1. Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
2. Department of Pulmonary and Critical Care Medicine, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
3. Department of Medicine, Graduate School, Kyung Hee University, Seoul, Republic of Korea
4. Department of Anesthesiology and Pain Medicine, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, Republic of Korea