1. Department of Anesthesiology, E-Da Hospital/I-Shou University, Kaohsiung City, Taiwan
2. Department of Anesthesiology, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan
3. Southern Taiwan University of Science and Technology, Tainan City, Taiwan
4. Department of Anesthesiology, Chi Mei Medical Center, Tainan City, Taiwan