A negative pressure pulmonary ventilator, also known as an iron lung or negative pressure ventilator, is a medical device used to assist individuals with breathing difficulties, particularly those affected by paralysis of the respiratory muscles or conditions that compromise their ability to breathe effectively. It works by using a negative pressure mechanism to stimulate inhalation and exhalation.
The device is a large cylindrical chamber made of rigid materials such as metal or plastic, enclosing the patient's entire body except for the head. The chamber contains a sealed airtight space that creates a vacuum or negative pressure when the pressure inside is reduced. Through a series of valves and switches, the ventilator alternates between cycles of low and high pressure.
During inhalation, the pressure within the chamber decreases, causing the patient's chest to expand and air to be drawn into the lungs. Conversely, during exhalation, the pressure inside the chamber increases, resulting in the patient's chest contracting and air being pushed out. This mimics the natural breathing process, maintaining a steady flow of oxygen to the patient's lungs.
Negative pressure pulmonary ventilators were extensively used during the 20th century before positive pressure ventilators became more prevalent. While less common now, they are still occasionally used in specific cases where positive pressure ventilation is not suitable or available.
Overall, a negative pressure pulmonary ventilator serves as a life-sustaining mechanical device providing respiratory support to patients with severe breathing difficulties, effectively assisting in the exchange of oxygen and carbon dioxide within the lungs.
