Ultrasound Assessment of Femoral Vein and Inferior Vena Cava Collapsibility to Predict Spinal Anesthesia-Induced Hypotension

Spinal anesthesia is commonly used in transurethral prostate resection (TUR-P) surgeries; however, post-spinal hypotension remains a frequent and clinically significant complication, particularly in elderly patients. Early prediction of hypotension may allow timely interventions and improve patient safety. This prospective observational study aims to evaluate the predictive value of preoperative ultrasound-based inferior vena cava collapsibility index (IVC-CI) and femoral vein collapsibility index (FVCI) for post-spinal hypotension in patients undergoing elective TUR-P under spinal anesthesia. Before spinal anesthesia, IVC and femoral vein measurements will be obtained using ultrasonography. Hemodynamic parameters will be recorded before and after spinal anesthesia, and the occurrence of hypotension will be assessed according to predefined criteria. The study seeks to compare the diagnostic performance of IVC-CI and FVCI in predicting post-spinal hypotension and to identify potential clinical predictors associated with hypotension in this patient population.

Inclusion Criteria: * Adult patients aged 18-75 years * American Society of Anesthesiologists (ASA) physical status I-III * Scheduled for elective transurethral resection of the prostate (TUR-P) * Planned spinal anesthesia * Ability to provide written informed consent Exclusion Criteria: * Refusal to participate in the study * Body mass index (BMI) \>30 kg/m² * Use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers * Emergency surgery * Baseline systolic arterial blood pressure \