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

NCT07474480 | Completed

• 1 other identifier: TK-LEP-001
• Study Type: observational
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Tissue Perfusion; Tourniquet-Induced Ischemia-Reperfusion Injury; Lower Extremity Surgery; General Anesthesia

Outcome Measures

Primary Outcomes (1)

• Percentage AUC Loss During Tourniquet Inflation

  Distal tissue oxygenation/perfusion loss measured by near-infrared spectroscopy (NIRS) as the percentage area-under-the-curve (AUC) loss of regional tissue oxygen saturation (rSO₂) during tourniquet inflation.

  From tourniquet inflation to tourniquet deflation during surgery

Secondary Outcomes (3)

• Reperfusion Response Assessed by ΔNIRS

  Baseline to 20 minutes after tourniquet deflation

• Early Hyperemia (rSO₂ Overshoot)

  Within 5 minutes after tourniquet deflation

• Association Between Tourniquet Duration and Percentage AUC Loss

  Intraoperative period, during tourniquet use

Other Outcomes (1)

• Metabolic and Inflammatory Markers

  Perioperative period

Study Arms (2)

General Anesthesia Group

Patients undergoing lower extremity surgery under general anesthesia.

Spinal Anesthesia Group

Patients undergoing lower extremity surgery under spinal anesthesia.

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Adults aged 18 to 65 years with ASA physical status I-II who were scheduled for elective lower extremity orthopedic surgery with tourniquet use at Prof. Dr. Cemil Taşcıoğlu City Hospital between 01 March 2025 and 30 September 2025. Eligible patients were assessed consecutively and enrolled after providing informed consent. Patients were analyzed in 2 observational cohorts according to anesthesia method used in routine clinical practice: general anesthesia and spinal anesthesia.

You may qualify if:

• Age 18 to 65 years
• Scheduled for elective lower extremity orthopedic surgery
• ASA physical status I or II
• Expected operation duration 30 to 120 minutes
• Expected tourniquet duration 30 to 90 minutes
• Informed about the anesthesia method and agreed to participate voluntarily
• No contraindication to neuraxial block

You may not qualify if:

• Refusal to participate
• History of peripheral arterial disease, diabetic neuropathy, or advanced vascular insufficiency
• Severe or uncontrolled systemic disease, including ASA III or higher
• Coagulopathy, local infection, or contraindication to spinal anesthesia
• Body mass index greater than 35 kg/m²
• Pregnancy or impaired consciousness
• Intraoperative hemodynamic instability or anticipated instability
• Need for additional intraoperative sedative or analgesic medication
• Inability to obtain adequate and reliable NIRS signal for technical reasons

Sponsors & Collaborators

• Prof. Dr. Cemil Tascıoglu Education and Research Hospital Organization: lead

Study Sites (1)

Cemil Tasciogu Research and Training Hospital

Istanbul, Sisli, Turkey (Türkiye)

Location

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Resident doctor

Study Record Dates

• First Submitted: March 11, 2026
• First Posted: March 16, 2026
• Study Start: March 25, 2025
• Primary Completion: September 12, 2025
• Study Completion: December 25, 2025
• Last Updated: May 28, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)