1. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, MacKay Memorial Hospital, Taipei 104217, Taiwan
2. Department of Medicine, MacKay Medical College, New Taipei City 25245, Taiwan
3. Department of Critical Care Medicine, MacKay Memorial Hospital, Taipei 104217, Taiwan
4. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Taitung MacKay Memorial Hospital, Taitung 950408, Taiwan
5. Department of Critical Care Medicine, MacKay Memorial Hospital, Tamsui 251020, Taiwan
6. Department of Chest Medicine, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan 33004, Taiwan