Anaesthesia
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Randomized Controlled Trial Clinical Trial
Economics of low-flow anaesthesia in children.
We have measured the consumption of isoflurane and fresh gas flows in 77 infants and children during 20 all-day operating sessions using either the enclosed Mapleson A or the circle absorber mode of the Carden 'Ventmasta' ventilator. The average consumption (SD) of isoflurane in 37 patients anaesthetised using the A mode of the Carden system with a mean fresh gas flow of 2.61 min-1 was 11.1 (4.2) g.h-1, while that in 40 patients anaesthetised using the circle absorber mode with a mean fresh gas flow of 1.21 min-1 was 4.7 (1.0) g.h-1. ⋯ With the addition of small bore breathing hoses the adult circle absorber system was practical to use in both infants and children. These findings should stimulate interest in the use of low-flow techniques in children.
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Randomized Controlled Trial Clinical Trial
Jaw thrusting as a clinical test to assess the adequate depth of anaesthesia for insertion of the laryngeal mask.
We have studied the efficacy of the loss of response to jaw thrust as a clinical test to assess adequate depth of anaesthesia for insertion of the laryngeal mask in 60 patients. After induction of anaesthesia with propofol (infused using a syringe driver), the patients were randomly allocated to one of two groups. In one group, insertion of the laryngeal mask was attempted immediately after the loss of verbal contact and in the other group, after the loss of motor response to a jaw thrust. ⋯ Conditions were significantly better when jaw thrust was used as a clinical test compared with loss of verbal contact (p < < 0.001). No marked haemodynamic depression occurred in any patient. Thus, jaw thrust is a reliable clinical test to assess the adequate depth of anaesthesia for uncomplicated insertion of the laryngeal mask after induction of anaesthesia with propofol.
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Clinical Trial Controlled Clinical Trial
Use of a neonatal noninvasive blood pressure module on adult patients.
A clinical and statistical comparison of systolic, mean and diastolic arterial blood pressures was made between a non-invasive technique using a neonatal oscillometric blood pressure monitor attached to the thumb versus an invasive technique using a catheter inserted into the ipsilateral radial artery in 18 patients undergoing general anaesthesia for major surgery. In 1258 readings, the mean differences between the pressures obtained (invasive versus non-invasive) were +9.1, -7.9, and -0.7 mmHg for systolic, diastolic and mean pressures respectively. Oscillometric blood pressure measurement using the thumb appears to be an acceptable method for monitoring blood pressure during anaesthesia and has advantages over conventional cuff placement on the upper arm.
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Case Reports
Epidural anaesthesia, ephedrine and phenylephrine in a patient taking moclobemide, a new monoamine oxidase inhibitor.
We report a case of low thoracic epidural and general anaesthesia in a patient receiving moclobemide, a new selective inhibitor of monoamine oxidase A. Intra-operative hypotension was initially treated with phenylephrine and then with ephedrine. The short half-life of moclobemide and its modest interaction with direct and indirect acting sympathomimetic drugs permit the use of epidural anaesthesia, since any associated hypotension can be safely treated.
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The ventilation-exchange bougie is a new airway device which can be mounted on a fibreoptic laryngoscope for passage through the larynx into the trachea via a laryngeal mask airway. Subsequent removal of the fibreoptic laryngoscope and laryngeal mask airway allows a tracheal tube to be railroaded into position over the ventilation-exchange bougie. This study described the use of this technique for elective tracheal intubation in two groups of 12 subjects in whom difficulty with intubation was not expected. ⋯ Cusum analysis confirmed the impression of a learning curve and the technique could be considered learnt after four and six intubations for the experienced and inexperienced fibreoptic laryngoscopists respectively. No difficulty was found either in intubating the larynx with the fibreoptic laryngoscope and ventilation-exchange bougie or when railroading the tracheal tube over the ventilation-exchange bougie. It is suggested that this new device could have an important role in teaching fibreoptic techniques, management of the difficult airway and failed intubations.