By Diana Barnes-Brown for Veins1
Hospitals are beginning clinical trials of a new kind of imaging technology that will make locating veins for purposes such as blood tests and intravenous drips (IVs) easier.
The veins that are located just below the skin are called subcutaneous veins. These are the veins that health care givers draw blood from, or “hook up” to IV drip devices. In some cases, for example in people with very pale skin or who are particularly thin, health care givers have little trouble locating subcutaneous veins, because they are easily visible under the bright lights used in hospitals or doctors’ offices. But others patients, such as children with extra “baby fat” or those with very dark skin, have to sit through multiple, and often painful, botched attempts before a suitable vein is found and the needle can be positioned safely and comfortably.
The new technology involves a charge coupled device (CCD) infrared camera and near-infrared light, to help health caregivers see where veins are. First, the light is directed at the area where a caregiver wants to find a vein. The light is easily absorbed by blood, but reflected by surrounding tissue. This means that when the resultant image is read with the aid of an infrared camera, the camera can capture an image that shows clearly where veins are – and where they are not. Once the image is captured, it is sent to a nearby computer, which can then be used to increase the contrast in the image so that the veins show up even more clearly. After this step, the new, high-contrast image is projected back onto the skin, acting like a highlighter of the veins’ locations.
The device was invented by Herbert Zeman, a biomedical engineer at the University of Tennessee. The key to its function is a special component called a “hot mirror,” which is sensitive to infrared light and can produce an accurate image of veins and surrounding tissue with the help of co-technologies.
Zeman hopes that his device will decrease patient suffering and possibly make it easier for emergency patients in urgent need of IVs to receive them in short order. One challenge, he noted, was making sure the device was calibrated to project the image exactly enough that it did not increase the chance of inaccurate needle-sticks, require a great deal of precision even for those with what doctors and care givers call “good” veins. “If you hit [a vein] off-center, it just rolls out of the way,” he explained in a recent interview with New Scientist magazine.
Zeman will unveil his invention at the Frontiers in Optics conference in Rochester, New York. The technology can now be fit into a case about the size of a shoebox, small enough for attachment to an IV stand.