Greetings, patient historico-medico aficionados. After a brief hiatus, your monthly dose of the medically weird is back again. In keeping with our transition from CEPI to the Center for Education, CEPI Curiosities is also receiving a new moniker: CPP (as in College of Physicians of Philadelphia) Curiosities. Make no mistake, however, despite the new name we are sticking to our tried-and-true formula of medical history stories to surprise you or at the very least make you look at the world of medicine just a bit differently.
This time around we are tackling the strange and fascinating history of the negative pressure ventilator, more commonly known as the “iron lung.”
“Iron Lung” is a colloquial term for a variety of artificial respiration machines that encapsulate all or part of a patient’s body. They help a person breathe through a method called negative pressure ventilation where the air pressure surrounding the patient’s body is reduced, forcing their lungs to expand and take in air; the pressure around the patient is then increased, causing them to exhale. For a time, iron lungs were a common treatment during the twentieth century for conditions where a patient could not sufficiently breathe unassisted.
However, they are most commonly associated with one particular disease: polio. Also known as infantile paralysis or poliomyelitis, polio is caused by the poliovirus, a contagious virus most commonly spread through infected feces that comes into contact with a patient’s mouth. The majority of people exposed to the poliovirus exhibit no symptoms; according to the Centers for Disease Control and Prevention, one in four people infected with the poliovirus will have relatively mild symptoms, including sore throat, nausea, fatigue, headaches, and stomach pain, and these symptoms generally go away after a few days (this is known as “abortive polio”). However, a small percentage of people exposed to the poliovirus develop temporary or permanent neurological symptoms, ranging from light sensitivity and stiffness to muscle spasms to partial or total paralysis.
According to our sister page, History of Vaccines, the earliest reported polio outbreak in the United States took place in 1894. The nation’s most severe outbreak occurred in the 1930s-1950s. The development of polio vaccines and public health initiatives to inoculate the public significantly reduced the number of polio cases. Thanks to vaccines, polio has been largely eradicated in the developed world (it was eliminated in the US in 1979). However, periodic outbreaks occur in areas with limited or inadequate medical resources. Between 2013 and 2015, a polio epidemic spread through Syria and into neighboring Iraq followed by a second outbreak in Syria in June 2017 as well as another in the Congo around the same time.
Conceptually, negative pressure ventilation dates back to the late 1700s, and the earliest negative pressure devices emerged in the mid 1800s. In 1864, Alfred F. Jones of Lexington, KY, filed the first patent for a negative pressure respirator. His device, which he dubbed a “Restorator,” required the patient to sit upright in a small chamber with only their head exposed, covered in a specialized hood to maintain an air seal. Air circulated through the chamber through a hand pump. However, it’s unclear if Jones ever developed a model for mass production. In 1876, a French physician named Eugene Woillez developed what is considered the first functional negative pressure ventilator. Woillez’s “Spirophone” allowed for a patient to lie flat on their back, encasing them up to their neck in a sealed enclosure. Air was pumped into the Spirophone through the use of hand-operated bellows.
However, the negative pressure ventilator did not receive wide usage or exposure until the early 20th century. In 1928, a pair of Harvard University professors–Drs. Philip Drinker and Louis Agassiz Shaw–developed an automated negative pressure ventilator. Similar to the Spirophone, a patient lay flat on a movable table with all but their head and neck encased within the device. The Drinker respirator generated negative pressure via a motor that pumped a bellows (this silent film demonstrates it in action). They initially tested the device by conducting preliminary experiments on a cat before moving into to human testing on an eight-year-old girl with respiratory paralysis from polio. According to Drinker’s later accounts the girl’s breathing significantly improved after being encased in the Drinker respirator for a short period of time, and their “iron lung” quickly gained wide circulation as a treatment for polio-induced respiratory failure (Louis A. Shaw, “Cutaneous Respiration of the Cat,” American Journal of Physiology. 85 (1928): 158-167; Philip Drinker and Charles F. McKhann, III. The Use of a New Apparatus for the Prolonged Administration of Artificial Respiration: I. A Fatal Case of Poliomyelitis. JAMA. 92.20 (1929): 1658-166). In 1931, a Boston machinist named John Haven Emerson devised improvements for the Drinker and Shaw design; reportedly, Emerson approached Drinker with his ideas but found a tepid response, prompting him to design and sell it on his own. The Emerson Iron Lung proved lighter, more efficient, and significantly cheaper to produce than the Drinker model and became a staple in polio treatment wards across the country (Drinker also unsuccessfully attempted to sue Emerson for patent infringement). The College of Physicians has an Emerson Iron Lung among its vast collection; however, it is not currently on display.
During the polio outbreaks of the 1930s-1950s, if paralysis impeded a person’s ability to breathe (respiratory paralysis), they would be placed into an iron lung until such time as they could breathe on their own, usually after 1-2 weeks of treatment. However, in cases of extreme paralysis, patients may periodically be encased in one over the course of months or years. For those curious about what it is like to be in an iron lung, in 2010, the Journal of the Royal Society of Medicine published an account from Marshall Barr, a patient who regularly used an iron lung for fifteen years.
With the rise in positive pressure ventilation devices (the kind used in modern ventilators), negative pressure respirators like the iron lung generally fell out of favor. However, there are reportedly a small handful of patients who still utilize an iron lung to help them breathe.
Until next time, catch you on the strange side!