Validation of Clara Cell Protein as a Novel Diagnostic Biomarker for the Differentiation of Cardiogenic Pulmonary Edema From Non-Cardiogenic Pulmonary Edema

Club cells or Clara cells (CCs) were first described in 1881 but their importance was forgotten until Max Clara's 1937 study identifying these bronchiolar exocrine cells. CCs constitute up to 44% of proliferating small airway cells, functioning as epithelial progenitors during lung regeneration and repair of injury.

CC16 can be useful in distinguishing between cardiogenic pulmonary edema (CPE), caused by increased pressure in the heart's left ventricle, and non-cardiogenic pulmonary edema, such as acute lung injury (ALI) or acute respiratory distress syndrome (ARDS), which are not related to heart failure. Patients with ALI/ARDS tend to have lower levels of CC16 in their plasma and pulmonary edema fluid compared to those with CPE, suggesting a potential diagnostic role for CC16 in these conditions.

Inclusion criteria

• Adult patients aged 18 years or older.
• Both sexes.
• Patients requiring intensive care unit (ICU) admission and intubation.
• Inclusion criteria followed the American-European Consensus Conference diagnostic guidelines for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS): acute respiratory failure onset, bilateral infiltrates on chest radiography, a PaO2/FiO2 ratio below 300 for ALI or 200 for ARDS and no evidence of left atrial hypertension

Exclusion criteria

• Critically ill but not intubated.
• Had a mixed cause of pulmonary edema like pneumonia with heart failure.