Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
The effect of tunnelling on epidural catheter migration.
A prospective, randomised study of 82 patients having postoperative epidural analgesia was performed to determine whether the tunnelling of an epidural catheter influences its migration. Tunnelling of the catheter subcutaneously for a distance of 5 cm reduced the incidence of inward migration of 1 cm or more (p < 0.01) compared to a standard method of fixation with a transparent adhesive dressing. ⋯ Sixty two percent (n = 26) of tunnelled catheters remained within 0.5 cm of their original position compared to 38% (n = 16) of non-tunnelled catheters, although this difference was not statistically significant. Outward catheter migration was not reduced by subcutaneous tunnelling.
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Randomized Controlled Trial Clinical Trial
The effect of alkalinisation of lignocaine on axillary brachial plexus anaesthesia.
Alkalinisation of local anaesthetic drugs is a controversial technique for improving regional blockade. Forty-two patients scheduled for upper limb surgery received axillary brachial plexus anaesthesia using a cannula technique. Patients were randomly allocated to receive either lignocaine 1.5% with 1 in 200,000 adrenaline (pH = 4.2) or lignocaine 1.5% with 1 in 200,000 adrenaline (pH = 7.2). ⋯ The percentage of patients with complete anaesthesia at 10, 20 and 30 min following injection was significantly increased in the alkalinized group with regard to the ulnar and median nerves, and the median cutaneous nerve of the arm (p < 0.05). In the alkalinized group, there was a significant reduction in the time to useful anaesthesia and a reduced requirement for adjuvants (p < 0.05). There was no effect on the duration of anaesthesia.
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Comparative Study Clinical Trial Controlled Clinical Trial
The palpation of pulses.
In 554 anaesthetised patients, the times taken to separately palpate and identify each of the carotid, radial, brachial and femoral pulses were recorded. The patients were divided into three groups based on the form of airway management chosen (tracheal tube, facemask or laryngeal mask airway). ⋯ The carotid pulse was not so easily identified, requiring 10 s to enable an identification rate of greater than 95%. The presence of a laryngeal mask airway or a tracheal tube did not hinder the identification of carotid pulse.
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Randomized Controlled Trial Clinical Trial
Enhancement of pressor response to ephedrine following clonidine medication.
We studied pressor responses and changes in plasma catecholamine concentrations following two consecutive doses of ephedrine 0.1 mg.kg-1 with (n = 20) and without (n = 20) clonidine 5 micrograms.kg-1 premedication in patients presenting for a variety of major surgical procedures under general anaesthesia. Arterial blood pressure and heart rate were measured at 1 min intervals for 10 min, and plasma catecholamines were measured before and 3 min after each dose of ephedrine. ⋯ Plasma catecholamine concentrations tended to be lower in the clonidine group throughout the study. The augmented pressor response to ephedrine in clonidine-treated patients can be attributed to enhanced cardiovascular response rather than clonidine-induced accumulation and subsequent increased release of catecholamine.