In addition, this study seeks to determine whether tracheal aspirates (TA) obtained in early acute respiratory failure can be substituted for distal airway aspirates, obtained by non-bronchoscopic broncho-alevolar lavage (nb-BAL), for the purposes of investigating markers of inflammation. We will compare the ratio of IL-10 to IL-12p70 at each time point measured in tracheal secretion, bronchial secretion, and blood to assess for sample equivalence.