Thursday, June 20, 2013

1743: The first mechanical ventilator

Stephen Hales (1, page 328)
I have been reading a book called "An introduction to the history of medicine" by Fielding Hudson Garrison. It's chock full of really neat knowledge, although at times it can be quite dry.  It's one of those books you have to read for a while, and then take a break and read something else.

Although tonight as I was perusing the book Garrison is writing about a doctor named Stephen Hales (1677-1761) who, Garrison wrote, "was an English clergyman of inventive genious, who enriched practical science in many ways, particularly as the originator of the mechanical ventilator (1743)."  (1, page 328) Hales published his invention and opinions in his 1758 book "Treaties on Ventilators."

I was practically salivating as I read this, because I was thinking he was the inventor of the first ventilator, or machine used for providing posisive pressure to the lungs.  Although, upon further research, this was not true.  What he was the inventor of was a machine that allowed for rooms to be ventilated with fresh air.  Of course in a day when one sick person can easily infect many other poeple in a closed and non-ventilated area, such an invention was very important.

Sir John Simon, in describing the importance of Hale's device not just at prisons, military barracks and military hospital wards, but also on ships.  He explains that:
Dr. Hales's "lungs"... seem to have been often advantageously used in ships, prisons and hospitals (the military was) ordered by the Lords of the Admiralty to adapt his "fire-pipes" to His Majesty's Navy 4 Readers of the present day who may find it hard to imagine the " putrid " quality of the atmospheres which in those days the inmates of prisons and ships and barracks and hospitals had to breathe, can well assist their imagination by referring to the pages of Hales and other contemporary reformers. (3, page 119)
According to the book "British Military and Naval Medicine, edited by Geoffrey L. Hudson, Hales devised the first mechanical ventilator and even came up with a name for it.  It was installed at a variety of hospitals, army barracks, mines and jails, because it was at these places where people lived in closed quarters, breathing the same, stale air, with infections spreading from one person to another.  (2, pages 241-3

(1, page 374)
The invention was helped along by John Pringle (1707-1782), who who was a surgeon general of the British Army from 1742-1758, and considered the father of modern military medicine, (1, page 373) studied the spread of diseases among the military, particularly fevers.  He observed, along with others, that the more poeple in a confined space the greater likelihood the spread of fevers would be.  Attributing it to the stale air inhaled, he championed to have Hale's mechanical ventilators installed in hospital hospital wards.  (2, pages 241-3)

He discussed the importance of military sanitation, especially the importance of Hale's mechanical ventilator, in his 1752 book "Observations on the Diseases of the Army." He likewise wrote about the importance of antiseptics to prevent the spread of disease. (1, page 373)

The problem with the ventilator was electricity hadn't been invented yet, and so the machine had to be man powered.  So, not only was the machine itself expensive, it was expensive to work and to maintain it.  So many military hosptal wards resorted to other means of ventilating the air in hospital wards, and this involved the difficult task of maintaining wards in well ventilated places such as "barns, churches, or ruinous houses.  Or, they simply maintained patinets in hospital wards that were poorly ventilated, risking the spread of disease.  Another option was to install many windows in such places. (1, pages 241-3)

By the late 1750s most hospitals had windows installed to improve ventilation without the added cost of  purchasing one of Hales mechanical ventilators, nor the added stress of moving patients to better ventilated places such as barns.  By 1764 Pringle wrote about increased efforts to try to separate patients. (2, pages 241-3)

By reports of others some patients would look up through the holes in the roof of barns or old, dilapidated houses to see the moon and stars.  However, the efforts to decrease the spread of disease worked, saving the lives of many.  So, for the divided rooms we have in today's hospitals, and the dry, well ventilated air that we often take for granted, we can thank the brilliant mind of the 18th century. 

References:
  1. Garrison, Fielding Hudson, "Introduciton to the history of medicine," 1922, London, W.B. Saunders Company
  2. Hudson, George L, "British Military and Naval Medicine, 1600-1830," 2007, Amsterdam, New York, Editions Rodopi B.V.
  3. Simon, John, "English Sanitary Institutions," 1897, 2nd edition, London, John Murray

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