Keywords: AE; acute exacerbation; APACHE; Acute Physiology and Chronic Health Evaluation; BALF; BAL fluid; CRP; C-reactive protein; IPF; idiopathic pulmonary fibrosis; KL-6; Krebs von der Lungen-6; LDH; lactate dehydrogenase; LMWH; low-molecularweight heparin; NIV;