Relationship between electron microscopic changes in alveolar septa and extravascular lung water volume

Abstract

Lung water accumulates partly in the alveolar septa. However, morphological changes in alveolar septa have never been analyzed quantitatively nor correlated with lung water volume changes. We aimed to delineate these unsolved questions.Twenty-four mongrel dogs were studied under general anesthesia and spontaneous breathing. Extravascular lung thermal volume was measured with double indicator dilution technique using heat and Indocyanine green. Experimental groups were as follows: Group C; 6 control dogs, Group D-30; 100 ml/kg of dextran-70 over 30 min in 6 dogs, Group D-90; 100 ml/kg of dextran-70 over 30 min and waiting for another 60 min in 6 dogs, Group A; 100 mg/kg of alloxan. After final measurement of extravascular lung thermal volume, we immediately killed the dogs with the lungs inflated and we removed the lungs for lung water measurement with direct destructive method. Samples for electron microscopic examination were obtained by excising tissues from the surface of right lower lobe where edema appeared severe. Twenty electron micrographs were prepared from each dog without prior knowledge of the experimental intervention.