Electrical Impedance Tomography-Based Dynamic Ventilation-Perfusion Functional Phenotype Trajectory in Acute Respiratory Distress Syndrome

Electrical Impedance Tomography-Based Dynamic Ventilation-Perfusion Functional Phenotype Trajectory in Acute Respiratory Distress Syndrome: A Prospective Observational Study

Acute Respiratory Distress Syndrome (ARDS) is characterized by severe hypoxemia and extensive lung injury. Recent studies indicate that lung functional phenotypes - particularly the distribution and evolution of lung perfusion - may be closely related to patient outcomes. Electrical impedance tomography (EIT) offers non-invasive, bedside, real-time monitoring of lung perfusion patterns and enables classification into distinct phenotypes and trajectory types over the course of illness. To date, limited data exist on perfusion phenotype trajectories in ARDS patients and their relationship with clinical outcomes. This study seeks to characterize dynamic lung dynamic ventilation-perfusion functional Phenotype using EIT and explore their prognostic significance. Objectives

Primary Objective:

To identify lung perfusion phenotype trajectories in ARDS patients using EIT and assess their association with 28-day mortality.

Secondary Objectives:

• To determine the relationship between different trajectory types and improvements in oxygenation and respiratory mechanics.
• To investigate how ventilator settings (PEEP, driving pressure) interact with perfusion changes.
• To support individualized mechanical ventilation strategies based on Ventilation-Perfusion Functional Phenotype monitoring

Study Overview

• Status: Active, not recruiting
• Conditions: ARDS; Mechanically Ventilated Patients
• Intervention / Treatment: Device: EIT Monitoring

Detailed Description

Design: Prospective, multicenter, observational cohort study

• Setting: ≥2 tertiary ICUs equipped with EIT capability
• Population: Adult patients with moderate-to-severe ARDS (Berlin definition, PaO₂/FiO₂ ≤ 200 mmHg) receiving mechanical ventilation
• Intervention: Daily lung perfusion assessment using a 16-electrode EIT belt. Regional ventilation-perfusion (V/Q) ratios are calculated by combining tidal and pulsatile impedance changes. Phenotypes are classified as Matched V/Q, High V/Q (dead space), Low V/Q (shunt), or Globally Impaired V/Q. Trajectories are categorized as Stable, Improving, Deteriorating, or Fluctuating.
• Endpoints:
• Primary: Association between phenotype trajectory type and 28-day mortality
• Secondary: Time to oxygenation improvement, duration of mechanical ventilation, ICU length of stay, interaction between trajectory and ventilator settings

• Study Type: Observational
• Enrollment (Estimated): 120

Contacts and Locations

Study Locations

• China
  • Shanghai Municipality
    • Shanghai, Shanghai Municipality, China, 200025
      • Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

ARDS Mechanically Ventilated Patients

Description

Inclusion Criteria:

• ge ≥ 18 years
• Moderate-to-severe ARDS (Berlin definition, PaO₂/FiO₂ ≤ 200 mmHg)
• Mechanically ventilated and eligible for EIT monitoring
• Informed consent obtained from patient or legal surrogate

Exclusion Criteria:

• Pregnancy
• Presence of implanted metallic devices interfering with EIT (e.g., pacemaker)
• Severe chest wall deformity or skin condition preventing electrode placement
• Expected survival < 24 hours

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

EIT Monitoring group; 16-electrode belt positioned around the thorax; Daily perfusion assessment (10 min recording) at baseline and after major clinical interventions (e.g., PEEP change, position change); Pulmonary perfusion analysis will primarily be based on the pulse-synchronous impedance signal derived from EIT during brief respiratory pauses, estimating regional perfusion from cardiac-related impedance changes. When signal quality is insufficient, or in cases of significant arrhythmia or other conditions affecting pulse signal detection, the saline indicator method will be applied for validation or calibration.; This involves rapid intravenous bolus injection of 10-20 mL room-temperature saline, using the induced transient conductivity change as a perfusion marker:Ventilation-Perfusion Functional Phenotype will be derived by combining EIT-based tidal and pulsatile impedance changes, calculating the regional V/Q ratio.

Device: EIT Monitoring; 16-electrode belt positioned around the thorax; Daily perfusion assessment (10 min recording) at baseline and after major clinical interventions (e.g., PEEP change, position change); Pulmonary perfusion analysis will primarily be based on the pulse-synchronous impedance signal derived from EIT during brief respiratory pauses, estimating regional perfusion from cardiac-related impedance changes. When signal quality is insufficient, or in cases of significant arrhythmia or other conditions affecting pulse signal detection, the saline indicator method will be applied for validation or calibration.; This involves rapid intravenous bolus injection of 10-20 mL room-temperature saline, using the induced transient conductivity change as a perfusion marker:Ventilation-Perfusion Functional Phenotype will be derived by combining EIT-based tidal and pulsatile impedance changes, calculating the regional V/Q ratio.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
28-day all-cause mortality	From enrollment to 28 days

Secondary Outcome Measures

Outcome Measure	Time Frame
Time to oxygenation improvement (PaO₂/FiO₂ > 200 mmHg)	From enrollment until the event occurs, assessed up to 14 days
Duration of mechanical ventilation	From intubation until successful extubation, assessed up to 28 days or until ICU discharge/death
ICU length of stay	From ICU admission until discharge from ICU, assessed up to 60 days
Interaction between phenotype trajectory and ventilator settings (PEEP, driving pressure)	Daily during EIT monitoring period, up to 14 days

Collaborators and Investigators

• Sponsor: Ruijin Hospital
• Investigators: Study Chair: Hongping Qu, Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2025
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): January 1, 2027

Study Registration Dates

• First Submitted: January 19, 2026
• First Submitted That Met QC Criteria: January 19, 2026
• First Posted (Actual): January 27, 2026

Study Record Updates

• Last Update Posted (Actual): April 13, 2026
• Last Update Submitted That Met QC Criteria: April 9, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Acute Respiratory Distress Syndrome; eit; lung perfusion patterns
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Respiration Disorders; Respiratory Distress Syndrome
• Other Study ID Numbers: 20250516

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