Vascular ARDS Recruitment After Inhaled Nitric Oxide

• Status: Not yet recruiting
• Trial end date: 2026-05-30
• Target enrollment: 0
• Participant gender: All

Summary

Acute respiratory distress syndrome (ARDS) is a condition where a person's lungs become inflamed, which can be caused by infection, trauma, surgery, blood transfusion, or burn. ARDS often leads to a situation where the person cannot breathe independently and needs machines' help. Once the lungs are inflamed, the small air sacs responsible for exchanging gases (i.e., ventilation) and the blood flow in the lungs (i.e., perfusion) can be affected. In the past, most research focused on studying ventilation physiology and how to help people breathe with machines. Less was done on studying perfusion because it requires imaging techniques such as computed tomography with the use of intravenous contrast and radiation. One treatment option for low oxygen levels is inhaled nitric oxide (iNO), a gas that can dilate the lung blood vessels and improve oxygenation; however, it is not always clear whether this treatment will work. Electrical Impedance Tomography (EIT) is a bedside and accessible imaging technique that is radiation-free and non-invasive and has the potential to detect changes in lung perfusion. EITI can perform multiple measurements; it is portable and accessible. This prospective interventional study aims to assess changes in regional blood perfusion in the lungs of patients with ARDS in response to iNO utilizing EIT. The main questions it aims to answer are:

1. If EIT can measure lung regional perfusion response to an iNO challenge of 20ppm for 15 minutes.

2. If EIT is comparable to dual-energy computed tomography (DECT), the gold-standard method to detect changes in regional lung perfusion.

3. If EIT can be an imaging marker to identify ARDS severity

Participants will be divided into two cohorts:

1. Cohort 1 (n=60): Participants will be asked to be monitored by EIT before, during, and after the administration of iNO (20 ppm) for 15 minutes (OFF-ON-OFF)

2. Cohort 2 (N=10): Participants will be asked to be monitored by EIT and DECT before and during the administration of iNO (20 ppm) for 15 minutes (OFF-ON).

• Phase: N/A
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: Massachusetts General Hospital
• Treatments: Nitric Oxide

Criteria

Inclusion Criteria:

• Adult intubated and mechanically ventilated patients (≥ 18 years old) admitted to the intensive care unit (ICU)

• ARDS diagnosis with mild to moderate severity by Berlin criteria1 (100 mmHg < PaO2/FiO2 <= 300 mmHg)

• Presence of an arterial line for blood gas measurement and blood pressure monitoring and of a central line for hypertonic saline injection

Exclusion Criteria:

• Suspected pregnancy, pregnancy or less than six weeks postpartum

• Younger than 18 years or older than 80 years

• Baseline methemoglobin ≥ 5%

• Subjects enrolled in another interventional research study

• Presence of pneumothorax

• Usage of any devices with electric current generation, such as a pacemaker or internal cardiac defibrillator

• Preexisting chronic lung disease or pulmonary hypertension

• Past medical history of lung malignancy or pneumonectomy, or lung transplant

• Left ventricle ejection fraction <20%

• Hemodynamic instability is defined as:

• Persistent systolic blood pressure <90 mmHg and/or >180 mmHg despite the use of vasopressor or vasodilators, or

• Requiring an increment in inotropic vasopressors over the past two hours just before enrollment: more than 15 mcg/min for norepinephrine and dopamine, more than 10 mcg/min in epinephrine, and more than 50 mcg/ min for phenylephrine.

• Hypernatremia (serum sodium > 150 mEq/L)

• Patients cannot be enrolled for DECT if they have:

• History of allergic reaction to intravenous contrast

• Renal dysfunction on the day of the study (serum creatinine > 1.5 mg/dL)