Oxford Vaporiser

WLMD ID: almv
The Nuffield Department of Anaesthetics at the University of Oxford was established in 1937.  Its first Chairman was Dr. Robert R. Macintosh (1897-1989).  He built a research staff of experts in many fields in order to develop improved anesthesia techniques and equipment. Much of their effort was at first directed to assisting the British armed forces.  In 1941, the Department introduced the Oxford Vaporiser, a temperature-compensated circle-breathing apparatus for ether anesthesia.  This example was collected by Dr. Ralph M. Tovell during his service as the U. S. Army’s Senior Consultant in Anesthesia to the Chief Surgeon, European Theatre of Operations.

Catalog Record: Oxford Vaporiser

Access Key: almv
Accession No.: 2008-01-03-1 G

Title: Oxford Vaporizer.

Author: Epstein, Hans G., 1909-2002.
Author: Macintosh, R. R. (Robert Reynolds), Sir, 1897-1989.
Author: Mendelssohn, K. (Kurt Alfred Georg), 1906-1980.
Author: Oak, A. V.

Publisher: [Oxford?] : [Morris Motors Ltd?], [between 1941 and 1947?].

Physical Descript 1 vaporizer : metals, plastics, enamel, rubber, glass ; 28.5 x 30 x 32 cm.

Subject: Vaporizers.
Subject: Ether, Ethyl.
Subject: Military Medicine – Great Britain.
Subject: World War II.

Note Type: General
Notes: The early year in the date range for the possible year of manufacture of this
example is based on the year that R.R. Macintosh, MD, H.G. Epstein, PhD, and
K. Mendelssohn, PhD, introduced the Oxford Vaporiser in the Lancet. The end
date is an estimate. The end-date is based on the following from, “A History
of the Nuffield Department of Anaesthetics, Oxford, 1937-1987”: “Manufacture
of the Oxford Vaporizer continued at Morris Motors until 1947” (pg. 57). The
date range could change if documentation, or expert opinion, indicates that
it should be corrected.

Note Type: General
Notes: The names of the designers came from the 1941 article by Epstein, Macintosh
and Mendelssohn published in The Lancet.

Note Type: Citation
Notes: Ball C, Westhorpe R. The Oxford vaporizer. Anaesth Intensive Care.

Note Type: Citation
Notes: Beinart J. Anaesthetics in difficult conditions (1937-1945). In: A History of
the Nuffield Department of Anaesthetics, Oxford, 1937-1987. Oxford: Oxford
University Press; 1987;54-59.

Note Type: Citation
Notes: Elam J. The Oxford ether vaporizer. Anesth Analg. 1944;23(4):164-170.
aspx. Accessed February 27, 2015.

Note Type: Citation
Notes: Epstein HG, Macintosh RR, Mendelssohn K. The Oxford vaporiser no. 1. Lancet.
July 19, 1941;238(6151):62-64.

Note Type: Citation
Notes: Maltby JR, Epstein H. Epstein Macintosh Oxford (EMO) Vaporizer: Hans G.
Epstein (1909- ). In> Maltby JR, ed. Notable Names In Anaesthesia. London:
Royal Society of Medicine Press Limited; 2002:56-59.

Note Type: Citation
Notes: Maltby JR. Macintosh Laryngoscope Blade: Sir Robert Reynolds Macintosh
(1897-1989). In: Notable Names In Anaesthesia. London: Royal Society of
Medicine Press Limited; 2002:120-122.

Note Type: Citation
Notes: Prys-Roberts C. The evolution of Anaesthesia in the British Isles. In: Eger
ED II, Saidman LJ, Westhorpe, RN, eds. The Wondrous Story of Anesthesia. New
York: Springer; 2014:395-396.

Note Type: Physical Description
Notes: One round ether vaporizer; On the base at the front of the vaporizer is a
fluid level for ether; On the front above this is an ether concentration
control lever that moves horizontally along a line marked from 0 to 25;
Engraved along a metal band that wraps around the center of the vaporizer is,
“OXFORD VAPORISER”; In smaller lettering, to the left of this text, the
following numbers are also engraved along this band: 2616/4; The filling port
for water is located in back on the left and the filling port for ether is
located in back on the right; A handle is located on top of the vaporizer and
rubber concertina bellows sit on top just behind the handle; Embossed on the
bottom of the vaporizer is, “BRIT. PROV PAT No 12561/40”; The vaporizer is
stored in a rectangular case, possibly made of compressed fiberboard, and
coated in black enamel; The top of this example has an irregularly shaped
hole broken open in the center; The case measures 32.5 x 34 x 37.5 cm; In the
case with the vaporizer are a number of other items all badly aged and or
corroded; They include an oronasal mask, valves, connectors, rubber tubing,
mask harness, a red nasal tube[?], and a metal Connell airway with an elbow
connector; Inside the case is a label marked with, “IMPORTANT [new line] The
oxford Vaporiser is a scientific apparatus and must be handled with care.
[new line] The transit case is to be used for local movement only; for
transporting the vaporiser by road, rail, etc., the transit case must be
properly packed in a case made for the purpose. [new line] Straw, wood wool,
etc., must not come into contract with the vaporiser itself. [new line] If
repairs become necessary, the vaporiser should be returned complete with
accessories to [new line] MORRIS MOTORS LTD., [new line] GOWLEY, OXFORD,
[new line] ENGLAND [new line] to whom a separate advice note, quoting the
serial number, should be sent. [new line] Generally, it will be possible to
despatch a replacement vaporiser ex[?} stock.”

