Pulse pressure variation (PPV) and pleth variability index (PVI) are widely used in clinical practice as indicators of the responsiveness to fluid therapy in patients receiving mechanical ventilation. PPV, which measures changes in arterial pressure, requires arterial puncture, which is invasive, and PVI, which detects subtle changes in oxygen saturation, requires an expensive, commercial monitoring equipment. In this study, we aimed to measure peripheral venous pressure variation using less invasive waveform variation in peripheral veins and to determine whether this indicator can be clinically used to predict the responsiveness to fluid therapy. In addition, the investigators aimed to confirm the superiority of the indicators by comparing them with the responsiveness to fluid therapy of the PPV and PVI.

Pulse pressure variation (PPV) and pleth variability index (PVI) are widely used in clinical practice as indicators of the responsiveness to fluid therapy. The investigators aimed to measure peripheral venous pressure variation using less invasive waveform variation in peripheral veins and to determine whether this indicator can be clinically used to predict the responsiveness to fluid therapy.

Inclusion Criteria:

• Patients voluntarily agreed and signed the written informed consent form before participating in the study
• Adults aged 19 years or older
• American Society of Anesthesiologists physical class (ASA) 1-3
• Patients scheduled for elective hepatectomy under general anesthesia
• Patients who require arterial pressure monitoring and additional peripheral venous access for routine anesthesia preparation
• Non-smokers with normal pulmonary function

Exclusion Criteria:

• Patients with abnormal findings on electrocardiogram before surgery
• Patients who cannot undergo peripheral venous puncture

Patients scheduled for elective hepatectomy under general anesthesia