Effects of Dexmedetomidine on Sublingual Microcirculation and Vascular Waterfall Phenomenon in Patients With Septic Shock

NCT07657715 | Not Yet Recruiting

• 1 other identifier: 2026-ICU07
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 2

Brief Summary

This prospective, multicenter, single-arm, open-label interventional pilot study aims to evaluate the short-term physiological effects of intravenous dexmedetomidine on sublingual microcirculation and vascular-waterfall parameters in adult patients with septic shock. Eligible patients will have septic shock according to Sepsis-3 criteria, require norepinephrine support after adequate fluid resuscitation, receive invasive mechanical ventilation, and have PiCCO-based hemodynamic monitoring available before dexmedetomidine initiation. After baseline assessment, participants will receive intravenous dexmedetomidine according to the study protocol. Dexmedetomidine will be administered as a continuous intravenous infusion at 0.2-0.7 µg/kg/hour without a loading dose. The infusion rate may be adjusted according to the target sedation level, hemodynamic status, and adverse effects. Sublingual microcirculatory variables, including microvascular flow index, perfused vessel density, proportion of perfused vessels, and heterogeneity index, as well as vascular-waterfall parameters, including estimated critical closing pressure, estimated mean systemic filling pressure, and the Pcc-Pmsf gradient, will be measured at baseline, 3 hours, and 6 hours after initiation of dexmedetomidine. Systemic hemodynamic, perfusion, vasopressor, PiCCO-derived, sedation-related, and safety outcomes will also be collected. The primary objective is to characterize immediate changes in sublingual microcirculation and vascular-waterfall physiology after dexmedetomidine administration and to provide preliminary data for future controlled studies.

Conditions

Septic Shock; Sepsis; Critical Illness

Keywords

dexmedetomidine; septic shock; sublingual microcirculation; microvascular flow index; vascular waterfall; critical closing pressure; mean systemic filling pressure; Pcc; Pmsf; PiCCO; mechanical ventilation; sedation; bradycardia; hypotension; norepinephrine

Outcome Measures

Primary Outcomes (2)

• Change From Baseline in Pcc-Pmsf Gradient

  The vascular-waterfall pressure gradient will be calculated as the difference between estimated critical closing pressure and estimated mean systemic filling pressure. The outcome is the change in Pcc-Pmsf from baseline to 3 and 6 hours after dexmedetomidine initiation.

  Baseline, 3 hours, and 6 hours after initiation of dexmedetomidine

• Change From Baseline in Sublingual Microvascular Flow Index

  Microvascular flow index will be assessed using sublingual microcirculatory imaging. Three to five sublingual video fields will be recorded at each time point, and MFI will be calculated according to standard microcirculatory scoring methods. The outcome is the change in MFI from baseline to 3 and 6 hours after dexmedetomidine initiation

  Baseline, 3 hours, and 6 hours after initiation of dexmedetomidine

Secondary Outcomes (16)

• Change From Baseline in Perfused Vessel Density

  Baseline, 3 hours, and 6 hours after initiation of dexmedetomidine

• Change From Baseline in Proportion of Perfused Vessels

  Baseline, 3 hours, and 6 hours after initiation of dexmedetomidine.

• Change From Baseline in Microcirculatory Heterogeneity Index

  Baseline, 3 hours, and 6 hours after initiation of dexmedetomidine

• Change From Baseline in Estimated Critical Closing Pressure

  Baseline, 3 hours, and 6 hours after initiation of dexmedetomidine

• Change From Baseline in Estimated Mean Systemic Filling Pressure

  Baseline, 3 hours, and 6 hours after initiation of dexmedetomidine

Study Arms (1)

Dexmedetomidine Arm

EXPERIMENTAL

Adult patients with septic shock receiving invasive mechanical ventilation, norepinephrine support, and PiCCO-based hemodynamic monitoring after initial resuscitation will receive intravenous dexmedetomidine. Sublingual microcirculatory, vascular-waterfall, PiCCO-derived, macrocirculatory, perfusion, sedation-related, and safety variables will be assessed at baseline, 3 hours, and 6 hours after dexmedetomidine initiation.

