This is the 4030 article
With the improvement of public health awareness, sphygmomanometers have become a must-have item for many families, but people’s biggest concern when choosing a sphygmomanometer is whether the electronic sphygmomanometer is accurate? Before answering this question, let’s review the development history of mercury sphygmomanometers and electronic sphygmomanometers. “Taking history as a mirror” can make our choices more rational.
In the early 18th century, an English priest connected a 9-foot-long glass tube to a copper tube and then inserted it into the horse’s leg artery to measure the horse’s blood pressure. The water column in the vertical glass tube rises to a height of 8.3 feet, creating a precedent for blood pressure measurement. In 1819, a French physician and physicist invented a method of measuring blood pressure with a mercury manometer. Since then, various blood pressure monitors have been invented one after another. However, these methods not only damage the blood vessels, but also are inconvenient, so it is difficult to apply to the human body.
After 80 years of development, in 1896, the real mercury sphygmomanometer was born. An Italian invented the world’s first blood pressure monitor that does not damage blood vessels. This sphygmomanometer consists of a rubber ball, a rubber cuff, and a glass tube containing mercury. When measuring blood pressure, just wrap the rubber cuff around the upper arm, squeeze the rubber ball, and observe the mercury level of the glass tube to measure the blood pressure value. Compared with today’s blood pressure monitor, it is only a stethoscope. In 1905, the Russian Nikolai Kolotkov used a stethoscope to listen for Korotkoff sounds to determine systolic and diastolic blood pressure. So far, the most classic modern method of measuring blood pressure with mercury sphygmomanometer, known as the “gold standard”, was born. The mercury sphygmomanometer has gone through more than 100 years from its theoretical foundation to its final perfection.
The development of electronic sphygmomanometers, unlike mercury sphygmomanometers, can only start from animal experiments. The development of evidence-based medicine has accumulated a large number of clinical theories for the development of electronic sphygmomanometers, the development of engineering mathematics has provided its algorithm basis, and the manufacturing basis of integrated circuits has made it possible to create lighter and more accurate sphygmomanometers. With such a strong foundation, it is not difficult to create an electronic sphygmomanometer for accurate measurement.
The current understanding of blood pressure is very different from the past. In the past, people paid more attention to the measurement results of one or several blood pressures, but now they pay more attention to the change trend of blood pressure. Here is the AHA (American Heart Association) view on blood pressure measurement.
(1) In all clinical medicine, blood pressure measurement is one of the most important measurement data, but unfortunately its measured value is also one of the most inaccurate results.
(2) The current “gold standard” for checking blood pressure is measurement by a trained medical staff with a mercury column sphygmomanometer and readings by the Korotkoff sound technique. But there is growing evidence that this approach may lead to the misclassification of large numbers of hypertensive patients and to miss diagnoses in patients with normal blood pressure in the office but elevated blood pressure in other settings. There are three reasons for this result:
1. Improper or wrong measurement methods, which can be avoided.
2. The fluctuation of blood pressure is an inherent nature of blood pressure and cannot be avoided. The only way to reduce the impact of blood pressure fluctuations on the measurement results is to increase the number of measurements. Only one or two measurements in the clinic can only roughly estimate the average blood pressure level.
3. When there is a doctor, the subject’s blood pressure tends to increase (ie white coat effect). To avoid the influence of this factor, only measure outside the clinic.
In addition to the three reasons for the inaccurate measurement of mercury sphygmomanometers proposed by the AHA above, the measurement method (Korotkoff sound technique) itself also has inevitable error factors, requiring the operator to measure blood pressure It is necessary to coordinate the hands, eyes and ears to measure blood pressure accurately.
(3) There are three types of blood pressure measurements that can be used to predict the possible adverse effects of high blood pressure on the human body: the first is the average blood pressure level, the second is the diurnal variation of blood pressure, and the third is short-term blood pressure variability. These three kinds of measurement data all require multiple measurements at different time periods to obtain, especially for 24-hour continuous monitoring. The mercury sphygmomanometer is not suitable for long-term continuous monitoring.
From the above three points, we can draw two conclusions:
The “gold standard” mercury sphygmomanometer is not as accurate as everyone thinks, so fans of mercury sphygmomanometers need not scoff at electronic sphygmomanometers.
Blood pressure measurements that have clinical predictive value must be measured multiple times, and electronic sphygmomanometers that are convenient for automatic program control can be easily done, and can automatically draw blood pressure changes.
With the development of the times, the drawbacks of mercury-containing sphygmomanometers, especially the hidden dangers of environmental health, have gradually emerged, and it has become necessary for humans to seek mercury-free sphygmomanometers; in addition, in the digital age, all walks of life are In the digital revolution, the data that is easy to transmit and share on the Internet will be used more effectively, and the data generated by the electronic blood pressure monitor is easy to transmit and share on the Internet.
Author: Hematology Hospital, Chinese Academy of Medical Sciences
Wang Hailong Attending Physician