PEEP-induced airspace overdistension complicating paraquat lung

This report describes a case of paraquat poisoning, treated with continuous positive airway pressure. After an initial phase of acute respiratory failure with diffuse pulmonary edema, we observed radiologically a complete clearing of both lungs, associated with an aspect of overdistension. Surprisingly, FRC was above normal, as was total quasi static compliance. The patient died on the 15th day, with intractable hypoxemia. Pathologic analysis revealed large zones of parenchyma with overdistended airspaces, explaining the emphysematous-like aspect of the lungs. We propose that the attempts to increase lung volume with CPAP, at an early phase of diffuse epithelial disorganization, may have, partially at least, dilated the remaining distal airspaces.