1. Department of Critical Care Medicine, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
2. Division of Infectious Disease, Department of Internal Medicine, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
3. Division of Pulmonology, Department of Internal Medicine, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
4. Division of Cardiology, Department of Internal Medicine, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Korea.