How a Russian Surgeon Heard Blood Pressure

Nikolai Korotkoff was a 31-year-old surgical assistant at the Imperial Military Medical Academy in St Petersburg when he stood up at a conference on November 8, 1905, and read a paper that ran 281 words. The talk, "On the issue of the methods for measuring blood pressure," took less than a page in the academy's reports. It described what he had been doing with a stethoscope and a Riva-Rocci cuff during the Russo-Japanese War, treating arterial injuries in Harbin.

The Riva-Rocci cuff, invented by an Italian pediatrician in 1896, could already give the systolic pressure. You inflated it until the radial pulse vanished, read the gauge, and that was the top number. The bottom number — the pressure inside the artery between beats — was guesswork.

Korotkoff was studying aneurysms in soldiers and using a stethoscope to listen for collateral flow. He noticed something the cuff alone could not show. As he let the pressure down past the systolic point, a series of clear sounds appeared distal to the cuff, then changed character, then vanished. The vanishing point was the diastolic pressure. He described four phases; a fifth, the muffling, was added soon after.

The method needs almost nothing. A cuff, a column of mercury, a stethoscope, a quiet room. It became standard within a decade and is still the reference against which automated monitors are validated.

Korotkoff did not get to see most of that. He stayed in Russia through revolution and civil war, ran the Mechnikov Hospital in Petrograd, and died of tuberculosis in March 1920. He was 46. The reading you get at every checkup is the one he heard first.