Acute Respiratory FailureNCT07542366
The Feasibility of Pulmonary Perfusion Assessment Using Sodium Bicarbonate Contrast With Electrical Impedance Tomography: A Prospective Pilot Study
An observational study of Acute Respiratory Failure and Acute Respiratory Distress Syndrome (ARDS), run by First Affiliated Hospital of Wannan Medical College at 1 site in China.
Trial summary
The goal of this observational pilot study is to learn if sodium bicarbonate can be used safely and effectively as a contrast agent to map lung blood flow using electrical impedance tomography (EIT) in adults on mechanical ventilation. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Acute Respiratory Failure, Acute Respiratory Distress Syndrome (ARDS), Pneumonia
- Type of treatment
- Injection or infusion
- How many people
- 41 participants
- Where
- 1 siteChina
- Study dates
- 26 Sep 2024to 25 Sep 2026
- How long will I take part?
- 28 Days
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Critically ill adult patients admitted to a mixed intensive care unit, receiving invasive mechanical ventilation and equipped with a central venous catheter. All participants undergo a single bedside electrical impedance tomography examination with sequential bolus injections of hypertonic saline and 5% sodium bicarbonate for pulmonary perfusion assessment.
Who may be able to join
- Age ≥ 18 years
- Admitted to the intensive care unit (ICU)
- Receiving invasive mechanical ventilation with controlled or assisted-controlled mode
- Presence of a central venous catheter suitable for contrast bolus injection
- Hemodynamically stable (no ongoing cardiopulmonary resuscitation; no uncontrolled shock judged by treating physician)
- Expected to remain on mechanical ventilation for the duration of the EIT examination
- Written informed consent obtained from the patient or legally authorized representative
Who cannot join
- Known pregnancy
- Known allergy, intolerance, or contraindication to sodium bicarbonate or hypertonic saline
- Severe arrhythmia or unstable cardiovascular status in which small bolus injection is deemed unsafe by the treating physician
- Uncontrolled agitation or conditions that preclude correct EIT belt placement (e.g., extensive chest wounds, large chest dressings, chest wall deformity that prevents belt use)
- Implanted electronic devices or metallic implants in the thoracic area considered a contraindication to EIT by the manufacturer's instructions
- End-stage disease with expected survival of only a few hours, in whom participation is not appropriate as judged by the treating physician
- Participation in another interventional trial that, in the opinion of the investigator, could interfere with EIT measurements or safety assessment
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
China1 site, 1 recruiting
- Recruiting
The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College)
Wuhu, Anhui, 241001
qiancheng xu, PhD, +86-18315329399, xu19871011@163.com
About this study
The goal of this observational pilot study is to learn if sodium bicarbonate can be used safely and effectively as a contrast agent to map lung blood flow using electrical impedance tomography (EIT) in adults on mechanical ventilation. Electrical impedance tomography (EIT) is a bedside imaging method that uses a soft belt with small sensors around the chest to track changes in electrical signals related to breathing and blood flow.
The main questions are:
Read more
Does sodium bicarbonate create clear, readable lung blood flow images with EIT? Are these images similar in quality and pattern to images made with hypertonic saline (10% sodium chloride)? Is the short-term safety profile acceptable, including effects on blood pressure, heart rhythm, and blood tests?
Researchers will compare two contrast agents within the same participant to see if image quality and lung blood flow patterns match:
Hypertonic saline (10% sodium chloride) Sodium bicarbonate (5%)
Participants will:
Have an EIT belt placed around the chest during routine ICU care Pause the ventilator briefly during image capture to reduce motion Receive two small intravenous boluses through an existing central line, one of hypertonic saline and one of sodium bicarbonate, with time between doses Have routine monitoring of vital signs; blood gases and electrolytes may be checked per clinical care Be observed for any short-term side effects Findings from this study will show whether sodium bicarbonate is a practical and safe option for EIT-based lung blood flow assessment and will guide larger future studies.
Read the detailed description
This single-center, prospective, observational pilot study evaluates sodium bicarbonate as a conductivity contrast agent for electrical impedance tomography (EIT) to assess pulmonary perfusion in mechanically ventilated adults. EIT uses a belt with surface electrodes placed at a standard chest level to measure changes in electrical impedance. A small intravenous bolus of a conductive solution produces a short first-pass signal that can be analyzed to map relative lung blood flow.
