Anaesthesia
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Surgical procedures that involve a local anaesthetic block are often accompanied by light general anaesthesia. It is possible that under these circumstances, the patients are more likely to register auditory events while apparently unconscious. Two groups of children were exposed to auditory stimuli during surgery; one group received a lighter level of anaesthesia than the other. ⋯ The light anaesthesia group retained more items than did the other two groups but this difference was significant (p less than 0.05) only when compared with the other experimental group. This is not very strong evidence of auditory registration, but a greater effect might be found with exposure to emotionally significant material. It is suggested that patients should be protected from unfortunate theatre conversation.
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Comparative Study
Pregnanolone emulsion. A new steroid preparation for intravenous anaesthesia: an experimental study in mice.
The anaesthetic activity of pregnanolone (a metabolite of progesterone) in emulsion formulation administered intravenously to male mice was compared with that of Althesin. The loss of righting reflex for 15 seconds was used to estimate the anaesthetic effect. The mean anaesthetic dose (AD50) for the pregnanolone emulsion was 5.25 mg/kg and for Althesin, 2.8 mg/kg. ⋯ The onset of action was fast for both drugs, with only minor signs of excitation, and recovery was rapid and without excitation. The results indicate that the anaesthetic properties of pregnanolone emulsion are very similar to those of Althesin. Further studies will show whether it can fill the major vacuum left in anaesthetic practice after the withdrawal of Althesin.
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A study was undertaken to determine the incidence, magnitude and direction of catheter migration in 100 patients who had epidural analgesia for pain relief in labour. Over 50% of catheters migrated from the original position at siting. The relevance of this migration and the usefulness of its measurement are discussed.