Effects of Inspiratory vs Expiratory Breath-Hold on Lung Perfusion Measured by EIT Saline Indicator Method: A Self-Controlled Study

December 23, 2025 updated by: Shanghai Zhongshan Hospital

Electrical Impedance Tomography Saline Indicator Technique for Assessing Differences in Lung Perfusion Between Inspiratory and Expiratory Breath-Hold Phases: A Prospective Self-Controlled Study

This study aims to compare lung perfusion distribution between inspiratory breath-hold and expiratory breath-hold phases using the saline indicator method combined with electrical impedance tomography (EIT). A self-controlled crossover design will be used in which each participant undergoes both breath-hold conditions with standardized rapid intravenous saline injections. The primary objective is to evaluate changes in global and regional pulmonary perfusion under different lung volume states. The findings may improve understanding of perfusion redistribution with lung inflation and support optimized ventilatory strategies in clinical practice.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Electrical impedance tomography (EIT) with saline bolus injection is a noninvasive technique capable of generating real-time regional lung perfusion images based on transient impedance changes. Lung perfusion is highly dependent on lung volume, vascular resistance, and gravity, yet quantitative bedside evaluation remains limited.

This prospective self-controlled study investigates the differences in lung perfusion between inspiratory breath-hold (near total lung capacity) and expiratory breath-hold (near functional residual capacity). Each participant will undergo two standardized procedures: (1) expiratory breath-hold followed by a rapid intravenous injection of saline, and (2) inspiratory breath-hold followed by the same injection protocol. The order will be randomized.

Perfusion images will be reconstructed using time-impedance curves derived from saline indicator dilution. Regional perfusion parameters, including dependent vs nondependent zones and global perfusion distribution, will be compared between the two phases.

This study may provide foundational physiological evidence for understanding perfusion redistribution across lung volumes and support the clinical application of EIT in respiratory monitoring, ventilatory management, and rehabilitation in critically ill patients.

Study Type

Interventional

Enrollment (Estimated)

100

Phase

  • Not Applicable

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Age 18 to 65 years
  • Able to provide written informed consent
  • Able to perform standardized inspiratory and expiratory breath-hold maneuvers for at least 8 seconds
  • No known acute cardiopulmonary disease
  • Suitable for noninvasive electrical impedance tomography monitoring and intravenous saline administration

Exclusion Criteria:

  • Known severe cardiopulmonary disease (e.g., advanced chronic obstructive pulmonary disease, severe pulmonary hypertension, or heart failure)
  • Hemodynamic instability or clinically significant cardiac arrhythmia
  • Contraindication to intravenous saline administration or fluid bolus
  • Pregnancy or breastfeeding
  • Skin conditions or chest wall abnormalities preventing proper placement of EIT electrodes

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Single Group - Self-Controlled
Procedure: Electrical Impedance Tomography Saline Indicator Procedure
Participants undergo continuous electrical impedance tomography (EIT) monitoring with a circumferential electrode belt placed around the thorax. During the procedure, participants perform standardized inspiratory and expiratory breath-hold maneuvers. At each breath-hold phase, a rapid intravenous bolus of sterile saline (10-20 mL) is administered, followed by a saline flush, to generate transient impedance changes for lung perfusion imaging using the saline indicator technique. EIT data are recorded continuously before, during, and after each saline injection. Each participant undergoes both breath-hold conditions and serves as their own control.
Device: Electrical Impedance Tomography Device
An FDA-cleared electrical impedance tomography (EIT) device is used to noninvasively monitor thoracic impedance changes during the study procedures. The device is used solely for physiological monitoring and image acquisition and is not being evaluated for safety, performance, or a new indication.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Global Lung Perfusion Distribution
Time Frame: During the study procedure (within 1 hour)
Quantitative assessment of global lung perfusion distribution derived from saline-induced impedance changes measured by electrical impedance tomography during inspiratory and expiratory breath-hold phases. Global perfusion is expressed as the percentage contribution of regional perfusion relative to total lung perfusion.
During the study procedure (within 1 hour)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Global Lung Perfusion Heterogeneity Index
Time Frame: During the study procedure (within 1 hour)
Spatial heterogeneity of lung perfusion quantified using a perfusion heterogeneity index derived from regional perfusion maps obtained with the electrical impedance tomography saline indicator technique.
During the study procedure (within 1 hour)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Shanghai Zhongshan Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

January 1, 2026

Primary Completion (Estimated)

January 1, 2027

Study Completion (Estimated)

January 1, 2028

Study Registration Dates

First Submitted

December 12, 2025

First Submitted That Met QC Criteria

December 23, 2025

First Posted (Actual)

December 26, 2025

Study Record Updates

Last Update Posted (Actual)

December 26, 2025

Last Update Submitted That Met QC Criteria

December 23, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • EIT-BH-PERF-2025-01

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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