How to use a mercury sphygmomanometer

Blood pressure is abbreviated as BP, and doctors often write it that way.

Blood pressure is arterial pressure and is usually measured with a sphygmomanometer. Some of the sphygmomanometers used today are mercury column, spring and electronic sphygmomanometers. However, it is still the mercury column sphygmomanometer that is often used.

Every family should have a sphygmomanometer, especially if they have an elderly person or a heart patient, and learn how to use it.

Before measuring blood pressure, have the patient rest in bed for a few minutes. Expose the right arm, all the way to the shoulder, and straighten the elbow with the palm up and flat.

Place the sphygmomanometer on the bed, or on a table, so that the "0" point of the sphygmomanometer is on the same plane as the patient's heart.

Wrap the cuff of the sphygmomanometer around the patient's upper arm. The lower edge of the cuff should be 2 to 3 centimeters from the elbow socket, not too tight, not too loose.

Wearing a stethoscope, feel the brachial artery in the patient's elbow socket and place the stethoscope over it, and you will hear the "thud" of the artery.

Close the balloon, to the cuff, the pressure is added to the brachial artery beating sound can not be heard until, and then slowly release the valve, reduce the pressure, and pay attention to the mercury column pointed out by the scale, until you hear the first beat. At this point, the scale indicated by the mercury column is the systolic blood pressure.

Pressure continues to decrease gently until the sound of arterial pulsation gradually increases to a point where it suddenly becomes soft and weak, at which point the scale indicated is the diastolic pressure (note that the sound of pulsation does not disappear completely).

Blood pressure is usually measured two or three times in a row, taking the lowest value.

In normal people, blood pressure rises with age. Systolic blood pressure in a normal adult should be less than 140 millimeters of mercury (doctors write mmHg) or 18.6 kilopascals (abbreviated as kPa). Diastolic blood pressure should be less than 90 mmHg (or 12.0 kPa). The difference between systolic and diastolic blood pressure is called the "pulse pressure difference". Pulse pressure difference is 30 to 40 mm Hg (or 4.0 to 5.3 kPa).

Kilopascals are also a unit of measurement for blood pressure, and many doctors use them as a unit of measurement. 1 kPa = 7.5 mmHg or 1 mmHg = 0.133 kPa.

Patients who are experiencing a shock situation will have a rapid drop in blood pressure, to the point where it cannot be measured (i.e., the blood pressure is 0).