The effect of volatile anaesthetic agents on the filtration performance of paediatric breathing system filters.

The aim of this study was to determine the filtration performance of five commonly used paediatric breathing system filters following exposure to desflurane, isoflurane and sevoflurane. It has been suggested that oil may degrade the performance of filter material. Volatile anaesthetic vapours are organic and hence may affect the filtration performance of breathing system filters during anaesthesia. This has not been tested for various concentrations of volatile agent, type and duration of exposure. The filtration performance of the filters was measured following exposure to desflurane, isoflurane and sevoflurane at 1 and 2 minimum alveolar concentration (MAC) for 1 and 4 h. Penetration of particles through the Clear-Therm Micro, Clear-Therm Mini and Humid-Vent Filter Pedi increased by between 2.4 and 2.8 times after exposure to desflurane at 2 MAC for 4 h compared to that through unexposed filters (p < 0.0001 for all three filters). Further investigation is required to determine whether this reduction in filtration performance by desflurane is clinically significant.