Interventional data collection study to evaluate the ability of pleth variability index (PVI) to predict fluid responsiveness in comparison with other dynamic parameters including pulse pressure variation (PPV) and stroke volume variation (SVV).

No subjects were enrolled into the validation portion of this study.

Inclusion Criteria:

• 18 years of age or older
• Scheduled for elective surgery requiring general anesthesia and mechanical ventilation
• Arterial line and Swan-Ganz catheter placement indicated as part of the scheduled surgical procedure

Exclusion Criteria:

• 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