[1] Yonsei Univ, Coll Med, Anesthesia & Pain Res Inst, Dept Anesthesiol & Pain Med, 50-1 Yonsei Ro, Seoul 03722, South Korea
[2] Yonsei Univ, Coll Med, Biostat Collaborat Unit, Dept Biomed Syst Informat, Seoul, South Korea
[3] Seoul Natl Univ, Coll Med, Dept Otorhinolaryngol Head & Neck Surg, Seoul, South Korea