Mercury column sphygmomanometer in the measurement of blood pressure is mainly the patient at least quiet rest for more than 5-10 minutes, take lying or sitting position, the heart and cuff position in the same level to measure blood pressure, measurement of blood pressure in the process of patients pay attention to not loud, mood swings, etc.. When measuring blood pressure, the cuff is placed on the brachial artery and the cuff is not too tight. The stethoscope is placed on the brachial artery underneath the cuff for auscultation, and the mercury column is gradually deflated by increasing the air pressure to about 180 mmHg. The first heart sound on auscultation is the systolic pressure, and the last heart sound on auscultation is the diastolic pressure, which is the completion of blood pressure measurement.