British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
The reinforced laryngeal mask airway for dento-alveolar surgery.
We have evaluated the reinforced laryngeal mask airway (LMA) for use during dento-alveolar surgery in 100 ASA I and II day-case patients allocated randomly to receive either a nasotracheal tube or reinforced LMA. We recorded ease of airway insertion, airway complications, quality of recovery and replies to a 24-h postoperative questionnaire. In addition, a fibreoptic assessment was made of laryngotracheal soiling, and the effect of head movement and the position of the reinforced LMA. ⋯ There were no differences in postoperative complications. No surgeon reported poor access to the operating field. Overall the reinforced LMA provided satisfactory conditions for this surgery but vigilance of the airway was required, especially at the time of extraction.
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Sedation may influence the responses of some experimental pain models used to test analgesic efficacy. In this study we compared the effects of a sedative (propofol) and analgesic (alfentanil) on: nociceptive reflex to single and repeated electrical stimulations; mechanical pressure pain; and evoked potentials elicited by nociceptive (electrical and laser) and non-nociceptive (acoustical) stimulation. We studied 12 healthy volunteers with two subanaesthetic concentrations of propofol and two analgesic concentrations of alfentanil. ⋯ The pressure pain tolerance thresholds were increased significantly by alfentanil, whereas propofol significantly decreased the thresholds (hyperalgesia). Propofol and alfentanil induced similar reductions in the amplitudes of the evoked potentials elicited by nociceptive (electrical and laser) and non-nociceptive (acoustical) stimulation, whereas only alfentanil reduced the perceived pain to nociceptive stimulations. We have shown that sedation can influence both the psychophysical and electrophysiological responses of some experimental pain tests used to measure analgesic efficacy, and that propofol in subhypnotic doses, has no analgesic effect on painful electrical and heat stimulations, but has a hyperalgesic effect on mechanical pressure pain.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of propofol and a propofol-methohexitone mixture for induction of day-case anaesthesia.
We studied 99 patients undergoing day-case urological surgery, allocated randomly to receive a sleep dose of either 1% propofol or a mixture of equal volumes of 1% propofol and 0.5% methohexitone, and thereafter a standardized anaesthetic. With the exception of minor differences in intraoperative heart rate there were no significant differences between the two groups in induction properties and complications, intraoperative variables, rate of recovery or postoperative sequelae.
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Comparative Study
Quantitative EEG in assessment of anaesthetic depth: comparative study of methodology.
Methodology for assessment of depth of anaesthesia based on analysis of the electroencephalogram (EEG) is controversial. Techniques range from display of single measures, for example median value of the frequency spectrum, to dedicated pattern recognition systems based on measures of several EEG features. We have compared the performance of four techniques using tape-recorded data from 23 patients anaesthetized with either halothane or isoflurane using standardized regimens. ⋯ Dose-response curves are presented for stepwise increases in stable end-tidal concentrations of each agent. Results indicated considerable inter-patient variability and the limitations of single EEG measures, particularly with deeper anaesthesia producing a burst suppression pattern in the EEG. Pattern recognition techniques reduced these difficulties and appeared to be promising over a wide range of anaesthetic levels.