A passive method of disposal of expired anaesthetic gases.

A passive method for the disposal of waste anaesthetic gases is described. The resistance characteristics of the collector valve, the balancing device and the disposal system were studied. It was found that the resistances offered by the conduction channels and the terminal exhaust valve were extremely low. The collector valves were found to be responsible for most of the expiratory resistance. Swabs taken from various components of the system showed that these were contaminated mainly with commensals and non-pathogenic organisms.