Indwelling needle assembly

1. An indwelling needle assembly usable in combination with an infusion system for infusion into a patient's body, the indwelling needle assembly comprising:

a needle having a needlepoint insertable into the patient's body;

a sleeve slidably fitted on the needle;

a catheter including a catheter tube slidably fitted on the sleeve;

a base body fixed to a proximal end of the needle; and

a slider fixed to the sleeve and slidably engaged with the base body so as to be movable between a first position to have the needlepoint projecting out of the sleeve and a second position to have the needlepoint retracted in the sleeve,

wherein the needle, the sleeve, the base body and the slider are unitarily extractable from the catheter,

wherein the sleeve includes an obliquely cutoff flat end, and the obliquely cutoff flat end projects from the catheter toward the needlepoint, and

wherein the catheter includes a distal end portion directly fitted on the needle, and a taper portion continuously tapering from the catheter tube toward the distal end portion.

2. The indwelling needle assembly of claim 1 , wherein the sleeve is so formed as to fill a space held between the needle and the catheter.

3. The indwelling needle assembly of claim 1 , further comprising:

a latch configured to hold the slider at the first position.

4. The indwelling needle assembly of claim 1 , further comprising:

a stopper latch configured to stop the slider at the second position.

5. The indwelling needle assembly of claim 3 , further comprising:

an elastic body configured to urge the slider toward the second position; and

a release configured to release the slider from the first position, the release being fixed to the base body to allow operation from an exterior of the base body.

6. The indwelling needle assembly of claim 1 , wherein the sleeve includes a first portion and a second portion fitting on the first portion.

7. The indwelling needle assembly of claim 1 , wherein the needle includes a hollow piercing portion and a translucent body portion, and the sleeve includes a translucent material.

8. An indwelling needle assembly usable in combination with an infusion system for infusion into a patient's body, the indwelling needle assembly comprising:

a needle having a needlepoint insertable into the patient's body;

a sleeve slidably fitted on the needle;

a catheter including a catheter tube slidably fitted on the sleeve, a distal end portion directly fitted on the needle, and a taper portion continuously tapering from the catheter tube toward the distal end portion;

a base body fixed to a proximal end of the needle; and

a slider fixed to the sleeve and slidably engaged with the base body so as to be movable between a first position to have the needlepoint projecting out of the sleeve and a second position to have the needlepoint retracted in the sleeve,

wherein the needle, the sleeve, the base body and the slider are unitarily extractable from the catheter; and

wherein the needle, the sleeve and the catheter are so dimensioned as to enter into the patient's body.

9. The indwelling needle assembly of claim 8 , wherein the sleeve includes an end selected from the group of a tapered end and an obliquely cutoff flat end, the end projecting from the catheter toward the needlepoint.

10. The indwelling needle assembly of claim 8 , wherein the sleeve is so formed as to fill a space held between the needle and the catheter.

11. The indwelling needle assembly of claim 8 , further comprising:

a latch configured to hold the slider at the first position.

12. The indwelling needle assembly of claim 8 , further comprising:

a stopper latch configured to stop the slider at the second position.

13. The indwelling needle assembly of claim 11 , further comprising:

an elastic body configured to urge the slider toward the second position; and

a release configured to release the slider from the first position, the release being fixed to the base body to allow operation from an exterior of the base body.

14. The indwelling needle assembly of claim 8 , wherein the sleeve includes a first portion and a second portion fitting on the first portion.

15. The indwelling needle assembly of claim 8 , wherein the needle includes a hollow piercing portion and a translucent body portion, and the sleeve includes a translucent material.

16. An indwelling needle assembly usable in combination with an infusion system for infusion into a body, the indwelling needle assembly comprising:

a needle having a needlepoint insertable into the body;

a sleeve slidably fitted on the needle;

a catheter including a catheter tube slidably fitted on the sleeve;

a base body fixed to a proximal end of the needle; and

a slider fixed to the sleeve and slidably engaged with the base body so as to be movable between a first position to have the needlepoint projecting out of the sleeve and a second position to have the needlepoint retracted in the sleeve,

wherein the catheter includes a distal end portion directly fitted on the needle, and a taper portion continuously tapering from the catheter tube toward the distal end portion,

wherein the needle, the sleeve, the base body and the slider are unitarily extractable from the catheter,

wherein the sleeve includes a first surface parallel to an outer surface of the needle and a second surface formed in a flat shape and adjacent to the first surface so that an oblique angle is formed between the first surface and the second surface.

17. The indwelling needle assembly of claim 16 , wherein the sleeve includes a third surface formed at an end surface of the sleeve and the second surface extends to the third surface of the sleeve.

18. The indwelling needle assembly of claim 17 , wherein a portion of the third surface of the sleeve has a rounded shape.