Cerebral Oximetry During Awake Carotid Endarterectomy

NCT07816081 | Not Yet Recruiting

• 2 other identifiers: 7-9/QĐ-BVBMBM_2026_79
• Study Type: observational
• Target: 150
• Locations: 1 country
• Sites: 1

Brief Summary

Surgery to remove plaque from the carotid artery in the neck requires the artery to be clamped for a period of time. In some patients this reduces blood flow to the brain enough to cause temporary symptoms, and a temporary plastic tube called a shunt has to be inserted to restore flow. When the operation is performed with the patient awake under a local anaesthetic block, doctors decide whether a shunt is needed by talking to the patient and testing the strength of the hand on the opposite side during clamping. This is called the awake neurological test. A device called a cerebral oximeter can measure the oxygen level in the front part of the brain continuously and without needles, using light shone through the forehead. It has been suggested as a way of detecting reduced brain blood flow during this operation, and would be particularly useful for patients who are asleep under general anaesthesia and cannot be tested. However, previous studies have often chosen their alarm level after looking at their own results, and have often allowed the operating team to see the oximeter readings, which makes the results appear better than they really are. In this study, 150 adults having planned carotid surgery under a local anaesthetic block will have a cerebral oximeter attached to the forehead throughout the operation. The screen will be covered so that neither the anaesthetist nor the surgeon can see the readings, and the decision to insert a shunt will be based only on the awake neurological test, exactly as it is now. The oxygen readings will be stored inside the device and examined only after the operation. The main question is how accurately a fall of 20% or more in brain oxygen level, a level chosen in advance from previous published research, identifies the patients whose awake test becomes abnormal during clamping. The second question is whether the total amount of low brain oxygen during clamping is related to confusion or stroke in the first three days after surgery, and to memory change one month later. Participants complete a short memory test before the operation and again at one month, using different versions of the test on each occasion.

Conditions

Carotid Stenosis; Carotid Artery Diseases; Brain Ischemia; Carotid Endarterectomy; Postoperative Delirium; Postoperative Cognitive Dysfunction (POCD); Anesthesia, Conduction

Keywords

near-infrared spectroscopy; cerebral oximetry; regional cerebral oxygen saturation; carotid endarterectomy; ; awake neurological test; ; selective shunting; carotid sheath block; superficial cervical plexus block; regional anaesthesia; diagnostic accuracy; STARD; cerebral desaturation burden

Outcome Measures

Primary Outcomes (2)

• 1. Sensitivity and specificity of a 20% or greater relative decline in ipsilateral rSO2 for a positive awake neurological test

  The pre-specified primary index test threshold is compared with the awake neurological test as reference standard in a two-by-two table. Sensitivity and specificity are reported as percentages with 95% Wilson confidence intervals, together with positive and negative predictive values, positive and negative likelihood ratios and overall accuracy.

  First 3 minutes after carotid cross-clamping

• Incidence of new neurological deterioration within 72 hours

  Composite outcome defined as the occurrence of either a new focal neurological deficit or stroke, assessed using the National Institutes of Health Stroke Scale with imaging confirmation, or postoperative delirium, assessed twice daily using the Confusion Assessment Method for the Intensive Care Unit or the 3-Minute Diagnostic Confusion Assessment Method. Reported as the number and percentage of participants with the composite outcome, and analysed in relation to cumulative intraoperative cerebral desaturation burden.

  From end of surgery to 72 hours after surgery

Secondary Outcomes (9)

• Area under the receiver operating characteristic curve of the relative decline in ipsilateral rSO2

  First 3 minutes after carotid cross-clamping

• Sensitivity and specificity at additional pre-specified rSO2 thresholds

  First 3 minutes after carotid cross-clamping

• Cumulative cerebral desaturation burden

  Duration of carotid cross-clamping, up to 2 hours

• Device-reported area under the curve index

  Duration of carotid cross-clamping, up to 2 hours

• Cognitive change at one month

  Baseline and 1 month after surgery

Study Arms (1)

Single cohort - Carotid endarterectomy under regional anaesthesia

Adults undergoing elective carotid endarterectomy under combined superficial cervical plexus and carotid sheath block, monitored with continuous bilateral cerebral oximetry masked from the clinical team, with shunt decisions based solely on a standardised awake neurological test. Followed to 30 days. Assigned exposures: Diagnostic Test: Masked continuous cerebral oximetry; Diagnostic Test: Standardised awake neurological test; Diagnostic Test: Serial cognitive assessment.

