A vein finder is a medical device which is designed to help health care practitioners find veins quickly. This facilitates rapid access to veins in emergency situations, when every second can count, and patients may be experiencing health problems which can make veins difficult to find. Vein finders can also be used to facilitate routine blood draws and other medical procedures, increasing patient comfort and procedure efficiency.
These devices can work in several different ways. The classic vein finder consists of a device with a very bright source of illumination which is held against the skin to literally light up the veins, as they will show up in bright contrast to the surrounding tissue. In addition to custom devices designed to use light to find veins, doctors and nurses have also long used flashlights in much the same way, usually for a fraction of the cost.
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The other type of vein finder relies on Doppler radar. This handheld device is held over the skin, and it emits sound waves which will interact with blood flowing by in the veins. Using the handheld device, a health care practitioner can guide a needle insertion into a vein, and remain confident that the needle is in the right place.
In addition to being used to guide medical procedures such as the insertion of intravenous catheters, vein finders can also be used in clinical studies, and to map the veins of an organism or patient. Researchers who are curious about the details of the circulatory system may utilize a vein finder to look at the veins and arteries of a living organism, rather than dissecting a deceased organism to see the underlying architecture of the circulatory system without the dynamic aspect provided by a living heart.
![](http://images.wisegeek.com/slideshow-mobile-small/blood-being-drawn-from-person.jpg)
For medical professionals, using a vein finder can save a lot of time, and make it easier to focus on the procedure at hand, rather than the finicky details of finding a vein. Even skilled practitioners can miss the mark in some patients, and using this type of medical device can also increase patient comfort by eliminating multiple needle sticks in search of a vein.
![](http://images.wisegeek.com/slideshow-mobile-small/diagram-of-artery-and-vein.jpg)
Most vein finders are designed to be sterilized between patients, or they have disposable components which are used for patient contact, and housings which can be periodically wiped down. When a vein finder is used, patients should confirm that the components have been properly sterilized, ideally by watching a nurse or doctor take disposable components out of their packaging and fit them to the vein finder.