a short history of blood pressure
It is Galen in ancient Greece who first proposed the existence of a circulatory system in the human body. However, building on ideas conceived by Hippocrates and because the arteries stopped bleeding when death occurred, Galen believed that this circulatory system was composed of an interconnected set of arteries filled with “pneuma” (life giving force) or air. He maintained that the human body was comprised of three systems. Nerves and the brain were responsible for sensation and thought, the heart filled the body with life-giving energy (pneuma) and the liver provided the body with nourishment and growth. Galen believed that the heart was like a fountain, constantly giving the needed pneuma and blood to the system.
In 1616 William Harvey announced that Galen was wrong in his assertion that the heart constantly produced blood, like a fountain. Harvey proposed that there was a finite amount of blood that circulated the body in one direction only. Harvey's views were initially met with a lot of skepticism and resistance. The idea that blood was not constantly produced in the body raised doubts about the benefit of bloodletting, a popular medical practice at the time. As a matter of routine, bloodletting was used as a universal panacea for just about every symptom known to man.
First blood pressure
The first recorded instance of the measurement of blood pressure was in 1711 by the Reverend Stephen Hales. Hales inserted a glass tube into an artery of a horse and observed the rise and fall of blood in the tube and concluded that this must be due to fluctuating pressure in the arteries of the horse. However, Hales’ technique was not suitable for testing with humans, as it was very invasive and highly inappropriate for clinical use. The horse died every time...
Human blood pressure measurement
In 1856 Faivre recorded human blood pressure for the first time during a limb amputation. Faivre used Carl Ludwig's recently invented kymograph with catheters inserted directly into an artery. Ludwig's kymograph consisted of a U-shaped manometer tube connected to a brass pipe canula plugged directly into the artery. The manometer tube had an ivory float onto which a rod with a quill was attached. This quill would sketch onto a rotating drum hence the name “kymograph” (wave writer in Greek).
However, at this time, blood pressure could still only be measured by invasive means. The race was now on to find a suitable way to measure blood pressure non-invasively.
In 1855, Karl Vierordt discovered that with enough pressure the arterial pulse could be obliterated. Vierordt introduced the sphygmograph, based on this principle of obliteration. Vierordt used an inflatable cuff around the arm to constrict the artery. However, Vierordt’s device was huge and unwieldy (168 cm tall) and produced very uneven results.
Etienne Jules Marey, a French physician (also a cinematographer who is considered to be the father of modern photography) developed this idea further in 1860. His sphygmograph could accurately measure the pulse rate, but was very unreliable in determining the blood pressure. Yet this design was the first that could be used clinically was some degree of success. In 1882, Robert Ellis Dudgeon simplified and refined the Marey sphygmograph, rendering it eminently portable and easy to use. At the time, Dudgeon's device was so successful that it became standard equipment for the U. S. Navy.
In 1881, Samuel Siegfried Karl Ritter von Basch invented the sphygmomanometer. His device consisted of a water or mercury-filled rubber ball connected to a manometer. The rubber ball was then pressed against the radial artery until the pulse was obliterated and the blood pressure was then estimated using the manometer and palpation was used to determine when the arterial pulse disappeared.
However von Basch's design never had the success it deserved, many physicians of the time being skeptical of this new technology, claiming that it sought to replace traditional ideas of diagnosis based on palpation. The real problem was however that most doctors questioned the medical usefulness of blood pressure. This did not stop some from attempting to produce a more useful device, such as the sphygmometer by Bloch, which was essentially a spring-loaded tire-gage that was applied to an artery to see how much pressure was necessary to obliterate the pulse.
In 1889, Potain improved all of the compression devices available by replacing water and mercury in the devices with air, thus substantially improving their accuracy. From this moment on, air became the compression medium of choice.
1896 was a decisive year in the history of blood pressure. Scipione Riva-Rocci developed his first mercury sphygmomanometer. This design was the forerunner of the modern mercury sphygmomanometer. An inflatable cuff was placed over the upper arm to constrict the brachial artery. This cuff was connected to a glass manometer filled with mercury to measure the pressure exerted onto the arm.
Riva-Rocci's sphygmomanometer was then spotted by the American neurosurgeon Harvey Cushing while he was traveling through Italy. Seeing the potential benefit of this device, he returned to the US with the design in 1901. After the design was modified to be more adapted for clinical use, the sphygmomanometer became commonplace. This year really marks the beginning of modern sphygmomanometry.
However, it is useful to remember that this sphygmomanometer was then only used to determine the systolic blood pressure. The importance of the diastolic pressure had not yet been clearly defined at this time. In 1905, a young Russian surgeon, Nikolai Korotkoff, observed the sounds made by the constriction of the artery, using a stethoscope. Korotkoff found that there were characteristic sounds at certain points in the inflation and deflation of the cuff. These Korotkoff sounds were caused by the passage of blood through the artery, corresponding to the systolic and diastolic blood pressures. The technique that we still use today to measure systolic and diastolic blood pressure was born.
A crucial difference in Korotkoff's technique was the use of a stethoscope to listen for the sounds of blood flowing through the artery. This auscultatory method proved to be more reliable than the previous palpation techniques and thus became the standard practice.
Modern blood pressure
In 1974, Panasonic released the first digital oscillometric device. These sphygmomanometers measure the pressure imparted onto the cuff by the blood pushing through the constricted artery over a range of cuff pressures. This data is used to estimate the systolic and diastolic blood pressures.
In the 1980's, home monitoring of blood pressure becomes commonplace.
A short video on blood pressure history