VWF and acute respiratory distress syndrome: Specifically, we could observe that patients with moderate to severe ARDS (i.e., with values of PaO2/FiO2 ≤ 200%) were characterized by significantly (p < 0.05) higher levels of vWF antigen, leukocyte, and neutrophil counts, compared with patients with mild ARDS (i.e., PaO2/FiO2 >200%) (Fig. 2).