Materials and Methods
Description of the VALID Cohort
We studied patients who were prospectively enrolled from January 23, 2006 to February 18, 2012 in the VALID study. The VALID study was designed to identify and validate plasma biomarkers for diagnosis and prognosis of ARDS. The Vanderbilt University Institutional Review Board approved the study protocol, and written informed consent was obtained from the patient or their surrogate when possible. Because the study carries minimal risk to the study participants, the institutional review board also granted a waiver of informed consent.