Anaesthesia
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Comparative Study
Comparison of recovery index of rocuronium or vecuronium with simultaneously administered pancuronium in the isolated forearm.
A series of isolated forearm experiments is described in which rocuronium or vecuronium were injected into one arm, and pancuronium injected simultaneously into the contralateral arm. The time for 25%-75% twitch recovery (recovery index) was recorded in both arms. The recovery indices of rocuronium and vecuronium were similar, but that of pancuronium significantly longer. Because the recovery indices compared in any one experiment occurred in the presence of identical background plasma concentration, the differences observed in recovery index between pancuronium and either rocuronium or vecuronium are due to different rates of dissociation from the effect compartment at the neuromuscular junction.
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The management of a patient who required positive pressure ventilation following pharyngolaryngo-oesophagectomy during which tracheal injury was sustained is described. Ventilation with a tracheal tube resulted in a massive pneumoperitoneum. Bilateral bronchial intubation was employed with success.
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The accuracy of a computer-controlled infusion of midazolam, based on previously published pharmacokinetic parameters, was tested prospectively in 12 adult female patients undergoing general anaesthesia. Anaesthesia consisted of an initial bolus followed by an exponentially decreasing infusion of midazolam given according to body weight, fentanyl, nitrous oxide and vecuronium. Venous blood samples were taken at 15 min-intervals throughout the procedures and for 1-2 h postoperatively. ⋯ Retrospective fitting of an alternative set of published parameters for midazolam resulted in significant deterioration of the model. The precision was similar to that found in past studies of intravenous anaesthetic agents. Further improvement in the accuracy of midazolam infusion awaits improved understanding of the causes of pharmacokinetic variability.
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Twenty patients undergoing elective procedures on the larynx and pharynx were anaesthetised using a propofol infusion and a bolus of vecuronium. High frequency jet ventilation was employed via a 7 French gauge catheter, with a second catheter being used to measure expired carbon dioxide levels. The Bullard laryngoscope was compared with the Macintosh instrument both for visualising the larynx and subsequently inserting a catheter. ⋯ Using the Bullard laryngoscope, intubation was possible in all 20 patients, in a mean time of 22 (6.8) s. Using the Macintosh laryngoscope only 16 patients could be intubated and this took significantly longer at 34 (18.3) s (p < 0.05). The Bullard laryngoscope and high frequency jet ventilation offer a reliable method of intubating and anaesthetising patients with upper airways pathology and further benefits may accrue in the recovery period.