An observational study in ARDS (Acute Respiratory Distress Syndrome), Electrical Impedance Tomography (EIT) and Mechanical Ventilation, sponsored by Union Hospital, Tongji Medical College, Huazhong University of Science and Technology. Recruiting at 1 site in China. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-11-02.
Sponsored by Union Hospital, Tongji Medical College, Huazhong University of Science and Technology · Observational
Monitoring pulmonary perfusion is crucial in critical care, especially for conditions like ARDS. Electrical Impedance Tomography (EIT) is a valuable, non-invasive tool for real-time bedside monitoring.While well-established for lung ventilation, EIT faces a challenge in perfusion imaging because the related impedance signal is very weak. Currently, two main methods are used:Saline Bolus EIT: Involves injecting a saline solution during a breath-hold to track blood flow.Pulse Wave EIT: Utilizes cardiac-induced vascular pulsations to assess perfusion.However, both methods have limitations in ARDS patients, as the disease's altered physiology can affect their accuracy.
This study compares pulse wave versus saline bolus EIT for pulmonary perfusion assessment in ARDS patients and investigates the impact of different PEEP levels.
During clinical diagnosis and treatment, a patient's oxygenation status is not only related to ventilation but also closely associated with pulmonary blood flow perfusion. In many diseases, physicians need to closely monitor patients' pulmonary perfusion function, such as pulmonary embolism (PE), pulmonary hypertension (PH), and acute respiratory distress syndrome (ARDS).
Particularly during mechanical ventilation for ARDS or fluid resuscitation for shock patients, there is an urgent need for bedside, dynamic, non-invasive, continuous, real-time, and visual monitoring of critically ill patients. Simultaneously, understanding the real-time dynamic changes in cardiac and respiratory pathophysiology is essential for implementing individualized, goal-directed precision therapy, improving patient outcomes, and reducing mortality.
Electrical Impedance Tomography (EIT) is an imaging technique that reconstructs images based on the impedance characteristics of biological tissues. Thoracic EIT can non-invasively, real-time, and dynamically monitor changes in pulmonary electrical impedance, capturing impedance images and data that vary with lung ventilation and perfusion. This reflects lung pathology and dynamic processes, holding significant value for the diagnosis and treatment of critically ill patients.
EIT has long been established in the field of lung ventilation and is widely used clinically. However, using EIT for pulmonary perfusion imaging is challenging. The impedance changes caused by pulmonary blood perfusion are less than one-tenth of those caused by ventilation and are easily masked by various types of noise, making them extremely difficult to extract. Currently, there are two main solutions:Injecting a high-conductivity contrast agent, also known as saline bolus EIT imaging or contrast-enhanced EIT imaging;The pulse wave method.
The former is performed by injecting a 3%-20% sodium chloride (NaCl) solution via a catheter during an end-expiratory breath-hold, eliminating respiratory interference. As the saline passes sequentially through the right atrium, right ventricle, and pulmonary artery, it produces a first-pass kinetic dilution effect. The resulting impedance changes reflect forward pulmonary blood flow-regions with rich perfusion exhibit high conductivity, and the collected thoracic impedance data show a decrease. Images are then reconstructed based on the obtained impedance-time curve. However, in moderate to severe ARDS patients, variations in lung compliance and pulmonary vascular resistance may affect perfusion detection during apnea.
The latter method monitors pulmonary perfusion based on the principle that lung blood perfusion coincides with vascular pulsations. Nevertheless, increased pulmonary vascular permeability in ARDS patients may impact the accuracy of pulse wave-based perfusion detection.
This study aims to compare pulse wave EIT and saline bolus EIT for assessing pulmonary perfusion in ARDS patients, and to evaluate the changes in monitoring indices under different PEEP levels.
382 studies on the registry are indexed under Acute Lung Injury; 73 are open to participants now.
This study's planned enrollment of 20 is below the median of 100 across 131 observational studies indexed under Acute Lung Injury.
Browse Acute Lung Injury studies →Union Hospital, Tongji Medical College, Huazhong University of Science and Technology is the lead sponsor of 181 studies on the registry; 144 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Patients who meet the inclusion and exclusion criteria will undergo both pulse wave and saline bolus EIT monitoring at PEEP levels of 5 and 15 cmH₂O.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Pulmonary perfusion was assessed using both pulse wave and saline bolus EIT at PEEP levels of 5 and 15 cmH₂O.
At a PEEP of 5 cmH₂O, pulse wave EIT data were recorded for 3 minutes. Subsequently, during an inspiratory or expiratory hold, a 10 mL bolus of 10% hypertonic saline was administered via the central venous catheter while EIT data were simultaneously recorded for another 3 minutes. This procedure was repeated at a PEEP of 15 cmH₂O. Pulmonary perfusion data were obtained through offline analysis of the EIT data.
Time frame: Under both PEEP 5 cmH₂O and PEEP 15 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
At PEEP 5 cmH₂O and 15 cmH₂O, perform EIT monitoring of pulmonary perfusion during a 15-second inspiratory or expiratory hold.
At a PEEP of 5 cmH₂O, EIT data were first recorded for 1 minute, followed by a 15-second inspiratory hold, after which data acquisition was continued for an additional 2 minutes. The entire procedure was repeated at a PEEP of 15 cmH₂O. Pulmonary perfusion data were subsequently analyzed using offline software.
Time frame: Under both PEEP 5 cmH₂O and PEEP 15 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
Under PEEP 5 cmH₂O conditions, EIT data were acquired during bolus injections of either 10 mL of 0.9% saline or 10 mL of 10% hypertonic saline for pulmonary perfusion analysis.
