Anaesthesia
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We have demonstrated in a rat model that the intrathecal injection of 0.02 ml of 6.3% magnesium sulphate, a concentration iso-osmolar with rat plasma, will produce a state of spinal anaesthesia and general sedation, lasting approximately 1 h. These effects reversed completely after 6 h, without evidence of neurotoxicity, immediately or during the period 1 week following the injection. The accompanying changes in haemodynamic and respiratory functions were minimal throughout the period of anaesthesia and compare favourably with those induced by an intrathecal bolus of 0.04 ml of 2% lignocaine.
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Randomized Controlled Trial Comparative Study Clinical Trial
Topical lignocaine and thiopentone for the insertion of a laryngeal mask airway; a comparison with propofol.
We assessed conditions for insertion of a laryngeal mask airway in 90 unpremedicated adult patients who received either thiopentone 5 mg.kg-1 preceded by 40 mg of topical lignocaine spray to the posterior pharyngeal wall or propofol 2.5 mg.kg-1 alone in a randomised, single-blinded trial. All patients received fentanyl 1 microgram.kg-1. ⋯ The decrease in systolic and diastolic blood pressure, following induction and the insertion of a laryngeal mask with propofol was significantly greater than following thiopentone (p < 0.05--systolic, p < 0.01--diastolic). We conclude that thiopentone preceded by topical lignocaine spray provides conditions for insertion of a laryngeal mask equal to those of propofol, with more haemodynamic stability and a shorter period of apnoea.
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We have measured the brightness (luminance) of the light spot produced by 105 Macintosh 3 laryngoscope blades (33 bulb, 72 fibrelight) using a Hagner photometer. An estimate of the minimum luminance required for laryngoscopy (circa. 100 cd.m-2), was determined using a laryngoscope adapted to provide a variable light output. ⋯ In total, 61 (84%) of the fibrelight blades and three (9%) of the bulb blades were found to provide a light spot that encompassed areas of luminance below 30 cd.m-2, which is a level for comfortable reading. The light spot from a mains-powered fibreoptic bronchoscope was found to be four times brighter (2000 cd.m-2) than a new battery-powered fibrelight laryngoscope.
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Arteriovenous fistulae originating from the vertebral artery are rare. We report a patient in whom a vertebral artery-jugular venous fistula developed following insertion of a central venous catheter via the internal jugular vein. The fistula was successfully occluded surgically.