With the continuous advancement of technology and changing lifestyles, cardiovascular diseases have become the most important diseases threatening human health, and hypertension is the most important independent risk factor in this category of diseases. Therefore, accurate blood pressure measurement is very important in the diagnosis, treatment, prevention and evaluation of hypertension. In order to ensure the accuracy and reliability of blood pressure measurement, it is important to measure blood pressure at a fixed time, at a fixed location, in a fixed position, and with a fixed sphygmomanometer. The choice of a blood pressure monitor is crucial. However, have you ever had your blood pressure measured by different blood pressure monitors during different medical visits? Do you have questions such as “is this blood pressure monitor accurate” or “how much does this electronic blood pressure monitor differ from the mercury column blood pressure monitor”? Do not worry, this will answer your questions. 1, the type of sphygmomanometer (1) mercury column sphygmomanometer: mercury, etc. as a manometer, through the medical staff with a stethoscope to listen to the original blood pressure Koch sound (from heavy to light, and then to disappear or change the sound), and according to hear the Koch sound with the manometer read out the systolic and diastolic blood pressure, to achieve the purpose of measurement. Advantages: It is currently the most accurate method of measuring blood pressure. This type of blood pressure monitor occurs less failure, simple design, no variability in accuracy from brand to brand. Disadvantages: large size, not easy to carry, easy to damage, glass tube rupture mercury easy to leak, evaporation of pollution of the environment, causing harm to the human body. Manual auscultation method is susceptible to the professional level of the measurer, hearing, attention, etc. (2) electronic sphygmomanometer using the oscillometric method, that is, according to the relationship between pulse amplitude and air cuff pressure to determine the blood pressure value. Electronic sphygmomanometer has three forms, one is the arm type, the second is the wrist type, the third is the finger type. Advantages: small size, easy to carry, easy to use. Disadvantages: not suitable for patients with excessive obesity, heart rate disorders, extremely weak pulse, severe inspiratory difficulties and hypothermia. (3) ambulatory blood pressure meter: Determine the blood pressure value of a person during a certain time interval within 24 hours day and night. Advantages: It removes the chance of occasional blood pressure measurement and avoids factors such as emotion, exercise, eating, smoking and drinking that affect blood pressure, and reflects blood pressure more objectively and truly. Ambulatory blood pressure provides more blood pressure data and can actually reflect the pattern of blood pressure changes throughout the day. Ambulatory blood pressure can guide drug treatment. Disadvantages: The main disadvantage is that the cuff is frequently inflated and deflated, which affects the patient’s rest at night. In addition, physical activity may interfere with the measurement, making the measurement results inaccurate. 2.Measurement method (1) The room should be kept quiet and the room temperature should be kept at about 20℃. (2) Before measurement, the subject should be mentally relaxed, preferably resting for 20-30 minutes, emptying the bladder, not drinking alcohol, coffee and tea, and stop smoking. (3) The subject should be in a sitting or supine position, and the arm should be placed at the same level as the right atrium (the arm should be at the same level as the fourth rib cartilage when sitting, and at the mid-axillary level when lying down), and abducted 45 degrees. Roll the sleeve up to the armpit, or take off one side of the sleeve to facilitate measurement. (4) Before measuring the blood pressure, the gas in the cuff of the sphygmomanometer should be evacuated and then the cuff should be tied flatly to the upper arm, not too loose or too tight, so as not to affect the accuracy of the measurement value. (5) After the first measurement is completed, the cuff should be completely deflated, wait at least one minute, and then repeat the measurement once more, taking the average of the two times as the resulting blood pressure value. In addition, if you want to determine if you have hypertension, it is best to also take measurements at different times. It is generally accepted that at least 3 different time measurements of blood pressure values in a quiet state without medication are required to be designated as hypertension. (6) If you need to observe blood pressure changes every day, you should use the same position at the same time and measure the blood pressure of the same arm with the same sphygmomanometer, so that the measured results are more reliable. 3.Caution Because of the relationship between blood flow, usually the blood pressure measured by the left hand and the right hand will be somewhat different; usually the blood pressure value of the left hand will be slightly higher than that of the right hand, but the difference is 10~20mHg are normal. Blood pressure measurement should not be recorded only once, but should be taken several times throughout the day and recorded in order to understand the changes in your blood pressure during the day. Electronic blood pressure monitors are affected by the aging of components and need to be calibrated once a year on average.