The indwelling needle will not break in the blood vessel. The indwelling needle is a plastic hose at the point where the tip comes in contact with the blood vessel, which will not break or fracture, allowing the needle to remain in the blood vessel. The indwelling needle is very common in the clinic, the cost is a little more expensive than ordinary needles, there is mainly a stainless steel core, the rest is composed of plastic, the stainless steel core will be withdrawn after a successful puncture, leaving only the plastic tube at the blood vessels and the skin for fixation. The indwelling needle can be placed in the body for 2-3 days, too long time is prone to staphylococcal infection, so there are strict requirements in the clinic. The indwelling needle is very convenient, not only does it not bleed when doing various actions, but also does not have the phenomenon of needle breakage.