The amount of urine per hour after pituitary tumor surgery depends on whether the pituitary stalk was damaged during the surgery. If the pituitary stalk was not damaged during surgery, the postoperative urine volume per hour is normal, usually less than 250 ml/h. If the urine volume exceeds 250 ml/h for 1-2 hours after surgery and the specific gravity of urine is less than 1.005, a combination of urosepsis needs to be considered. Patients who develop uremia should be treated more safely with fluid replacement based on central venous pressure monitoring. If the rate of fluid loss is too fast for intravenous or oral repletion to keep up, if it is greater than 300 ml/h for 4 hours or 500 ml/h with a urine specific gravity less than 1.005, vasopressin needs to be given for treatment.