Preoperative Evaluation of IVC Collapsibility Index and Caval Aorta Index After Induction of General Anesthesia

Inclusion Criteria: * Age from 18 to 40 years. * Both sexes. * Body Mass Index\< 40 kg/m². * American Society of Anesthesiologists (ASA) physical status I, II. * Fasted according to the ASA guidelines: 2 hours for clear fluids, 6 hours after light meal, 8 hours after a full meal with high calorie or fat content. * Scheduled for elective craniotomy surgeries before induction of general anesthesia. Exclusion Criteria: * Current or recent pregnancy (within 3 months). * Pre-existing cardiac disease or hypertension. * On medications affecting blood pressure \[Beta-blockers (BBs) and calcium channel blockers (CCBs)\] . * Refusing to undergo the study.