During infusion, hardening of blood vessels often occurs when hypertonic solutions and some fluids containing potassium ions are sedated for long periods of time. If this situation occurs, first of all, we should replace another blood vessel for alternate static puncture, you can also carry out localized hot compresses in the hardened blood vessels, or slow down the speed of infusion, try to dilute the high concentration of hypertonic fluids, and then carry out static puncture, which may alleviate the situation of hardened blood vessels. In addition, magnesium sulfate can also be applied externally, especially when complicated by vascular phlebitis. Therefore, in the process of intravenous infusion, for the relatively thin blood vessels, or often use the venous blood vessels, try to alternate repeated infusion, do not apply a long time for a long period of time for a single blood vessel infusion treatment, to avoid leading to phlebitis situation.