2017 年 68 巻 1 号 p. 14-22
Background: B-lines are the important signs of pulmonary edema in acute respiratory distress syndrome (ARDS) detected with ultrasonography. We studied the mechanism of the origin and disappearance of B-lines in
ARDS piglets using ultrasonography and microscopy.
Methods: ARDS was induced by intratracheal administration of 0.1M Hydrochloric Acid (HCl) in 23 anesthetized, ventilated piglets. The occurrence of B-lines was evaluated using transthoracic echography (TTE) and
transesophageal echography (TEE). Changes in B-lines were recorded after a saline infusion into the pleural space,
and after pulmonary consolidation developed and reached the pleura. Left lower lobe was excised and lung sections
were examined by light microscopy.
Results: Following the saline infusion into the pleural space, we observed B-lines fanning out from the visceral
pleura. As pulmonary consolidation developed, B-lines disappeared. The structure that B-lines fanned out from was
the complex of thickened pleura and sub-pleural interlobular septa surrounded by gas. In the tissue where B-lines
disappeared, the thickened sub-pleural interlobular septa were surrounded by cells and liquid.
Conclusions: We found that B-lines derive from the complex of thickened pleura and sub-pleural interlobular septa surrounded by gas. B-lines disappeared when the sub-pleural thickened interlobular septa were surrounded by cells and liquid.