparison of preparation times.
We compared the preparation times of three solutions commonly used for epidural top-up for emergency Caesarean section. Twenty-two anaesthetists were asked to prepare fresh solutions in random order as quickly as possible: 0.5% bupivacaine 20 ml (B); 2% lidocaine 20 ml with 1:200,000 epinephrine (LE); and 0.5% bupivacaine 10 ml and 2% lidocaine 10 ml with 1:200,000 epinephrine and 8.4% sodium bicarbonate 2 ml (BLEB). Preparation times for B were approximately half of those for LE, which in turn were approximately half of those for BLEB (P = 0.0001). If local anaesthetic solutions with additives such as epinephrine or bicarbonate are prepared just before emergency Caesarean section, any possible reduction in onset time that they might afford may be offset by the additional preparation time required.