Each year, at least 310 million patients undergo major surgery worldwide, procedures that involve the administration of intravenous fluids Intraoperative hemodynamic management is challenging because precise assessment of the adequacy of the intravascular volume is difficult during surgery Achieving optimal IV fluid therapy should improve perioperative outcomes and is a key component in many perioperative guidelines and pathways. IV fluids, like other medications, should only be given in well-defined protocols according to individual needs More recently, so called dynamic predictors of fluid responsiveness such as pulse pressure variation (PPV), stroke volume variation (SVV), or Perfusion Index (PI) have been used in intraoperative goal directed fluid therapy ( GDT) hemodynamic protocols

Inclusion Criteria:

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Inclusion Criteria:

ASA 1, 2 Age: 18-65 Undergoing major abdominal surgeries Mechanically ventilated and sedated patients

Exclusion Criteria:

Chronic cardiac arrhythmias High doses of vasopressors Altered myocardial function (left ventricular ejection fraction < 50%) Peripheral vascular disease Severe respiratory disease Pulmonary or intra-abdominal hypertension Open chest

Exclusion Criteria:

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adult patients under general anaesthesia scheduled for major abdominal surgeries between the period from January 2025 to june 2025 will be observed for comparison between PI and PPV in detecting intravascular volume.