Validation of RPVi as a Parameter to Predict Fluid Responsiveness

This is a prospective, nonrandomized, sequential data collection study to evaluate the ability of RPVi to predict fluid responsiveness in comparison with other dynamic parameters including stroke volume variation (SVV) and/or pulse pressure variation (PPV).

Inclusion Criteria: * 18 years of age or older at the time of consent * Scheduled for elective surgery requiring general anesthesia and mechanical ventilation * Arterial line and other standard of care line placement indicated as part of the scheduled surgical procedure Exclusion Criteria: * Patients diagnosed with or history of heart failure, angina, pulmonary heart disease, rheumatic heart disease, cardiomyopathy, congenital heart disease, or valvular heart disease. * Patients scheduled for or has had a liver transplant * Patients with surgeries at or around site of sensor placement or skin abnormalities affecting the sensor placement area such as psoriasis, eczema, angioma, scar tissue, burn, fungal infection, substantial skin breakdown, nail polish or acrylic nails that would prevent monitoring of pulse-oximeter physiological parameters during the study. * Patients with cardiac arrhythmias * Patients with intracardiac shunts