Hemodynamic Determinants of Urine Output During Spinal Anesthesia

Inclusion Criteria: * Written informed consent provided by patients or their legally authorized representatives. * Adults aged 18 years and older. Exclusion Criteria: * Contraindications to Spinal Anesthesia: * Patient refusal * Presence of coagulopathy. * Current use of anticoagulant or antiplatelet medications. * Critical or severe aortic stenosis or other fixed cardiac output states. * High risk of infection at the spinal needle insertion site. * Elevated intracranial pressure. * Allergy * Sepsis * Procedures Not Amenable to Spinal Anesthesia: * Planned concurrent procedures that cannot be performed under spinal anesthesia.