To record the digital data from monitoring instruments (standard patient monitor) containing cardiovascular system information, and from depth-of-anesthesia monitoring modules (Bispectral index, Entropy module, Surgical Plethysmography Index, Analgesia Nociception 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. The investigators also record the precise time points of detail surgical steps during the shoulder arthroscopic 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 performance of each monitoring index in detail surgical steps.

The dynamic interaction between surgery and anesthesia is closely monitored by the anesthesiologist using various monitoring instruments in the operating room. However, it requires the recording and collecting the data for further analysis to answer the question that what is the exact effects of the surgical procedure to human body. In particular, the measurement performance of transient bradycardia calculated from electrocardiography and the monitoring indices such as Surgical Plethysmography Index, Analgesia Nociception Index should be compared side-by-side using data from the same subject.

In this prospective observational study, the investigators will enroll 40 patients undergoing elective laparoscopic surgery. Anesthetic management and surgery will be performed as usual clinical practice.

The investigators will record the digital data exported from monitoring instruments, including cardiovascular system information (electrocardiography, photo-plethysmography , blood pressure and any additional monitoring items clinically required), neurological system information (Bispectral index, Entropy, Surgical Plethysmography Index ) and the respiratory gas monitoring (gas analyzer, respiratory waveform). All above data are provided by standard patient monitor (CARESCAPE Monitor B850, GE Healthcare). Analgesia Nociception Index are provides by Analgesia Nociception Index monitoring instruments (Mdoloris Medical Systems).

The detailed surgical steps will be noted with precise time stamps to pinpoint the surgical effects afterwards. Registered events including anesthetic induction, intubation, disinfection, skin incision, dissecting muscle layer, fixing rupture site, suture to close tear site and wound closure. The recording is ended before the end of monitoring in the operating room. All physiological data and demographic data will be stored in digital media after being de-linked from personal identification.

Data analysis and Statistics will be particularly performed to explore the temporal effect and relationship. Methods including modeling, windowing and non-parametric spectral estimation will be used.

Inclusion Criteria:

• patients agree and plan to undergo elective shoulder arthroscope surgery for rotator cuff tear

Exclusion Criteria:

• major cardiac problems
• uncontrolled hypertension
• arrhythmia shown in pre-operative ECG
• major neurological disease
• vulnerable populations per institutional regulation, including under-age, history of drug abuse, HIV carrier, AIDS, aborigine, prisoner.

anticipated difficult airways

Patients agree and plan to undergo elective shoulder arthroscope surgery for rotator cuff tear

De-identified individual participant data for all primary and secondary outcome will be made available at Dataverse. (https://dataverse.harvard.edu/)

Data will be available within 6 months of study completion

Data access will be under the term of use of Dataverse website.