Chunli Liu1, Jinlai Li2, Wenqing Sun3, Ruyan Yang1, Wen Lu2, Dachuan Gao1, Dawei Wu4. 1. Department of Intensive Care Unit, Shandong Chest Hospital, Jinan, Shandong 250013, China. 2. Department of Intensive Care Unit, Zaozhuang Municipal Hospital, Zaozhuang, Shandong 277102, China. 3. Department of Intensive Care Unit, Shandong Chest Hospital, Jinan, Shandong 250013, China. Email: 13791122772@139.com. 4. Department of Intensive Care Unit, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China.