Procedure:
Placement: An EIT belt is positioned around the thorax and signal quality is verified.
Acquisition: Perfusion-focused recordings are obtained during brief end-expiratory pauses on the ventilator to limit breathing-related signal changes.
Contrast sequence: Each participant receives two small contrast boluses through a central venous catheter in a prespecified order with adequate washout between injections:
10% sodium chloride (hypertonic saline) 5% sodium bicarbonate Monitoring: Continuous bedside monitoring (for example, heart rhythm and blood pressure) accompanies each acquisition. Blood gases and electrolytes may be obtained in temporal proximity to injections when clinically available.
Data handling and endpoints:
Image quality is assessed by predefined criteria for analyzable recordings and signal strength adequate for first-pass analysis.
Regional perfusion patterns from sodium bicarbonate are compared within participants to patterns from hypertonic saline to evaluate similarity in image quality and distribution.
Short-term safety is described by changes in vital signs and clinically available laboratory values, and by recording adverse events possibly related to the boluses.
This pilot uses a small convenience sample appropriate for feasibility work and is not designed to detect differences in long-term clinical outcomes. Results will inform parameter selection and sample size for subsequent studies that use EIT to assess lung blood flow.
- Conditions
- Acute Respiratory Failure, Acute Respiratory Distress Syndrome (ARDS), Pneumonia, Critical Illness, Feasibility of Contrast-enhanced Electrical Impedance Tomography (EIT) for Pulmonary Perfusion Assessment in Mechanically Ventilated Adults
- Keywords
- Electrical Impedance Tomography (EIT), Pulmonary Perfusion, Contrast-Enhanced EIT, Sodium Bicarbonate Contrast, Hypertonic Saline (10% NaCl), First-Pass Impedance Signal, Mechanical Ventilation, Intensive Care Unit (ICU), Ventilation-Perfusion (V/Q) Matching, Feasibility Study
- Medical subject headings
- Respiratory Distress Syndrome, Pneumonia, Critical Illness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Mechanically Ventilated ICU Cohort | Adult ICU participants on controlled mechanical ventilation with a central venous catheter. Participants undergo bedside electrical impedance tomography (EIT) perfusion imaging during brief end-expiratory pauses. Two small intravenous contrast boluses are given in a prespecified sequence with adequate washout: 10% sodium chloride (hypertonic saline) and 5% sodium bicarbonate. Continuous physiologic monitoring is performed; blood gases/electrolytes may be obtained per clinical care. No randomization. Within-participant comparison of image quality, perfusion patterns, and short-term safety. Observational; EIT monitor used per routine care. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Proportion of analyzable sodium bicarbonate-enhanced EIT perfusion recordings
Feasibility defined as the proportion of 5% sodium bicarbonate (NaHCO3) EIT perfusion acquisitions that meet predefined analyzable image quality criteria (clear first-pass bolus curve, no noncorrectable artifacts, successful reconstruction over expected thoracic region). Reported as n analyzable / n attempted, with 95% CI.
Measured: During the single EIT session on the study day (from contrast injection to completion of image reconstruction; within ~2 hours of enrollment)
Secondary outcomes (6)
Overall first-pass impedance reduction amplitude (AU): NaCl vs NaHCO3
Median (IQR) amplitude of overall first-pass impedance reduction for 10% NaCl vs 5% NaHCO3 with within-participant comparison and statistical test; also summarize per ROI (1-4).
Measured: During the single EIT session (immediately after each bolus).
Global V/Q match and mismatch (%): NaCl vs NaHCO3
Percent V/Q match and V/Q mismatch derived from EIT for each agent; report median (IQR), within-participant differences, and corresponding P values.
Measured: During the single EIT session.
Global intrapulmonary shunt (%) and dead space (%): NaCl vs NaHCO3
Report shunt and dead space percentages for both agents (median [IQR]) with within-participant comparison and P values.
Measured: During the single EIT session.
Agreement between agents for global V/Q indices (ICC and Bland-Altman)
Intraclass correlation coefficients (95% CIs) and Bland-Altman bias/limits of agreement between NaCl and NaHCO3 for global V/Q match, shunt, and dead space.
Measured: Derived from paired acquisitions within the same session on the study day.
Correlation between agents for global and regional parameters (Pearson R)
Pearson correlation coefficients (R, P) between NaCl and NaHCO3 for global V/Q match, shunt, dead space, and ROI-level V/Q match, ventilation, and perfusion.
