The discovery of hypertension and its linkage with renal disease came remarkably late.  Richard Bright (1836) observed that “the hypertrophy of the heart seems, in some degree, to have kept pace with the advance of disease of the kidneys”.  But he had no way to measure blood pressure, and even by the early 1900s a doctor’s bag was likely to contain a urine testing kit, but not a device for measuring blood pressure.  It was 35 years before blood pressure measurements became possible and 35 more before it began to become an everyday practice. 

After Bright, two more Guy’s Hospital physicians advanced the story.  In 1853 Samuel Wilks, described a hardening of the arteries in Bright’s disease, but only in the 1870s did Frederick Akbar Mahomed obtain measurements that led him to describe isolated hypertension, the association of hypertension with kidney disease, and the consequences of long-term hypertension including cerebral haemorrhage and nose bleeds.  

His sphygmograph conducted the waveform of the pulse of the radial artery.  The pressure of the device on the pulse was gradually increased by adding weights. This was measured in Troy ounces, like gold. 

Mahomed’s achievements came through progressive technical development and application of the sphygmograph, work he began while a medical student. His device was based on that of Edinburgh physician John Burdon Sanderson, who had in turn adapted an 1854 design of Parisian Etienne-Jules Marey.  It clearly needed great care and practice to generate reliable results, but was an exciting discovery.  Mahomed died in 1884 of typhoid at the age of 35. 

Mahomed’s observations were the first to link blood pressure with renal disease.  His contribution to the understanding of hypertension was forgotten for a long time but is now widely recognised.   

The earliest successful measurements of blood pressure had described the physiology, not pathology.  In 1733 English curate and scientist William Hales had joined a glass tube to an artery in a living horse and measured the systolic pressure at 8 feet 3 inches (2.51 metres) of blood. French physician-scientist Jean Poiseuille directly connected a mercury manometer to the vessels of experimental animals in 1828, his device making it possible to take measurements from much smaller vessels. This substantially advanced understanding of blood flow and made possible experimentation to understand how the kidneys cause high blood pressure. 

The sphygmograph was the first device for non-invasive blood pressure measurement.  Subsequent improvements included using water-filled then air-filled balloons to compress the radial artery (Samuel von Basch), until Italian doctor Scipione Riva-Rocci (1863-1937) made the real breakthrough of using a cuff that encircled the arm completely to compress the brachial artery. He first described this in 1896.  The remaining improvements were the introduction of a wider cuff by von Recklinghausen in 1901, and the use of a stethoscope, instead of simply feeling the pulse, to detect the commencement of blood flow (systolic pressure) and free flow (diastolic pressure). These are named the Korotkoff sounds after the Russian surgeon who described them in 1905.  

With these developments, instruments based on the Riva-Rocci design became the standard blood pressure measuring device for over 80 years, until the perceived hazards of mercury led to its progressive replacement by aneroid manometers.  

It is impressive that as soon as it became possible to measure blood pressure the implications of it for health were appreciated. Blood pressure quickly became and remains today one of the standard observations carried out in clinical consultations.  Urinalysis has arguably become its poor relation.

Thanks to Stewart Cameron for the detailed research behind key parts of this story.  

JS Cameron and J Hicks, 1996.  Frederick Akbar Mahomed and his role in the description of hypertension at Guy’s Hospital  Kidney Int 49 1488-1506. An outstanding account of not only the work, but also the man, and the exciting environment at Guy’s hospital at the time. 

J Booth, 1977.  A short history of blood pressure measurement. Proc R Soc Med 70:793-9.
The doctors bag circa 1910 (this blog)