British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of preoperative with postoperative lignocaine infiltration on postoperative analgesic requirements.
Ninety patients undergoing appendicectomy were allocated randomly to receive 1.5% lignocaine 15 ml with adrenaline infiltrated into the proposed wound line 3 min before incision, lignocaine 15 ml with adrenaline infiltrated into the wound on closure or no wound infiltration. After operation, all patients received pethidine by patient-controlled analgesia. ⋯ There were no significant differences in the cumulative dose of pethidine required or pain scores between the three groups at any time point after operation. We conclude that pre-incisional infiltration with 1.5% lignocaine had no advantage compared with infiltration at wound closure or no wound infiltration in reducing postoperative analgesic requirements or pain scores after appendicectomy.
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We have studied plasma protein binding of alfentanil in 10 patients given a mean total dose of 949 micrograms kg-1 as the principal anaesthetic agent for coronary artery bypass grafting. The mean unbound fraction of plasma alfentanil increased from 0.09 to 0.16 after administration of heparin and to 0.26 after beginning cardiopulmonary bypass (CPB). ⋯ Within the first 1 min of CPB, total alfentanil concentration had decreased by more than the unbound concentration and the decrease observed in the latter disappeared rapidly. From induction of anaesthesia until awakening of the patient, plasma protein binding of alfentanil was related significantly (P = 0.0166) to the serum concentration of orosomucoid (alpha 1-acid glyco-protein).
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Comment Letter Comparative Study
Comparison of the Belscope with the Macintosh laryngoscope.
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We have described the design and design considerations of the desflurane Tec 6 "vaporizer" and have tested its performance characteristics. The vaporizer differs from previous vaporizers designed for anaesthesia in that electromechanical rather than mechanical controls accommodate the different physical characteristics of desflurane. This design, while offering perhaps an increased risk of failure (owing to sophisticated electronic components and circuitry), on the other hand offers the decreased likelihood of accidental delivery of very large concentrations of liquid anaesthetic resulting from tilting or overfilling and alarms and warnings not previously incorporated into the design of anaesthetic vaporizers. The output characteristics of the vaporizer are as expected, based on the design: desflurane concentration output in oxygen has accuracy (+/- 15%) which is similar to that of the mechanical vaporizers; output decreases when nitrous oxide is added owing to the lower viscosity, but remains within 20% of the dial setting or 0.5% absolute.
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A late development model of the Tec 6 vaporizer for the administration of desflurane vapour has been evaluated. It is heated electrically and has both electronic monitors of vaporizer function and alarms. The new filling system is a significant improvement over previous Tec filling systems. The vaporizer requires a warm-up period before it may be used, but when activated it provides an output that is approximately linear between 1 and 18% vapour concentrations, at flow rates between 200 ml min-1 and 10 litre min-1.