At a PEEP of 5 cmH₂O, the following protocol was performed: First, EIT data were recorded for 1 minute, followed by a bolus injection of 10 mL of 0.9% saline via the central venous catheter; data acquisition then continued for an additional 2 minutes. Then, the procedure was repeated with a bolus injection of 10 mL of 10% hypertonic saline. Pulmonary perfusion data were subsequently analyzed using offline software.
Time frame: Under a PEEP of 5 cmH₂O, EIT data acquisition was performed after 30 minutes of stable ventilation.
The ventilation-perfusion matching percentage was assessed using both pulse wave and saline bolus EIT at PEEP levels of 5 and 15 cmH₂O.
The ventilation-perfusion matching percentage was derived from EIT images using offline analysis software.
Time frame: Under both PEEP 5 cmH₂O and PEEP 15 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
The ventilation-perfusion matching percentage was monitored by EIT during 15-second inspiratory or expiratory holds at PEEP levels of 5 and 15 cmH₂O.
The ventilation-perfusion matching percentage was derived from EIT images using offline analysis software.
Time frame: Under both PEEP 5 cmH₂O and PEEP 15 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
Under PEEP 5 cmH₂O conditions, EIT data were acquired during bolus injections of either 10 mL of 0.9% saline or 10 mL of 10% hypertonic saline for ventilation-perfusion matching percentage.
The ventilation-perfusion matching percentage was derived from EIT images using offline analysis software.
Time frame: Under a PEEP of 5 cmH₂O, EIT data acquisition was performed after 30 minutes of stable ventilation.
The dead space percentage was assessed using both pulse wave and saline bolus EIT at PEEP levels of 5 and 15 cmH₂O.
The ventilation-perfusion matching percentage was derived from EIT images using offline analysis software.
Time frame: Under both PEEP 5 cmH₂O and PEEP 15 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
The dead space percentage was monitored by EIT during 15-second inspiratory or expiratory holds at PEEP levels of 5 and 15 cmH₂O.
The ventilation-perfusion matching percentage was derived from EIT images using offline analysis software.
Time frame: Under both PEEP 5 cmH₂O and PEEP 15 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
Under PEEP 5 cmH₂O conditions, the dead space percentage was obtained by EIT monitoring following bolus injections of either 10 mL of 0.9% saline or 10 mL of 10% hypertonic saline.
The ventilation-perfusion matching percentage was derived from EIT images using offline analysis software.
Time frame: Under PEEP 5 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
The shunt percentage was assessed using both pulse wave and saline bolus EIT at PEEP levels of 5 and 15 cmH₂O.
The ventilation-perfusion matching percentage was derived from EIT images using offline analysis software.
Time frame: Under both PEEP 5 cmH₂O and PEEP 15 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
The shunt space percentage was monitored by EIT during 15-second inspiratory or expiratory holds at PEEP levels of 5 and 15 cmH₂O.
The ventilation-perfusion matching percentage was derived from EIT images using offline analysis software.
Time frame: Under both PEEP 5 cmH₂O and PEEP 15 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
Under PEEP 5 cmH₂O conditions, the shunt space percentage was obtained by EIT monitoring following bolus injections of either 10 mL of 0.9% saline or 10 mL of 10% hypertonic saline.
The ventilation-perfusion matching percentage was derived from EIT images using offline analysis software.
Time frame: Under PEEP 5 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
At PEEP 5 cmH₂O, heart rate was monitored: at baseline, during 15-second inspiratory and expiratory holds, following bolus injections of 10 mL of 0.9% saline and 10% hypertonic saline, and during combined breath-hold-and-injection procedures.
Heart rate was obtained from the patient monitor.
Time frame: Under PEEP 5 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
At PEEP 15 cmH₂O, heart rate was monitored: at baseline, during 15-second inspiratory and expiratory holds, and during combined breath-hold-and-injection procedures.
Heart rate was obtained from the patient monitor.
Time frame: Under PEEP 15 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
At PEEP 5 cmH₂O, blood pressure was monitored: at baseline, during 15-second inspiratory and expiratory holds, following bolus injections of 10 mL of 0.9% saline and 10% hypertonic saline, and during combined breath-hold-and-injection procedures.
Blood pressure was obtained from the patient monitor.
Time frame: Under PEEP 5 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
At PEEP 15 cmH₂O, blood pressure was monitored: at baseline, during 15-second inspiratory and expiratory holds, and during combined breath-hold-and-injection procedures.
Blood pressure was obtained from the patient monitor.
Time frame: Under PEEP 15 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
At PEEP 5 cmH₂O, central venous pressure was monitored: at baseline, during 15-second inspiratory and expiratory holds, following bolus injections of 10 mL of 0.9% saline and 10% hypertonic saline, and during combined breath-hold-and-injection procedures
Central venous pressure was obtained from the patient monitor.
Time frame: Under PEEP 5 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
At PEEP 15 cmH₂O, central venous pressure was monitored: at baseline, during 15-second inspiratory and expiratory holds, and during combined breath-hold-and-injection procedures.
Central venous pressure was obtained from the patient monitor.
Time frame: Under PEEP 15 cmH₂O conditions, EIT data were acquired after 30 minutes of stable ventilation.
The PaO₂/FiO₂ ratio was recorded prior to patient enrollment.
The PaO₂/FiO₂ ratio was obtained from arterial blood gas analysis.
Time frame: Prior to enrollment
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Union Hospital, Tongji Medical College, Huazhong University of Science and Technology →