Sphygmomanometer

A sphygmomanometer is a device used to measure arterial blood pressure. It consists of a cuff that wraps around the upper arm, an inflatable bladder, a pressure gauge or sensor, and a mechanism to inflate the cuff. Some models include a built-in display or electronic sensors.

There are three main types: mercury, aneroid (mechanical gauge), and electronic or digital. Mercury sphygmomanometers rely on a column of mercury and are considered highly accurate but are less common due to mercury handling. Aneroid devices use a mechanical dial. Digital devices provide an automatic reading and may combine oscillometric and auscultatory methods.

Measurement methods: In the auscultatory method, a stethoscope is used to listen for Korotkoff sounds as the cuff is slowly released. The first sound indicates systolic pressure and the disappearance indicates diastolic pressure. Palpation can estimate systolic pressure without auscultation.

Accuracy and maintenance: Proper cuff size, arm supported at heart level, and patient at rest are important. Regular calibration is important for mechanical devices. Cuff leaks, air loss, and device drift affect accuracy. Digital devices require occasional calibration and checking against a manual reading.

History: The modern cuff-based device was developed by Scipione Riva-Rocci in 1896, introducing a cuff around the upper arm and a mercury manometer. The auscultatory method and Korotkoff sounds described by Nikolai Korotkoff in 1905 improved accuracy.

Usage: Used in clinical settings and home monitoring; essential in diagnosing and managing hypertension, preeclampsia, and cardiovascular risk. Safety: follow manufacturer instructions, monitor cuff fit, and seek professional instruction for children or pregnant patients.