ARCHIVE FEATURE
December 1956 – Iron lung
More than seventy years ago, faced with the
prospect of large-scale epidemics of polio, UK
hospitals were a empting to get to grips with a
challenge that has become frighteningly familiar
to us all in recent months: a shortage of adequate
breathing equipment to treat those aff ected by the disease.
1956 — the year of this article — had been a particularly
bad year, with epidemics in Ireland and the Netherlands
claiming hundreds of lives. The vaccine, which has since
eradicated the disease in the industrialised world and
come close to wiping it out worldwide, had been developed
by Jonas Salk only a few years previously and was still in
trials.
In the absence of a vaccine, a key method of treatment
for the disease was the iron lung, a fore-runner to present
day ventilators that was used to help patients breathe
whilst the muscles controlling their lungs were paralysed.
Although there were a number of variations on the
technology, the basic principle relied on enclosing the
patient’s body in a sealed cylinder and using changes in air
pressure within the cylinder to help the patient breathe.
In a historical echo of the way in which engineers from
non-medical sectors are pu ing their skills to use in the
current push for NHS ventilators – celebrated automotive
engineer Captain George Smith-Clarke was determined to
do something about it.
In an article for The Engineer Captain George Smith-
Clarke, who had been chief engineer at British car
manufacturer Alvis from 1922 to 1950 (and had designed
cars which won races at Brooklands and Le Mans) detailed
improvements in the designs of iron lungs to help with the
polio epidemics.
May 2020 / www.theengineer.co.uk 536
In 1952, Smith-Clarke had taken on the chairmanship
of the Coventry and Warwickshire Hospital board of
management, and as part of this role he’d been asked to
look at the engineering of mechanical ventilators.
He wasn’t impressed. ‘Some may think, as many
patients have done, that it had a very uncomfortable
resemblance to a coffi n, and for this reason screens
were sometimes placed around it so that patients
could not see it when being put in.’ Upset at the
distress he’d seen in children being taken out of iron
lungs, he redesigned the machine used most at the
hospital, the Nuffi eld-Both machine, which had
been in use since 1939.
‘I took over a disused air-raid shelter in the
hospital grounds and with the help of the senior
physicist and a member of his staff , a Nuffi eld-
Both machine was completely dismantled,’ he
recalled in his lecture. ‘It was found impossible
to obtain working drawings and I had to make
dimensional free-hand sketches.’ Alvis made the
castings for the larger parts, while Smith-Clarke himself
machined the smaller parts needed.
As well as making the machines more controllable and
effi cient at helping patients to breathe, Smith-Clarke also
thought it important to make them more comfortable.
He included more ports in the side of the machine, so
the patient could be reached for nursing care without
aff ecting breathing. He also designed be er head-rests and
stretcher support system.
Smith-Clarke later helped Alvis employees to set up a
company to supply kits to modify breathing
machines.”
December 1956
Improving
iron lungs
One of Britain’s most prominent automotive engineers turned
his a ention to alleviating the suff ering of polio victims at the
height of epidemics during the 1950s
written by jon excell
/www.theengineer.co.uk