90th Anniversary of the Development by Nikolai S. Korotkoff of the Auscultatory Method of Measuring Blood Pressure
Every day, all over the world, many thousands of physicians, nurses, and paramedics measure systemic arterial pressure by applying a cuff with an inflatable bladder around the patient's arm and using a stethoscope to listen to the sounds in the brachial artery. Many care providers know that they are listening to “Korotkoff sounds,” but very few know that the method was introduced 90 years ago by a Russian doctor and scientist, Nikolai Sergeevich Korotkoff (Fig 1⇓).
Indeed, a report on a new method of measurement of arterial pressure1 was presented on November 8, 1905, at a scientific seminar of the Imperial Military Medical Academy, Saint Petersburg, Russia, by Korotkoff, a young surgeon from the clinic of Prof Sergei P. Fedorov. (The authors found the date of the presentation mentioned in Korotkoff's dissertation.2(p116)) An English translation of the text of Korotkoff's presentation1 was published by W.H. Lewis, Jr, in 1941.3
In the 90 years since Korotkoff presented the new method to measure the arterial pressure, medical science and medical technology have made big strides. However, because of its simplicity and high degree of accuracy, the method of auscultatory measurement of arterial pressure remains the most acceptable in everyday medical practice. Moreover, this method is one of only a few techniques for clinical examination of patients that has not undergone significant changes since it was introduced.
Very little is known, even in his native Russia, about the life and work of this doctor and scientist.4 Outside Russia, even less is known about Korotkoff. Some biographical information by Segall was published in English in 1965.5 However, because of differences between the Russian and American systems of education, Segall misinterpreted some facts of Korotkoff's life.
Information in the present article was based on materials available in the archives of the Russian Military Medical Academy in Saint Petersburg, Russia, where Korotkoff conducted and presented his studies and his dissertation. Other materials are available in the Saint Petersburg Public Library.
Korotkoff was born in 1874 into a merchant family; he received his high school diploma in 1893 from the Kursk Gymnasium and in 1898, he graduated cum eximia laude from the Moscow University Medical School with a degree of Physician (equivalent to the US degree of Doctor of Medicine).2 After graduation, Korotkoff stayed in Moscow in “ordenatura” (equivalent to residency) in the Department of Surgery. During the Boxer Rebellion in China in 1900, he was sent by the University to the Far East as a physician for the Red Cross.
In 1902, Korotkoff completed his residency and started working in the position of an assistant (similar to an instructor) at the Military Medical Academy in Saint Petersburg in the Women's Section of the clinic headed by Professor Sergei P. Fedorov. During the Russian-Japanese War (1904 to 1905), he was directed to Harbin, northeast China, where he worked as a physician in different hospitals. From 1908 to 1909, he worked in Siberia as a physician in the Vitemsk-Oleklinsk region of Russia.
In 1905, Korotkoff developed a new method to measure blood pressure in humans. This auscultatory method of arterial pressure measurement was later described in detail for the first time in “Experiments for Determining the Strength of Arterial Collaterals,” his dissertation for the advanced scientific degree of Doctor of Medical Sciences.2 The dissertation was presented in 1910 to the Scientific Council of the Imperial Military Medical Academy. His reviewers, Professors S.P. Fedorov and V.A. Oppel and Privat-Docent (equivalent to Associate Professor) N.N. Petrov, unanimously acknowledged that Korotkoff's scientific results represented a major discovery, which revolutionized the existing field of diagnosis of diseases of the heart and vessels.4
During World War I, Korotkoff worked in the military hospital in the town of Tsarskoye-Selo, Russia. After the 1917 revolution in Russia, he became the senior physician of the Metchnikov Hospital in Petrograd (as Saint Petersburg was then called) and later was a senior physician at Petrograd Hospital on Zagorodny Avenue. Korotkoff died in 1920; the cause of his death is unknown.4
His education and experience in treating those wounded in battle led Korotkoff to study damage to major arteries. These studies resulted in his discovery of the new method of arterial blood pressure measurement.
