Auenbrugger, Wine barrels and the Art of Percussion

If a patient complains of breathlessness one possible cause is collection of fluid around the lungs called a pleural effusion. This diagnosis can be made easily by tapping the chest with the fingers - a technique known as percussion. Percussion was invented by Joseph Leopold Auenbrugger (1722-1809), the son of an innkeeper from Gratz, in Austria. In 1751, after completion of his medical studies, he became assistant physician at the Holy Trinity and Spanish Military Hospital in Vienna. He discovered that tapping his fingers on the patient's chest produced sounds of varying pitch depending on what structure was underneath. As a child he had seen the barrels in his father’s cellar being tapped to find out how much wine they contained and in his work on percussion he wrote that “empty casks are resonant but they become dull when full of wine”.  By systematic percussion over the chest he observed that the note was dull over the heart. Likewise if the pleural cavity surrounding the lungs became filled with fluid, the sound of the percussion note was so muffled it became completely or stony dull. He went on to correlate his percussion findings with conditions found at post-mortem and to prove the existence of fluid inside the chest by withdrawing it with a trocar. Auenbrugger practised the percussion technique for seven years before, in 1761, he published his treatise titled: “Inventum Novum ex Percussione Thoracis Humani Ut Signo Abstrusos Interni Pectoris Morbos Detegendi” which translates as “New Invention, by means of percussing the human chest, as a sign of detecting obscure disease in the interior of the chest”.  In the 18th Century publication of anything medically often invoked criticism rather than adulation from colleagues. In the preface of his book he wrote: “In making public my discoveries respecting this matter, I have been actuated neither by an itch for writing, nor a fondness for speculation, but by the desire of submitting to my brethren the fruits of seven years observation and reflection. In doing so, I have not been unconscious of the dangers I must encounter, since it has always been the fate of those who have illustrated or improved the arts and sciences by their discoveries, to be beset by envy, malice, hatred, detraction and calumny”.

Auenbrugger’s method of percussion was to strike the chest wall directly with the extended fingertips. He found that the note produced was better if the shirt was tightly drawn across the chest (like the covering of a drum) or if the physician’s hand was covered with a leather glove. Today we lay one hand flat on the chest and strike the back of its middle finger with the tip of the middle finger of the other hand. This prodcues a better percussion note and makes it less uncomfortable for the patient compared to striking the chest directly with the fingertips.

After his publication the percussion technique was ignored for many years. Baron van Swieten, Professor of Medicine at Vienna University and Auenbruggers teacher, did not mention it in his 1764 treatise on fluid around the lungs in pulmonary tuberculosis and other contemporaries like Vogel confused it with the Hippocratic practice of succussion whereby the patient was shaken vigerously to detect the presence of fluid and air in the thorax. One favourable review appeared describing the discovery as “a torch that was designed to illumine the darkness in which diseases of the thorax had up to this time lain concealed".

The poor reception of his book and being dismissed from the Spanish Military Hospital did not seem to harm Auenbrugger's his career prospects. Private practice prospered and he was popular at the Court of Vienna where he was enobled by the Emperor Joseph II with the title “Edler von Auenbrugger".  He was also an accomplished musician and at the Emperor’s request wrote the libretto for a comic opera, Der Rauchfangskehrer (The Chimney Sweep) for the court composer Salieri.

Percussion remained hidden until 1808 when Jean Nicholas Corvisart, the personal physician to Napoleon, translated Auenbrugger's work from Latin into French and then the technique rapidly came to world-wide attention and use. Today percussion remains a basic clinical skill learnt by all medical students and practised by doctors on a daily basis.

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