[1] Univ Pittsburgh, Div Pulm Allergy Crit Care & Sleep Med, Dept Med, Pittsburgh, PA 15261 USA
[2] Dong A Univ, Coll Med, Dept Emergency Med, Busan, South Korea
[3] Dankook Univ, Coll Med, Dept Social Med, Cheonan, South Korea
[4] Korean Acad Med Sci, Seoul, South Korea