Non-apnea Electrical Impedance Tomography for Bedside Ventilation-Perfusion Assessment: a Prospective Cross-over Validation Study

NCT07489950 | Completed

• 1 other identifier: 2026063
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 1

Brief Summary

Title: Validating the Accuracy of Lung Blood Flow Monitoring Without Breath-Holding Under Spontaneous Breathing Support Purpose: The purpose of this study is to evaluate the accuracy of a new Electrical Impedance Tomography (EIT) technique that measures lung blood flow (perfusion) without requiring patients to hold their breath. We aim to determine if this "non-apnea" method provides results consistent with the current clinical gold standard (the "pause" method). Background: EIT is a non-invasive bedside tool used to monitor lung function. The traditional method for measuring lung blood flow requires patients to hold their breath for 5-8 seconds during a saline injection to avoid interference from breathing. However, many patients-especially those using a nasal cannula, high-flow nasal oxygen (HFNO), or pressure support ventilation (PSV)-must maintain continuous spontaneous breathing and find it difficult or unsafe to hold their breath. If a "non-apnea" method is proven accurate, it will make monitoring safer and easier for these patients. What the Study Involves: The study includes stable adult patients who are breathing spontaneously. Each patient undergoes two measurements in a randomized order: Standard Reference (Pause Method): Measurement taken during a brief, guided breath-hold. Test Method (Non-Apnea Method): Measurement taken during normal, uninterrupted breathing while receiving respiratory support (Nasal Cannula, HFNO, or PSV). Expected Significance: By comparing the lung images and ventilation/perfusion (V/Q) data from both methods, this study seeks to validate the reliability and precision of the non-apnea approach. This would allow clinicians to assess lung health in spontaneously breathing patients without interrupting their natural breathing rhythm.

Conditions

Pulmonary Perfusion; Ventilation-Perfusion Ratio; Respiratory Insufficiency; Critical Illness

Keywords

Spontaneous Breathing; Lung Perfusion; Electrical Impedance Tomography; Ventilation-Perfusion Matching

Outcome Measures

Primary Outcomes (1)

• Spearman correlation coefficient (r)

  The Spearman correlation coefficient will be calculated to assess the voxel-by-voxel agreement of lung perfusion maps generated by the non-apnea algorithm compared to the reference standard (breath-hold method).

  Within 30 minutes

Study Arms (2)

Standard Breath-hold Method

ACTIVE COMPARATOR

1. This arm serves as the reference standard for EIT perfusion measurement. 2. A 10 mL bolus of 10% NaCl is injected during a 5-8 second end-expiratory pause. 3. For patients on Nasal Cannula or HFNO, the pause is achieved via coached respiratory instruction; for patients on PSV, the ventilator's end-expiratory hold function is used

Diagnostic Test: Saline-contrast EIT with a non-apnea algorithm

Non-apnea Method

EXPERIMENTAL

1. This arm evaluates the feasibility and accuracy of perfusion measurement during uninterrupted breathing. 2. A 10 mL bolus of 10% NaCl is injected while the patient maintains a natural, continuous breathing rhythm. 3. This method is tested across all included respiratory support modes, including Nasal Cannula, HFNO, and PSV, without any respiratory pause or instruction.

Diagnostic Test: Saline-contrast EIT with a non-apnea algorithm

Interventions

Saline-contrast EIT with a non-apnea algorithm DIAGNOSTIC_TEST

Participants receive a central venous bolus injection of 10 mL 10% NaCl. Lung perfusion is then assessed using Electrical Impedance Tomography (EIT). The intervention evaluates two acquisition conditions: one during a brief respiratory pause (reference) and one during uninterrupted spontaneous breathing (test).

Also known as: EIT Lung Perfusion Imaging

Non-apnea Method; Standard Breath-hold Method

Eligibility Criteria

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

You may qualify if:

• Patients aged ≥ 18 years.
• Requiring respiratory support including Nasal Cannula, High-Flow Nasal Oxygen (HFNO), or Pressure Support Ventilation (PSV).
• Hemodynamically stable.
• Able to tolerate a brief respiratory pause (for the reference group).
• Signed informed consent.

You may not qualify if:

• Pregnancy or breastfeeding.
• Contraindications to electrical impedance tomography (e.g., cardiac pacemaker, skin integrity issues on the chest).
• Severe circulatory failure or cardiogenic shock.
• Known allergy to hypertonic saline.

Sponsors & Collaborators

• Ruijin Hospital: lead

Study Sites (1)

Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine

Shanghai, Shanghai Municipality, 200025, China

Location

MeSH Terms

Conditions

Respiratory Insufficiency; Critical Illness

Condition Hierarchy (Ancestors)

Respiration Disorders; Respiratory Tract Diseases; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Hongping Qu

  Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine

  STUDY CHAIR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 18, 2026
• First Posted: March 24, 2026
• Study Start: March 19, 2026
• Primary Completion: April 13, 2026
• Study Completion: April 13, 2026
• Last Updated: April 23, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)