The goal of this observational study is to develop a computation model for accurately predicting post-induction hypotension in patients receiving laparoscopic surgery under general anesthesia. The main question[s] it aims to answer are:

• whether the corresponding characteristics on pressure wave forms could be use to predict post-induction hypotension.

Participants will be observed before and after induction of general anesthesia for non-invasive arterial pressure wave forms and blood pressure changes.

In this project, an equivalent circuit model will firstly be established to simulate patient's hemodynamics. This model will be applied into analyzing blood pressure wave forms in the MIMIC II database. It will facilitate deep understanding of the effects of induction drugs on pressure waveforms. As a result, the corresponding characteristics on pressure wave forms will be identified. The extracted characteristics from the MIMIC II database will then be applied for developing a computation model via machining learning approaches. The developed model will be validated with another available dataset of 100 patients. This project will then conduct a non-invasive and observational clinical study of 50 patients to prove the clinical value of this project. In this trial, a novel pressure sensor will be employed on patient's fingertip to continuously collect pressure waveform before and after anesthesia induction. Medical records and vital signs will also be collected for exploring the potential of the developed model for predicting other events. Endoscopic surgery patients will be recruited in this study.

Inclusion Criteria:

• Age >= 20 years
• Ease of access to the hand used for the ArteVu device during the one-hour it is being used during the operation.
• Able to provide written informed consent for participation in the study.

Exclusion Criteria:

• Pregnant patients.
• Medical or surgical condition that prevents the ability to apply the ArteVu device on an upper extremity finger for a period of one-hour during anesthesia and operation.
• Impaired skin integrity of the fingers (e.g. injuries to the finger, burn injuries, or skin graft surgery on the finger).
• Operations involving the upper extremities or the blood vessels of the upper extremities.
• Arthritis or severe deformities of the hand and fingers
• Prosthetic devices or jewelry (such as a wedding band) that cannot be removed from the finger to be used for the ArteVu device.
• History of malignant hyperthermia
• Raynaud's disease affecting the fingers or hands.
• Topical allergy to ABS or silicone
• Swelling, edema or lymphedema of the upper extremity
• Participants with upper extremity occlusive peripheral vascular diseases
• Inability of the patient to provide written informed consent.

Patients receiving laparoscopic surgeries under general anesthesia.