Comparison of the Effects of General Anesthesia and Spinal Anesthesia on Tissue Perfusion in Patients Undergoing Lower Extremity Surgery

This prospective, single-center observational study compares the effects of general anesthesia and spinal anesthesia on tissue perfusion in patients undergoing lower extremity surgery with tourniquet use. Tissue oxygenation in the limb distal to the tourniquet is monitored noninvasively using near-infrared spectroscopy (NIRS), and perfusion loss is quantified using an area-under-the-curve (AUC) approach. The primary objective is to evaluate whether spinal anesthesia better preserves distal tissue oxygenation during tourniquet inflation compared with general anesthesia. Secondary objectives are to assess reperfusion response after tourniquet release using changes in NIRS values at 20 minutes relative to baseline, the presence of early hyperemia (rSO₂ overshoot), and the association between tourniquet duration and perfusion loss. Additional exploratory analyses evaluate selected metabolic and inflammatory markers, including pH, lactate, and potassium.

NCT Number	NCT07474480
Lead Sponsor	Prof. Dr. Cemil Tascıoglu Education and Research Hospital Organization
Conditions	Tissue Perfusion, Lower Extremity Surgery, Tourniquet-Induced Ischemia-Reperfusion Injury, General Anesthesia
Enrollment	60 participants
Start Date	2025-03-25
Primary Completion	2025-09-12 (estimated)
Study Completion	2025-12-25 (estimated)
Updated on ClinicalTrials.gov	2026-05-28