1. Department of General Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Yuedong Hospital, Meizhou, Guangdong 514700, China
2. Department of Gastroenterological Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510630, China
3. Department of Anesthesiology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, Guangdong 518017, China
4. Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510630, China