Carbon Dioxide Absorption

Anesthesiologists from the first half of the 20th century were not privileged to visit just one hospital during a day's work. Visits to several institutions might take place in a single day, with the practitioners bringing their own delivery systems and drugs with them as they traveled. Understandably, there was a priority for portability and elimination of waste, because these anesthesiologists paid for the agents themselves. One development that conserved gases and vapors was the use of systems that absorbed expired carbon dioxide and allowed rebreathing of expired gases.

Several ineffectual attempts were made to introduce carbon dioxide absorption methods in the 19th century. John Snow and Alfred Coleman (1828–1902) were motivated to conserve anesthetic gases that escaped into the atmosphere through nonrebreathing valves. Coleman devised a system of absorbing carbon dioxide by passing the expired gases over slaked quick lime.^{[366] [367]} The recovered gases were then used for subsequent anesthetics ( Fig. 1-15 ). Franz Kuhn (1866–1929) described soda lime absorption of exhaled carbon dioxide in 1905, but the report did not attract attention.^[368]

Dennis Jackson demonstrated the use of soda lime absorption to maintain stable levels of anesthesia for several hours in animals with minimal ether consumption.^[369] The animals were given additional oxygen to meet metabolic needs, but the anesthetic gases were rebreathed, resulting in economy and improved maintenance of body temperature and airway humidity. In 1923, Ralph Waters (1884–1979) (see Fig. 1-18B ), working then as an anesthesia practitioner in Sioux City, Iowa, contacted Jackson and devised a soda lime canister for clinical use.^[370] The canister was attached to a breathing hose close to the face, and although it was cumbersome to use, the device was widely distributed. The in-line soda lime canister launched the academic career of Waters, who later became one of the most prominent figures in anesthesiology during the first half of the 20th century. In 1930, Brian C. Sword^[371] altered the Waters canister by attaching it to the chassis of a movable cart with two hoses directed to the airway, one for inspired gases and one for exhaled gases.