Anaesthesia
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Randomized Controlled Trial
The effects of perineural dexmedetomidine on the pharmacodynamic profile of femoral nerve block: a dose-finding randomised, controlled, double-blind study.
This randomised, controlled, double-blind study investigated the effects of different doses of perineural dexmedetomidine on the pharmacodynamic profile of femoral nerve block in patients undergoing arthroscopic knee surgery. Ultrasound-guided femoral nerve block was performed before general anaesthesia using 25 ml of bupivacaine 0.5% combined with normal saline in the control group, and 25 μg, 50 μg or 75 μg of dexmedetomidine in three treatment groups (n = 15 for each group). All patients received a standard general anaesthetic and multimodal postoperative analgesic regimen. ⋯ The total 24-h postoperative morphine consumption was 7.6 (5.1) mg in the control group, and 6.5 (3.5), 3.9 (3.4), 1.8 (2.6) in the 25 μg, 50 μg and 75 μg treatment groups, respectively. Postoperative morphine consumption was significantly higher in the control group compared with the 50 μg (p = 0.045) and the 75 μg (p = 0.001) treatment groups. The best analgesic profile was achieved at the 75 μg dose, but this was associated with increased risk of hypotension.
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This study compared two methods of controlling the intracuff pressure in laryngeal mask airways. One hundred and eighty patients were randomly assigned into two groups. In the first group (n = 90), after training, the intracuff pressure was controlled using digital palpation of the pilot balloon. ⋯ The median (IQR [range]) intracuff pressure in the palpation group was 130 (125-130 [120-130]) cmH2 O compared with 29 (20-39 [5-60]) cmH2 O in the manometry group (p < 0.001). In the palpation group, 37% of patients experienced pharyngolaryngeal complications vs. 12% in the manometry group (p < 0.001). We conclude that the digital palpation technique is not a suitable alternative to manometry in controlling the intracuff pressure in laryngeal mask airways.
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Concerns have been raised about the effects on cognition of anaesthesia for surgery, especially in elderly people. We recorded cognitive decline in a cohort of 394 people (198 women) with median (IQR) age at recruitment of 72.6 (66.6-77.8) years, of whom 109 had moderate or major surgery during a median (IQR) follow-up of 4.1 (2.0-7.6) years. Cognitive decline was more rapid in people who on recruitment were: older, p = 0.0003; male, p = 0.027; had worse cognition, p < 0.0001; or carried the ε4 allele of apoliprotein E (APOEε4), p = 0.008; and after an operation if cognitive impairment was already diagnosed, p = 0.0001. Cognitive decline appears to accelerate after surgery in elderly patients diagnosed with cognitive impairment, but not other elderly patients.
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We undertook a randomised control led trial to evaluate the effect of a prototype device which attaches to the intravenous drug administration port, and allows injection of intravenous drugs only after the user scans the barcode on the syringe label. This requires two steps: first, that the correct drug label is generated; and second, that the syringe-with-label is scanned before administration. ⋯ A total of 182 intravenous drug administrations occurred in the study (91 in each group). We found that the use of our prototype increased safe drug administration behaviour in experienced anaesthetists; 33 (36.3% [95% CI 26-47%]) vs. 91 (100% [95% CI 96-100%]) in the control and intervention groups, respectively (p = 0.0001).
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In addition to being effective and easy to learn how to use, the ideal laryngoscope should be associated with minimal reduction in skill performance during gaps in practice over time. We compared the time taken to intubate the trachea of a manikin by novice medical students immediately after training, and then after 1 month, with no intervening practice. We designed a two-period, four-group, randomised, cross-over trial to compare the Macintosh, Venner(™) A. ⋯ P. Advance was worse compared with the Macintosh and the Airtraq. While the clinical significance of this is doubtful, we believe that reliable and consistent performance at laryngoscopy is desirable; for the devices that we tested, this requires regular practice.