Acute lung injury (ALI)/Acute Respiratory Distress Syndrome (ARDS) is a severe lung condition that causes respiratory failure. This study will examine if differences in genes and biomarkers involved in the inflammation and blood clotting process may affect the severity of and recovery from ALI/ARDS in children hospitalized with the condition.

ALI/ARDS is a life-threatening condition that involves inflammation of the lungs and fluid accumulation in the air sacs, which leads to low blood oxygen levels and respiratory failure. Common causes include pneumonia, sepsis, and lung trauma. Symptoms, including breathing difficulty, low blood pressure, and organ failure, usually develop within 24 to 48 hours of the original injury or illness. Most patients require immediate care in an intensive care unit, and the main form of treatment is mechanical ventilation, which delivers oxygen and a continuous level of pressure to the damaged lungs. Although progress has been made in understanding how ALI/ARDS develops, it is still unknown why recovery outcomes differ among people. Differences in the genetic basis of protein C and fibrinolysis pathways, which both play a role in preventing blood clots, may be a factor in determining the severity of and recovery from ALI. The purpose of this study is to analyze plasma and DNA from children with ALI/ARDS to identify biomarkers and genetic variations that may be related to clinical outcomes.

This study will enroll children who are hospitalized with ALI/ARDS. Participants' medical records will be reviewed to gather information about symptoms, physical exam findings, mechanical ventilator settings, and laboratory test results. A blood collection will occur on Days 1 and 3. Study researchers will analyze plasma biomarkers and use high throughput DNA sequencing technology to analyze participants' DNA.

Inclusion Criteria:

• Hospitalized and requiring supplemental oxygen
• Meets the American-European consensus definition of ALI/ARDS, defined as partial pressure of oxygen in arterial blood/fraction of inspired oxygen (PaO2/FiO2) ratio of less than 300 mm Hg, bilateral opacities on a chest radiograph, and either a pulmonary wedge pressure of less than 18 mm Hg or the absence of clinical evidence of left atrial hypertension
• Acute pulmonary parenchymal disease (i.e., onset of bilateral infiltrates on chest radiograph within 48 hours of screening)
• PaO2/FiO2 less than or equal to 300 mm Hg, regardless of the mean airway pressure
• At least one arterial blood gas confirming partial pressure of oxygen/fraction of inspired oxygen (PO2/FiO2) ratio less than 300 mm Hg or Fi02/Sao2 on pulse oximetry of less than 320

Exclusion Criteria:

• Clinical signs of left ventricular failure, pulmonary capillary wedge pressure greater than 18 mm Hg, or evidence, such as echocardiography, suggesting a cardiac basis for the pulmonary edema
• Presence of right-to-left intracardiac shunt

Patients who are admitted to the University of California, San Francisco hospital and participating sites including Children's Hospital of Oakland with ALI/ARDS.