Unsatisfactory Inhaled Anesthetics
During the first few decades of the 20th century, practitioners
were searching for new and improved anesthetics. An American anesthesia textbook
written by James T. Gwathmey (1865–1944) (see Fig.
1-18D
) was published in 1914 and briefly discussed more than 600 possible
anesthetic agents for the reader to consider.[146]
By 1930, all successful anesthetic agents except chloroform and nitrous oxide were
explosive. Chloroform by then was thought to be dangerous, and the popularity of
nitrous oxide was curtailed by the need for a nearly hypoxic mixture to provide adequate
anesthesia. Ethyl chloride was the last agent to be introduced in the 19th century
and, like ether, it was flammable. It was a unique agent that was first used as
a spray to induce local anesthesia, but if inhaled, it also produced general anesthesia.
In the early 20th century, several unsatisfactory volatile anesthetics
were introduced. Ethylene was used clinically in 1923. This agent required high
concentrations to achieve anesthesia, had an unpleasant smell, and was explosive.
[147]
Divinyl ether, developed by Chauncey Leake
[148]
(1896–1978), had some advantages over
ether for induction of anesthesia, but it was also flammable and never widely used.
Cyclopropane was introduced in 1934 by Ralph Waters[149]
(1884–1979) and was briefly popular,
but it was violently explosive. The flammable anesthetics prevented the use of surgical
cautery and electronic monitoring. One attempt to produce a nonflammable alternative
to ether and cyclopropane was made in 1935, when trichloroethylene was introduced.
[150]
It was promoted by Christopher L. Hewer[151]
(1896–1986) as a nonexplosive agent, but it was eventually withdrawn when it
was shown to decompose to the toxic nerve poison dechloroacetylene in the presence
of soda lime and to produce phosgene, a severe respiratory irritant, when electrocautery
was used. Clearly, new directions were needed.
