How is the pathophysiology of IPF?

As all ILDs: reduced lung volumes, restrictive defect, normal or increased expiratory flow, impaired gas exchange and reduced DLCO (indirectly reflects vasculature (loss of alveolar walls of capillaries) When emphysema occurs, lung volumes preserved and DLCO excessively reduced. We have reduced compliance (esophageal balloon) , impaired oxygenation (worsens with exercise, hypoxemai at rest universal). Cardiopulmonary stress test shows hypoxemia and widened A-a gradient (decreased O2 consumption with increased RR) Severe derangements in PFTs or oxygentation -> poor prognosis 6-min walk test with oxymeter (Sat<88% mortality, O2 therapy needed, correlates with DLCO as well)