Oscillatory blood pressure monitoring devices became popular over the last few years in hospitals as ambulatory blood pressure (BP) monitor as well as in private households as home blood pressure monitors. These devices measure the vibrations in the arterial wall caused by the blood, which flows through an artery between systolic and diastolic pressures.

The electrical signal resulting from it is shown on a digital display. The systolic pressure is the measurement of the pressure in the blood vessels during the heartbeat. The blood vessel pressure, which is measured while the heart is resting, is called diastolic pressure. The newer devices determine how much inflation is necessary to reach 20mm Hg above the systolic pressure.

The blood flow stops as soon as this pressure is reached, and the cuff deflates below the systolic pressure allowing the blood to flow again and causing a vibration of the artery wall. After the cuff pressure falls below the patient’s diastolic pressure, normal blood flow continues.

The vibrations of the artery wall can occur at any time when the cuff pressure is high enough for the blood to push the arterial wall open in order to flow through it. Digital devices deflate around 4 mm Hg per second. Although they seem to work slower than non-digital devices, some are more accurate.