Overview of electronic sphygmomanometer
The electronic sphygmomanometer is a medical device that uses modern electronic technology and the principle of indirect blood pressure measurement to measure blood pressure. The structure is mainly composed of pressure sensors, air pumps, measurement circuits, cuffs and other components; according to the different measurement positions, there are mainly arm type, There are several types of wrist type, desktop type and watch type.
The indirect blood pressure measurement method is divided into auscultation (Korotkoff-Sound) method and oscillometric method.
a. Since the auscultation method is completed by the operation and auscultation of the clinician, the measured value is easily affected by the following factors:
The doctor should constantly observe the changes of the mercury pressure gauge when listening to the sound. Because people’s reactions are different, there is a certain gap in reading the blood pressure value;
Different doctors have different hearing and resolution, and there are differences in the discrimination of Korotkoff sounds;
The deflation speed has a direct impact on the readings. The international standard deflation speed is 3～5mmHg per second, but some doctors often deflate the gas faster, which affects the accuracy of the measurement;
Depending on the clinician’s operational proficiency, the large personal determination factors of the mercury level, the unstable rate of deflation, how to determine the systolic and dilatational pressure values (the fourth or fifth sound of the Korotkoff sound is used as the criterion , The current clinical controversy is still large, and there is no final conclusion), and other subjective error factors affected by a series of factors such as mood, hearing, environmental noise, and subject’s tension, resulting in the blood pressure data measured by auscultation method being affected by subjective factors Larger, there are inherent shortcomings of large discrimination error and poor repeatability.
b. Although the electronic sphygmomanometer made on the principle of auscultation has realized automatic detection, it has not completely solved its inherent shortcomings.
c. In order to reduce the problem of large errors caused by subjective factors caused by the auscultation sphygmomanometer, and to reduce the influence of personnel operation, automatic electronic sphygmomanometers and blood pressure monitors that indirectly measure human blood pressure using the oscillometric method have appeared. The main principle is: automatically inflate the cuff, and start to deflate at a certain pressure. When the air pressure reaches a certain level, the blood flow can pass through the blood vessel, and there is a certain oscillating wave, which propagates through the trachea to the pressure sensor in the machine. The pressure sensor can detect the pressure and fluctuations in the measured cuff in real time. Gradually deflate, the oscillation wave gets bigger and bigger. Re-deflation As the contact between the cuff and the arm becomes looser, the pressure and fluctuations detected by the pressure sensor become smaller and smaller. Choose the moment of maximum fluctuation as the reference point (average pressure), based on this point, look forward to the peak 0.45 fluctuation point, which is the systolic blood pressure (high pressure), and look backward to find the peak 0.75 fluctuation point, this point The corresponding pressure is the diastolic pressure (low pressure), and the pressure corresponding to the point with the highest fluctuation is the average pressure.
Its main advantages are: eliminates errors caused by a series of personnel such as doctors manual operation, human eye reading, sound judgment, deflation speed, etc.; repeatability and consistency are better; sensitivity is high, and it can be accurately determined to ±1mmHg; parameters The setting of is derived from the clinical results, which is relatively objective. But it needs to be pointed out that from the principle of measurement, the two indirect measurement methods do not have the problem of which one is more accurate.
The difference between medical sphygmomanometer and household sphygmomanometer
According to industry standards and national metrological verification regulations, there is basically no concept of medical treatment and household use. However, according to the characteristics of fewer household times than medical times, and from cost considerations, the selection of “pressure sensors” for key components to measure blood flow pressure has There are differences, but there are the most basic requirements for “ten thousand times” repetitive tests. As long as the accuracy of the measurement parameters of the electronic sphygmomanometer meets the requirements after the “ten thousand times” repetitive test, it is ok.
Take an ordinary household sphygmomanometer as an example for analysis. Among them, it is measured three times a day in the morning and evening, six times a day, and a total of 10,950 measurements are performed 365 days a year. According to the above-mentioned “10,000 times” repeated test requirements, it is basically close to 5 years of simulated use time. Product quality testing.
Factors affecting the accuracy of the measurement results of the electronic blood pressure monitor
It is an electronic sphygmomanometer of different manufacturers, and its software is completely different, and the stability and accuracy of the measurement results are also far different;
The pressure sensors used in different manufacturing are different, and the performance indicators will also be different, resulting in different accuracy, stability and lifespan;
It is improper use method. The correct method of use is to keep the cuff (or wristband, ring) at the same level as the heart during the test, and pay attention to factors such as meditation and emotional stability;
The time for the fixed blood pressure measurement every day is different, and the blood pressure measurement value is also different. The value of the afternoon measurement time, the evening measurement time and the morning measurement time will be different. The industry recommends that the blood pressure be measured at a fixed time every morning.
Factors affecting the service life of electronic blood pressure monitors
The factors of prolonging the service life of electronic sphygmomanometer and improving product quality are mainly considered from the following aspects:
The design life of a general electronic sphygmomanometer is 5 years, which can be extended to 8-10 years depending on the usage.
To extend the service life, pressure sensors with higher performance parameters can be selected;
The use method and the degree of maintenance will also affect the service life. For example, do not place the sphygmomanometer under high temperature, humidity or sun exposure; do not wash the cuff with water or wet the wristband or body; avoid using it. Hard objects puncture the cuff; do not disassemble the machine without authorization; do not wipe the body with volatile substances;
The quality of sensors, peripheral interfaces, and power supply system also indirectly determines the service life of the blood pressure monitor.
Post time: Jul-05-2021