Identifying PARDS Endotypes

Enrolled subjects will have nasal and bronchial brushings collected at days 1, 3, 7, and 14
of intubation with collection of serum at these same time points. Brushing RNA will be
processed by microarray for gene expression analysis and compared to previously published
serum biomarkers (interleukin-8, advanced glycosylation end-product specific receptor, and
angiopoietin-2) to assess correlation and ability to discriminate PARDS endotypes. Changes in
gene expression over time will be assessed to define a PARDS recovery gene expression
signature, and correlation between bronchial and nasal gene expression will be determined.

Inclusion Criteria:

All potential participants must:

1. Be aged zero to 25 years (both control and ARDS, not age matched)

2. Weigh more than 5 kg

3. Be admitted to the PICU with a 3.5 mm or greater endotracheal tube with a duration of
endotracheal intubation anticipated to be four days or greater.

ARDS patients must:

4. Have non-cardiogenic pulmonary edema on chest x-ray (CXR)

5. Have a known or suspected insult within the prior 7 days that is consistent with ARDS

6. Have an oxygenation index (OI) of 4 or greater or and oxygen-sat index (OSI) of 5 or
greater

1. OI = mean airway pressure X fraction inspired oxygen (FiO2) / arterial oxygen
partial pressure (PaO2)

2. OSI = mean airway pressure X FiO2 / oxyhemoglobin saturation (SpO2) with sat <=
97%.

Exclusion Criteria:

1. Have a tracheostomy

2. Have a baseline oxygen requirement of 2 liters of oxygen or greater at home

3. Have a specific order not to perform routine airway clearance

4. Have a history of excessive bleeding or known bleeding disorders

5. Be undergoing therapeutic anticoagulation (thromboprophylaxis is acceptable) or be
thought to be at high risk of bleeding by the clinical team

6. Have had an airway surgical procedure below the level of the endotracheal tube

7. Have a do not resuscitate (DNR) or Limited Resuscitation Order