1. Department of Anesthesiology, Chi Mei Medical Center, Liouying , Tainan City , Taiwan
2. Department of Anesthesiology, E-Da Hospital, I-Shou University , Kaohsiung City , Taiwan
3. Department of Anesthesiology, Chi Mei Medical Center , No.901, ChungHwa Road, YungKung Dist, Tainan City 71004 , Taiwan