Vaporisers are designed to ensure the passage of anaesthetic from a liquid to vapour state. In addition, they ensure delivery of a volatile anaesthetic at controlled concentrations.
Vaporisers were initially used for ether and chloroform. The first models used a simple draw - over design (1) then, from 1917 Henry E.G. Boyle produced vaporisers using agitation or bubbling in a glass (2), and later a metal (3) container (now called Plenum vaporisers).
They could only be used for a single specific anaesthetic. These were for ether, then chloroform and finally the fluorinated agents from 1960 onwards (4). But the later vaporisers quickly evolved to be more precise and to allow for the cooling produced by the evaporation of the agent. Again, each halogenated agent had a specific vaporiser.
1 A draw–over vaporiser.
2 A plenum glass Boyle vaporiser.
3 a metallic bubble-through vaporiser.
4 a plenum glass vaporiser;
5 the Fluotec, a plenum temperature–compensated halothane vaporiser made by Cyprane Ltd (UK).