Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Tramadol: pain relief by an opioid without depression of respiration.
Two independent clinical trials were conducted simultaneously. In one, tramadol and pethidine were compared in 30 patients by patient-controlled analgesia during the first 24 h following abdominal surgery. The mean 24 h consumption of tramadol and pethidine was 642 mg and 606 mg respectively, giving a potency estimate of tramadol relative to pethidine of 0.94 (95% confidence interval 0.72-1.17). ⋯ At approximately 1.5 times the equipotent dose, as estimated from the first trial, tramadol transiently depressed the rate of respiration but had no effect on end-tidal carbon dioxide tension. Morphine caused apnoea or considerable depression of ventilation. The results suggest that mechanisms other than opioid receptor activity play a significant role in the analgesia produced by tramadol.
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Randomized Controlled Trial Comparative Study Clinical Trial
Nosocomial sinusitis in ventilated patients. Nasotracheal versus orotracheal intubation.
A total of 68 postoperative patients whose lungs were ventilated for more than 4 days were studied prospectively during a one-year study period to investigate the effect of the mode of intubation on the paranasal sinuses. After an initial X ray of the skull showing no pathological findings, patients were assigned randomly to one of the study groups; the lungs of patients in group A were ventilated via an orotracheal tube (n = 32), and patients in group B via a nasotracheal tube (n = 36). X ray examinations of the sinuses were performed at regular intervals. ⋯ Two patients in group A developed signs of sinusitis in comparison to 15 patients in group B (p less than 0.01). However, there were significantly more airway complications in the orotracheal group, particularly during the period of weaning from ventilation. We conclude that orotracheal intubation should be preferred as the routine route of intubation.
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Comparative Study
Cardiovascular responses to insertion of the laryngeal mask.
We have compared, in 40 healthy patients, the cardiovascular responses induced by laryngoscopy and intubation with those produced by insertion of a laryngeal mask. Anaesthesia was induced with thiopentone and maintained with enflurane and nitrous oxide in oxygen; vecuronium was used for muscle relaxation. ⋯ Increases in maximum heart rate were similar, (26.6% v 25.7%) although heart rate remained elevated for longer after tracheal intubation. We conclude that insertion of the laryngeal mask airway is accompanied by smaller cardiovascular responses than those after laryngoscopy and intubation and that its use may be indicated in those patients in whom a marked pressor response would be deleterious.
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The forces transmitted by the laryngoscope blade onto the base of the tongue are assumed to be a major cardiovascular stimulus. This study investigates the various forces applied onto a Macintosh laryngoscope during laryngoscopy. The forces acting along the axis of the handle are described, as well as the forces exerted by the anaesthetist to prevent the laryngoscope from turning. ⋯ Four different laryngoscopic parameters are determined: (1) the duration of laryngoscopy, (2) the maximally applied force, (3) the mean force and (4) the integral of the force over the time (area under the curve). The force measurements of 49 anatomically normal patients undergoing uncomplicated intubation are included in the study. The duration of laryngoscopy was 16.3s (SD 11.8), the applied peak force was 35N (SD 12) and mean force necessary was 20N (SD 6) while the force-time integral was 324N (SD 194).