General anesthesia is frequently used in daily clinical practice. Elderly patients often require a higher level of care than younger patients during the perioperative period, with higher health care costs.

Strategies to optimize anesthesia care to reduce complications and improve outcomes in elderly surgical patients will also be of great value to the individual patients and society.

Prevention of an undesired hypotensive event has a key role in providing patient safety. Patients' susceptibility to intra-operative hypotension can be influenced by the pre-operative volume status.

Despite worldwide improvement in preoperative optimization and changing practices, promoting the avoidance of unnecessary fasting and mechanical bowel preparation, optimized fluid therapy remains the cornerstone of treatment with excellent effectiveness.

The earlier, non-invasive and bedside investigation for assessment of volume status will enhance the effective prevention and management of post-induction hypotension and hence better clinical outcome .

Several methodologies have been tried with a specific goal to predict post-induction hypotension, including heart rate variability (HRV), passive leg raise test and perfusion index.

Despite this, assessing intravascular volume status is still challenging matter. Therefore, the aim of this study will be to compare between the collapsibility index of the inferior vena cava (IVCCI) and IVC to aorta diameter index (IVCD: AoD index) as a potential screening tool to identify patients who are vulnerable to hypotensive events related to general anesthesia.

IVCCI has been tested before in several studies as a predictor of post-induction hypotension. However, IVCD: AoD index has not been investigated before for prediction of hypotension after induction of general anesthesia in elderly. Among the earliest studies to assess the IVCD: AoD index was carried out by Kodiak et al., in hypovolemic patients.

Additionally, it has been investigated for predicting the postspinal anesthesia hypotension and showed promising results

Inclusion Criteria:

• Adult patients ( 60 - 85 ) years old of both sexes with American Society of Anesthesiologists (ASA) physical status I-II and scheduled for elective surgeries under general anesthesia.

Exclusion Criteria:

1. Refusal to join the study.
2. Mental and psychiatric disorders (un co-operative patients).
3. Emergency operations
4. ASA physical status > II
5. Dyspnea, respiratory distress, un-compensated respiratory disease (generalized wheezes, defective functional capacity, peripheral O2 saturation less than 90% on room air )
6. patients with uncontrolled hypertension, Systolic blood pressure ≥ 180 mmHg
7. IVC non visualized
8. Patients with increased intra-abdominal pressure (intra-abdominal mass compressing IVC).
9. anticipated or accidental discovered difficult airway
10. patients taking angiotensin converting enzyme inhibitors or angiotensin receptors blockers, documented heart failure, elevated pulmonary arterial pressure > 40 mmHg, significant valvular heart disease, significant carotid stenosis, peripheral vascular diseases, unstable angina or cardiac ejection fraction less than 40%, implanted pacemaker or cardioversion , known cases of abdominal aortic abnormality as aneurysm or previous operations.

Patients undergoing elective surgery under general anesthesia, ASA I, II