The requirements for preparation, body position, sitting posture, and cuff specifications before measurement are the same as those of the desktop mercury
Sphygmomanometer. However, the blood pressure measurement of the oscillometric
Electronic Blood Pressure Monitor has some special features. Attention should be paid.
1. Placement of the cuff The cuff takes into account the functions of blocking blood vessels and signal sensing at the same time. Therefore, proper cuff and proper cuff placement are even more important.
The cuff should not be placed at the elbow joint. Placed here, the cuff cannot be completely attached to the upper arm, but there is a large gap, and the movement of the elbow may cause errors in blood pressure measurement.
The cuff tube cannot be left in the air and should be placed securely.
2. Try to avoid physical activity Body movement and physical activity during measurement can significantly affect the accuracy and repeatability of blood pressure readings.
Because the oscillometric electronic
Blood pressure monitor relies on very weak changes in cuff pressure. Any interference will affect signal collection. In addition to active hand movements, passive movements such as ambulance vibrations, hospital bed movements, etc. may also affect the accuracy of blood pressure readings.
3. Pulse strength The accuracy of the oscillometric electronic
Blood Pressure Monitor in measuring blood pressure is questionable when the pulse is weak, such as in patients with shock, hypovolemia, and peripheral vascular disease. In addition, the oscillometric electronic
blood pressure monitor encounters challenges in the blood pressure measurement of neonates, which requires a special design to solve such problems.
4. Environmental noise Environmental noise such as ambulance moving signals can sometimes be larger than the physiological pulse signal to be detected, resulting in measurement errors. Fortunately, the current oscillometric electronic
blood pressure monitors have sound insulation settings, which can reduce the interference of environmental noise to a certain extent.
5. Heart rate variability Although the existing oscillometric electronic
blood pressure monitors are designed to take into account a certain degree of heart rate variability, the more serious heart rate variability significantly affects the accuracy of the blood pressure measurement of the oscillometric
electronic sphygmomanometer. The most obvious example of this is atrial fibrillation.
In the past, some scholars believed that the oscillometric electronic sphygmomanometer was not suitable for patients with atrial fibrillation, because the pulse wave of patients with atrial fibrillation was irregular, and the calculation method of systolic and diastolic blood pressure based on sinus rhythm could not be applied to atrial fibrillation. In fact, desktop mercury sphygmomanometers cannot accurately measure blood pressure in patients with atrial fibrillation.
The author believes that the average value of blood pressure readings measured by three oscillometric electronic sphygmomanometers in patients with atrial fibrillation can be used as a clinical reference.
6. Other diseases that can affect the measured value Diabetes, renal failure, preeclampsia, peripheral vascular disease, etc.
The accuracy of the oscillometric electronic sphygmomanometer may also be affected to some extent due to changes in vascular properties. In order to further solve such problems, it is necessary to optimize the system program based on the measurement data of a large number of patients to obtain a more reliable calculation method.
7. Problems with the electronic sphygmomanometer itself Some poor-quality oscillometric electronic sphygmomanometers lack the certification of bulk data due to the quality of their components and system procedures, and their accuracy and stability are also relatively poor. Blood pressure measurements may be inaccurate when the battery is near depleted and the voltage is low.
Only those oscillometric electronic sphygmomanometers verified by international standards can be used in clinical and home use.
At present, there are 3 internationally recognized medical clinical measurement verification schemes for electronic sphygmomanometers: (1) the scheme of the American Federation of Medical Devices; (2) the scheme of the British Hypertension Association; (3) the scheme of the European Society of Hypertension. The oscillometric electronic sphygmomanometer certified to international standards can be used in clinical diagnosis and related research. The International Society of Pediatrics is also concerned about the oscillometric electronic sphygmomanometer. The quality of the upper arm sphygmomanometers on the market varies, and whether the products have passed the verification of the relevant institutions can be checked online.
For the evaluation and calibration of the pressure accuracy of the electronic sphygmomanometer, it can be compared with the benchtop mercury sphygmomanometer. If the range of pressure difference is <5 mmHg, the pressure detection of the instrument can be considered to be accurate. If the difference is greater than this range, it indicates that the pressure sensor of the instrument is abnormal and should be repaired.
