Comparison of work of breathing using drawover and continuous flow anaesthetic breathing systems in children

We compared the work of breathing under general anaesthesia in children using drawover and continuous flow anaesthetic systems. A pilot study was conducted in four children weighing > 20 kg in whom it would usually be considered appropriate to use breathing systems designed for adult anaesthesia. The pilot study compared work of breathing using the Mapleson D breathing system and the Triservice Anaesthetic Apparatus (TSAA). Work of breathing was calculated using the modified Campbell technique that calculates work using a pressure volume loop derived from oesophageal pressure and airway gas volume measurements. We found no difference in the work of breathing when comparing the Mapleson D and the TSAA in children > 20 kg. Following completion of the pilot study, we conducted a study on 10 children weighing between 10 and 20 kg comparing work of breathing using the Mapleson F breathing system and the TSAA. We found no significant difference in the work of breathing between the Mapleson F and the TSAA for these children. The TSAA can therefore be recommended for use down to a lower weight limit of 10 kg.