1 From the Department of Anaesthesiology, Taipei Veterans General Hospital (HLW, YHT, KYC, SPL), The School of Medicine, National Yang-Ming University, Taipei (HLW, YHT, KYC, SPL), the Department of Anaesthesiology, Shuang Ho Hospital, Taipei Medical University, New Taipei City (YHT) and the Department of Anaesthesiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (YHT).