Measured: Same-session paired measurements on the study day.
Correlation of EIT-derived global indices with PaO2/FiO2
Pearson correlations (R, P) between PaO2/FiO2 and EIT-derived V/Q mismatch, dead space, and shunt for each contrast agent analyzed separately.
Measured: Paired with each EIT acquisition on the study day.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Apr 2026
- Study start26 Sep 2024
- Primary completion25 Sep 2026 (estimated)
- Study completion25 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Acute Respiratory FailureStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 41 participants (estimated)
- Target duration
- 28 Days
Sponsor and investigators
- Lead sponsor
- First Affiliated Hospital of Wannan Medical College
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Qiancheng Xu, First Affiliated Hospital of Wannan Medical College
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07542366
- Sponsor's protocol ID
- 2024-117
- Status last verified
- Apr 2026
- First submitted
- 14 Apr 2026
- Last updated
- 21 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 21 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Feasibility of Pulmonary Perfusion Assessment Using Sodium Bicarbonate Contrast With Electrical Impedance Tomography: A Prospective Pilot Study
- ClinicalTrials.gov ID
- NCT07542366
- Acronym / sponsor ID
- 2024-117
- Conditions
- Acute Respiratory Failure, Acute Respiratory Distress Syndrome (ARDS), Pneumonia, Critical Illness, Feasibility of Contrast-enhanced Electrical Impedance Tomography (EIT) for Pulmonary Perfusion Assessment in Mechanically Ventilated Adults
- Keywords
- Electrical Impedance Tomography (EIT), Pulmonary Perfusion, Contrast-Enhanced EIT, Sodium Bicarbonate Contrast, Hypertonic Saline (10% NaCl), First-Pass Impedance Signal, Mechanical Ventilation, Intensive Care Unit (ICU)
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 41 participants (estimated)
- Lead sponsor
- First Affiliated Hospital of Wannan Medical CollegeUniversity, hospital or other
- Study start
- 26 Sep 2024 (actual)
- Primary completion
- 25 Sep 2026 (estimated)
- Study completion
- 25 Sep 2026 (estimated)
- First posted
- 21 Apr 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this observational pilot study is to learn if sodium bicarbonate can be used safely and effectively as a contrast agent to map lung blood flow using electrical impedance tomography (EIT) in adults on mechanical ventilation. Electrical impedance tomography (EIT) is a bedside imaging method that uses a soft belt with small sensors around the chest to track changes in electrical signals related to breathing and blood flow.
The main questions are:
Does sodium bicarbonate create clear, readable lung blood flow images with EIT? Are these images similar in quality and pattern to images made with hypertonic saline (10% sodium chloride)? Is the short-term safety profile acceptable, including effects on blood pressure, heart rhythm, and blood tests?
Researchers will compare two contrast agents within the same participant to see if image quality and lung blood flow patterns match:
Hypertonic saline (10% sodium chloride) Sodium bicarbonate (5%)
Participants will:
Have an EIT belt placed around the chest during routine ICU care Pause the ventilator briefly during image capture to reduce motion Receive two small intravenous boluses through an existing central line, one of hypertonic saline and one of sodium bicarbonate, with time between doses Have routine monitoring of vital signs; blood gases and electrolytes may be checked per clinical care Be observed for any short-term side effects Findings from this study will show whether sodium bicarbonate is a practical and safe option for EIT-based lung blood flow assessment and will guide larger future studies.
Detailed description
This single-center, prospective, observational pilot study evaluates sodium bicarbonate as a conductivity contrast agent for electrical impedance tomography (EIT) to assess pulmonary perfusion in mechanically ventilated adults. EIT uses a belt with surface electrodes placed at a standard chest level to measure changes in electrical impedance. A small intravenous bolus of a conductive solution produces a short first-pass signal that can be analyzed to map relative lung blood flow.
Procedure:
Placement: An EIT belt is positioned around the thorax and signal quality is verified.
Acquisition: Perfusion-focused recordings are obtained during brief end-expiratory pauses on the ventilator to limit breathing-related signal changes.
Contrast sequence: Each participant receives two small contrast boluses through a central venous catheter in a prespecified order with adequate washout between injections:
10% sodium chloride (hypertonic saline) 5% sodium bicarbonate Monitoring: Continuous bedside monitoring (for example, heart rhythm and blood pressure) accompanies each acquisition. Blood gases and electrolytes may be obtained in temporal proximity to injections when clinically available.