It is worth noting that the idea for the new method to measure blood pressure was born during the Russian-Japanese War. Korotkoff was working to solve the problem that was first formulated as early as 1832 by one of the most respected Russian doctors, Nicolai I. Pirogov, in his dissertation for the degree of Doctor of Medical Sciences, “Can the Ligation of the Abdominal Aorta During Aneurism in Groin Region Be Performed Easily and Safely?” While treating wounded soldiers who had aneurysms, Korotkoff set a goal to find indications that would allow the surgeon to predict an outcome of ligation of arteries of the traumatized limbs, ie, to predict whether the limb would recover or die after surgery. While attempting to resolve this problem, he systematically listened to the arteries to estimate the potential strength of arterial collaterals after a major vessel of the wounded limb had been ligated. He established that certain specific sounds could be heard during the decompression of the arteries. This specific phenomenon, known in world literature as “Korotkoff sounds,” became the basis of the new method of blood pressure measurement.
In his studies, Korotkoff used the apparatus proposed by Riva-Rocci6 in Italy in 1896 (Fig 2⇓), which contained an arm-encircling inflatable elastic cuff, a rubber bulb to inflate the cuff, and a mercury sphygmomanometer to measure the cuff pressure. Riva-Rocci measured the systolic pressure by registering the cuff pressure at which the radial pulse was obliterated as determined by palpation. The palpation technique did not allow the measurement of diastolic pressure. Soon after Riva-Rocci's technique was described, Hill and Barnard7 in England in 1897 reported an apparatus with an arm-encircling inflatable cuff and a needle pressure gauge that allowed measurement of the diastolic pressure by the oscillatory method. This method used the oscillations transmitted to the gauge as the pulse wave came through the compressed artery. When the cuff pressure was reduced slowly from the suprasystolic pressure, the appearance of definitive oscillations denoted the systolic pressure, whereas the change from maximal oscillations to smaller ones denoted the diastolic pressure.
Similar to Riva-Rocci, Korotkoff used an inflatable sphygmomanometer cuff to obstruct arterial flow. His contribution was the discovery of a new, more accurate auscultatory technique to identify the times when the pressure in the cuff coincided with systolic and diastolic arterial pressures. When he examined patients who had damaged vessels, Korotkoff gradually compressed the arteries until the peripheral pulse disappeared. He also recorded sphygmograms while simultaneously listening to the sounds in the part of the artery distal to the compressed area. He determined that a totally compressed artery produced no sounds at all and that while the pressure in the artery was decreased gradually, certain sounds appeared that allowed one to judge the level of arterial pressure.1 2
To measure blood pressure, Korotkoff applied an elastic, rubber cuff of the Riva-Rocci apparatus (Fig 2⇓) on the middle third of the arm. The pressure in the cuff was increased until the blood supply to the periphery was completely stopped. Then the pressure in the cuff was decreased, and a stethoscope was used to listen to the pressure in the artery “directly below the cuff.”1 Once the pressure fell below a certain level, the first short tones could be heard; this indicated the passage of the first pulse wave along the artery below the cuff. The manometer reading at which the first tone appeared corresponded to the systolic pressure. With a further decrease in pressure in the cuff, the tones were replaced by murmurs that were followed in turn by second tones. Finally, all the sounds disappeared. The moment all sounds subsided, according to Korotkoff, blood was flowing freely through the arteries. The diastolic pressure in the artery at that moment slightly exceeded the pressure in the cuff, and the manometer reading at the moment the sounds disappeared corresponded to the diastolic pressure.1
Simultaneous auscultation and palpation of the compressed artery revealed the difference in the cuff pressures for the appearance of sounds and the formation of the pulse wave in a segment distal to the compressed area. The first sounds appeared at the cuff pressure, which was 10 to 12 mm Hg higher than the pressure at which the palpable pulse was produced, because generation of the pulse required some filling of the vessel.1
Korotkoff considered the tones and murmurs in the vessel to be compression sounds. He thought the tones were caused by the rushing “of a minuscule part of the pulse wave” through the compressed area during a very short time interval. Also, vibrations of the “unsticking” vessel walls contributed to the production of the tones. Korotkoff believed that the sound phenomenon depended on the elastic properties of the arterial walls.
