1. Tak Kyu Oh is an assistant professor, Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea, and Department of Anesthesiology and Pain Medicine, College of Medicine, Seoul National University, Seoul, South Korea.
2. In-Ae Song is an associate professor, Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, and Department of Anesthesiology and Pain Medicine, College of Medicine, Seoul National University.