Monitoring Noninvasively for Infusion and Transfusion Optimization

Inclusion Criteria: * 18 years or older at the time of consent. * Ability to provide written informed consent. * Scheduled for non-urgent major surgery with general anesthesia * At least one finger available and accessible for performing non-invasive pleth variability index (PVi) and hemoglobin (SpHb) monitoring. * The Attending surgeon, attending anesthesiologist and the clinical care team agree with enrollment in the study, including the restrictions on monitoring procedures defined in the control group. Exclusion Criteria: * Untreated or uncontrolled hypertension defined as mean arterial pressure (MAP) greater than 120 mmHg, despite medications. * Chronic kidney disease with glomerular filtration rate \<30 ml/min/1.73 m2 or requiring renal-replacement therapy for end-stage renal disease. * Surgeries where no bleeding is expected to occur (i.e., total knee surgery where blood loss is prevented by use of tourniquet). * Surgeries performed in the prone position. * Acute cardiovascular event, including acute or decompensated heart failure and acute coronary syndrome. * Aortic pathology that could lead to misinterpretation of hemodynamic variables (e.g. intra- aortic balloon pump, thoracic aorta aneurysm). * Renal vascular surgery. * Preoperative sepsis. * Circulatory shock. * Preoperative vasoactive substance infusion before study entry. * Concurrent participation in any interventional study. * Pregnant or lactating women. * Patients who refuse to receive blood transfusion(…