To prove the local generation of sound, Korotkoff performed a series of canine experiments. He reported the results of these experiments at a scientific seminar on December 13, 1905.8 Experiments demonstrated that sounds heard during the compression of vessels did not originate from the heart or the semilunar aortic valves, as was hypothesized by some of his critics. In one of the experiments, he placed a T-shaped cannula into an exposed femoral artery. The vertical branch of the cannula was connected to a container filled with saline. The artery was ligated proximal to the cannula and compressed by the cuff distal to the cannula. As pressure in the saline changed from 40 to 100 mm Hg, the wave of liquid passed through the vessel; the sounds produced first were tones, followed by murmurs, and then the sounds disappeared. Thus, the experiments demonstrated that the Korotkoff sounds originated at the site of vessel compression.8 Korotkoff's presentation was highly praised by Prof M.V. Yanovskiy. He stated that he was in complete agreement with Korotkoff's results: “…with this method, I believe, we will achieve quite accurate results…. I have to say that through your observations, you have demonstrated your talent and sharpness. You have noticed the fact that many other researchers who have been working on this problem missed.”8 (discussion)
Yanovskiy's clinic produced many studies in support of the auscultatory method of measurement of blood pressure. One of the earliest serious studies was the work by Krilov, “Determining Blood Pressure by Using the Sound Method of Doctor Korotkoff,”9 which was completed on the advice and under the supervision of Yanovskiy. The reports presented methods of study, described the types of sounds during the termination of the occlusion of the arterial vessel, and analyzed the sounds and the reasons for their generation and change.
Later research studies by Krilov, Vesternik, Lebedev, Lang, and Mansvetova showed a close correlation between arterial pressure measurements by Korotkoff's method and measurements by use of other methods (Reklinghausen, Pal, direct invasive measurements, etc).4 9 10 11
The method of measurement of blood pressure invented by Korotkoff quickly received wide recognition and became a standard medical procedure.3 4 5 This method played an important role in the study of various forms of disturbance of vascular tone and influenced our understanding of the etiology, pathogenesis, and treatment of hypertension. This method also made it possible to research the functioning of the cardiovascular system under normal conditions and during various diseases.
Introduced in 1905, the simple and accurate Korotkoff method of measuring blood pressure has been used by physicians, nurses, researchers, and paramedics around the world throughout this century. Korotkoff's method certainly will still be used extensively in the 21st century.
The authors are thankful to Dr Leonid Sakharny, Professor of the Saint Petersburg University, who, after extensive search at the Leningrad Public Library, provided Dr Tsitlik with copies of Korotkoff's presentations and his 1910 dissertation.
- Copyright © 1996 by American Heart Association
Korotkoff NS. On methods of studying blood pressure [in Russian]. Bull Imperial Mil Med Acad. 1905;11:365-367 (with discussions).
Korotkoff NS. Experiments for Determining the Strength of Arterial Collaterals. Saint-Petersburg, Russia: Imperial Military Medical Academy; 1910. Dissertation.
Nikitin VP. 50th anniversary of development by N.S. Korotkoff of the auscultatory method of measuring the arterial blood pressure [in Russian]. Klinicheskaya Medizina.. 1956;34:84-86.
Segall HN. Dr. N.C. Korotkoff: discoverer of the auscultatory method for measuring arterial pressure. Ann Intern Med. 1965;63:147-149.
Riva-Rocci S. Un sfigmomanometro nuovo. Gazetta Medica di Torino. 1896;47:981-986.
Hill L, Barnard H. A simple and accurate form of sphygmometer or arterial pressure gauge contrived for clinical use. Br Med J. October 2, 1897:904.
Korotkoff NS. On methods of studying blood pressure: second presentation [in Russian]. Izv Imper Voen-Med Acad. 1906;12:254-257 (with discussion).
Krilov DO. Determining blood pressure by using the sound method of Doctor Korotkoff [in Russian]. Izv Imper Voen-Med Acad. 1906;13:113-135, 221-233, 319-328.
Lebedev AC. [in Russian] Izv Imper Voen-Med Acad. 1911;23:175-213.
Yanovskiy MV. [in Russian] Izv Imper Voen-Med Acad. 1911;22:20-25.