What this Trial Is About

The goal of this observational clinical trial is to learn about the role white blood cells (macrophages) play in lung inflammation in people with Acute Respiratory Distress Syndrome (ARDS). The main questions it aims to answer are: 1. How does the immune system respond to different kinds of lung injury and inflammation and how do those processes differ from each other? 2. What roles do the cells that live in the lungs (macrophages) play in turning off inflammation? How does their role differ from other cells that are called to the lung to help repair injury (recruited macrophages)? 3. Will more frequent testing of lung cell samples help reduce the time it takes to start treatment for ventilator-associated pneumonia (VAP) and therefore reduce the rates of initial therapy failure? Participants will be in the intensive care unit (ICU) on a mechanical ventilator (machine that helps patients breathe) because they have ARDS or are on a mechanical ventilator for some other reason (control group). The following will happen: 1. Participants will be given 100% oxygen through the breathing machine (mechanical ventilator) for 3-5 minutes. This is called pre-oxygenation. 2. A lung specialist (pulmonologist), a member of Dr. Janssen's research team, or respiratory therapist will place small amount of saline into the lung using a long catheter going through the breathing tube. 3. The fluid will be removed with suction and will be sent to the laboratory for testing. 4. This will be repeated two more times over the course of 10 days, or less if participants are taken off of the ventilator. The procedure will be performed no more than three times. 5. Two nasal brushings will be taken from the participants' nose. 6. Approximately 3 tablespoons of blood will be removed by putting a needle into the participants vein. This is the standard method used to obtain blood for tests. A total of 9 tablespoons will be taken for research purposes over the course of this study 7. Data including the participants age, sex, severity of illness, and other medical conditions will be recorded to determine how these can affect the white blood cells. 8. If bacteria are isolated from the fluid in the participants lung, the participants' physician may choose to place the participants on antibiotics to treat an infection. 9. A follow-up phone call may be made by a member of the research team after discharge from the hospital. At this time, the participant may be invited to participate in the Post-ICU clinic at National Jewish Health.

Macrophage Programing in Acute Lung Injury: MiniBAL