Point-of-Care Ultrasound—A New Option for Early Quantitative Assessment of Pulmonary Edema

The aim of the work described here was to investigate the value of point-of-care ultrasound (POCUS) in the early assessment of the severity of pulmonary edema in rabbits. A rabbit oleic acid (OA)-induced pulmonary edema model was used. Thirty-two New Zealand rabbits were randomly divided into four groups: a control group and three pulmonary edema groups (mild, moderate and severe). Features of transthoracic B-line artifacts (BLA), blood pH, PaO 2 and PaCO 2 , serum inflammatory factors, lung coefficient (LC), lung wet-to-dry weight ratio (W/D) and lung histopathology were assessed. BLA features and severity of pulmonary edema were semiquantitatively scored. Correlations between the number of BLA and PaO 2 , PaCO 2 , serum inflammatory factors, LC and W/D were analyzed. An additional 8 rabbits with severe pulmonary edema were used as the verified group, in which the lung was divided into ex vivo BLA (BLA-ev)-free (BLA-ev-free) and BLA-ev-clustered subregions depending on the features of BLA-ev recorded by ex vivo lung ultrasound. Lung specimens from each subregion were collected for histopathological examination. Relationships between features of BLA-ev and lung histopathological abnormalities were analyzed. With increasing doses of OA, number of BLA, W/D and levels of serum inflammatory factors decreased. Meanwhile, lung pathologic abnormalities were aggravated. In addition, time of appearance of BLA, blood pH and PaO 2, and PaCO 2 decreased dose dependently on OA ( p < 0.05). Number of BLA was linear positively correlated with severity of pulmonary edema ( r = 0.953, p < 0.05). Consistently, the features of BLA-ev reflected the severity of lung histopathological abnormalities ( r = 0.936, p < 0.05). Thus, POCUS is useful in the early quantitative assessment of the severity of pulmonary edema.