An indwelling needle, which is commonly referred to as a cannula needle, can be used for critically ill patients, emergencies, and people who are receiving fluids for long periods of time. Pros and cons of indwelling needles. 1.Pros: (1) Through the indwelling needle can establish a venous channel, can ensure the rapid input of drugs, can achieve the purpose of timely treatment. (2) The use of indwelling needle for patients with long-term infusion can reduce the pain caused by repeated puncture and reduce the damage to local blood vessels caused by repeated puncture. (3) The use of indwelling needles can reduce the workload of medical personnel, and at the same time, it can also reduce the time of operation and protect the veins to a certain extent. 2.Disadvantages: (1)When not infusing fluids, improper sealing of the tube or not checking the patency of the needle and tube in time, the residue of drugs or blood reflux may lead to blockage of the tube. (2) The hose stays in the blood vessel for a long time, which will cause irritation to the blood vessel and may cause mechanical phlebitis. The indwelling needle needs to be replaced regularly. If it is not replaced in time, it may lead to bacterial infection and cause infectious phlebitis. (3) Untimely or irregular sealing of the tube may lead to localized oozing. Untimely treatment will affect the therapeutic effect and even induce bacterial infection. In summary, the use of indwelling needles has certain benefits and disadvantages. In order to prevent the occurrence of the above adverse phenomena, it is recommended to standardize the use and regular replacement. When local redness, swelling and pain occur, medical personnel need to be informed in time, and it needs to be treated as early as possible to avoid infection.