Pulmonary epithelial permeability in ARDS and cardiogenic pulmonary oedema

Abstract

Clearance of inhaled 99mTechnetium-labeled diethylene triamine pentacetate (99mTc-DTPA) from the lung, an index of pulmonary alveolar epithelial permeability (PAEP), was measured in 13 patients with cardiogenic interstitial pulmonary oedema (CIPO) and in 7 patients with adult respiratory distress syndrome (ARDS). Thirty-five normal subjects (22 nonsmokers and 13 smokers) were evaluated as controls. Half-time clearance (t0.5) values in ARDS patients (mean ± SD: 15 ± 2 min) were significantly lower than in CIPO patients (62 ± 9 min). This PAEP increase in ARDS was impressive, even in comparison to heavy smokers. Loss of the PAEP vertical gradient (apical PAEP > base PAEP) was observed in both cardiogenic and ARDS lungs and among smokers.