A sphygmomanometer is the medical instrument used to measure blood pressure. The name comes from the Greek sphygmos (pulse) combined with manometer (pressure gauge). The device consists of an inflatable cuff wrapped around the upper arm, a mechanism for inflating the cuff, and a pressure gauge that reads the pressure in millimetres of mercury (mmHg).
Traditional sphygmomanometers were auscultatory: the cuff was inflated to temporarily block arterial blood flow, then slowly deflated. Blood pressure was measured by listening with a stethoscope for Korotkoff sounds appearing when blood first passes through the compressed artery (systolic pressure) and disappearing when flow is fully restored (diastolic pressure). This method remains the gold standard for clinical accuracy.
Modern electronic (automated) sphygmomanometers detect oscillations in cuff pressure caused by arterial pulse waves, and a microprocessor calculates the blood pressure values. These devices are now widely used in clinical and home settings. Home blood pressure monitoring is encouraged for patients with hypertension, including many cardiac arrest survivors, as it provides a more accurate picture of average blood pressure than occasional clinic readings.
Sphygmomanometers are used across the full spectrum of cardiac care, from routine monitoring in the GP surgery to continuous beat-to-beat arterial blood pressure measurement via an arterial line in the intensive care unit. Accurate blood pressure measurement is central to the management of hypertension, heart failure, and post-cardiac arrest haemodynamic monitoring.
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