The present disclosure discloses an intravenous cannula that includes a catheter hub and tubular valve member adapted to allow a needle member to pass through. The valve member is defined with slits that allow the needle to pass through. Further, a valve closure member and needle guard assembly are provided, both adapted to close passage for fluid flow and prevent blood flow from the punctured vein of a subject. The needle guard assembly includes a body portion. A safety clip locks onto a flange defined in the body, and in a biased condition allows a needle to extend through the body and hub. Upon withdrawal of the needle from a proximal end of the hub, a safety pin disengages from the flange and arrests the tip portion of the needle within the device, thereby preventing needle prick injury upon withdrawal of the needle member from the hub.

A cross-plane seal having a distal end and a proximal end includes a disc at the distal end. The disc includes a distal face at a distal side, a proximal face at a proximal side, a plurality of cut outs in the distal face forming a raised X-shape on the distal face, a first slit having a partial through-cut into the distal face and aligned with a first leg of the raised X-shape, the through-cut extending more than halfway through the thickness of the disc, a second slit having a partial through-cut into the proximal face and aligned with a second leg of the raised X-shape, the through-cut extending more than halfway through the thickness of the disc, and an intersection formed by the first slit and the second slit. An annular portion is connected to and extends proximally away from the disc.

A valve body and a medical instrument provided with the valve body can stably maintain sealing performance for preventing air/blood leakage while maintaining a smooth insertion feeling even when various types of medical devices are repeatedly inserted and removed. The valve body includes a main body portion having oppositely facing first and second surfaces, an outer peripheral surface extending between the first and second surfaces, and an insertion portion having an inner surface defining a gap that allows insertion of a medical device and formed at least on the first surface. The main body portion contains a self-repairing material that allows self-repairing damage resulting from contact with the medical device. At least part of the inner surface of the insertion portion is provided with a coating layer that prevents the gap from being closed by self-repair when portions of the inner surface of the insertion portion contact each other.