Abstract: A device for locating a venous structure of a patient includes a frame having a bottom surface and a top surface, an adhesive disposed on the bottom surface of the frame to allow the frame to be removably attached to skin or a patient, and one or more sections removably attached to the top surface of the frame. The sections are formed of a liquid crystal material that is sensitive to human skin temperature ranges.

Abstract: A device for detecting a venous structure or vessels in a patient or animal. The device includes an optical source for transmitting optical energy into the tissue of the patient, an optical detector for detecting at least a portion of the optical energy that is transmitted into and reflected by the tissue, and an indicator operably associated with the optical source and the optical detector. The indicator is adapted to indicate relative changes in the detected reflection or scattering of the optical energy transmitted into the tissue of the patient.