Perfusion Index for Assessing Femoral and Sciatic Nerve Block Success in Lower Extremity Surgery (PI-FSNB)

March 27, 2026 updated by: Berna Kaya Ugur, University of Gaziantep

Evaluation of Femoral and Sciatic Nerve Block Success Using Perfusion Index Measurement in Patients Undergoing Lower Extremity Surgery

Peripheral nerve blocks are increasingly used in lower extremity surgery as an alternative to general anesthesia. However, traditional methods used to assess block success, such as sensory and motor testing, are subjective, time-consuming, and dependent on patient cooperation.

The perfusion index (PI), measured non-invasively using pulse oximetry, reflects peripheral perfusion changes associated with sympathetic blockade and may serve as an early indicator of block effectiveness.

This study aims to evaluate whether PI can be used as an early and reliable marker for assessing the success of combined femoral and sciatic nerve block in patients undergoing elective lower extremity surgery.

A total of 80 patients aged 18-65 years with ASA physical status I-III will receive ultrasound- and nerve stimulator-guided combined femoral and sciatic nerve block. Hemodynamic parameters and perfusion-related variables, including PI, capillary refill time, and skin temperature, will be recorded at baseline and at 5, 10, 20, and 30 minutes after block administration.

The results will be compared with traditional sensory and motor block assessments to determine whether PI provides an earlier and objective assessment of block success.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Peripheral nerve blocks are widely used in lower extremity surgery due to their advantages over general anesthesia, including reduced systemic complications and improved postoperative analgesia. The success of a nerve block is traditionally evaluated using sensory and motor block assessments; however, these methods are subjective and require patient cooperation.

Perfusion index (PI), measured non-invasively using pulse oximetry, reflects peripheral perfusion and is influenced by sympathetic blockade. Following a successful nerve block, sympathetic nerve inhibition leads to vasodilation and increased peripheral blood flow, which may result in an increase in PI.

This prospective clinical study includes 80 patients aged 18-65 years with ASA physical status I-III scheduled for elective lower extremity surgery. All patients receive combined femoral and sciatic nerve block using ultrasound guidance and nerve stimulation techniques. For the sciatic block, 30 mL of a mixture of 0.25% bupivacaine and 1% lidocaine is administered, and for the femoral block, 20 mL of the same solution is used.

Hemodynamic parameters, including heart rate, mean arterial pressure, and oxygen saturation, as well as perfusion-related parameters such as perfusion index, capillary refill time, and distal skin temperature, are recorded at baseline and at 5, 10, 20, and 30 minutes after block administration. Sensory and motor block assessments are performed using cold sensation, pin-prick test, and motor block scales.

The primary objective is to evaluate whether PI can serve as an early, objective, and non-invasive indicator of block success compared to traditional assessment methods.

Study Type

Interventional

Enrollment (Actual)

80

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
      • Gaziantep, Turkey (Türkiye)
        • Gaziantep University Faculty Of Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients aged between 18 and 65 years
  • ASA physical status I-III
  • Scheduled for elective lower extremity surgery
  • Patients undergoing combined femoral and sciatic nerve block
  • Ability to provide informed consent

Exclusion Criteria:

  • Patient refusal
  • Infection at the injection site
  • Known allergy to local anesthetic agents
  • Coagulopathy or bleeding disorders
  • Pre-existing neurological deficits in the lower extremities
  • Severe systemic disease (ASA IV and above)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Combined Femoral and Sciatic Nerve Block
All participants receive ultrasound- and nerve stimulator-guided combined femoral and sciatic nerve block prior to lower extremity surgery.
Procedure: Combined Femoral and Sciatic Nerve Block
Ultrasound- and nerve stimulator-guided femoral and sciatic nerve block performed using a mixture of bupivacaine and lidocaine for anesthesia in lower extremity surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Perfusion Index Following Nerve Block
Time Frame: Baseline, 5, 10, 20, and 30 minutes after block administration
Perfusion index values measured at predefined time intervals after combined femoral and sciatic nerve block and compared with baseline and contralateral limb values.
Baseline, 5, 10, 20, and 30 minutes after block administration

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Gaziantep

Investigators

  • Principal Investigator: Berna Kaya Uğur, Gaziantep University Faculty Of Medicine

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 1, 2018

Primary Completion (Actual)

September 1, 2018

Study Completion (Actual)

January 31, 2019

Study Registration Dates

First Submitted

March 27, 2026

First Submitted That Met QC Criteria

March 27, 2026

First Posted (Actual)

April 2, 2026

Study Record Updates

Last Update Posted (Actual)

April 2, 2026

Last Update Submitted That Met QC Criteria

March 27, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • GAZ-PI-BLOCK-2019

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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