After deep vein puncture and catheterization, if the dressing is dry on the same day, there is no need to change the dressing, change the dressing on the next day, and then observe the dressing at the catheterization site daily to see if there is any ooze or infection, if not, then change the dressing 1-2 times a week. 1. Prepare for dressing change before changing the dressing, wash hands, wear a hat, prepare items for changing the dressing, let the patient get ready for the proper position, wear gloves to remove the dressing, and pay attention to the catheter dislodging when removing the dressing. Observe and record the internal and external catheter scales. Place the removed dressing in the designated location to prevent contamination of sterile items; 2. Sterilize the catheter three times with iodophor (note that the iodophor cotton ball should not be too wet or too dry), sterilize the catheter as the center with a diameter of 8 to 10 cm, and then cover it with sterile gauze for fixation, and then cover the transparent dressing to prevent it from being twisted and dislocated. 3. After the dressing change, the garbage is sorted and placed in the specified garbage can, and the hands are washed again. The purpose of deep vein dressing change is to prevent infection of the puncture site, and it needs to be changed by professional health care personnel. If you need to change it, you should go to the hospital to change it in time, so as not to cause infection by improper operation.