Patients with urinary retention should release less than 1000 ml of urine for the first time; if it exceeds 1000 ml, it will lead to clinical symptoms of discomfort and may cause clinical symptoms such as hematuria and pain. In the process of retaining urine catheter, it is necessary to keep the catheter open, and if it is not open, it should be flushed with injection in time. If the catheter is not open, it needs to be flushed with injections to flush out foreign bodies or contaminants from the bladder.