Monday, June 27, 2016

1816: Laennec invents the stethoscope

Figure 1 --Rene Laennec (1781-1826).  Along with
crediting an old kid's game with giving him the idea of
creating his first stethoscope, he was also skilled with
the flute.  His memory and his musical skill  helped him
come up with the ingenious plan of rolling up paper into
a hollow tube.  He then used this to listen to lung sounds.
He later modestly chimed that he was amazed the device
wasn't invented years ago.  Hippocrates was known for
performing auscultation by placing his ear upon his
patient's chest.  A simple stethoscope would have
greatly benefited the ancient physician. (4, page xxiii)
Before the 19th century the only way for a physician to auscultate (hear) heart and lung sounds was to place his ear upon his patent's chest.  This would change thanks to a brilliant invention by French Physician Rene Laennec.

A procedure called Immediate Auscultation was probably used by priest/physicians in ancient Egypt, although it was first described for the medical community around 400 B.C. by Hippocrates.

Laennec quotes Hippocrates from De Morbis:
auYou shall know by this that the chest contains water and not pus, if in applying the ear during a certain time on the side, you perceive a noise like that of boiling vinegar. (4, pages 28-29) 
Immediate auscultation, or placing an ear directly on the chest of the patient, was never further investigated by the successors of Hippocrates, and therefore never became standard practice.  (4, page 29)

Not helping matters was the fact that most people did not take regular baths, and sick people were sometimes hot and wet from sweat.  Laennec said that it was flat out disgusting. (4, pages 29)

Also not helping matters was the fact that it was not gentlemanly to do this to a lady, and that fat tissue muffles sound.

When he was 38-years-old on a hot and humid day in 1816, Rene Theophile Hyacinthe Laennec was posed with all of these problems, yet the need to auscultate his patient's heart and lung sounds was essential.

He came up with an ingenious plan that helped him assess his patient, yet which also helped him improve the assessment skills for all physicians.

Who was Rene Laenec? 

Laennec was born on February 17, 1781, to to an an "advocate of the provincial courts, and held some appointments under government, in his native country (France)... Fortunately his son was heir of the more solid parts of his genius; without his wit, but without his volatility.  (1, page xix)

At an early age he was put under the care of his uncle, a clergy man in charge of the parish of Eliam, in the vicinity of Quimper.  However, after the French Revolution broke out his care was transferred to another uncle, Dr. Laennec of Nanates. (1, page xix)
Dr. Laennec was a man of highest respectability both as to talent and conduct, and directed the studies of his nephew with the interest and affection of a parent. The young scholar did credit to his friends and teachers; having obtained considerable distinction from his fellows at the chief school of the department of the Lower Loire, wither he had been sent by his uncle. Having completed his preparatory studies at this seminary, his thoughts naturally turned towards physic as a profession. He willingly engaged himself as the pupil of his uncle, and entered upon the study of his future profession with the zeal inherent in his character, and with success indicative of his subsequent eminence. Besides the instructions derived from his uncle, who was at that time senior physician of the hospital, and afterwards Professor of Medicine and Materia Medica at Nantes, he attended the courses of anatomy given by the surgeons of the same establishment, and is said, even at this early age, to have shown a decided predilection for morbid anatomy and clinical observation.(1, page xix)
Figure 2 --
Shown here:  Matthew Baille (1761-1823)
While under the tutelage of Corvisant,
Laennec became good friends with
Matthew Baillie.  Ironically, both were
famous for their studies of diseases of
the lungs, and both were diagnosed with
consumption,and eventually died of this disease.  
In 1800 he attended the medical school of La Charite, which was where he came to tutelage of a well respected and well known physician by the name of Jean Nicolas Corvisant.  He also became good friends at this school with Matthew Baillie, who himself would go on to gain great fame as a physician.  (1, page x)

He had actually gained recognition earlier in his career, for while in school he wrote a history of medicine, and, in the year 1802 at the age of 21, published articles that were well received by his fellow physicians.  (1, page x)

He opened a clinic in and began seeing patients.  In 1816 he was appointed chief physician to the Necker Hospital.  It was here where he was presented with the opportunity whereby he came up with an ingenious plan that changed medical diagnosis forever.  (1, page xxiii)

What was Laennec's ingenious plan? 

So on a hot and humid day in 1816, a 36-year-old physician by the name of Rene Laennec came up with an ingenious plan.

According to Kendall F. Haven in his book "One hundred greatest inventions of all time," Laennec was a "well established doctor and diagnostician of chest and abdominal disorders when he was asked by a fellow physician to assess an obese young woman with breathing difficulties." (2, page 96)

Not that it matters, but, for the record, the patient's name was Marie-Melanie Basset, and she was only 40.

