Saline indwelling needles need to be adjusted daily and replaced in case of infection or blockage. Retaining needles, also known as intravenous needles, are generally used for infants, the elderly, and patients whose veins are more difficult to puncture, and are also commonly used for patients who need to receive repeated infusions over a shorter period of time. When using an indwelling needle to re-infuse fluids, check for infection around the needle, and replace the needle if there is redness, swelling, or rash on the skin. After the end of infusion, the catheter of the indwelling needle should be flushed with saline, and then the tube should be sealed with heparin, etc., and the needle should be fixed, and when it is used again, it should be flushed with saline to make sure that there is no clogging, and whether or not the needle needs to be replaced. In general, the indwelling needle can be used for about 3 to 5 days, the longest can not exceed one week, in the process of use need to pay attention to do not arbitrarily folded, so as not to cause clogging.