Principle of sphygmomanometer?

An instrument that measures blood pressure is called a sphygmomanometer. Sphygmomanometers can be categorized into two types: direct and indirect. The two types of sphygmomanometers work on different principles. The direct type uses a pressure transducer to measure pressure changes directly, while the indirect type works by controlling the pressure exerted externally on the part to be measured and judging the result of the control against the information related to the production and disappearance of the Koch sound. The former allows continuous testing of either arteries or veins, while the latter measures only arterial systolic and diastolic pressures.

The indirect method of measuring instruments are mercury column sphygmomanometer, random zero sphygmomanometer, spring meter sphygmomanometer, automatic electronic sphygmomanometer, intermittent prolonged blood pressure meter, skin small artery blood pressure measurement meter and so on. These sphygmomanometers are designed according to different needs, such as random zero-point sphygmomanometer is to overcome the human error such as visual inspection and more accurate study of blood pressure changes in the application; intermittent prolonged blood pressure meter is used for continuous 24-hour monitoring of blood pressure changes; skin small arterial sphygmomanometers are for young children, infants, neonates and the design of the; due to the development of intelligent, electronic sphygmomanometers can be automatically inflatable cuffs to the internal The electronic sphygmomanometer can automatically inflate the cuff and display the reading of the blood pressure value. Finger cuff sphygmomanometers are more convenient as they can automatically measure blood pressure by simply placing a finger cuff on the finger. It should be noted that the blood pressure values measured by these automated electronic sphygmomanometers may differ from those measured by mercury column sphygmomanometers, which should be calibrated in advance and the difference memorized.

In recent years, according to the international recommendations of the International Organization for Legal Metrology (IOLM), "Draft Revision of Sphygmomanometers," the sphygmomanometer scale was changed from millimeters of mercury (mmHg) to kilopascals (kPa). 1kPa = 7.5mmHg, and the scale has a divisional value of 0.5kPa. Currently, there are two types of scales on the sphygmomanometer, so please pay attention to the application of the scale.

Spring-loaded sphygmomanometers should be checked before they are activated. Normal use of the blood pressure meter usually dial pointer should be pointed at the zero position, after the pressure, the response is flexible, and can still return to the original zero position.