Table 2 Summary of biological domains
From: Towards a biological definition of ARDS: are treatable traits the solution?
Domain | Sample material | Example biomarkers | Advantage | Disadvantage |
|---|---|---|---|---|
Endothelial injury | Plasma | Ang2 | Easy to obtain Pathophysiological contributor to lung injury development | Reflective of all endothelial dysfunction, not only in lung |
Epithelial injury | Plasma | sRAGE. SP-D | Easy to obtain Pathophysiological contributor to lung injury development | Not only related to epithelial injury but also to, i.e., clearance by the kidney |
Epithelial injury | BALF | sRAGE | Not influenced by clearance Evaluation at site of injury | Difficult to obtain sample Local injury may not be reflective of the rest of the lung |
Protein rich pulmonary edema | BALF | Total protein | Direct measurement of hallmark of ARDS | Difficult to obtain sample Local injury may not be reflective of the rest of the lung May not be targetable and reflective of injury to endothelium and epithelium |
Protein rich pulmonary edema | EBC | Total protein | Non-invasive collection of EBC Direct measurement of hallmark of ARDS | Requires specialized equipment that is not widely available May not be targetable and reflective of injury to endothelium and epithelium |
Protein rich pulmonary edema | HME fluid | Total protein | Non-invasive collection using standard HME Direct measurement of hallmark of ARDS | Novel technique that needs to be validated further May not be targetable and reflective of injury to endothelium and epithelium |
Systemic host response | Plasma | IL-6, IL-8, TNFRI | Easy to collect Used to classify subphenotypes | Not unique to ARDS and influenced by other organ dysfunction Unclear contribution to lung injury Not reflective of alveolar inflammation |
Alveolar host response | BALF | Neutrophils, macrophages IL-6, IL-8, TNFR1 | Direct measurement of hallmark of ARDS Pathophysiological contributor to lung injury development | Difficult to obtain sample Local injury may not be reflective of the rest of the lung |