Dopplers have long been used to evaluate heart rate in patients or fetuses. While the way we use Doppler has evolved over the years, the technology dates back more than a century.
In 1842, Christian Doppler noticed that sound waves have a higher frequency when moving toward and object and a lower frequency when moving away from an object. This is easy to see in the case of a police siren as it moves down the road. As it approaches where you are, the pitch is of a much higher frequency than it is after it passes. While the Doppler Effect in itself seems obvious, the scientific implications are endlessly varied.
The Doppler Effect is used to create ultrasound images. Transducers emit sound frequencies which, when they impact soft tissues, change and are reverberated back to the transducer. These frequencies are then translated into pictures that allow diagnosticians to visualize parts of the body beneath the skin.
The Doppler Effect is also used in medical Dopplers which operate on many of the same principles. Harmless sound waves are sent into the body and received to assess the velocity and direction of blood flow. In other words, Dopplers evaluate sound waves in the same way an ultrasound system does, but the interpretation of the sound waves received back to the transducer is in sound, not picture.
Edan, Huntleigh, Natus, Newman and Summit, leading manufacturers of Dopplers, provide practitioners with a variety of handheld or stationary instruments. Handheld, rechargeable devices are available that fit easily into the pocket of a lab coat. ABI Dopplers are available in easy to transport carts, providing convenient storage shelves for additional cuffs and tubing. With USB data storage and built-in printers, Summit and Newman Dopplers offer instant, readable, shareable results. Each vascular Doppler has interchangeable probes, some with built-in printers, which offer maximum ease of use with minimum footprint. From pocket-sized systems to portable table-top Dopplers, each instrument is calibrated and ready to use right out of the box.