Patent ID: 8226612

Claim:
A needle assembly of an indwelling catheter for introducing the indwelling catheter into a blood vessel of a patient, the needle assembly comprising: a handle including an outer sleeve, an inner sleeve coaxially fixed directly to the outer sleeve, and a flashback chamber configured to allow inflow of flashback blood, the flashback chamber being held between the outer sleeve and the inner sleeve; a hollow needle configured to pierce the patient to guide the catheter into the blood vessel; a needle hub fixed to the needle and movably fit in the handle, the needle hub being temporarily retained at a first position where the needle is exposed out of the handle and biased to move toward a second position where the needle retracts in the handle; and a passageway including a first through hole penetrating the inner sleeve and a second through hole penetrating the needle hub, the first through hole and the second through hole configured to align with and contact each other to allow flashback of blood from the needle to the flashback chamber of the handle without a mediating member between the first through hole and the second through hole when the needle hub is at the first position.