Haven said:
Laenec's normal technique was to have the woman partially disrobe so he could place his ear against a hanker chief over her chest.  He'd listen to lung sounds over five spots:  the underside of each arm, each side of upper back, and upper breast bone. 
Figure 3 --
Gabriel Andral (1797-1876)
He was a French pathologist at the
University of Paris.  He is best known
for his work on blood chemistry.
Andral wrote the comments in
the margins of the 1838 edition
of Laennec's book.
Yet when he did this on this Marie, he heard nothing.  So he tried percussion, a method of tapping on the chest to check for dull or resonant sounds that might indicate certain diseases. Yet this method proved useless as well.

Thinking off the cuff, Haven said, he "grabbed 24 sheets of paper, rolled them tightly into a bundle, and secured them in shape with paste glue. He applied one end of this paste roll against the young woman's chest, and the other to his ear." (2, page 97)

Leanecc was "delighted" to learn he could hear the woman's heart and lung sounds better this way than with the unaided ear against her chest.  He was so excited at how simple a device could make this job so much easier that he set out to do a series of experiments to find metals and tubes that would aid his ear in hearing heart and lung sounds.  (2, page 96)

He actually wanted to name the device le cylindre claiming it was frivolous to name such a device.  However, his colleagues thought it should have a name, and they came up with some of their own. Yet once he decided he didn't like any of these names, he decided to call it a stethoscope.  Stethe coming from the Greek term for chest, and scope coming from the Latin term for aim.  (2, page 97)

His stethoscope was actually a monaural stethoscope, meaning that it had only one ear piece.  You can see a picture of his monaural stethoscope in figure 4.

How did Laennec come up with his idea?

In his book "A treaties on the diseases of the chest, and on mediate auscultation," Laennec recollected a little kid's game, and it was this that gave him an idea.

He wrote:
In 1816, I was consulted by a young woman laboring under general symptoms of diseased heart, and in whose case percussion and the application of the hand were of little avail on account of the great degree of fatness. The other method just mentioned (auscultating with an ear to the chest) being rendered inadmissible by the age and sex of the patient, I happened to recollect a simple and well-known fact in acoustics, and fancied it might be turned to some use on the present occasion. The fact I allude to is the great distinctness with which we hear the scratch of a pin at one end of a piece of wood, on applying our ear to the other. Immediately, on this suggestion, I rolled a quire of paper into a kind of cylinder and applied one end of it to the region of the heart and the other to my ear, and was not a little surprised and pleased, to find that I could thereby perceive the action of the heart in a manner much more clear and distinct than I had ever been able to do by the immediate application of the ear. (4, page 6)
Figure 4 -- Laennec's Monaural Stethoscope (1820).  It was an inch
and a half in diameter and a foot long, perforated longitudinally
by a bore three lines wide, and hollowed out into a funnel shape
at one end to the depth of an inch and a half. A plug of wood
was fitted into this hollowed extremity with a perforation through
it of the same diameter as that of the rest of the tube. The plug
was used in auscultating heart sounds, and discarded in
 stethoscopes made at a later date. It was made in two sections
for convenience of carrying. (6, page 626)  Perhaps it
 provided some solace to Laennec that he was diagnosed with
consumption using a stethoscope similar to this. Photo Copyright
Science Museum/ Science and SocietyPicture Library
So he thereby discovered that his invention was better for hearing sounds inside the human body than the ear alone.

What was the first stethoscope like? 

Laennec described his first stethoscope in his book Mediate Auscultation:
The first instrument which I used was a cylinder of paper, formed of three quires, compactly rolled together, and kept in shape by paste. The longitudinal aperture which is always left in the centre of paper thus rolled, led accidentally in my hands to an important discovery. (4, page 7)
He  also set off on a quest to study and perform experiments using the device, and he fine tuned it until he came up with a better product.  He trialed a variety of materials, lengths, and sizes of aperture, until he came up with the product he thought was idea.

He said:
In consequence of these various experiments I now employ a cylinder of wood, an inch and a half in diameter, and a foot long, perforated longitudinally by a bore three lines wide, and hollowed out into a funnel-shape, to the depth of an inch and a half at one of its extremities. It is divided into two portions, partly for the convenience of carriage, and partly to permit its being used of half the usual length. The instrument in this form—that is, with the funnel-shaped extremity,—is used in exploring the respiration and rhonchus: when applied to the exploration of the heart and the voice, it is converted into a simple tube, with thick sides, by inserting into its excavated extremity a stopper or plug traversed by a small aperture, and accurately adjusted to. the excavation. (See figure 2)  (10, page 7)
What other experiments did Laennec perform with his stethoscope?

While his binaural stethoscope made it easy for him to hear the various sounds inside the chest, he soon realized that he had a rare opportunity to advance upon what was already known about diseases of the chest.

