Relationship of Pulmonary Contusion to Pulmonary Inflammation and Incidence of Acute Respiratory Distress Syndrome

Pulmonary contusion (PC) is a significant problem after blunt trauma that may often lead to acute respiratory distress syndrome (ARDS) and in some patients, death. Although the pathophysiology is incompletely understood, it is clear that there is a biochemical process involving changes in the inflammatory milieu after contusion which occurs in addition to simple direct mechanical injury to the lung. The relationship of severity of contusion on imaging, disturbances in the inflammatory phenotype, and outcome is unknown. This is a prospective, observational study which will evaluate the size and severity of contusion as measured on chest computed tomography (CT). Inflammatory mediators will be measured in the bronchoalveolar lavage (BAL) and in the serum of patients with pulmonary contusion to define the inflammatory nature of the post-contusion lung. The degree of abnormality within the inflammatory parameters will be correlated with lung contusion size and subsequent patient outcomes. These data will be compared to other patient groups: 1) Trauma patients without chest injury who are mechanically ventilated; 2) Uninjured patients undergoing elective surgical procedures that will require intubation and mechanical ventilation; 3) Patients in the Medical ICU who are mechanically ventilated with acute respiratory failure. The hypothesis tested within this study is resolution of lung injury is dependent upon the presence of Tregs in the alveolar space.