1. Respiratory Intensive Care Unit, Yantai Yuhuangding Hospital, Yantai, 264000 Shandong, China
2. Cardiac Intensive Care Unit, Yantai Yuhuangding Hospital, Yantai, 264000 Shandong, China
3. Pain Management Department, Yidu Central Hospital of Weifang, Weifang, 262500 Shandong, China
4. Medical Ward, Yantai Yuhuangding Hospital Laishan Branch, Yantai, 264000 Shandong, China