Effects of Inspiratory vs Expiratory Breath-Hold on Lung Perfusion Measured by EIT Saline Indicator Method: A Self-Controlled Study
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Electrical Impedance Tomography Saline Indicator Procedure, Electrical Impedance Tomography Device.
- Who it may be relevant to
- Registry conditions: Lung Perfusion, Respiratory Physiology, Electrical Impedance Tomography, Ventilation-Perfusion Mismatch. Basic parameters: 18 years — 65 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Center list to be confirmed — check the primary protocol.
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
Electrical Impedance Tomography Saline Indicator Technique for Assessing Differences in Lung Perfusion Between Inspiratory and Expiratory Breath-Hold Phases: A Prospective Self-Controlled Study
Overview
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.
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.
Interventions
- 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 reco - 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.
Primary outcome measures
- Global Lung Perfusion Distribution [Time frame: During the study procedure (within 1 hour)]
Secondary outcome measures (1)
- Global Lung Perfusion Heterogeneity Index [Time frame: During the study procedure (within 1 hour)]
Eligibility criteria
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
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Allocation
- N/A
- Model
- Single group
- Masking
- Open label
- Primary purpose
- Diagnostic
Study locations
Center list to be confirmed — check the primary protocol.
Identifiers
NCT: NCT07303972 · EIT-BH-PERF-2025-01