Preoperative Point of Care Ultrasound Guided Fluid Optimization and Intravenous Ondansetron to Prevent General Anesthesia-Induced Hypotension

"group A will undergo fluid repletion guided by their IVC-CI - if a collapsible IVC, defined as a CI equal or greater than 43%, is observed, patients will receive repeated Lactated Ringer's 500 ml boluses followed by repeated IVC-CI measurements until their CI is less than 43%, and up to 1.5L.~Group B will undergo the same intervention, with the addition of intravenous ondansetron 4 mg in 10 ml normal saline 20 minutes before induction of general anesthesia."