Note Type: Reproduction
Notes: Photographed by Mr. Steve Donisch November 13, 2014.

Note Type: Historical
Notes: Professor Robert R. Macintosh (later Sir Robert), the first chair of
anaesthetics at Oxford University, believed that anaesthetists working in
field hospitals and remote locations during WW II would not always have gas
cylinders available to them and thus would need a portable and accurate
device for the safe and effective administration of ether. He worked with
physicist Hans G. Epstein, PhD (1909-2002) and production engineers at the
Morris Motor Company to produce a portable vaporizer that did not require a
source of electricity to maintain liquid ether at a constant temperature.

The design of the “Oxford Vaporiser” drew heavily from the team’s knowledge
of thermal physics. As long as liquid ether is maintained at a known
temperature the corresponding vapor concentration is also known. The design
team also understood that a sealed reservoir of liquid and crystalline
calcium chloride (CaCl2) would maintain a constant temperature of 30°C (86°F)
as long as the calcium chloride remained in phase change (in a state in
between liquid and crystalline).

The vaporizer was constructed in concentric chambers using a heat conducting
metal. The central chamber contained water, and the outermost chamber
contained the ether. Between these two was a sealed chamber of CaCl2. The
CaCl2 chamber acted as a reservoir and buffer of heat which kept the liquid
ether at a constant temperature, just below its boiling point. This in-turn
kept the ether vapor concentration constant and allowed the anesthetist to
administer a known proportion of ether vapor and air to the patient. In
continuous use, the vaporizer would function in this way as long as about 15
fluid ounces of ether and 14.5 ounces of hot water were added each hour. An
integrated bellows allowed the anaesthetist to manually assist or administer
respirations if necessary.

Morris Motors Limited, a British motor vehicle manufacturer founded by
William Morris (1877-1963), manufactured the Oxford Vaporiser from 1941 to
1947. The Oxford Vaporiser was widely used by the British military during WW
II. Allied anesthesiologists who received training in Macintosh’s department
were also instructed in its use. After the war, some Oxford Vaporisers were
supplied to medical missionaries.

William Morris, Lord Nuffield, was a generous British philanthropist and was
largely responsible for the establishment of the Chair of Anaestheics at
Oxford, which was the first academic anesthesia department in Europe. Lord
Nuffield was also responsible for Dr. Macintosh’s appointment to that
position. Sir Robert Reynolds Macintosh (1897-1989) was a British pioneer of
anesthesiology who greatly influenced the development of anesthesia worldwide
Many health care professionals are familiar with Dr. Macintosh through his
eponymously named laryngoscope blade. Dr. Hans Georg Epstein (1909-2002),
born and educated in Germany, continued to work with Dr. Macintosh in the
Nuffield Department of Anaesthetics. Epstein operated the research
laboratories of the anaesthetics department and designed a number of other
influential vaporizers, such as the Epstein Macintosh Oxford (EMO) Inhaler
and the Oxford Miniature Vaporizer (OMV).

Note Type: Publication
Notes: Bannister FB. The Oxford vaporizer in routine hospital practice. Proc R Soc
Med. 1943;36(5):205-206. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1998580/
Accessed February 27, 2015.

Note Type: Publication
Notes: Epstein HG, Macintosh R. An anaesthetic inhaler with automatic
thermo-compensation. Anaesthesia. 1956;11(1):83-88. https://onlinelibrary.
wiley.com/doi/10.1111/j.1365-2044.1956.tb07943.x/pdf. Accessed February 27,

Note Type: Publication
Notes: Leatherdale RAL. The EMO ether inhaler: clinical experience in a series of a
thousand anæsthetics. Anaesthesia. 1966;21(4):504. https://onlinelibrary.wiley
com/doi/10.1111/j.1365-2044.1966.tb02656.x/abstract. Accessed February 27,
2015. [“In 1965, Macintosh and Epstein produced an improved version of the
Oxford Vaporizer, the EMO Ether Inhaler.”]

Note Type: Publication
Notes: Macintosh RR, Mendelssohn K. The Quantitative administration of ether vapour.
Lancet. 1941;238(6151):61-62.

Note Type: Exhibition
Notes: Exhibited at the National World War II Museum in New Orleans, October, 2014.