Mean and SD for (A) PaO2/FiO2, (B) oxygenation index (OI), (C) lung injury score (LIS), (D) lactate, and (E) sequential organ failure assessment (SOFA) score for subjects treated with placebo air (n = 4), iCO 100 ppm (n = 4), or iCO 200 ppm (n = 4) at baseline, study days 1, 2, 3, 4, 5, and 7.