1940s: The Collision Nebulizer

Photo compliments of E.M. Collision's own book (5, page 4)

While the 1930s gave us the first electric nebulizer, they were large, bulky, and expensive.  Most people who needed aerosolized inhalations simply resorted to other means, such as a glass nebulizer with rubber bulbs like the DeVilbiss number 40, or by igniting asthma powders of various sorts. Some people still resorted to using asthma cigarettes.

It was believed that the aersolized particles produced by most nebulizers or atomizers were large and impacted in the upper airways.  This was proved by experiments performed by Huckel and published in 1925.  He determend that aerosol particle had to be 5 microns or less, and be dense enough, to make it to the bronchi and alveoli to be effective. (1, page 10-11)

Another concern of physicians was that experiments "demonstrated that atomization robs air of oxygen."  This was a major concern especially when a treatment was given with a rubber face mask.  It was for this reason atomization was mostly "limited to hand sprays, and it's employment confined to quite short inhalations of a palliative nature to stop an asthma attack or for the treatment of the upper air passages." These short treatments were generally accomplished with two or three puffs using glass nebulzers.(1, page 6-7)

1, page 23)

So there was an obvious need for an improved product that would solve these problems.  And such a product was invented in the early 1930s  by W.W. Collisoin and introduced to the market in 1932 by a company named Collision.  The product was aptly called the Collision Nebulizer.(2)

It was an interesting product that was connected to the top of an oxygen tank, and this pretty much solved the oxygen dilemma.

Flow was adjusted to meet the demands of the patient, and was generally set between 7-8 liters per minute.  (1, page 5, 14, and 25)  

Flow from the oxygen tank filled a reservoir bag, so flow was monitored by monitoring "movements of a bag."  (1, page 5)

It also had a baffle in it to filter out large particles, and this ensured most of the particles inhaled by the patient were small enough and dense enough to make it into the smaller airways where they could do some good.  In this way, this product distinguished an "atomizer" from a "nebulizer."  Atomizers from this point on were used for perfume, disinfectants and paint products, and nebulizers were used for respiratory medicine. 

Studies at this time also showed that the rate and depth of breathing also effected where the aerosolized particles deposited.  If the patient breathed too fast and too deep most of the particles impacted in the larger airway, so it was determined the patient should breathe calmly.  (5, page 14)

Worded another way, laminar (smooth) air flow was preferable to turbulent airflow. Turbulent air is fast and furious and has an increased risk of causing the aerosolized particles to impact in the larger airways, such as the mouth and throat. A smooth, laminar flow is needed for the medicine to make it to the smaller airways. This is created by slow, or simply normal breathing during a breathing treatment.

This device was nice because it allowed the physician to prescribe a "precise" dose of medicine, and also be assured the medicine would reach the lungs where it's desired and have the greatest effect.  Collision describes his own device this way:

"It presents none of the tiresome features associated with medical apparatus, and is readily understood by patients.  While providing a vapour that meets the requirements of modern medicine, it embodies most simple and easily understood controls, and is comparatively small and compact.  These features have overcome the impracticability of patients taking a proper course of duly prescribed treatment at home, and of having the inhalations available at any time and during the hours of the night." (1, page 21)

There were two phials, one amber and one and one white.  The amber phial was for photosensitive inhalents.  A large teaspoon of each inhalent prescribed was placed in one or the other phial.  For daily curative (preventative) treatments Collision recommended placing camphor, menthol, or creosote in the white phial.  The recommendation was for these treatments to be taken every day as a preventative therapy.  Many asthmatics, however, stopped taking the medicine when they felt good. (1, page 22-3, 32-33)

To end an acute episode of asthma, Collision recommended placing adrenaline in the amber phail.  If the patient had an asthma attack while inhaling from the white phial, a handle can be switched from "white phial" to "amber phial." Or, when necessary, the handle could be switched to "both phials" to take in medicine from both.(1, page 22-3)

Rubber tubing leads to a mask with two one way valves, one opens on inspiration, and the other opens on expiration.  This prevents exhaling into the system, and allows expiration into ambient air.  A small hole allows for some ambient air to be drawn in during inspiration.  (1, page 24)

After each use the oxygen gauge should be checked to assure there's enough oxygen in the tank to support a treatment, if the patient requires one for an asthma attack during the night. 

References:

1. Collision, W.E., "Inhalation therapy technique," 1935, London, William Heinemann
2. Rau, Joseph L, "Conference Proceedings:  Design Principles of Liquid Nebulization Devices Currently In Use," November 2002, Volume 47, Number 11, Page 1257einemann