1. When rescuing critically ill and shock patients, it is necessary to correctly record the urine volume and proportion so as to observe the condition.

2。 Before pelvic organ surgery, catheterization and indwelling catheter will empty the bladder, which is beneficial to the operation and avoid accidental injury to the bladder during the operation.

3. Preoperative indwelling catheterization and indwelling some urinary system organs is convenient for continuous drainage and irrigation after operation, which can reduce the tension of surgical incision and is beneficial to healing.

4. Coma, urinary incontinence or perineal injury, when indwelling catheter, keep the perineum clean and dry.