In general, soft needles can be used for 5-7 days, which need to be evaluated comprehensively with the patient’s puncture site, vascular condition, and nursing care as follows: i. Soft needles, if not properly cared for, are prone to lead to needle displacement or needle clogging, which will then need to be promptly removed and re-punctured. ii. Therefore, when the above symptoms appear, it may be less than five days. Second, infants can not cooperate, hands and other parts of the more active, most of the retention time of 3-5 days, some of which may be due to activities, improper care leading to needle dislodgement. Third, elderly patients with large vascular fragility or poor nutritional status, due to their own factors, soft needles can be left to about three days. Some of the better care can be up to seven days. Fourth, patients with hypercoagulable state, such as thrombosis, post-infarction patients are prone to block the needle, thus affecting the use of soft needle time. Therefore, the time of use of soft needles in the clinic varies from person to person, depending on the actual situation, combined with the nursing situation, drug flow rate, local skin conditions, etc. to analyze, to avoid blind misjudgment.