Drug: Dexmedetomidine Intravenous Infusion

Interventions

Dexmedetomidine Intravenous Infusion DRUG

Dexmedetomidine will be administered as a continuous intravenous infusion at 0.2-0.7 µg/kg/hour without a loading dose. The infusion rate may be adjusted according to the target sedation level, heart rate, mean arterial pressure, vasopressor requirement, PiCCO-derived hemodynamic variables, and adverse effects. Dose reduction, temporary interruption, or discontinuation is permitted for safety reasons, including clinically significant hypotension, bradycardia, new-onset or worsening arrhythmia, high-grade atrioventricular block, suspected myocardial ischemia, increased vasopressor requirement, or other clinically significant adverse events. The actual dose, infusion duration, and reasons for dose adjustment or discontinuation will be recorded.

Also known as: Dexmedetomidine hydrochloride, Dex

Dexmedetomidine Arm

Eligibility Criteria

• Age: 18 Years - 85 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age 18-85 years.
• Diagnosis of septic shock according to Sepsis-3 criteria, defined as suspected or documented infection with vasopressor requirement to maintain mean arterial pressure ≥65 mmHg and serum lactate \>2 mmol/L after adequate fluid resuscitation.
• Enrollment within 24 hours after diagnosis of septic shock in the ICU.
• Receiving invasive mechanical ventilation.
• Receiving continuous intravenous sedative and/or analgesic therapy other than dexmedetomidine before enrollment, with a clinical decision to add dexmedetomidine for sedation management.
• Continuous norepinephrine infusion at enrollment.
• PiCCO catheter in place and PiCCO-based hemodynamic monitoring available before dexmedetomidine initiation.
• Written informed consent obtained from the patient or legally authorized representative.

You may not qualify if:

• Shock primarily caused by non-septic etiologies, including cardiogenic, hypovolemic, obstructive, hemorrhagic, or anaphylactic shock.
• Expected death or withdrawal of life-sustaining treatment within 24 hours.
• Known allergy or hypersensitivity to dexmedetomidine.
• Severe bradycardia or clinically significant conduction abnormality before enrollment, including heart rate \<50 beats/min, second-degree or third-degree atrioventricular block, sick sinus syndrome, or other conduction abnormality without a functioning pacemaker.
• Severe uncontrolled arrhythmia, acute coronary syndrome, or clinically significant myocardial ischemia before enrollment.
• Severe hemodynamic instability judged unsuitable for dexmedetomidine by the treating physician, including refractory hypotension or rapidly escalating vasopressor requirement.
• Severe hepatic dysfunction judged by the investigator to substantially increase the risk of dexmedetomidine accumulation or adverse effects.
• Conditions interfering with sublingual microcirculatory assessment, including major oral or sublingual lesions, active oral bleeding, inability to access the sublingual area, or poor baseline image quality.
• Pregnancy or lactation.
• Participation in another interventional clinical trial that may affect study outcomes or safety.

Sponsors & Collaborators

• First Affiliated Hospital of Wannan Medical College: lead

Study Sites (2)

The First Affiliated Hospital of Bengbu Medical University

Bengbu, Anhui, 233000, China

Location

The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College)

Wuhu, Anhui, 241000, China

Location

MeSH Terms

Conditions

Shock, Septic; Sepsis; Critical Illness; Hemophilia B; Bradycardia; Hypotension

Interventions

Dexmedetomidine

Condition Hierarchy (Ancestors)

Infections; Systemic Inflammatory Response Syndrome; Inflammation; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Shock; Disease Attributes; Blood Coagulation Disorders, Inherited; Blood Coagulation Disorders; Hematologic Diseases; Hemic and Lymphatic Diseases; Coagulation Protein Disorders; Hemorrhagic Disorders; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Genetic Diseases, X-Linked; Arrhythmias, Cardiac; Heart Diseases; Cardiovascular Diseases; Vascular Diseases

Intervention Hierarchy (Ancestors)

Imidazoles; Azoles; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds

Central Study Contacts

qiancheng xu

CONTACT

+86-18297529106; qianchengxu@wnmc.edu.cn

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: All enrolled participants will receive intravenous dexmedetomidine and undergo repeated physiological assessments before and after treatment.

Study Record Dates

• First Submitted: June 14, 2026
• First Posted: June 18, 2026
• Study Start: August 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 30, 2027
• Last Updated: June 18, 2026

Record last verified: 2026-06

Locations

CN (2)