Subjects will first have a blood pressure reading recorded on both arms using a non-invasive blood pressure monitoring (NIBP) cuff in the preoperative area. Then blood pressure will be recorded using the ClearSight monitor on each hand over a one-minute period. If mean arterial pressure (MAP) as assessed by either the noninvasive blood pressure (NIBP) monitoring cuff or the ClearSight system differs by more than 10% from arm to arm, the subject will be excluded from the study.

Before induction of anesthesia, the subject will be randomized to either:

ClearSight group + usual clinical care: Information from ClearSight monitor will be available to the clinicians. According to ASA guidelines, usual blood pressure monitoring includes non-invasive blood pressure measurements every 5 minutes during a surgical case.

Non-ClearSight group (blinded) + usual clinical care: Information from ClearSight monitor will not be available to the clinicians.

Both patient groups will have continuous ClearSight monitoring and non-invasive blood pressure monitoring every 5 minutes. The difference will be in the intervention group data from the monitor will be available to the clinicians in the operating room, but in the control group data from the ClearSight monitor will not be available (blinded) to the clinicians. Regardless of the study group assignment, second-by-second ClearSight monitor continuous blood pressure data will be recorded for each study patient and will be used for analysis.

The morning of post-operative day 3 the subject will be given the QoR-15 questionnaire and will complete POMS morbidity surveys.

Inclusion Criteria:

• Written informed consent
• Age > 45 years
• ASA Physical Status 3 or 4
• Moderate- or high-risk non-cardiac surgical procedures (i.e., orthopedic, spine, urology, and general surgery) in patients in whom invasive blood pressure monitoring is not planned
• Anticipated surgical duration >2 hours

Exclusion Criteria:

• Any contraindications to the proposed interventions
• Patient with invasive blood pressure monitoring
• Patients with contraindications to oscillometric blood pressure monitoring on one arm and ClearSite monitoring on the other
• Preoperative discrepancy in mean arterial pressure >10% between the arms