Data handling and endpoints:
Image quality is assessed by predefined criteria for analyzable recordings and signal strength adequate for first-pass analysis.
Regional perfusion patterns from sodium bicarbonate are compared within participants to patterns from hypertonic saline to evaluate similarity in image quality and distribution.
Short-term safety is described by changes in vital signs and clinically available laboratory values, and by recording adverse events possibly related to the boluses.
This pilot uses a small convenience sample appropriate for feasibility work and is not designed to detect differences in long-term clinical outcomes. Results will inform parameter selection and sample size for subsequent studies that use EIT to assess lung blood flow.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 28 Days
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Mechanically Ventilated ICU Cohort | – | –Adult ICU participants on controlled mechanical ventilation with a central venous catheter. Participants undergo bedside electrical impedance tomography (EIT) perfusion imaging during brief end-expiratory pauses. Two small intravenous contrast boluses are given in a prespecified sequence with adequate washout: 10% sodium chloride (hypertonic saline) and 5% sodium bicarbonate. Continuous physiologic monitoring is performed; blood gases/electrolytes may be obtained per clinical care. No randomization. Within-participant comparison of image quality, perfusion patterns, and short-term safety. Observational; EIT monitor used per routine care. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Critically ill adult patients admitted to a mixed intensive care unit, receiving invasive mechanical ventilation and equipped with a central venous catheter. All participants undergo a single bedside electrical impedance tomography examination with sequential bolus injections of hypertonic saline and 5% sodium bicarbonate for pulmonary perfusion assessment.
Key inclusion criteria (7 listed)
- Age ≥ 18 years
- Admitted to the intensive care unit (ICU)
- Receiving invasive mechanical ventilation with controlled or assisted-controlled mode
- Presence of a central venous catheter suitable for contrast bolus injection
- Hemodynamically stable (no ongoing cardiopulmonary resuscitation; no uncontrolled shock judged by treating physician)
Key exclusion criteria (7 listed)
- Known pregnancy
- Known allergy, intolerance, or contraindication to sodium bicarbonate or hypertonic saline
- Severe arrhythmia or unstable cardiovascular status in which small bolus injection is deemed unsafe by the treating physician
- Uncontrolled agitation or conditions that preclude correct EIT belt placement (e.g., extensive chest wounds, large chest dressings, chest wall deformity that prevents belt use)
- Implanted electronic devices or metallic implants in the thoracic area considered a contraindication to EIT by the manufacturer's instructions
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Proportion of analyzable sodium bicarbonate-enhanced EIT perfusion recordings
Time frame: During the single EIT session on the study day (from contrast injection to completion of image reconstruction; within ~2 hours of enrollment)
Feasibility defined as the proportion of 5% sodium bicarbonate (NaHCO3) EIT perfusion acquisitions that meet predefined analyzable image quality criteria (clear first-pass bolus curve, no noncorrectable artifacts, successful reconstruction over expected thoracic region). Reported as n analyzable / n attempted, with 95% CI.
6 secondary outcomes
Overall first-pass impedance reduction amplitude (AU): NaCl vs NaHCO3
Time frame: During the single EIT session (immediately after each bolus).
Global V/Q match and mismatch (%): NaCl vs NaHCO3
Time frame: During the single EIT session.
Global intrapulmonary shunt (%) and dead space (%): NaCl vs NaHCO3
Time frame: During the single EIT session.
Agreement between agents for global V/Q indices (ICC and Bland-Altman)
Time frame: Derived from paired acquisitions within the same session on the study day.
Correlation between agents for global and regional parameters (Pearson R)
Time frame: Same-session paired measurements on the study day.
Correlation of EIT-derived global indices with PaO2/FiO2
Time frame: Paired with each EIT acquisition on the study day.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Apr 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Acute Respiratory Failure and Acute Respiratory Distress Syndrome (ARDS), run by First Affiliated Hospital of Wannan Medical College at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 21 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact qiancheng xu, PhD (+86-18297529106, qianchengxu@wnmc.edu.cn), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Proportion of analyzable sodium bicarbonate-enhanced EIT perfusion recordings (time frame: During the single EIT session on the study day (from contrast injection to completion of image reconstruction; within ~2 hours of enrollment)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Apr 2026.