Surgeons need to know that elevated vasopressin significantly contributes to fluid retention after liver resection, impacting postoperative management.

• Vasopressin (AVP) levels peaked immediately after major liver resections and stayed elevated through postoperative day 3, while aldosterone levels dropped by postoperative day 2.
• Patients showed greater short-term weight gain and decreased urine output during the AVP elevation, indicating pronounced fluid retention.

Understanding vasopressin’s role can inform fluid management strategies to mitigate postoperative edema in liver surgery.

• The findings highlight the need to consider hormonal profiles when planning postoperative care, especially for major resections.