iron lung cough may sound like a strange occupation to most of us, but it was one of the assignments given to engineers of the New York University Engineering Research Division. The purpose of the project was to bring relief and aid to some paralyzed victims of poliomyelitis, tuberculosis, and other respiratory diseases.
When a patient suffers from one of these diseases, thick mucous secretions gather in his lungs and bronchial tubes. Usually the mucus does no harm, since the patient promptly coughs it up. But if his chest and diaphragm are paralyzed so that he cannot cough, the mucus piles up until it interferes with his breathing. Every year some patients die, literally drowned by the secretions in their lungs.
The idea of the coughing iron lung originated with Dr. Alvan L. Barach of Columbia University who initiated the work on the coughing iron lung, then brought it to the Research Division for improvements in design and operation.
Basically, the lung simulates the physical forces that occur naturally in a vigorous cough. It consists of two pressure sections, a head section and a chest section. The sections are divided by a wall, with a small opening near the neck. The chamber is pressurized from the head end. After a few seconds, both sections are in equilibrium at pressure greater than that of the atmosphere. To make the lung cough, pressure at the head end is decreased very suddenly. It escapes rapidly to the room, so that the head is almost immediately at room pressure. The higher pressure in the chest section also tries to escape. In doing this, it compresses the patient's chest, simulating a cough, and bringing the mucus up out of the lungs.
After trials had proved that the lung worked safely and effectively on human beings, a unit was set up at Willard Parker Hospital and operators were trained in its use. The first medical use of the coughing lung was in October 1950, when it saved the life of a 21-year old girl suffering from bulbarpoliomyelitis complicated by collapse of a major portion of her lung. In fifteen minutes the girl's upper respiratory tract was cleared out and she went on to make a good recovery from the polio.
Since then, the new type of mechanical lung has undergone a series of clinical trials that indicate that the principle of the mechanically-induced cough will be useful in poliomyelitis, bronchial asthma, atelectasis of the lungs in adults and the newborn, and in other diseases where inadequate removal of bronchial secretion occurs.
The National Foundation for Infantile Paralysis has granted the Engineering Research Division a contract for the design and construction of an improved, all-purpose mechanical respirator embodying the cough chamber feature. The new lung, which will work on 110-volt current, will operate from the head end as well as the body end, and will be capable of providing equalizing pressure respiration as well as mechanically-induced coughing. It will be a sideopening chamber, for quick opening and closing. The improved model will be in transparent plastic, to help relieve the patient's sensation of claustrophobia.