Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison of 8% and 12% sevoflurane for inhalation induction in adults.
Sevoflurane is a non-pungent volatile anaesthetic agent with a low blood-gas solubility coefficient. It has been studied in concentrations of up to 8% for induction of anaesthesia. Previous work has suggested that there may be a ceiling effect with increasing concentration of sevoflurane above 6%, but there are no published studies using 12% sevoflurane. ⋯ Sevoflurane was administered using two adapted datum vaporisers with the interlock removed. Induction with 12% sevoflurane compared to 8% sevoflurane produced a significant decrease in the time to achieve central pupils, corresponding to surgical anaesthesia and the third part of Guedel's stage 3 of anaesthesia (mean time (SD) 201 s (81) and 247 s (39), respectively, p < 0.05). Twelve-percent sevoflurane produced a similar stable cardiovascular profile to 8% sevoflurane, and there was no increase in respiratory complications.
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Comparative Study
Comparison of four different emergency airway access equipment sets on a human patient simulator.
This study used a patient simulator to study the ease of use and efficacy of four currently available cricothyroidotomy sets. We assessed the success of insertion of each piece of equipment and measured the subsequent adequacy of oxygenation and ventilation. ⋯ There was an unacceptably high failure rate in achieving a patent airway when using the 'Transtracheal airway catheter with ENK-flow modulator' and 'Patil's airway'. The pre-assembled and user-friendly 'Quiktrach' set provided the fastest and most effective means of oxygenation in the simulated patient requiring an emergency surgical airway.
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Depth of anaesthesia has proved to be a complex process to quantify. Monitors based on bispectral analysis of the electroencephalogram and auditory evoked potential have been available, but only recently has a monitor based on entropy become available. This study determined state entropy and response entropy in nine healthy volunteers during propofol hypnosis with a brief intervening period of wakefulness. ⋯ However, an overlap was observed in real time indices between different stages of the Observer's Assessment of Alertness/Sedation Scale. Only three of the nine volunteers had explicit memories from the episode of wakefulness. Electroencephalographic entropy monitors seem to have potential for staging clinical hypnotic effects.
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Patients with coronary artery disease presenting for major noncardiac surgery may have indications for both peri-operative beta-blockade and haemodynamic optimisation. The combination of peri-operative cardiorespiratory failure and myocardial ischaemia has a grave prognosis. ⋯ There may, therefore, be a place for both peri-operative beta-blockade and haemodynamic optimisation. The indications for peri-operative beta-blockade and haemodynamic optimisation, the effect of acute beta-blockade on cardiac output in patients with coronary artery disease, and the interaction of peri-operative beta-blockade and haemodynamic optimisation are discussed.