IMAGES IN ANESTHESIA
The distinctly Canadian origins of cyclopropane
Kim E. Turner, BScPhm, MSc, MD, FRCPC
Received: 10 May 2018 / Accepted: 10 May 2018
Ó Canadian Anesthesiologists’ Society 2018
There was a worldwide quest during the early part of the
20th century to discover an anesthetic agent that could
augment or replace the commonly used agents of the time –
namely ether, choloroform, and nitrous oxide. Among
those pursuing this line of research was Dr. Velyien E.
Henderson, Professor of Pharmacology at the University of
Toronto, working with Dr. W. Easson Brown, an assistant
in the University’s Department of Pharmacology, who was
an anesthesiologist at the Toronto General Hospital.
Their initial experimentation with propylene had shown
promise when the gas was freshly prepared. After storage
under pressure in steel tanks, however, its administration
induced nausea and cardiac irregularities. Dr. George H.
Lucas, a new chemist working with Dr. Henderson,
wondered if the toxic contaminant might be
cyclopropane, formed when propylene is prepared.
Indeed, his analysis of the stored propylene revealed that
its isomer, cyclopropane, was also present in the stored
tank. In 1928, Dr. Lucas subsequently isolated and puriﬁed
a sample of cyclopropane, believing it to be a toxic
To his great surprise, when the cyclopropane
was tested on two kittens in a bell jar, ‘‘the animals went to
sleep quietly … and recovered rapidly’’.
study, Dr. Brown administered cyclopropane to Dr.
Henderson, the ﬁrst human to receive cyclopropane.
Several demonstrations of cyclopropane’s use on other
members of the laboratory staff (including Dr. Lucas) soon
The Toronto group went on to further
Figure ‘‘No. 6 Amplon’’ cylinder (the tradename assigned by the
manufacturer E.R. Squibb and Sons) was designed to yield 6 gallons
(22.7 L) of cyclopropane administered at a concentration of 12-35%.
In a series of 350 cases reported in 1934, Dr. Grifﬁth estimated that he
used an average of 1.79 gallons per case at a cost of 50 cents per
gallon that, although costly at the time, was considerably less
expensive than when the gas was ﬁrst produced at $2.00 per gallon.
(Image courtesy of the RBC Art and Heritage Centre of McGill
University Health Centre)
K. E. Turner, BScPhm, MSc, MD, FRCPC (&)
Department of Anesthesiology & Perioperative Medicine and
Public Health Sciences, Medical Lead Health Quality Programs,
Queen’s University, Kingston, ON, Canada
Can J Anesth/J Can Anesth