British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Improvement in i.v. regional anaesthesia by re-exsanguination before surgery.
A modification of an i.v. regional anaesthesia (IVRA) technique is described in which the arm is re-exsanguinated before surgery (re-IVRA). IVRA and re-IVRA were compared for quality of operative field, sensory and motor block, quality of analgesia and blood concentrations of prilocaine, lignocaine and mepivacaine in a double-blind study in 120 patients undergoing hand surgery. ⋯ Re-exsanguination improved tolerance of the tourniquet. Plasma concentrations in the re-IVRA group showed some increases, but these were not in the toxic range.
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In 20 patients studied under general anaesthesia, we found good agreement between gastric fluid volumes aspirated blindly and total volumes determined by fibreoptic gastroscopy (mean under-estimation 6 ml (22%); range 0-50 ml). Gastric fluid acidity measurements using an electronic pH meter and pH indicator paper also provided results with good agreement (mean difference in pH 0.1; range -0.3 to 0.5). As the use of a standardized blind gastric aspiration technique and pH indicator paper is simpler and provided sufficiently accurate measurements for clinical study purposes, we think this method is preferable.
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We have studied the effects of extrinsically applied PEEP (PEEPe) and intrinsic PEEP (PEEPi) on lung volume and peak airway pressure (Paw,peak) in 10 patients with airflow limitation during mechanical ventilation. PEEPe was applied in 2-4 cm H2O increments until values greater than PEEPi were reached. Total lung hyperinflation was quantified by measuring the expired volume resulting from deflation (starting at end inspiration) until cessation of expiratory flow. ⋯ PEEPe at pressures less than PEEPi increased delta FRC by (mean) 186 (SEM) 34 ml/kPa PEEPe (P < 0.05) and increased Paw,peak by 0.6 (0.12) kPa/kPa PEEPe (P < 0.05). In contrast, PEEPe at pressures greater than PEEPi, increased delta FRC by 695 (128) ml/kPa PEEPe (P < 0.05) and Paw,peak by 1.8 (0.26) kPa/kPa PEEPe. We conclude that PEEPe may be applied cautiously at values less than PEEPi when clinically indicated, but the application of PEEPe at values greater than PEEPi may substantially aggravate lung hyperinflation.
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Randomized Controlled Trial Comparative Study Clinical Trial
Clinical and radiological comparison of perivascular and transarterial techniques of axillary brachial plexus block.
The perivascular technique of axillary brachial plexus block results in incomplete block of radial and musculocutaneous nerves in 10-20% of patients. With the transarterial technique and a large dose of mepivacaine, success rates of 99% have been reported. We have compared the clinical efficacy of these techniques in 50 patients using 1% mepivacaine 45 ml with adrenaline. ⋯ There were no statistically significant differences in sensory or motor block between the groups at 20 min or in the plasma concentrations of mepivacaine measured 0-45 min after injection. In the CT scans, both proximal and distal spread of the contrast medium were more common after perivascular than after transarterial block. The distribution of the contrast medium was not related to the efficacy of the block.
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Randomized Controlled Trial Comparative Study Clinical Trial
Haemodynamic and catecholamine responses to induction of anaesthesia and tracheal intubation: comparison between propofol and thiopentone.
We have studied the haemodynamic changes, QT intervals and catecholamine responses to induction of anaesthesia and tracheal intubation in 24 ASA I patients allocated randomly to receive either propofol 2.5 mg kg-1 or thiopentone 5 mg kg-1 over 60 s. After disappearance of the eyelash reflex, the lungs were ventilated with 100% oxygen for 3 min. The trachea was intubated after administration of vecuronium. ⋯ One patient in the thiopentone group with a significantly prolonged QT interval had episodes of bigeminy and ventricular tachycardia. In both groups, concentrations of noradrenaline in mixed venous plasma increased after intubation (P < 0.001). Concentrations of adrenaline increased after intubation only in the thiopentone group (P < 0.001).