The length of time the catheter is left in the body. The ability of the bacteria themselves to colonize. The aseptic operation of the placement process and the patient’s own immune function are the main causes of bloodstream infections. When placing the catheter, it is necessary to operate in strict accordance with aseptic technique, carefully wash the hands, wear sterile gloves, use medical devices and instruments, which must meet the standard of sterilization, and the patient’s puncture site must be disinfected with iodophor or alcohol. If the patient is suffering from skin disease or respiratory disease at this time and is not cured, it is recommended to hold off placing the catheter, otherwise there may be an increased risk of infection, and after placing the catheter, the dressing should be changed regularly to keep it clean.