From 1900 onwards, anaesthetic devices were created that allowed the delivery of controlled concentrations of agent.
In 1902 Braun invented the ‘Narko’ system which could combine ether and chloroform.
In 1908, Professor Nélaton asked his assistant, Louis Ombrédanne to construct a safe ether anaesthetic device. This he did, with the aid of his chauffeur. The prototype is shown here (but without the English modification which allowed the addition of ether). The prototypes were produced by the Collin factory in Paris. All these devices are still numbered. It was simple to use. By moving the cursor, the concentration of ether could be varied. At zero concentration, the patient inspired only air and exhaled carbon dioxide. At level 8 he inspired only ether and expired air. The device produced a degree of safety.
Nevertheless, it had a considerable world – wide success since more than 70,000 units were sold. It continued in use world – wide until 1970!
Other devices were also produced including the Ricard device for chloroform (1913).
In 1920 the Dupuy de Frenelle device appeared which allowed the mixture of three agents (ether, chloroform and ethyl chloride) followed by the Dufaut apparatus in 1922 with two agents employed, followed by several others.
The introduction of cyclopropane, a highly explosive agent led to the use of closed-circuit devices with a CO2 absorber but these were not used in France until after 1940.