A prospective, single-arm, open-label, multicenter post-approval study to determine whether the use of the Acumen HPI Software to guide intraoperative hemodynamic management in non-cardiac surgery reduces the duration of intraoperative hypotension below a threshold of Mean Arterial Pressure (MAP)

Inclusion Criteria:

1. Written informed consent;
2. Age ≥ 18 years;
3. ASA Physical Status 3 or 4;
4. Moderate- or high-risk non-cardiac surgery (for example, orthopedic, spine, urology, and general surgery);
5. Planned pressure monitoring with an arterial line;
6. General anesthesia;
7. Surgery duration expected to last ≥ 3 hours from induction;
8. Planned overnight hospitalization.

Exclusion Criteria:

1. Participating in another (interventional) study;
2. Contraindication to the invasive blood pressure monitoring;
3. Patient who is confirmed to be pregnant and/or nursing mothers;
4. Emergency surgery;
5. Known clinically important intra-cardiac shunts;
6. Patient in whom an intraoperative MAP target will be < 65 mmHg;
7. Known aortic stenosis with valve area ≤ 1.5 cm2;
8. Known moderate to severe aortic regurgitation;
9. Known moderate to severe mitral regurgitation;
10. Known moderate to severe mitral stenosis;
11. Patient or surgical procedure type known as an SVV limitation (5) (e.g. tidal volume <8mL/kg of theoretical ideal weight, spontaneous ventilation, persistent cardiac arrhythmia, known atrial fibrillation, open chest surgery, Heart Rate/Respiratory Rate (HR/RR) ratio <3.6);
12. Current persistent atrial fibrillation;
13. Known acute congestive heart failure;
14. Craniotomy;
15. Surgery duration expected to last < 3 hours;
16. Burn surgeries;
17. Patients with an intra-aortic balloon pump (IABP) or ventricular assist device(s);
18. Patient transfer from ICU requiring multiple vasoactive agents and known diagnosis of ongoing active sepsis.

Subjects recruited and enrolled should be classified as American Society of Anesthesiologist (ASA) physical status 3-4 who are scheduled for moderate-to-high-risk non-cardiac surgery and will be receiving pressure monitoring with an arterial line. Potentially qualifying patients will be evaluated during their preoperative anesthesia clinic visits.