| 摘要 |
A flash cavity is positioned between the inside of a translucent over the needle catheter and a needle for providing flash detection. The needle bore is connected to the cavity by an access port positioned near the location where the tip of the catheter sealably engages the needle. The needle bore is flow restricted between the access port and a hub for manipulating the needle. In one form of the introducer, a guide wire positioned by a syringe plunger carried for movement in a syringe barrel, is used to advance the catheter into the vessel. The syringe barrel restricts passage of liquid blood, but vents gases. In another arrangement of the introducer, a porous vent plug cooperates with the end of the needle and the catheter adapter to restrict blood flow through the needle bore and to prevent escape of blood while permitting escape of gases. A method of using the flash cavity for the early detection of blood provides for the proper placement in a blood vessel of the tip of the needle and catheter carried therewith wherein the needle has a restricted needle bore and a needle hub prevents escape of blood.
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