1. Department of Anesthesiology and Pain Medicine, National Police Hospital, Seoul 05715, Republic of Korea
2. Department of Dental Anesthesia and Pain Medicine, Dental Research Institute, School of Dentistry, Pusan National University, Yangsan 50612, Republic of Korea
3. Department of Anesthesiology and Pain Medicine, Korea University Ansan Hospital, Korea University College of Medicine, Ansan 15355, Republic of Korea