Everything about Iron Lung totally explained
An
iron lung is a large machine that enables a person to
breathe when normal
muscle control has been lost or the work of breathing exceeds the person's ability. It is a form of
medical ventilator. Properly, it's called a
negative pressure ventilator.
Method and use
The person using the iron lung is placed into the central chamber, a cylindrical steel drum. A door allowing the head and neck to remain free is then closed, forming a sealed, air-tight compartment enclosing the rest of the person's body. Pumps that control airflow periodically decrease and increase the
air pressure within the chamber, and particularly, on the chest. When the pressure falls below that within the lungs, the lungs expand and air from outside the chamber is sucked in via the person's nose and airways to keep the lungs filled; when the pressure rises above that within the lungs, the reverse occurs, and air is expelled. In this manner, the iron lung mimics the physiologic action of breathing: by periodically altering intrathoracic pressure, it causes air to flow in and out of the lungs. The iron lung is a form of
non-invasive therapy.
Invention and progression
The machine was invented by
Philip Drinker and
Louis Agassiz Shaw, of the
Harvard School of Public Health, originally for treatment of
coal gas poisoning. But it found its most famous use in the mid-1900s when victims of
poliomyelitis (more commonly known as polio), stricken with paralysis (including of the
diaphragm, the cone shaped muscle at the bottom of the rib-cage whose action controls intrathoracic pressure), became unable to breathe, and were placed in these steel chambers to survive. The first iron
lung was used on
October 12,
1928 at
Children's Hospital,
Boston, in a child unconscious from
respiratory failure; her dramatic recovery, within seconds of being placed within the chamber, did much to popularize the "Drinker Respirator."
In 1931, inveterate tinkerer
John Haven "Jack" Emerson unveiled an improved iron lung, which was smaller, cheaper, lighter, quieter, and much more reliable than Drinker's. Drinker and Harvard promptly sued Emerson for patent violations, which proved unwise. In the subsequent legal battles Emerson demonstrated that every aspect of Drinker's patents had been patented by others at earlier times. Emerson won the case, and Drinker's patents were declared invalid.
Entire hospital wards were filled with rows of Emerson iron lungs at the height of the polio outbreaks of the
1940s and
50s. With the success of the worldwide
polio vaccination programs which have virtually
eradicated the disease, and the advent of modern ventilators that control breathing via the direct
intubation of the airway, the use of the iron lung has sharply declined.
Modern usage
The
positive pressure ventilator, which instead blows air into the patient's lungs by intubation through the airway, was used for the first time in
Blegdams Hospital,
Copenhagen, Denmark during a polio outbreak in
1952. It proved a success and soon superseded the iron lung all over Europe.
The iron lung now has a marginal place in modern
respiratory therapy. Most patients with paralysis of the breathing muscles use modern
mechanical ventilators that push air into the airway with positive pressure. These are generally efficacious and have the advantage of not restricting patients' movements or caregivers' ability to examine the patients as significantly as an iron lung does. However,
negative pressure ventilation is a truer approximation of normal physiological breathing and results in more normal distribution of air in the lungs. It may also be preferable in certain rare conditions, such as
Ondine's curse, in which failure of the medullary respiratory centers at the base of the brain result in patients having no
autonomic control of breathing. Thus, there are patients who still today use the older machines, often in their homes, despite the occasional difficulty in finding replacement parts.
Biphasic Cuirass Ventilation is a modern development of the iron lung, consisting of a wearable rigid upper-body shell (a
cuirass) which functions as a negative pressure respirator.
Further Information
Get more info on 'Iron Lung'.
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