Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Neuromuscular and cardiovascular advantages of combinations of mivacurium and rocuronium over either drug alone.
We investigated isobolic mixtures of mivacurium and rocuronium to determine if the combination offered any advantages over either drug alone. We used five dose regimens to achieve ED95 x 2: [(1.5 x ED95 mivacurium) + (0.5 x ED95 rocuronium); (1 x ED95 mivacurium) + (1 x ED95 rocuronium); (0.5 x ED95 mivacurium) + (1.5 x ED95 rocuronium); (2 x ED95 mivacurium); (2 x ED95 rocuronium)]. We studied onset time, duration of block, recovery of block, arterial blood pressure and heart rate. ⋯ Onset time was shortest in the rocuronium alone group and was significantly faster in all the rocuronium treated groups compared to mivacurium alone (p < 0.001). Arterial blood pressure and heart rate decreased transiently in the mivacurium alone group but not in the other groups. These results demonstrate increased cardiovascular stability and more rapid onset of block with combinations of mivacurium and rocuronium without significant prolongation of the block.
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison between the Macintosh and the McCoy laryngoscope blades.
The view of the larynx using the Macintosh laryngoscope and the McCoy levering laryngoscope was assessed in 177 adult patients. The view with the McCoy blade in the neutral position and in the position (neutral or elevated) that gave the 'best' view were recorded. The McCoy blade in the neutral position was associated with a lower incidence of grade 1 views and a higher incidence of grade 2 views than the Macintosh blade. ⋯ In 25 patients, the vocal cords could not be seen with the Macintosh blade; in these patients the view was better with the McCoy blade (the cords were visible) on 14 occasions and worse in one (p = 0.001). We conclude that the McCoy blade in its neutral position does not behave identically to the Macintosh blade. The McCoy blade is a useful aid to difficult intubation but should not replace the Macintosh blade as the first choice laryngoscope.
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A 13-year-old boy presenting for correction of bat ears was anaesthetised with thiopentone and suxamethonium, the administration of which was followed by jaw spasm, poor peripheral perfusion (without cyanosis) and marked tachycardia. The procedure was abandoned, dantrolene and Ringer lactate IL were given intravenously and the patient regained consciousness 1 h later. ⋯ Despite a peak serum myoglobin of 58.000 micrograms.l-1 and peak urinary level of 446,000 micrograms.l-1, no renal impairment occurred. Subsequent testing for susceptibility to malignant hyperthermia proved positive for the patient and four other members of the family.
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We pointed out in the first of these two articles that the commonest cause of an anaesthetic disaster in young healthy patients is a loss of airway patency then a failure to intubate occurring unexpectedly in the absence of head or neck pathology. Upper airway obstruction is a very common complication of general anaesthesia and all anaesthetists must be trained in the management of this problem. Less obvious are the changes that can occur in the lower airways which can impair gas exchange by increasing ventilation-perfusion mismatch. This article is concerned with these pathophysiological changes that occur during general anaesthesia.
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The rôle of the laryngeal mask airway for thyroid and parathyroid surgery was studied in 97 consecutive patients. In 50% the technique combined electrical stimulation of the recurrent laryngeal nerve with visualisation of vocal cord movement via a fibreoptic bronchoscope. Stimulation was required in 10% to assist in identifying recurrent laryngeal nerve position during difficult surgical dissection. ⋯ Tracheal intubation was required for seven patients but in only two of these was intubation unplanned. The incidence of postoperative recurrent laryngeal nerve dysfunction was zero. These data suggest that the technique offers a safe alternative in airway management and may provide advantages in terms of preservation of recurrent laryngeal nerve function.