1. Department of Anesthesiology and Pain Medicine, Kwandong University College of Medicine, Goyang, Korea.
2. Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul, Korea.
3. Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Anesthesiology and Pain Medicine, Inha University College of Medicine, Incheon, Korea.