Table 1.

Definition of acute exacerbation of IPF described by Hyzy et al. [10].

Previous or concurrent diagnosis of IPF*
Unexplained worsening or development of dyspnea within 30 d
High-resolution CT scan with new bilateral ground-glass abnormality and/or consolidation superimposed on a background reticular or honeycomb pattern consistent with a UIP pattern†
Worsening hypoxemia from a known baseline arterial blood gas‡
No evidence of pulmonary infection by endotracheal aspiration or BAL
Exclusion of alternative causes, including
left heart failure
pulmonary embolism
identifiable cause of acute lung injury§

*This criterion can be met by the presence of radiologic and/or histopathologic changes consistent with a UIP pattern if a diagnosis of IPF has not been previously established by American Thoracic Society/European Respiratory Society criteria.

^†Current high-resolution CT scan is acceptable without prior high-resolution CT scan for comparison if none is available.

^‡Includes evaluation for common bacterial organisms and viral pathogens.

^§Causes of lung injury include sepsis, aspiration, trauma, transfusion of blood products, pulmonary contusion, fat embolization, drug toxicity, acute pancreatitis, inhalational injury, and cardiopulmonary bypass.