Economics of low-flow anaesthesia in children

We have measured the consumption of isoflurane and fresh gas flows in 77 infants and children during 20 all-day operating sessions using either the enclosed Mapleson A or the circle absorber mode of the Carden 'Ventmasta' ventilator. The average consumption (SD) of isoflurane in 37 patients anaesthetised using the A mode of the Carden system with a mean fresh gas flow of 2.61 min-1 was 11.1 (4.2) g.h-1, while that in 40 patients anaesthetised using the circle absorber mode with a mean fresh gas flow of 1.21 min-1 was 4.7 (1.0) g.h-1. These figures represent an overall saving of 58% in the use of isoflurane (p < 0.0001) and a mean reduction in fresh gas flow of 54% (p < 0.0001) as a result of using low-flow anaesthesia. With the addition of small bore breathing hoses the adult circle absorber system was practical to use in both infants and children. These findings should stimulate interest in the use of low-flow techniques in children.