General Anesthesia causes systemic vasodilation and reduced venous return which is accompanied by hypotension which leads to tissue hypoperfusion and post operative complications like renal injury, ischemic stroke, myocardial injury, prolonged hospitalization and post operative mortality. Hypotension is defined as MAP less than 65mm Hg or BP less than 20% of the baseline value. This is particularly relevant in major abdominal surgeries which are high risk and associated with fluid shifts, blood loss and anesthetic induced hemodynamic instability. Hypovolemia si the most common modifiable risk factor for hypotension after anesthetic administration.

Hence intra operative fluid management and assessment of volume status plays a vital role in major abdominal surgeries hence ensuring adequate tissue perfusion and hemodynamic stability. Therefore accurate and timely assessment of fluid responsiveness becomes crucial to guide volume resuscitation. Fluid responsiveness is defined as patient’s ability to increase stroke volume or the cardiac output more than 10% ni response to fluid administration. Standard fluid challenge test will be done using 300ml of crystalloid which can significantly increase the stroke volume or the cardiac output in response to fluid administration.

Fluid responsiveness can be predicted by both invasive and non invasive dynamic parameters. Arterial pulse pressure variation is an invasive dynamic parameter that relies on cycle changes in stroke volume and arterial pressure during the respiratory cycle ni mechanically ventilated patients. Non invasive parameter like ultrasonography of Internal Jugular Vein will be done to predict the volume status of the patient.

IJV measurements including maximum diameter, minimum diameter and distensibility index will be measured in supine position using a linear ultrasound 5-12MHz. Observation will be done for baseline values and after induction, after incision, and then hourly and last measurement will be taken after closure of the surgical incision. PPV measurements wil also be taken at the same observation points. The changes ni IJV DI and PPV will thus be analyzed for any correlation in mechanically ventilated patients.