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What is a Digital Sphygmomanometer and how does it function?

Published Date : July 19, 2017

A Sphygmomanometer is a gadget that is dependable for measuring blood pressure also termed as blood pressure gauge, blood pressure meter or blood pressure monitor. The Sphygmomanometer is consistently used with a purpose to decide at what rate the blood flow is starting, and at what rate it is unhampered.

The Sphygmomanometer includes an apparatus for inflation that can be a manually used bulb and valve or a pump which is regulated electrically, a measuring unit which is the aneroid gauge or the mercury manometer and an inflatable cuff.Digital and manual meters are presently in use in accord with advantages and accuracy.

Digital Sphygmomanometer

Digital Sphygmomanometer have measurements that are oscillometric and calculations that are electronic instead of auscultation. They are simple in terms or operating and can be used in unharmonious environments even though they use automatic or manual inflation. Pulse rate and the pressure of blood can be precisely measured by them and diastolic and systolic pressures have great accuracy as compared to meters that are manual. Patients suffering from pulsusparadoxus, preeclampsia, arteriosclerosis, and arrhythmia are not advised digital oscillometric monitor as their calculations may be incorrect. Such patients are then advised an analog sphygmomanometer only to be used by a person who is trained.


A stethoscope is customarily needed auscultation. Meters that are manual are used by practitioners that are trained and this only gives out the systolic pressure as it is possible to have a generic reading through palpation only.

  • Sphygmomanometers with mercury are categorized as gold standard. They reflect the pressure of the blood by touching the height of a column of mercury that does not need rectifications. Accuracy being the reason, they are usually used for clinical calculations of patients that are at high risks including women who are expectant and ones who are undergoingclinical trial of drugs.
  • Aneroid Sphygmomanometers are frequently used that may need corrections in contrast to Sphygmomanometers with mercury. Sphygmomanometers with aneroid are said to be safer than mercury Sphygmomanometers though the reasonable ones are inaccurate.


When used for humans, the cuff is sleekly and adequately placed on the upper part of the arm which can be roughly of the similar perpendicular height as the heart of the patients arm is supported while being seated. The cuff may be placed in different areas as depending upon the species lie the tail if being placed on animals. It is imperative that the size of the cuff being used must be correct in accord with the patient. If the cuff is too small the pressure through it will be too high and similarly if the cuff is too big the pressure will be extremely low. For the measurements to be accurate it is normal to clinically measure the arms in the starting stages of consultation avoiding one arm to have higher pressure than the other. The values of the pressure that blood is flowing in can be read in ‘n mm Hg’ if while discharging the air pressure with a control valve the mercury in the column is observed.