British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Cricoid pressure applied after placement of laryngeal mask impedes subsequent fibreoptic tracheal intubation through mask.
We studied 70 patients to see if cricoid pressure applied after insertion of the laryngeal mask altered the success rate of tracheal intubation through the mask. After induction of anaesthesia and neuromuscular blockade, patients were randomly allocated to have either cricoid pressure (Group C) or sham pressure (Group S). The view of the glottis through the laryngeal mask was assessed before and after the test pressure, and tracheal intubation through the mask was attempted using a fibreoptic bronchoscope. ⋯ The success rate of tracheal intubation in group S (31 patients) was significantly higher than in group C (21 patients, P << 0.001; 95% CI for difference: 9-48%). The time for insertion of the fibrescope in group S (median (95% CI): 12 (11-12) s) was significantly faster than in group C (16 (14-17) s, P << 0.001; 95% CI for difference: 3-6 s), and the time for tracheal intubation in group S (16 (15-18) s) was significantly faster than in group C (22 (19-24) s, P < 0.0005; 95% CI for difference: 3-7 s). Cricoid pressure after insertion of the laryngeal mask makes tracheal intubation through the mask significantly more difficult.
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Randomized Controlled Trial Comparative Study Clinical Trial
Which is most pungent: isoflurane, sevoflurane or desflurane?
We compared the pungency and tolerability of three inhaled anaesthetics in a randomized, double-blind study. Eighty-one unpremedicated patients (n = 27, each group) inhaled 2 MAC of isoflurane (2.3%), desflurane (12%) or sevoflurane (4%) for 60 s from an anaesthetic breathing circuit via a mask. Two blinded observers recorded coughing, complaints of burning and irritation, and how long the inhalation was tolerated. ⋯ All sevoflurane, 20 isoflurane and seven desflurane patients completed the study period (average 60, 49 and 33 s, respectively, P < 0.05). The irritability grading was: desflurane > isoflurane > sevoflurane (P < 0.05). Sevoflurane is the least irritating agent for inhalation at 2 MAC concentration.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of intravenous and oral ketoprofen for postoperative pain after adenoidectomy in children.
One hundred children, aged 1-9 yr, undergoing adenoidectomy were randomized to receive ketoprofen 1 mg kg-1 either i.v. with an oral placebo (n = 40) or ketoprofen 1 mg kg-1 orally with an i.v. placebo (n = 40), or both oral and i.v. placebo (n = 20). The study design was prospective and double blind with parallel groups. The pain was assessed at rest and during swallowing using the Maunuksela pain scale (0 = no pain, 10 = worst possible pain) after surgery for 3 h. ⋯ Children in the i.v. group needed significantly less doses (1, 1-3; median and 10th/90th percentiles) of rescue analgesic compared with the oral group (2, 1-3; P = 0.024). Of those who needed rescue analgesic, three out of 30 children in the i.v. group required three or more doses of fentanyl compared with 10 out of 28 children in the oral group. There were no differences between the groups with respect to pain scores, operation times, perioperative bleeding or frequency of adverse events.
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Randomized Controlled Trial Clinical Trial
Randomized study of intravenous fluid preload before epidural analgesia during labour.
We performed a randomized controlled trial of the effect of intravenous fluid preload on maternal hypotension and fetal heart rate (FHR) changes in labour after the first epidural injection. Group 1 (49 women) received 1 litre of crystalloid preload. Group 2 (46 women) received no preload. ⋯ Deterioration in FHR pattern was found in four women in group 1 and 11 in group 2 (P = 0.08). This study has not shown a significant increase in the incidence of hypotension when intravenous preload is omitted before epidural analgesia using a low concentration of bupivacaine during labour. Because of the clinical importance of the difference in the rate of FHR deterioration between the two groups, we continue to administer preload for high-risk cases.
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We investigated the safety of a patient-maintained system that allows individuals to operate a target-controlled infusion of propofol to achieve sedation. Ten healthy volunteers were recruited and instructed to try to anaesthetize themselves with the system. A target-controlled infusion of propofol was set to deliver a target propofol concentration of 1 microgram ml-1, and the subjects allowed to increase the target in increments of 0.2 microgram ml-1 by pressing a control button twice in 1 s. ⋯ Two subjects became oversedated, one of whom was unrousable with loss of eyelash reflex. No subject could recall the keyword, although one recognized it from a list of 10 words. We conclude that the patient-maintained sedation system described could not be guaranteed to produce only conscious sedation in all patients, and that close clinical supervision by an anaesthetist would still be required for safe operation.