First, when rescuing patients with critical shock, it is necessary to correctly record the urine volume and proportion, which can be used to observe the condition.

Secondly, it is suggested that urethral catheterization should be kept during pelvic organ surgery to empty the bladder, which is beneficial to avoid bladder injury during operation.

Thirdly, some organs of urinary system need to retain catheterization before operation, so as to continuously drain and rinse after operation, which can reduce the tension of surgical incision and facilitate postoperative healing.

Fourthly, patients who are in a coma, urinary incontinence, or have perineal injury are advised to keep catheterization to keep the perineum clean, dry and hygienic.