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 knee-chest position for lumbar spine surgery is favoured because decreased filling of the epidural veins is associated with reduced peroperative bleeding. However, the position may be unfavourable from a circulatory point of view. In the present study, non-invasive assessment of circulation in the lower limbs was performed in 21 unanaesthetised, healthy volunteers who were placed in the surgical knee-chest position. ⋯ The change from prone to knee-chest position resulted in an increase in arterial blood pressure of the upper limb; the increase in diastolic arterial pressure was statistically significant (p < 0.001). It is concluded that the surgical knee-chest position involves deterioration of both the arterial and venous flow of the lower limbs. This should be considered in patients undergoing surgery in this position and, in particular, in those at risk of developing cardiovascular complications.