Abstract
Systemic volume changes during acute lung injury (ALI) are closely related to lung injury severity, disease progression, and treatment methods. Twenty-one goats were divided into control, mild injury, and severe injury groups via oleic acid injection. Carotid ultrasound measured carotid diameter and corrected flow time (FTc), while cardiac ultrasound assessed aortic and pulmonary artery velocity-time integral (VTI). Post-euthanasia at 6 h, lung wet-to-dry (W/D) ratio and pathological scores were analyzed. Statistical trends, correlations between ultrasound parameters and lung injury markers, and diagnostic performance via ROC analysis were evaluated. The severe injury group had significantly higher lung W/D ratios and pathological scores than the mild injury group. Carotid ultrasound showed a progressive decrease in carotid diameter and FTc post-injury, with FTc significantly lower in the severe injury group at 6-h. FTc was negatively correlated with lung W/D ratio and pathological scores. Cardiac ultrasound indicated a decreasing trend in aortic and pulmonary artery VTI post-injury, with pulmonary artery VTI significantly lower in the severe injury group at all times and negatively correlated with lung W/D ratio and pathological scores. ROC analysis showed that pulmonary artery VTI had the highest area under the curve (AUC), with values greater than 0.8 at all time points. The combined use of pulmonary artery VTI and carotid FTc had AUC values greater than 0.85 at all time points, peaking at 6-h (AUC = 0.951). In conclusion, pulmonary artery VTI is an excellent indicator for evaluating ALI severity post-injury, and the combination of pulmonary artery VTI and carotid FTc shows strong diagnostic performance for assessing ALI severity.