Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Anaesthesia for day-care arthroscopy. A comparison between desflurane and isoflurane.
A study was undertaken to compare desflurane- and isoflurane-based anaesthesia in patients undergoing day-care arthroscopic surgery. Anaesthesia was induced with propofol 2-3 mg.kg-1 and a laryngeal mask airway was inserted after loss of the eyelash reflex. Patients were then randomly divided into two groups to receive maintenance anaesthesia with either isoflurane or desflurane delivered in oxygen and nitrous oxide. ⋯ The mood adjective checklist showed that patients in the isoflurane group had a greater total mood score and were more calm than those in the desflurane group; this was particularly evident 2 h after anaesthesia. The discharge times were similar for the two groups. Desflurane is a satisfactory alternative to isoflurane for day care anaesthesia.
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Randomized Controlled Trial Clinical Trial
The use of the McCoy laryngoscope in patients with simulated cervical spine injuries.
We studied the laryngoscopic view in 167 patients with their head and necks held in the neutral position with manual in-line stabilisation and cricoid pressure to simulate the patient with a suspected cervical spine injury. Each patient underwent laryngoscopy using both a McCoy and a Macintosh laryngoscope. The best view obtained by each larngoscope was graded according to standard guidelines. ⋯ It improved the Macintosh grade by 1 grade in 41% and by 2 grades in 8% (p < 0.001). Difficult laryngoscopy, defined as the inability to see the glottis (grade 3 or 4), was found in 56 (33%) with the Macintosh laryngoscope and only eight (5%) (P < 0.001) with the McCoy laryngoscope. We suggest that patients with a suspected cervical spine injury and a full stomach should be intubated using a McCoy in preference to a Macintosh laryngoscope.
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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 hypothesis that anaesthetic uptake during maintenance of anaesthesia is related to cardiac output was tested on 21 patients undergoing cardiac surgery. Using a computer-controlled closed breathing system, enflurane was administered to maintain an end-expired concentration of 1%. ⋯ A clear qualitative but not quantitative relationship was demonstrated. Changes in anaesthetic requirements at a constant end-expired concentration are a better guide to changes in cardiac output than changes in end-expired carbon dioxide with constant ventilation in patients undergoing cardiac surgery.
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Randomized Controlled Trial Clinical Trial
Antiemetic efficacy of prophylactic ondansetron in laparoscopic cholecystectomy. A randomised, double-blind, placebo-controlled trial.
The antiemetic efficacy of ondansetron given prophylactically was investigated in a randomised, double-blind, placebo-controlled trial of 63 patients undergoing laparoscopic cholecystectomy. The patients received intravenously prior to anaesthesia either ondansetron 4 mg or placebo. The same standardised general anaesthetic technique was used. ⋯ The proportions of patients given rescue antiemetic medication were 45% and 44%, respectively. No clinically important adverse events were observed. In conclusion, ondansetron given prior to anaesthesia in a dosage of 4 mg did not prevent postoperative nausea and vomiting after laparoscopic cholecystectomy.