An intravenous indwelling needle is a medical device used to provide temporary access to a patient’s venous system. It is commonly placed into a peripheral vein, usually in the hand, forearm, or occasionally the foot, to allow the repeated or continuous administration of fluids, medications, blood products, or nutritional support. Compared with a standard injection needle that is removed immediately after use, an indwelling needle remains in place for a period of time, reducing the need for repeated needle punctures and improving patient comfort.The device generally consists of a hollow stainless-steel introducer needle, a flexible plastic cannula, a hub, and sometimes an injection port or extension tubing. During insertion, the steel needle guides the flexible cannula into the vein. Once the cannula is properly positioned, the steel needle is withdrawn, leaving the soft catheter inside the vessel. This design helps minimize vein irritation and lowers the risk of vessel injury compared with leaving a rigid metal needle in place.Intravenous indwelling needles are widely used in hospitals, emergency care, outpatient treatment, and home care. They are essential for patients who require frequent intravenous therapy, such as antibiotic treatment, hydration, pain management, chemotherapy, or perioperative care. They are also useful in emergencies when quick vascular access is needed for fluid resuscitation or medication delivery. In addition, they can be used for blood sampling in some clinical settings, depending on the catheter type and local practice.Proper insertion and maintenance are important to ensure safety and effectiveness. Before insertion, the clinician typically selects an appropriate vein, performs skin antisepsis, and uses sterile technique to reduce the risk of infection. After placement, the site is secured with a dressing and checked regularly for signs of swelling, redness, pain, leakage, or infiltration. Flushing the catheter with sterile saline may be required to keep it patent. If the device is no longer needed or if complications occur, it should be removed promptly.Like any invasive device, an intravenous indwelling needle has potential risks. These include infection, phlebitis, infiltration, occlusion, bleeding, and accidental dislodgement. Careful site monitoring, correct handling, and timely replacement when indicated help reduce these risks. Patient education is also important, especially for those who may need the device for an extended period.Overall, the intravenous indwelling needle is a simple but highly important tool in modern healthcare. It supports efficient treatment delivery, reduces repeated punctures, and plays a major role in patient management across many clinical situations.