The aim of this study is to evaluate whether Trendelenburg maneuver can be used to predict fluid responsiveness in high-risk surgical patients in intensive care unit as compared to Passive Leg Raising test.

Passive Leg Raising test is a well validated dynamic method to predict fluid responsiveness with many advantages as it doesn't use fluid loading, its effect is reversible, and it doesn't rely on heart-lung interaction. However, it has many limitations as (has false negative effect in patients with intra-abdominal hypertension), also, it may not be suitable in some surgical patients.

Trendelenburg maneuver (TM) is often used to treat hemodynamic unstable patients when hypovolemia is suspected, through a mechanism similar to Passive Leg Raising test Yonis, et al reports that change in cardiac output during Trendelenburg maneuver is a reliable predictor of fluid responsiveness in patients with acute respiratory distress syndrome in prone position under protective ventilation. Another study reports that change in velocity time integral during trendelenburg maneuver predicts fluid responsiveness in cardiac surgical patients in operating rooms

Inclusion Criteria:

• Aged ≥ 18 years old.

• Criteria of high-risk surgical patients:

  1. Elderly ≥ 70 years old undergoing major surgery.
  2. Physical status ≥ 3 or more undergoing major surgery.
  3. Major intraoperative hemorrhage with Surgical Apgar Score (SAS 0-4).
  4. Emergency of upper abdominal surgery.

• Criteria of hypoperfusion ≥ 2 or more the following:

  1. Mean arterial blood pressure < 65 mmHg.
  2. Urine output < 0.5 ml/Kg/hr.
  3. Capillary refilling time > 4 seconds.
  4. Blood lactate > 2 mmol/L.
  5. ScvO2 < 70%.
  6. CO2 gap > 6 mmHg.

• Provided that:SpO2 ≥ 90% and Hb ≥ 7 g/dl.

Exclusion Criteria:

• Patients with body mass index > 35 kg/m2.
• Pregnant female.
• Contraindications to the Trendelenburg position or PLR test (major head trauma, intra-abdominal hypertension and gastric retention).
• Poor echo window or unsatisfactory cardiac echogenicity (an inability to correctly align the Doppler beam to generate reliable velocity time integral measurements at the left ventricular outflow tract [LVOT]).

The data will be available upon a reasonable request from the corresponding author after the end of study for one year.

After the end of study for one year.

The data will be available upon a reasonable request from the corresponding author