Diagnostic Test: Masked continuous cerebral oximetry; Diagnostic Test: Standardised awake neurological test; Diagnostic Test: Serial cognitive assessment

Interventions

Masked continuous cerebral oximetry DIAGNOSTIC_TEST

Continuous bilateral frontal near-infrared spectroscopy recorded at a minimum of one value every 5 seconds throughout surgery using a single oximeter model, with the display covered and alarms disabled so that no value is visible to the anaesthetic or surgical team. Readings contribute to no clinical decision.

Single cohort - Carotid endarterectomy under regional anaesthesia

Standardised awake neurological test DIAGNOSTIC_TEST

Serial structured assessment of verbal responsiveness, naming, contralateral hand grip strength and level of consciousness at fixed intervals during carotid cross-clamping, performed by an anaesthetist masked to rSO2 and serving as the sole basis for shunt placement.

Single cohort - Carotid endarterectomy under regional anaesthesia

Serial cognitive assessment DIAGNOSTIC_TEST

Montreal Cognitive Assessment administered using alternate versions at baseline and at one month by an assessor masked to all oximetry data.

Single cohort - Carotid endarterectomy under regional anaesthesia

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Consecutive adults with carotid artery stenosis scheduled for elective carotid endarterectomy under regional anaesthesia at a single tertiary referral centre in Hanoi, Vietnam.

You may qualify if:

• Age 18 years or older.
• Internal carotid artery stenosis of at least 50% if symptomatic, or at least 70% if asymptomatic, measured by NASCET criteria, with an indication for carotid endarterectomy.
• Elective surgery planned under regional anaesthesia using combined superficial cervical plexus and carotid sheath block.
• Able to cooperate with awake neurological testing and with cognitive assessment.
• Written informed consent.

You may not qualify if:

• Emergency or urgent surgery within 48 hours of an acute stroke.
• Inability to cooperate with testing, including aphasia, dementia, a baseline Montreal Cognitive Assessment score below 18, or severe visual or hearing impairment.
• Redo ipsilateral endarterectomy, simultaneous bilateral endarterectomy, or a combined procedure such as concomitant coronary artery bypass grafting.
• Bilateral forehead skin lesions preventing sensor placement.
• Known allergy or contraindication to lidocaine.
• General anaesthesia planned from the outset.

Sponsors & Collaborators

• Nguyen Toan Thang: lead

Study Sites (1)

Centre of Anaesthesiology and Surgical Intensive Care, Bach Mai Hospital

Hanoi, Phuongmai, 10000, Vietnam

Location

MeSH Terms

Conditions

Carotid Stenosis; Carotid Artery Diseases; Brain Ischemia; Emergence Delirium; Postoperative Cognitive Complications

Condition Hierarchy (Ancestors)

Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Arterial Occlusive Diseases; Vascular Diseases; Cardiovascular Diseases; Delirium; Confusion; Neurobehavioral Manifestations; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Neurocognitive Disorders; Mental Disorders; Cognitive Dysfunction; Cognition Disorders

Study Officials

• Thang Toan Nguyen, MD, PhD

  Centre of Anaesthesiology and Surgical Intensive Care, Bach Mai Hospital, 78 Giai Phong Street, Dong Da, Hanoi, Vietnam

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Thanh Duy Nguyen, MD, MSc

CONTACT

0936137328; thanhnd.ttgmhs@bachmai.edu.vn

Thang Toan Nguyen, MD, PhD

CONTACT

+84916874795; nguyentoanthang@hmu.edu.vn

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: MD, PhD, Anesthesiologist, Centre of Anaesthesiology and Surgical Intensive Care

Study Record Dates

• First Submitted: September 7, 2026
• First Posted: September 11, 2026
• Study Start (Estimated): January 1, 2027
• Primary Completion (Estimated): January 1, 2028
• Study Completion (Estimated): February 1, 2028
• Last Updated: September 11, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF
• Time Frame: Beginning 6 months and ending 5 years after publication of the primary results.
• Access Criteria: Requests should be directed to the corresponding author with a methodologically sound proposal. Data will be shared following approval and execution of a data access agreement.

Locations

VN (1)