Primary outcome
blood loss, Hb loss
BLOOD LOSS
The primary outcome was the volume of perioperative total blood loss, which was calculated as follows.First, the blood volume of the patient was calculated in liters using the following formula according to Nadler et alSecond, Hb loss was calculated according to the following formula.Finally, the total blood loss was calculated as follows:In addition, Hb drop at postoperative days 1, 3 and 7 and the amount of postoperative drainage volume were measured and compared between two groups.