Cerebral Desaturation Burden After Interscalene or Suprascapular-Axillary Block for Shoulder Arthroscopy

November 10, 2026 updated by: Muhammed E Aydin, Ataturk University

Comparison of the Effects of Preoperative Interscalene Block and Combined Suprascapular and Axillary Nerve Blocks on Cerebral Desaturation Burden in Patients Undergoing Elective Shoulder Arthroscopy in the Beach-Chair Position Under General Anesthesia: A Prospective Randomized Study

Shoulder arthroscopy is often performed with the patient in an upright beach-chair position. Changes in position and anesthesia may affect blood pressure and oxygen delivery to the brain. This study compares two ultrasound-guided nerve block approaches performed before general anesthesia: interscalene block and combined suprascapular and axillary nerve blocks. Participants will be randomly assigned to one of these approaches. Both groups will receive the same general anesthetic and 20 mL of 0.25% bupivacaine for the assigned block approach. Cerebral oxygen saturation will be monitored continuously using sensors placed on the forehead. The main outcome is the total cerebral desaturation burden, measured as the area below 80% of each participant's baseline cerebral oxygen saturation during monitoring. Other outcomes include the occurrence and duration of desaturation, minimum cerebral oxygen saturation, blood pressure and heart rate events, vasopressor use, and immediate recovery and a Mini-Mental State Examination to assess cognitive functions.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
60

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Muhammed Enes Aydin, Associate Professor
  • Phone Number: +905543318289
  • Email: enesmd@msn.com

Study Contact Backup

Study Locations

  • Turkey (Türkiye)
      • Erzurum, Turkey (Türkiye), 25000
        • Recruiting
        • Ataturk University
        • Contact:
          • Muhammed Enes Aydin, principal investigator
          • Phone Number: 05543318289
          • Email: enesmd@msn.com
        • Contact:

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Age 18-65 years
  • ASA physical status I or II
  • Scheduled for elective shoulder arthroscopy under general anesthesia in the beach-chair position
  • Provides written informed consent

Exclusion Criteria:

  • Allergy to local anesthetics
  • Previous cervical spine surgery
  • History of cerebrovascular disease or carotid artery surgery
  • Serious cardiac disease, including advanced heart failure or significant valvular disease
  • Neurological disease, including epilepsy, multiple sclerosis, or Parkinson's disease
  • Dementia or cognitive impairment
  • Coagulopathy or contraindication to peripheral nerve block due to anticoagulant use
  • Pregnancy
  • Body mass index greater than 35 kg/m²
  • Technical or anatomical obstacle to performing the planned nerve block

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Interscalene Block (ISB)

Participants will receive a preoperative ultrasound-guided interscalene nerve block using 20 mL of 0.25% bupivacaine.
Procedure: Ultrasound-Guided Interscalene Nerve Block

A preoperative ultrasound-guided interscalene block will be performed with the patient supine and the head turned to the opposite side. A total of 20 mL of 0.25% bupivacaine will be injected around the brachial plexus roots.
Experimental: Combined Suprascapular and Axillary Nerve Blocks (SSAX)

Participants will receive preoperative ultrasound-guided suprascapular and axillary nerve blocks. A total of 20 mL of 0.25% bupivacaine will be divided between the two blocks.
Procedure: ltrasound-Guided Combined Suprascapular and Axillary Nerve Blocks

Preoperative ultrasound-guided suprascapular and axillary nerve blocks will be performed. A total of 20 mL of 0.25% bupivacaine will be divided between the two block sites.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Total Cerebral Desaturation Burden (AUC)
Time Frame: From baseline measurement before the nerve block until 10 minutes after return to the supine position.

The area under the curve below the desaturation threshold, defined as 80% of baseline regional cerebral oxygen saturation (rSO₂). AUC will be calculated separately for each hemisphere; the mean of the two hemispheres will be used for the primary comparison. Only desaturation episodes lasting at least 15 seconds will be included. The unit is %·min.
From baseline measurement before the nerve block until 10 minutes after return to the supine position.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Incidence and Number of Cerebral Desaturation Events
Time Frame: From baseline measurement before the nerve block until 10 minutes after return to the supine position.

Proportion of participants with, and number of, cerebral desaturation events, defined as a decrease in rSO₂ of at least 20% from baseline lasting at least 15 seconds.
From baseline measurement before the nerve block until 10 minutes after return to the supine position.
Total Time Below the Cerebral Desaturation Threshold
Time Frame: From baseline measurement before the nerve block until 10 minutes after return to the supine position.

Total time during which rSO₂ remains below 80% of baseline.
From baseline measurement before the nerve block until 10 minutes after return to the supine position.
Minimum Right and Left Cerebral rSO₂
Time Frame: From baseline measurement before the nerve block until 10 minutes after return to the supine position.

Minimum rSO₂ values recorded from the right and left frontal hemispheres; values will be assessed separately.
From baseline measurement before the nerve block until 10 minutes after return to the supine position.
Ipsilateral and Contralateral Cerebral Desaturation Burden
Time Frame: From baseline measurement before the nerve block until 10 minutes after return to the supine position.

AUC below the desaturation threshold in the cerebral hemisphere ipsilateral and contralateral to the operated shoulder.
From baseline measurement before the nerve block until 10 minutes after return to the supine position.
Incidence of Intraoperative Hypotension and Bradycardia
Time Frame: During the intraoperative period.

Proportion of participants with hypotension, defined as a decrease in baseline systolic blood pressure of more than 20% or MAP below 65 mmHg, and bradycardia, defined as heart rate below 50 beats/min.
During the intraoperative period.
Total Intraoperative Ephedrine and Norepinephrine Dose
Time Frame: During the intraoperative period.

Total ephedrine dose in mg and total norepinephrine dose in µg administered intraoperatively.
During the intraoperative period.
Post-Anesthesia Care Unit Length of Stay
Time Frame: Perioperative period (immediate postoperative recovery, from post-anesthesia care unit admission to discharge).

Time elapsed, in minutes, from postoperative admission to the post-anesthesia care unit to discharge to the surgical ward. Patients are discharged when the Modified Aldrete Score reaches 9 or higher.
Perioperative period (immediate postoperative recovery, from post-anesthesia care unit admission to discharge).
Modified Aldrete Score at Post-Anesthesia Care Unit Discharge
Time Frame: Perioperative period (at discharge from the post-anesthesia care unit).

The Modified Aldrete Score is recorded at discharge from the post-anesthesia care unit to the surgical ward. The scale assesses activity, respiration, circulation, consciousness, and oxygen saturation. Each component is scored from 0 to 2, yielding a total score ranging from 0 to 10. Higher scores indicate better physiological recovery from anesthesia. Patients are discharged when the total score reaches 9 or higher.
Perioperative period (at discharge from the post-anesthesia care unit).
Assessment of cognitive functions at the 24th postoperative hour
Time Frame: At the 24th postoperative hour

A Mini-Mental State Examination was performed at the 24th postoperative hour to assess cognitive functions.
At the 24th postoperative hour

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Ataturk University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

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Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 10, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 29, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 29, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 3, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 10, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 12, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 12, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 10, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • B.30.2.ATA.0.01.00/144
  • 2026/5 (Other Identifier: Atatürk University Clinical Research Ethics Committee)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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