Objective: This study aimed to investigate the diagnostic efficacy of lung ultrasound score (LUS) in evaluating oleic acid-induced acute lung injury (ALI) in goats

providing insights for the early and rapid assessment of ALI. Methods: Sixteen goats were randomly assigned to mild and severe injury groups

each comprising eight goats. The ALI models were induced by injecting varying doses of oleic acid (0.05 ml/kg for the mild group and 0.10 ml/kg for the severe group) via the ear vein. The goats' bilateral chest walls were divided into four lung regions: upper left

lower left

upper right

and lower right. LUS was conducted on the entire lung and each lung region before and at 1 h

3 h

and 6 h post-injury. Receiver operating characteristic (ROC) curves were generated to assess the diagnostic value of LUS in determining ALI severity at these time points. Arterial blood gas indicators (partial pressure of oxygen (PaO2)

oxygen saturation (SaO2)

and oxygenation index (PaO2/FiO2)) and tumor necrosis factor-α (TNF-α) were measured through blood gas analysis and inflammatory factor detection at each time point. The differences in these indicators between the mild and severe injury groups were compared. Subsequently

the goats were euthanized

and the entire lung was extracted for gross examination of lung injury. Lung tissue samples were subjected to pathological histological examination and pathological injury score determination. The lung wet-dry ratio was calculated to analyze the correlation between LUS in each lung region and the lung wet-dry ratio and pathological injury score. Results: One goat in the mild injury group succumbed 5 h after injury

while the remaining goats successfully established the oleic acid-induced goat ALI model. The LUS of the entire lung after injury exhibited a progressive increase over time

with the severe injury group demonstrating significantly higher LUS values than the mild injury group at 1 h

3 h

and 6 h post-injury (all P＜0.05). Partitioned LUS results revealed a statistically significant difference between the two groups in the right lower lung LUS at each time point post-injury (all P＜0.05). However

no statistical difference was observed in the LUS of the other three lung regions at each time point post-injury. The LUS of the left lower lung in the severe injury group was notably higher than that in the left upper lung after 6 h of injury. Additionally

the LUS of the right lower lung in the severe injury group was significantly higher than that in the right upper lung after 3 h and 6 h of injury (all P＜0.05)

with no statistical difference in the LUS of each area in the mild injury group. ROC curve analysis indicated that the area under the curve (AUC) of LUS predicting the severity of ALI in the entire lung at each time point post-injury was ＞0.8. The highest predictive efficacy was observed for the right lower lung LUS at 1 h post-injury (AUC=0.938)

although no statistical difference was found between the AUC values of each lung region at each time point. The differences in PaO2

SaO2

and PaO2/FiO2 between the mild and severe injury groups at 3 h and 6 h post-injury were statistically significant (all P ＜0.05). TNF-α increased gradually over time post-injury in both the mild and severe injury groups

but no statistical difference was observed compared to pre-injury levels. The lung wet-dry ratio in the severe injury group was significantly higher than that in the mild injury group (wet-dry ratio of the severe injury group: 7.36 ± 0.97; wet-dry ratio of the mild injury group: 5.86 ± 0.50) (P＜0.01). Furthermore

the pathological injury score of the entire lung in the severe injury group was significantly higher than that in the mild injury group (P＜0.05). Partitioned results revealed that the pathological injury score of the left lower lung and right lower lung in the severe injury group was significantly higher than that of the left upper lung and right upper lung

while the pathological injury score of the right lower lung in the mild injury group was significantly higher than that of the right upper lung (all P＜0.05). Correlation analysis demonstrated that LUS of the entire lung

left lower lung

right upper lung

and right lower lung at 6 h post-injury were positively correlated with the lung wet-dry ratio (all P＜0.05)

with the right lower lung exhibiting the highest correlation coefficient among all lung regions (r=0.634). Correlation analysis demonstrated that LUS of the entire lung

left lower lung

and right lower lung at 6 h post-injury were positively correlated with the pathological injury score of the lung (all P＜0.05)

with the right lower lung exhibiting the highest correlation coefficient among all lung regions (r=0.624). Conclusion: Lung ultrasound score (LUS) proves effective in promptly assessing the degree and progression of early lung injury in goats with ALI

offering valuable diagnostic insights. Variations in LUS exist among different lung regions

with a higher correlation observed between the right lower lung and the degree of lung injury.