This in mind, he used his new tool to study diseases of the chest, matching what he observed what he observed while his patients were alive with what he found on autopsy after death.  He said:
From this moment I imagined that the circumstance might furnish means for enabling us to ascertain the character, not only of the action of the heart, but of every species of sound produced by the motion of all the thoracic viscera, and, consequently, for the exploration of the respiration, the voice, the rhonchus (the sound of air flowing through diseased air passages), and perhaps even the fluctuation of fluid extravasated (leaked) in the pleura (sack around the lungs) or the pericardium (sack around the heart). (4, page 6)
Figure 3 -- Laennec listens to man with tuberculosis*
He took upon this opportunity to study diseases of the chest at the Necker Hospital where he also received patients at his clinic.  He therefore bravely came into close contact with some of the sickest and contagious people in France at the time, which can be seen in figure 3.  It was this type of dedication to his work whereby he contacted the disease that ended up ending his life.

How was the stethoscope accepted by Laennec's peers? 

Despite how useful he found this new tool in diagnosing and researching diseases of the chest, it was initially rejected by his peers in the medical community.
"What a ridiculous idea," his colleagues would say.  "We doctors are called upon for our brilliant medical minds.  To say we should carry some frivolous tool around with us is absolutely ridiculous and below us." 
This is a plate of the parts of the Laennec's stethoscope
as it appeared in the first edition of his book in 1819.
(4, pages 783) 
Another doctor wrote, "He that hath ears to hear, let him use his ears and not a stethoscope."

This was yet another example of a dogmatic and proud medical profession refusing to accept anything new or different. For thousands of years physicians rejected any scientific idea that opposed Galen's superstitions, and now they flat out rejected a tool that would allow them to do their jobs better.

Perhaps under the encouragement of Corvisart, Laennec published a book reporting what both he and Corvisart had learned about the diseases of the chest by using their new discoveries: chest percussion, vocal fremitus, and the stethoscope.

The book was published in 1819 and titled "De Auscultation Mediate, ou Traitt du Diagnostic des Maladies despoumons ct du Cceur, fonde principalement sur ce nouveau moyen. (A treaties on the diseases of the chest, and on mediate auscultation)" 

The book was well received, and, in 1821, it was translated into English by John Forbes (whose book was referenced in writing this post).

Slowly over the next few years his hard work payed off.  So even though he only lived six years after his discovery, he was able to see its acceptance before he passed away in 1826.

Perhaps there was no better evidence as to his tool's usefulness than by his own perseverance in studying the various diseases of the chest, a quest which may have ultimately cost him his life.  

Figure 4 -- Painting of Laennec using his stethoscope on a boy.
This picture was taken from a painting by Robert Thom,
copyrighted in 1960.  

Laennec married in 1824 and had two children. However, he was only able to enjoy his young family for a short time.

He continued to work arduously at his clinic, both seeing physicians and performing research.

He also worked hard in perfecting the book he became famous for, releasing the second edition in 1826.  Subsequent editions were then published by John Forbes.

In the process of accomplishing this, along with his other duties as a physician and researcher, he became so exhausted that he was forced to give up his work and return to the home he was born in. Although some say he was simply tired from being ridiculed by his colleagues.

Either way, he was ultimately diagnosed with phthsis pulmonalis, which is the Latin form of consumption, or tuberculosis.  Ironically, he was diagnosed with the very same tool he invented.  Perhaps this was consolation, proof that the passion of his life's work was finally accepted.

He passed away on August 13, 1826,

In the ensuing years his invention adjusted by others, and eventually a stethoscope with two ear pieces (binaural) was invented. In 1852 George Camman fine tuned the stethoscope so it was similar to the models we use today.

  1. Forbes, John, The life of the author, translator of "A treaties on the diseases of the chest, and on mediate auscultation," a book written by Rene Theophile Hyacinthe Laennec, 1838, New York, Philadelphia, Samuel S., pages xix-xxiii
  2. Haven, Kendall F, "One hundred greatest inventions of all time," 2006, U.S., Greenwood Publishing Group, Inc., pages 96-98
  3. "Now I hear:  The history of the stethoscope,", 1998-2011, accessed 12/28/13
  4. Laennec, Rene Theophile Hyacinthe, "A treaties on the diseases of the chest, and on mediate auscultation," translated by John Forbes, notes by Dr. M. Andral, 4th edition, 1838, New York, Philadelphia, Samuel S. and William Wood, Thomas Cowperthwaite and Company
  5.  Barchers,Suzanne, "I've Discovered Sound," Brainworks, 2009, Leopard, page 9
  6. Camman, Donald M, "Historical Sketch: Stethoscopes," A Reference Handbook for Medical Sciences, edited by Albert Henry Buck, by various writers, volume VI, 1888, New York, William Wood and Company, 626-628
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