Iron lungs for polio victims, 1930s-1950s

In the early 20th century, polio was one of the most dreaded diseases in industrialized countries, crippling hundreds of thousands of children each year.

A highly contagious disease, polio attacks the nervous system and can cause paralysis, disability, and even death. Symptoms -- pain and weakness, fatigue and muscle loss -- can occur at any time 15 to 50 years after the initial illness.

In 1952, more than 21,000 Americans contracted a paralytic form of polio, and 3,000 died from it. Once infected, there was no cure other than taking care of the symptoms and symptoms.

No device is more linked to polio than a tank respirator, known as the iron lung. Before its invention, children with polio often died. Physicians treating people in the acute, early stages of polio noticed that many patients were unable to breathe when the action of the virus paralyzed muscle groups in the chest.

The first iron lung used to treat polio victims was invented by Philip Drinker, Louis Agassiz Shaw, and James Wilson at Harvard, and tested on October 12, 1928, at the Children's Hospital in Boston.

The original drinker iron lunge was powered by an electric motor attached to two vacuum cleaners and worked by varying the pressure inside the machine.

When the pressure is reduced, the chest cavity expands, trying to fill this partial vacuum. When the pressure is increased the chest cavity contracts. This expansion and contraction mimics the physiology of normal breathing. Although the patient could breathe into the machine, he could do nothing more than look at the mirror reflecting the room behind him.

The iron lung design was later improved by using a bellows attached directly to the machine, and John Haven Emerson modified the design to make production less expensive. The Emerson Iron Lung was produced until 1970. Other respiratory aids, such as "rocking beds", were used in patients with less severe breathing difficulties.

During the polio epidemic, the iron lung saved many thousands of lives, but the machine was large, cumbersome, and very expensive: In the 1930s, the iron lung cost about $1,500—the equivalent of the average home price.

The cost of operating the machine was also prohibitive, as patients were confined in metal chambers for months, years, and sometimes life: even for bulbar polio patients with iron lungs. The mortality rate was over 90%.

These shortcomings led to the development of more modern positive pressure ventilators and the use of positive pressure ventilation by tracheostomy. The positive pressure ventilator reduced the mortality rate in bulb patients from 90% to 20%.

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