Most electronic blood pressure monitors use a highly sensitive sensor in the cuff to measure blood pressure using the oscillometric method. It can automatically record the state of blood flow in the arteries and convert it into digital form. There is no need for a stethoscope during measurement, which makes it very convenient. Mercury column blood pressure monitors, on the other hand, use the Korotkoff sounds method for blood pressure measurement. Their readings are stable and less influenced by external factors.
Since electronic blood pressure monitors operate on different principles compared to mercury-based blood pressure monitors, they are not suitable for the following groups of people: ① excessively obese individuals; ② people with arrhythmia; ③ patients with extremely weak pulse, severe breathing difficulties, and hypothermia; ④ patients with heart rates below 40 beats per minute or above 240 beats per minute; ⑤ Parkinson's disease patients, etc.