Abstract: The penetration of a vein or the like by a fluid collecting or dispensing needle is rapidly confirmed by the transfer of thermal energy from fluid entering the needle bore upon such penetration to a temperature responsive medium in intimate contact with the exterior of the needle. The temperature responsive medium may comprise thermochromic liquid crystals which signal a change in temperature from ambient temperature by changing color.

Abstract: A self-blunting needle assembly comprises a hollow needle, which may be of conventional construction having a needle mouth and a needle shank terminating in a puncture tip, has mounted within it a blunting member including an elongate probe which slidably fits within the bore of the needle shank. The probe terminates in a distal tip which is initially positioned short of the puncture tip of the needle so as not to interfer with injection of the needle either into a patient or into a connecting device. After injection, the blunting member is advanced to an extended position in which its distal tip protrudes beyond the puncture tip, thereby effectively blunting the needle. This protruding probe disables the needle from a re-use and blunts it sufficiently to prevent or greatly reduce accidental needlestick wounds. A mechanical extension member, such as a pin or fluid flowing through the needle may be used to advance the blunting member to its extended position.