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The Feasibility of Pulmonary Perfusion Assessment Using Sodium Bicarbonate Contrast With Electrical Impedance Tomography: A Prospective Pilot Study

ConditionsAcute Respiratory FailureAcute Respiratory Distress Syndrome (ARDS)PneumoniaCritical IllnessFeasibility of Contrast-enhanced Electrical Impedance Tomography (EIT) for Pulmonary Perfusion Assessment in Mechanically Ventilated Adults
Trial statusRecruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
Age18+
SponsorFirst Affiliated Hospital of Wannan Medical College

About this trial

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.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

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

Disqualifiers

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)

Trial 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.

Trial design

Design model

Cohort

Time perspective

Prospective

Treatments tested in this trial

Not listed

Trial groups

41 Participants
are grouped into 1 trial group
Group A: Mechanically Ventilated ICU Cohort

Trial outcomes

Primary outcomes

1

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.

Time frame
During the single EIT session on the study day (from contrast injection to completion of image reconstruction; within ~2 hours of enrollment)

Secondary outcomes

1

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).

Time frame
During the single EIT session (immediately after each bolus).
2

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.

Time frame
During the single EIT session.
3

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.

Time frame
During the single EIT session.
4

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.

Time frame
Derived from paired acquisitions within the same session on the study day.

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

First Affiliated Hospital of Wannan Medical College

Lead sponsor

Source ClinicalTrials.gov
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