Anaesthesia
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Randomized Controlled Trial Comparative Study
A randomised controlled trial comparing the GlideScope(®) and the Macintosh laryngoscope for double-lumen endobronchial intubation.
Double-lumen endobronchial tubes are the most common method of achieving lung isolation and one-lung ventilation during thoracic anaesthesia and surgery. We compared the clinical performance of the Macintosh laryngoscope and the GlideScope(®) during endobronchial intubation with a double-lumen tube. Seventy patients with no predictors for difficult laryngoscopy were allocated randomly to the Macintosh laryngoscope or GlideScope. ⋯ On a numerical rating scale (scored from 0 to 10), the 30 anaesthetists who took part in the study rated endobronchial intubation overall as easier using the Macintosh compared with the GlideScope, 2 (1-3 [0-8]) vs 3 (2-6 [0-10]), respectively, p = 0.003. Postoperative voice changes were also less common in the Macintosh group (8 (22%) vs 17 (58%), p = 0.045). Anaesthetists found the GlideScope more difficult to use than the Macintosh laryngoscope and endobronchial intubation took longer; therefore, we cannot recommend its routine use with double-lumen tubes in patients who are predicted to have a normal airway.
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This study compared the predicted effect-site concentration of propofol at loss and recovery of consciousness when using target-controlled infusion devices with the same pharmacokinetic model (Marsh) but a different plasma effect-site equilibration rate constant (ke0 ), the Diprifusor(TM) (ke0 0.26 min(-1) ) and Base Primea™ (ke0 1.21 min(-1) ). We studied 60 female patients undergoing minor gynaecological surgery under general anaesthesia. ⋯ In conclusion, the effect-site concentration of propofol differs depending on the ke0 , despite the use of the same pharmacokinetic model. Therefore, the ke0 should be considered when predicting loss and recovery of consciousness based on the effect-site concentration of propofol.
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Observational Study
The relationship between experience and mental workload in anaesthetic practice: an observational study.
Mental workload is seen as a key factor in defining performance and expertise in some complex work environments, but there are no validated instruments for assessing mental workload in anaesthesia. We studied the mental workload of 20 anaesthetists of varying levels of experience, during five routine cases each, by measuring the delay in their responses to a frequently, but randomly, administered vibrotactile stimulus as a secondary task. We delivered, and recorded response times for, 6096 stimuli, with a median (range) of 55.5 (9-178) responses per case. ⋯ However, average differences between trainees and qualified practitioners in response times to the stimulus were overshadowed by differences between subjects at the same level of experience. Finally, although the number of 'hands full' responses was small, removing these from the analysis had a greater effect than expected, suggesting that the 'hands full' condition is not random, but varies with experience and may be independently associated with expertise. This method appears feasible for use in clinical practice and may, with refinement, aid the identification and tracking of the development of expertise in anaesthetic trainees.