A device for drawing fluid from a lumen, and particularly blood from a blood vessel, is disclosed. The device may provide indication of the entry of an intravenous cannula into the lumen. The device may include a central body having an outer wall and an inner fluid passage. The device may include a luer-type...http://www.google.co.uk/patents/US20050245869?utm_source=gb-gplus-sharePatent US20050245869 - Blood drawing device with flash detction
