Anaesthesia
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The unique pharmacology of remifentanil makes it a popular intra-operative analgesic. Short-acting opioids like remifentanil have been associated with acute opioid tolerance and/or opioid-induced hyperalgesia, two phenomena which have different mechanisms and are pharmacologically distinct. Clinical studies show heterogeneity of remifentanil infusion regimens, durations of infusion, maintenance of anaesthesia, cumulative dose of remifentanil and pain measures, which makes it difficult to draw conclusions about the incidence of acute tolerance or hyperalgesia. ⋯ Infusion rates greater than 0.2 μg.kg-1 .min-1 are characterised by lower mechanical/pressure/cold/pain thresholds, which suggests hyperalgesia. The use of concurrent multimodal analgesia, especially N-methyl-D-aspartate receptor antagonists, may be an effective preventive strategy. The clinical significance and long-term consequences of these entities is still uncertain.
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Randomized Controlled Trial Comparative Study
A randomised controlled trial comparing the effects of propofol with isoflurane in patients with diastolic dysfunction undergoing coronary artery bypass graft surgery.
There is a strong association between pre-operative diastolic dysfunction and difficulty in weaning from cardiopulmonary bypass. We compared the effects of propofol and isoflurane on left ventricular diastolic function in patients with pre-existing diastolic dysfunction undergoing coronary artery bypass grafting. We randomly allocated 60 patients to receive either propofol or isoflurane anaesthesia, and assessed left ventricular diastolic function using transoesophageal echocardiography. ⋯ Both propofol and isoflurane improved left ventricular diastolic function as evidenced by significant increases in E/A ratios, and significant decreases in deceleration time and isovolumetric relaxation time; the improvement was greater in the isoflurane group (between groups, p = 0.001 for both E/A ratio and deceleration time at T1 and T2 and p = 0.006 for isovolumetric relaxation time at both T1 and T2 ). Furthermore, Em/Am ratio, S, D and S/D ratios were significantly better in the isoflurane group. The administration of isoflurane during cardiac surgery improves diastolic function comparatively more than propofol.
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Multicenter Study
A national survey of practical airway training in UK anaesthetic departments. Time for a national policy?
The Fourth National Audit Project (NAP4) recommended airway training for trainee and trained anaesthetists. As the skills required for management of airway emergencies differ from routine skills and these events are rare, practical training is likely to require training workshops. In 2013, we surveyed all UK National Health Service hospitals to examine the current practices regarding airway training workshops. ⋯ Reported barriers to training include lack of time and departmental or individual interest. Workshop-based airway training is variable in provision, frequency and content, and is often not prioritised by departments or individual trainers. It could be useful if guidance on workshop organisation, frequency and content was considered nationally.
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Randomized Controlled Trial Comparative Study
A prospective randomised study of a rigid video-stylet vs. conventional lightwand intubation in cervical spine-immobilised patients.
Compared with a lightwand which is used blind, Optiscope™ , a rigid video-stylet, can provide direct imaging of airway structures, potentially offering improved conditions in cervical spine-immobilised patients. We randomly assigned 168 patients who required cervical immobilisation during tracheal intubation to use of the Optiscope or the lightwand. ⋯ The incidence of postoperative airway complications was similar in the two groups. The devices were equivalent with respect to initial intubation success rate but the Optiscope yielded slightly longer intubating times.
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Controlled Clinical Trial
High-flow humidified nasal oxygenation vs. standard face mask oxygenation.
Ten healthy volunteers received oxygen for 1 min, 2 min and 3 min at 10 l.min-1 via a face mask, or humidified oxygen at 60 l.min-1 via nasal prongs (OptiflowTM ) with the mouth closed and with the mouth open. The mean (SD) end-tidal oxygen partial pressure after 3 min face mask and Optiflow oxygenation, with mouth closed and open, were: 88.5 (6.2) kPa; 85.6 (6.4) kPa and 48.7 (26.4) kPa, respectively, p = 0.001. The equivalent mean (SD) transcutaneous oxygen partial pressures were: 34.6 (5.4) kPa; 36.4 (6.5) kPa and 25.5 (15.7) kPa, respectively, p = 0.03. High-flow humidified nasal oxygenation for 3 min with the mouth closed was as effective as 3 min face mask oxygenation.