Hypotension Prediction Index Study (HPI Study)

Inclusion criteria

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

Exclusion criteria

• Participating in another (interventional) study;
• Contraindication to the invasive blood pressure monitoring;
• Patient who is confirmed to be pregnant and/or nursing mothers;
• Emergency surgery;
• Known clinically important intra-cardiac shunts;
• Patient in whom an intraoperative MAP target will be < 65 mmHg;
• Known aortic stenosis with valve area ≤ 1.5 cm2;
• Known moderate to severe aortic regurgitation;
• Known moderate to severe mitral regurgitation;
• Known moderate to severe mitral stenosis;
• 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);
• Current persistent atrial fibrillation;
• Known acute congestive heart failure;
• Craniotomy;
• Surgery duration expected to last < 3 hours;
• Burn surgeries;
• Patients with an intra-aortic balloon pump (IABP) or ventricular assist device(s);
• Patient transfer from ICU requiring multiple vasoactive agents and known diagnosis of ongoing active sepsis.