Anaesthesia
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Randomized Controlled Trial Clinical Trial
Learning fibreoptic skills in ear, nose and throat clinics.
We have compared the progress of anaesthetists taught fibreoptic techniques on awake patients in ear, nose and throat clinics with that of anaesthetists taught by traditional methods. Twelve anaesthetists participated in the study and were randomly allocated to the ear, nose and throat group or to the traditional training group. Each individual in the ear, nose and throat group attended the outpatient clinic and performed ten nasendoscopies on awake patient, whose upper airway had been anaesthetised with cocaine, under the supervision of an ear, nose and throat surgeon. ⋯ To assess the effectiveness of the two training methods, each anaesthetist in each group then attempted ten fibreoptic nasotracheal intubations on anaesthetised oral surgery patients. There was no significant difference between either the success rates or mean successful tracheoscopy times between the two groups. Nasendoscopy training in the ear, nose and throat clinic appears to be good way of learning fibreoptic skills, which can then be readily applied to fibreoptic tracheal intubation in anaesthetic practice.
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The triggering of phantom limb pain by subarachnoid or epidural anaesthesia has been well described leading to the suggestion that neuraxial regional anaesthesia is relatively contraindicated in lower limb amputees. We report our experience of the provision of anaesthesia for repeat Caesarean section on two occasions in such a patient. Intrathecal fentanyl and morphine supplementation of bupivacaine successfully abolished peri-operative phantom limb pain, whereas epidural anaesthesia was associated with recurrence of phantom limb pain upon regression of the block.
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An analysis of 1500 laryngeal mask airway uses by one anaesthetist using the standard insertion technique was conducted to determine successful insertion rates, position by fibreoptic larynoscopy, complication rates and whether there is a long-term learning curve. The correlation between laryngeal mask airway placement and modified Mallampati grade was also determined. The first time insertion rate was 95.5% with an overall failure rate after three attempts of 0.4%. ⋯ The vocal cords were visible from the mask aperture bars in 97.1%. Comparison of insertion rates, fibreoptic position and complications for the first and second 750 insertions provides evidence for a 'long' term learning curve. These data could be used as a guide for 'optimal' or expected successful laryngeal mask airway insertion rates in adults undergoing routine anaesthesia.
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Recent published data suggest that despite apparently satisfactory recovery from nondepolarising block (train-of-four ratios in excess of 0.90), even very small doses of additional relaxant may re-establish significant paralysis. We sought to verify this observation and quantify its magnitude. Twelve adult patients were studied under nitrous oxide-propofol-opioid anaesthesia and neuromuscular block was monitored electromyographically. ⋯ The control ED50 of mivacurium (calculated from the initial dose of mivacurium) averaged 43 micrograms.kg-1. When the same dose of drug was given at 95% recovery of the train-of-four ratio, the ED50 was reduced to 19 micrograms.kg-1 (p < 0.0001). Hence, there remains a considerable reduction in the neuromuscular margin of safety even at a train-of-four ratio of 0.95.
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The amount of desflurane required to maintain an end-expired concentration of 8% was measured in 30 ASA 1 and 2 patients undergoing elective spinal surgery. The anaesthetic was administered using a computer-controlled closed circle system. After an initial period during which the expired concentration of desflurane was stabilised (4 min) the rate of uptake showed a bi-exponential decline. Mean cumulative usage of desflurane was 10.1 ml of liquid at 30 min, 14.8 ml at 60 min, 25.4 ml at 120 min, 35.8 at 180 min.