Senior – B.P Apparatus Mercury – NSL

Digital B.P Apparatus is most commonly measured via asphygmomanometer, which historically used the height of a column of mercury to reflect the circulating pressure.^[1]Blood pressure values are generally reported inmillimetres of mercury(mmHg), though aneroid and electronic devices do not containmercury.

For each heartbeat, blood pressure varies between systolic and diastolic pressures. Systolic pressure is peak pressure in the arteries, which occurs near the end of thecardiac cyclewhen theventriclesare contracting. Diastolic pressure is minimum pressure in the arteries, which occurs near the beginning of the cardiac cycle when the ventricles are filled with blood. An example of normal measured values for a resting, healthy adult human is 120 mmHgsystolicand 80 mmHgdiastolic(written as 120/80 mmHg, and spoken as “one-twenty over eighty”).

Systolic and diastolic arterial blood pressures are not static but undergo natural variations from one heartbeat to another and throughout the day (in acircadianrhythm). They also change in response tostress, nutritional factors,drugs, disease, exercise, andmomentarily from standing up. Sometimes the variations are large.Hypertensionrefers to arterial pressure being abnormally high, as opposed tohypotension, when it is abnormally low. Along withbody temperature,respiratory rate, andpulse rate, blood pressure is one of the four main vital signs routinely monitored by medical professionals and healthcare providers.^[2]

Measuring pressureinvasively, by penetrating the arterial wall to take the measurement, is much less common and usually restricted to a hospital setting.