Anaesthesia
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The effect of flow on the filtration performance of six different types of filter intended for use in paediatric anaesthesia was measured by challenging the filters with sodium chloride particles at five different flows: 6, 10, 15, 20 and 30 l x min(-1). Twenty-five unused samples of each filter type were evaluated. The pressure drop across each filter was measured at the same flows as those used to measure penetration. ⋯ Allowing for the variation in pressure drop, the penetration of particles increased fairly linearly as flow increased for all six filter types. The increase in penetration per unit increase in flow varied from 0.11 to 0.82% per litre per minute. Over the range of flows studied, the increase in penetration with flow is fairly predictable.
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Direct laryngoscopy is performed regularly in paediatric anaesthetic practice for the purpose of intubating a patient's trachea. A minimum illumination of 700 lux at a distance of 20 mm has been suggested in a draft standard for laryngoscopes from the International Organization for Standardization. We investigated the minimum and optimum illumination required by anaesthetists during laryngoscopy. ⋯ Two of the six combinations could produce more than 700 lux. In all, 78% and 54% of anaesthetists considered 700 lux too bright with a halogen and xenon bulb, respectively. Our study suggests that the proposed standard of 700 lux may possibly be too bright.