Effects of Stellate Ganglion Block on Delirium and Circadian Rhythm in Geriatric Intensive Care Patients

Effects of Stellate Ganglion Block on Delirium and Circadian Rhythm in Geriatric Intensive Care Patients: A Prospective Randomized Controlled Trial

Delirium is a common complication in elderly intensive care unit (ICU) patients and is associated with poor clinical outcomes. Circadian rhythm disruption is considered an important contributing factor in delirium development. Stellate ganglion block (SGB) may modulate autonomic nervous system activity and improve circadian rhythm regulation.

This prospective randomized placebo-controlled trial aims to evaluate the effects of ultrasound-guided stellate ganglion block on delirium incidence and circadian rhythm in ICU patients aged 65 years and older. Delirium will be assessed using validated clinical scales, and circadian rhythm will be evaluated through serial measurements of serum melatonin and plasma cortisol levels

Study Overview

• Status: Not yet recruiting
• Conditions: Stellate Ganglion Block
• Intervention / Treatment: Procedure: Placebo Injection; Procedure: stellate ganglion block with 0.5% bupivacaine

Detailed Description

Delirium is a common and serious complication among elderly intensive care unit (ICU) patients and is associated with increased morbidity, mortality, prolonged hospitalization, and poor long-term outcomes. Although the pathophysiology of delirium is multifactorial, growing evidence suggests that disruption of circadian rhythm and autonomic nervous system imbalance play an important role in its development. Current pharmacological and non-pharmacological treatment strategies remain limited, highlighting the need for novel preventive and therapeutic approaches.

Stellate ganglion block (SGB) is an ultrasound-guided autonomic modulation technique that has been shown to influence sympathetic activity, sleep regulation, and circadian rhythm. However, its potential role in reducing ICU delirium and modulating circadian biomarkers has not been clearly established.

This study is designed as a prospective, randomized, placebo-controlled to investigate the effects of ultrasound-guided stellate ganglion block on delirium and circadian rhythm in geriatric ICU patients. Eligible patients aged 65 years and older will be randomized in a 1:1 ratio to receive either stellate ganglion block with 0.5% bupivacaine or placebo saline injection. Randomization will be computer-generated, and outcome assessors will be blinded to group allocation.

Delirium will be assessed twice daily for seven days using validated clinical tools, including the Richmond Agitation-Sedation Scale (RASS) and Confusion Assessment Method for the ICU (CAM-ICU). Delirium severity will be evaluated using the Delirium Rating Scale-Revised-98, and motor subtypes (hyperactive, hypoactive, mixed) will be categorized according to RASS scores. Sleep quality will be assessed using the Richards-Campbell Sleep Questionnaire.

To evaluate circadian rhythm, serum melatonin and plasma cortisol levels will be measured at predefined circadian time points during the first three days following ICU admission. The study combines objective biomarker assessment with standardized delirium evaluation to explore potential mechanistic pathways linking autonomic modulation and neurocognitive outcomes.

The primary objective is to determine whether stellate ganglion block reduces delirium incidence in elderly ICU patients. Secondary objectives include evaluating delirium severity, motor subtype distribution, sleep quality, circadian biomarker changes, and ICU and hospital length of stay. This trial aims to provide mechanistic and clinical evidence regarding the potential role of stellate ganglion block in ICU delirium management.

• Study Type: Interventional
• Enrollment (Estimated): 130
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Nilgun Kavrut Ozturk, professor; Phone Number: +905334196049; Email: kavrut@yahoo.com
• Study Contact Backup: Name: Cagla Doganci, Resident; Phone Number: +905416480782; Email: cagladogancii@gmail.com

Study Locations

• Turkey (Türkiye)
  • Muratpaşa
    • Antalya, Muratpaşa, Turkey (Türkiye), 07100
      • Antalya Training and Research Hospital
      • Contact: Cagla Doganci, Resident; Phone Number: +905416480782; Email: cagladogancii@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients aged 65 years or older expected to remain in the intensive care unit for more than 48 hours
• RASS score > -4

Exclusion Criteria:

• History of neurodegenerative disease (e.g., Alzheimer's disease, dementia, vascular dementia)
• Uncontrolled psychiatric disorders
• Alcohol use disorder and/or substance abuse
• History of traumatic brain injury or ischemic/hemorrhagic cerebrovascular event
• Severe hearing and/or visual impairment
• Benzodiazepine use
• Renal failure (Acute Kidney Injury stage 2-3) and/or liver failure
• Beta-blocker use
• Contraindications to stellate ganglion block (e.g., coagulopathy, glaucoma, recent myocardial infarction)
• Sepsis
• Allergy to bupivacaine
• Inability to communicate in Turkish or English
• Severe hyponatremia
• Hemodynamic instability

