1. Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul, Korea.
2. Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Cardiovascular Surgery, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Anesthesiology and Pain Medicine, Ajou University College of Medicine, Suwon, Korea.