I was shocked to find out that medical students, entering their clinical years, have not been taught the proper method and interpretation of blood pressure measurement. The current approach almost invariably uses electronic sphygmomanometers and, while convenient, it is often not performed well and misses important information which simply cannot be gleaned from an electronic sphygmomanometer.

First, and foremost, the patient must be comfortably seated with their back supported and their feet planted on the ground or supportive surface. The patient is to have rested for at least five minutes and not have had any caffeine to drink in the previous hour.

The bladder of the cuff should encircle at least 80% of the patient’s arm and the width to length ratio of the cuff should be at least 40%.

I would recommend that the systolic pressure be estimated first by palpation. One does this by reasonably rapidly inflating the cuff to 80 mmHg while palpating the radial pulse. If the pulse remains palpable, slowly increase the cuff pressure (approximately 10 mm Hg every 2 to 3 seconds) until it disappears.  Note at what pressure the pulse is obliterated. Next release the pressure of the cuff completely and raise the patient’s arm above their head (especially if he or she is obese) for at least ten seconds so as to help drain any excess venous blood that had accumulated in the arm as that has may muffle Karotkoff sounds.

Next while supporting the patient’s relaxed arm at heart level, pump up the cuff to 20 mm Hg above the previously estimated systolic blood pressure. Slowly deflate the cuff at no more than 2 mm every second while listening for Karotkoff sounds. The appearance of Karotkoff sounds (stage I) signals the patient’s systolic blood pressure. Continue to deflate the cuff paying attention to a time when Karotkoff sounds become muffled or disappear (stage II). This stage is not always present. Continue to deflate the cuff listening for the recurrence of Karotkoff sounds, if they had disappeared, or an increase in their intensity if they had only been muffled (stage III). Continue to deflate the cuff until Karotkoff sounds muffle again (stage IV). Continue to deflate the cuff until Karotkoff sounds disappear completely (stage V). True diastolic blood pressure is found between stages IV and stage V. However, if those stages occur within a narrow range, the disappearance of Karotkoff sounds identifies the diastolic blood pressure. Persistence of Karotkoff sounds well beyond phase IV is termed “systolic persistence” and, in such a case, I would record the blood pressure with three digits – systolic, phase IV and phase V readings

I would also strongly recommend that blood pressure be tested in both arms. A difference of 10 mm Hg or more can indicate, amongst other things, arteriosclerotic vascular disease and has been correlated with an increased risk of cardiovascular events.

A very prominent auscultatory gap (i.e., stage II) in which there is disappearance of Kartkoff sounds also correlates with an increased risk of cardiovascular events.2

In patients over the age of 60, those with “resistant hypertension”, diabetics and/or patients with chronic kidney disease check for evidence of possible pseudohypertension. To do so, determine if the radial pulse is still palpable after the blood pressure cuff has been inflated to above systolic. If so, this signifies stiffening of the radial artery due to Monckeberg’s medial sclerosis. This procedure is known as “Osler’s maneuver”. Such a finding carries significant ramifications.3

1. Williams, J. S., Brown, S. M., & Conlin, P. R. (2009). Blood-pressure measurement. N Engl J Med, 360(5), e6.

2. Cavallini, M. C., Roman, M. J., Blank, S. G., Pini, R., Pickering, T. G., & Devereux, R. B. (1996). Association of the auscultatory gap with vascular disease in hypertensive patients. Annals of internal medicine, 124(10), 877-883.

3. Mishriki YY. Resistant hypertension: A stepwise approach. Cleveland Clinic Journal of Medicine May 2023, 90 (5) 273-274; DOI: https://doi.org/10.3949/ccjm.90c.05001