Anaesthesia
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In 1994, 66% of all surgery in the USA was performed as ambulatory surgery. Day surgery is also expanding to other countries worldwide. To provide safe anaesthesia and good outcomes for longer and more extensive operations performed in ambulatory facilities, patients must be carefully evaluated before surgery, their home readiness must be assessed, and they must fully understand all relevant information. ⋯ If a patient does not have an escort home, the surgical procedure should be cancelled or the patient admitted to the hospital. As the number of patients and complexity of scheduled surgical procedures increases, the outcome of day surgery will increasingly depend on the anaesthetist's skills. The recently introduced short-acting drugs may further improve the outcome after day surgery by facilitating rapid recovery and an early return to normal daily activities.
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Although many anaesthesia machines are equipped with circle rebreathing systems, inhalational anaesthesia remains frequently performed using relatively high fresh-gas flows. The major advantages of rebreathing techniques can be achieved only if the fresh-gas flow is reduced to 1 l.min-1 or less. Although there are potential risks associated with low-flow anaesthesia, modern anaesthesia machines meet all the technical requirements for the safe use of low-flow techniques if they are used in conjunction with equipment for monitoring inhaled and exhaled gas concentrations; these monitors are already increasingly available and, in the near future, are likely to become an obligatory safety standard in many countries. For both economic and ecological reasons, the use of new inhalational anaesthetics, with low tissue solubility and low anaesthetic potency, can be justified only if the efficiency of administration is optimised by using low-flow anaesthetic techniques.
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The relevant physiological and pharmacokinetic differences between adults and infants and children are considered, and the advantages and disadvantages of the available inhalational anaesthetics are discussed. Desflurane shows promise as a new paediatric anaesthetic as it allows rapid changes in the depth of anaesthesia. However, irritant effects on the airways make desflurane unsuitable for induction. Desflurane anaesthesia, following halothane induction, seems to be well tolerated.
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Molecular sieves are used in industry to 'scrub' industrial gases. We examined, during simulated low-flow closed system anaesthesia, (1) the carbon dioxide adsorbing potential of molecular sieves and (2) the reactivity of the sieves compared to soda lime using sevoflurane as an indicator. A low-flow anaesthetic system containing 13X molecular sieves was connected to a model lung. ⋯ No increase in compound A was observed when molecular sieves were used for carbon dioxide removal. The highest mean (SD) temperature of the molecular sieves was 41.5 (3.2) degrees C. Molecular sieves are effective adsorbents of carbon dioxide when used in a simulated low-flow, closed anaesthetic system.(ABSTRACT TRUNCATED AT 250 WORDS)
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The Ohmeda Universal PAC drawover apparatus, a modification of an earlier series of vapour-specific vaporizers, was assessed with regard to its output under varying gas flows and temperatures and its clinical usage with isoflurane and enflurane. The device tended to over-deliver vapour, particularly at low flows and at high temperatures. ⋯ The device was not assessed with ether or halothane. The robust construction, relatively large capacity and thermocompensation make it suitable for field or military anaesthesia.