What is a blood pressure monitor? What is the principle of a sphygmomanometer?
The instrument that measures blood pressure is called a blood pressure monitor. Sphygmomanometers can be divided into direct and indirect types. The working principle of the two sphygmomanometers is different. The direct type uses the pressure sensor to directly measure the pressure change; the indirect type works to control the pressure applied from the outside to the measured part, and the result of the control is related to it. The information on the generation and disappearance of Korotkoff sound is judged. The former can be continuously tested for arteries or veins, while the latter can only measure arterial systolic and diastolic blood pressure.
Indirect method measuring instruments include a mercury sphygmomanometer, a random zero sphygmomanometer, a spring-type sphygmomanometer, an automatic electronic sphygmomanometer, an intermittent long-term blood pressure meter, and a skin arterial blood pressure meter. These sphygmomanometers are designed according to different needs. For example, the random zero sphygmomanometer is used to accurately study blood pressure changes to overcome human error such as visual observation. The intermittent long-term blood pressure monitor is used to monitor blood pressure for 24 hours. The cutaneous calculus blood pressure monitor is designed for infants, babies, and newborns; due to the development of intelligence, the electronic sphygmomanometer automatically inflates and displays blood pressure readings into the inflatable cuff. The finger-type electronic sphygmomanometer can automatically measure blood pressure by simply wearing a finger cot on the finger, which is more convenient. It should be noted that the blood pressure measured by these automatic electronic sphygmomanometers may be different from the blood pressure measured by the mercury sphygmomanometer. It should be checked in advance and the difference should be remembered.
In recent years, according to the International Recommendations of the International Legal System, the revised sphygmomanometer regulations, the sphygmomanometer scale changed to millimeters of mercury (mmHg) to dry kPa (kPa). 1 kPa = 7.5 mmHg, and the scale value on the scale is 0.5 kPa. There are currently two scales on the blood pressure meter, please pay attention when applying.
The spring-type sphygmomanometer should be checked before it is activated. The normal use of the blood pressure meter usually refers to the dial position at zero position. After pressurization, the reaction is flexible and can still return to the original zero position.