In general, prolonged catheter insertion can lead to sequelae such as urinary tract infection and urethral mucosal damage. Clinical insertion of catheters is usually used to treat urinary retention and voiding disorders in order to avoid overfilling of the bladder causing urinary reflux and affecting renal function. In addition, its also commonly used for catheterization in comatose patients to facilitate the measurement of 24-hour urine volume for rehydration volume calculation. If the catheter is left in place for too long, it can easily bring bacteria into the urinary system and cause urinary tract infections. If not done properly it may cause damage to the mucosa of the urethra, and patients are prone to complications such as urethral stricture after removal of the catheter. In addition, since the bladder forced urinary muscle is in a contracted state for a long time, after the catheter is suddenly removed, it is also easy to develop symptoms such as difficulty in urination due to the weakness of the forced urinary muscle contraction. Therefore, patients generally need to choose oral antibiotics to prevent infection when the catheter is inserted for more than 5-7 days, and the catheter should be removed as soon as physical conditions allow in order to reduce complications.