Physiological Data Analysis of Patients Undergoing Anesthesia for Liver Transplantation

To record the intra-operative digital data from the standard monitoring instruments containing cardiovascular system information, and from depth-of-anesthesia monitoring modules (Bispectral index, Entropy module, Surgical Plethysmography Index) containing neurological system information captured in the patient monitor, as well as the physiological data regarding anesthetic dosage, respiratory gas analysis and the standard monitoring requirement of anesthesia. All above data comes from patients undergoing liver transplantation surgery for medical reason. The investigators also record the precise time points of detail surgical stages during the surgery . Clinical data collected from these monitoring instrument will be used to gain more understanding of the complex interaction between anesthetic effect, surgical procedure, autonomic response and drug modeling. The goal is to obtain the clinical value of various features extracted from physiological data, in particular the waveform data from cardiovascular system.