1. Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, China
2. Department of Anesthesiology, Weihai Municipal Hospital, Weihai, China
3. Department of Thyroid Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
4. Department of Thoracic Surgery, Tangdu Hospital of Air Force Military Medical University, Xi’an, China