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

NCT07542366 | Recruiting

• 1 other identifier: 2024-117
• Study Type: observational
• Target: 41
• Locations: 1 country
• Sites: 1

Brief 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. 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.

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

Outcome Measures

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.

  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

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

• Global V/Q match and mismatch (%): NaCl vs NaHCO3

  During the single EIT session.

• Global intrapulmonary shunt (%) and dead space (%): NaCl vs NaHCO3

  During the single EIT session.

• Agreement between agents for global V/Q indices (ICC and Bland-Altman)

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

• Correlation between agents for global and regional parameters (Pearson R)

  Same-session paired measurements on the study day.

Study Arms (1)

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.

Eligibility Criteria

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

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.

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• First Affiliated Hospital of Wannan Medical College: lead

Study Sites (1)

The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College)

Wuhu, Anhui, 241001, China

RECRUITING

MeSH Terms

Conditions

Respiratory Distress Syndrome; Pneumonia; Critical Illness

Condition Hierarchy (Ancestors)

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

Central Study Contacts

qiancheng xu, PhD

CONTACT

+86-18297529106; qianchengxu@wnmc.edu.cn

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 28 Days
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: April 14, 2026
• First Posted: April 21, 2026
• Study Start: September 26, 2024
• Primary Completion (Estimated): September 25, 2026
• Study Completion (Estimated): September 25, 2026
• Last Updated: April 21, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)