Skip to main content

How do Blood Pressure monitors work?

blood pressure monitor


A proper scientific name for a blood pressure monitoring device is a sphygmomanometer.

For many decades, physicians used a manually inflated air-bladder cuff and a listening device called a stethoscope to listen to arterial wall sounds. This is known as the auscultatory method of measuring blood pressure. Using this method required some practice and it was typically performed by trained medical practitioners.

Recent advances in medical technology paved the way for inexpensive, easy-to-use, digital BP monitors that anyone could use in the comfort of their homes without specialized knowledge or training.

A digital BP monitor uses an inflatable air-bladder cuff, a battery-powered air pump, and a pressure sensor for sensing arterial wall vibrations to measure blood pressure in an artery. This is known as the oscillometer method.

There are two types of digital BP monitors: the upper-arm (shown above) and the wrist models (shown below). The upper-arm model has a cuff that is placed on the upper arm and is connected by a tube to the monitor that rests on a surface near the arm. The wrist model is smaller and the entire unit wraps around the wrist. Regardless of the BP monitor type, the measurement method is the same.

A digital blood pressure monitor uses an air pump to inflate a cuff surrounding an upper arm or a wrist with sufficient pressure to prevent blood flow in the local main artery. This pressure is then gradually released using a digitally-controlled solenoid valve until the moment that the blood begins to flow through the artery.

The blood pressure measured by a pressure sensor at this point determines the systolic pressure. Pulse rate is also sensed at this time. The measurement is taken when the blood flow is no longer restricted determines the diastolic pressure. This complete measurement cycle is controlled automatically by the microcontroller.

Comments

Popular posts from this blog

How do Ants sense Food?

  S ugar has a slight odor, particularly granulated beet sugar. While all species of ants can differentiate between a wide variety of odors, the smelling range differs from a few centimeters to meters. Desert ants can smell sugar from up to 3 meters. the food sources that ants cannot smell from a distance they 'smell' it (contact chemoreception) by touching it. So in a way, all the food they detect, they detect it by smelling. So yes, ants smell (although contact chemoreception is more like taste) the sugar. The ant colonies send scout ants to search for food in various directions, often up to a range of 100 to 200 meters.(Depends on the territorial boundary and time of the year). The scout marches steadily in less circuitous paths initially if it has memories of previous feeder locations. (Ants use visual landmarks, and a stereo-smell system to create an odor map and navigate) Periodically it will halt and look for olfactory cues. It will then take into a more circuitous rando...

What is the smallest possible Distance in The Universe?

In physics, the Planck length, denoted ℓP, is a unit of length that is the distance light travels in one unit of Planck time. It is also the reduced Compton wavelength of a particle with Planck mass. It is equal to 5.72938×10⁻³⁵ m (Lorentz–Heaviside version) or 1.61623×10⁻³⁵ m (Gaussian version). It is a base unit in the system of Planck units, developed by physicist Max Planck. The Planck length can be defined from three fundamental physical constants: the speed of light in a vacuum, the Planck constant, and the gravitational constant. It is the smallest distance about which current, experimentally corroborated, models of physics can make meaningful statements. At such small distances, the conventional laws of macro-physics no longer apply, and even relativistic physics requires special treatment. The smallest possible size for anything in the universe is the Planck Length, which is 1.6 x10 -35 m across. It is impossible to determine the difference between two locations less than one ...

What is The International Space Station?

  The International Space Station is a large spacecraft. It orbits around Earth. It is a home where astronauts live. The space station is also a science lab. Many countries worked together to build it. They also work together to use it. The space station is made of many pieces. The pieces were put together in space by astronauts.  The ISS consists of pressurized modules, external trusses, solar arrays and other components. ISS components have been launched by Russian Proton and Soyuzrockets as well as American Space Shuttles. The space station's orbit is about 220 miles above Earth. NASA and other space agencies uses the station to learn about living and working in space. The first piece of the International Space Station was launched in 1998. A Russian rocket launched that piece. After that, more pieces were added. Two years later, the station was ready for people. The first crew arrived in October 2000. People have lived on the space station ever since. Over time more pieces...