1. Department of Social Medicine, School of Public Health, Sichuan University, Chengdu, Sichuan Province, China
2. Department of Health Statistics, School of Public Health, Sichuan University, Chengdu, Sichuan Province, China
3. Department of Emergency Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
4. Operating Room, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
5. Department of Anaesthesia, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China