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo Group; Ultrasound-guided intramuscular injection of 2 mL normal saline to the anterolateral cervical region	Procedure: Placebo Injection; Ultrasound-guided sham procedure will be performed, consisting of 2 mL normal saline administered as an intramuscular injection into the anterolateral cervical region, without targeting the stellate ganglion.
Experimental: Stellate Ganglion Block Group; Ultrasound-guided stellate ganglion block using 5 mL of 0.5% bupivacaine	Procedure: stellate ganglion block with 0.5% bupivacaine; Ultrasound-guided stellate ganglion block will be performed in the supine position using 5 mL of 0.5% bupivacaine administered by an experienced anesthesiologist.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of delirium	Delirium incidence will be assessed in patients receiving stellate ganglion block and in patients not receiving stellate ganglion block using a standardized two-step evaluation process. Patients will first be assessed with the Richmond Agitation-Sedation Scale (RASS), which ranges from -5 (unarousable) to +4 (combative). Only patients with a RASS score greater than -4 will undergo delirium assessment using the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU), a validated diagnostic instrument for delirium. Delirium will be recorded as present or absent according to CAM-ICU findings. Higher RASS scores indicate increased agitation, whereas lower scores indicate deeper sedation. Minimum and maximum scores are not applicable to CAM-ICU because it is used as a binary diagnostic tool rather than a numerical scale.	From randomization until Day 7 of ICU stay or ICU discharge, whichever occurs first, assessed twice daily (06:00-08:00 and 20:00-22:00).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serum melatonin circadian pattern	Serum melatonin levels will be measured at predefined time points to assess circadian rhythm pattern. Blood samples will be obtained at 03:00, 08:00, and 16:00. Results will be reported in pg/mL. Circadian rhythm assessment will be based on whether the temporal profile of melatonin secretion across these predefined sampling times is consistent with the expected physiological circadian pattern, rather than on isolated measurements alone.	From ICU admission to Day 3 (samples collected at predefined circadian time points: 03:00, 08:00, and 16:00)
Plasma cortisol circadian pattern	Plasma cortisol levels will be measured at predefined time points to assess circadian rhythm pattern. Blood samples will be obtained at 03:00, 08:00, and 16:00. Results will be reported in µg/dL. Circadian rhythm assessment will be based on whether the temporal profile of cortisol secretion across these predefined sampling times is consistent with the expected physiological circadian pattern, rather than on isolated measurements alone.	From ICU admission to Day 3, measured three times daily at predefined time points (03:00, 08:00, and 16:00).
Delirium severity (Delirium Rating Scale-Revised-98 score)	Delirium severity will be assessed using the Delirium Rating Scale-Revised-98 (DRS-R-98), which ranges from 0 to 46. Higher scores indicate more severe delirium. The scale will be applied only in patients diagnosed with delirium according to CAM-ICU.	From the first diagnosis of delirium until Day 7 of ICU stay or ICU discharge, whichever occurs first, assessed daily.
Delirium motor subtype distribution	Delirium motor subtypes will be classified as hyperactive, hypoactive, or mixed based on the Richmond Agitation-Sedation Scale (RASS) scores in patients diagnosed with delirium using CAM-ICU. Hyperactive delirium will be defined as RASS > 0, hypoactive delirium as RASS < 0, and mixed delirium as fluctuation between positive and negative RASS scores during the assessment period. The outcome will be reported as the distribution of delirium subtypes across study groups.	From the first diagnosis of delirium until Day 7 of ICU stay or ICU discharge, whichever occurs first, assessed daily.
Sleep quality (Richards-Campbell Sleep Questionnaire score)	Sleep quality will be assessed using the Richards-Campbell Sleep Questionnaire (RCSQ), which consists of five items evaluating sleep depth, sleep latency, number of awakenings, ease of returning to sleep, and overall sleep quality. Each item is scored on a visual analog scale from 0 to 100, and the overall score is calculated as the mean of the five items. Higher scores indicate better perceived sleep quality.	From ICU admission to Day 7 of ICU stay or ICU discharge, whichever occurs first, assessed daily.
ICU and hospital length of stay	Hospital length of stay will be defined as the total number of days from hospital admission to hospital discharge.	From hospital admission to discharge home or in-hospital death, whichever occurs first, calculated as total days of hospitalization, assessed up to 60 days.

Collaborators and Investigators

• Sponsor: Antalya Training and Research Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): May 6, 2026
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): February 1, 2027

Study Registration Dates

• First Submitted: March 26, 2026
• First Submitted That Met QC Criteria: April 27, 2026
• First Posted (Actual): April 30, 2026

Study Record Updates

• Last Update Posted (Actual): May 13, 2026
• Last Update Submitted That Met QC Criteria: May 11, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Melatonin; Intensive Care Unit; Cortisol; Circadian Rhythm; Delirium; Stellate Ganglion Block
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Confusion; Neurobehavioral Manifestations; Neurocognitive Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Delirium; Organic Chemicals; Anilides; Amides; Aniline Compounds; Amines; Bupivacaine
• Other Study ID Numbers: Cagla

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No