This prospective observational study aims to evaluate the diagnostic performance of the preoperative Diastolic Shock Index in predicting postspinal hypotension and to compare its performance with other shock indices, including the Shock Index, Modified Shock Index, and Age Shock Index. The study will include patients aged 50 years and older undergoing elective unilateral inguinal hernia surgery under spinal anesthesia. Hemodynamic parameters will be recorded before and after spinal anesthesia as part of routine clinical monitoring. The primary outcome is the development of postspinal hypotension. Secondary outcomes include vasopressor requirement, total ephedrine dose, lowest intraoperative mean arterial pressure, and the diagnostic performance of the evaluated shock indices using receiver operating characteristic curve analysis. No additional intervention beyond routine anesthetic and perioperative care will be performed for study purposes.