A poorly lanced vessel may be because the vessel is more tortuous or the diameter of the vessel is finer, or the patient’s blood pressure is lower, resulting in poor blood filling in the vessel, so the vessel is not easy to check when the needle is lanced. So the first two are a physiological cause, you can change another blood vessel for lancing. If it is the third cause, the patient needs to be given a comprehensive treatment to maintain the patient’s blood pressure so that the veins are filled with blood and can be lanced more easily.