An iron lung, also known as a negative pressure ventilator, is a historical medical device used primarily in the mid-20th century to treat patients suffering from respiratory muscle paralysis, often caused by polio. Here's how it worked:
1. Enclosing the body: The patient lay inside a sealed metal chamber, with only their head remaining outside. This chamber created an airtight environment crucial for the machine's function.
2. Creating pressure changes: Electrically or manually operated bellows, located outside the chamber, would change the air pressure inside.
3. Mimicking breathing:
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Inspiration (inhalation): The bellows would increase the pressure inside the chamber, similar to pushing on the chest and abdomen during normal breathing. This forced air out of the patient's lungs.
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Expiration (exhalation): The bellows would decrease the pressure inside the chamber, creating a vacuum effect. This allowed the chest cavity to expand, drawing air back into the lungs.
4. Rhythmic cycle: The pressure changes cycled rhythmically, mimicking the natural rhythm of human breathing and assisting the paralyzed respiratory muscles.
5. Limitations:
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The iron lung was a cumbersome and isolating experience for patients, requiring them to be confined within the chamber for extended periods.
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It wasn't a cure for the underlying condition and provided only support for breathing.
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With advancements in medical technology, smaller and more portable ventilators have replaced the iron lung, offering greater mobility and comfort to patients.
While the iron lung is no longer in common use, it holds historical significance in the fight against polio and serves as a reminder of the evolution of medical technology in assisting patients with respiratory difficulties.