通过复制油酸型急性肺损伤动物模型，观察胸部弥漫性"彗星尾"征与动脉血氧分压（PaO₂）变化的相关性。

选用肺超声检查均正常的日本大耳白兔21只，麻醉后心脏采血，检测动脉血气；随即按照0.1 ml/kg的剂量注射分析纯油酸，致兔肺出现弥漫性"慧星尾"征。分别在注射油酸后1、2、3、6、9、12、24 h经心脏采动脉血观察PaO₂测值。

6只实验兔在注射油酸1 h后采血，与制模前相比，4只实验兔PaO₂升高，2只测值未见明显改变；制模2 h、3 h、6 h后各采血实验兔一只，PaO₂均未见下降；制模9 h后采血2只，1只PaO₂升高，1只下降；制模12 h后采血5只，2只PaO₂升高，2只下降，1只制模失败；制模24 h后采血5只，与制模前相比，PaO₂均出现较明显的下降。光学显微镜下观察：注射油酸1~24 h处死的实验兔肺脏均出现肺水肿、肺淤血及淤血性出血（20/20）；其次为过敏性肺炎（15/20）；部分实验兔可见肺淤血性坏死（2/20）及小灶状、片状肺梗死（3/20）。24 h组与1 h组比较，实验兔肺水肿、肺淤血性出血的面积百分比的平均值随制模时间延长明显增加。

油酸型急性肺损伤动物模型的声像图改变及镜下病理改变早于PaO₂的下降，实验兔的代偿能力及个体差异致PaO₂下降的时间点不同；制模后24 h是PaO₂整体下降的时间点；肺部超声检查可用于急性肺损伤的早期影像学诊断。

To study the correlation between the changes of the chest diffuse comet-tail sign and arterial oxygen partial pressure (PaO₂) in oleic acid-induced acute lung injury model.

Twenty-one Japanese big-eared white rabbits with normal lung ultrasound examination were selected. After anesthesia, the heart blood was collected and the arterial blood was detected. Then the pure oleic acid was injected according to 0.1 ml/kg dosage, which caused the chest diffuse comet-tail sign in rabbit lungs in 1 h. The PaO₂ values were measured by collecting blood from the heart at 1 h, 2 h, 3 h, 6 h, 9 h, 12 h, and 24 h after injection of oleic acid.

Blood sample was collected in 6 experimental rabbits at 1 h after injecting oleic acid. 4/6 experimental rabbits had higher PaO₂ than that before the injection. No significant changes were found in the other two experimental rabbits. The blood test showed that PaO₂ did not decrease at 2 h, 3 h, 6 h after injection of oleic acid, respectively. Two blood samples were collected at 9 hours after injection of oleic acid. PaO₂ increased in one case, and decreased in the other case. After 12 hours of molding, 5 blood samples were collected. PaO₂ increased in 2 cases, decreased in 2 cases, and failed in 1 case. After 24 hours of blood collection, 5 rats were found to have a significant decrease in PaO₂ compared with that before the model. On microscope, the pathologic findings were as followed: pulmonary edema, pulmonary congestion, and congestive bleeding occurred in the lungs of rabbits sacrificed from 1 to 24 h after oleic acid injection; Some experimental rabbits appeared alveolar collapse, pulmonary congestion necrosis, lung infarction, pulmonary fibrosis, etc; 12 experimental rabbits appeared pleural folds, of which 2 cases presented at 1 h (2/6), 5 cases presented at 24 h (4/5), and 6 cases presented at 2~12 h (6/9). The presence of pleural folds increased with the time after oleic acid injection.

The changes on ultrasonography in animal model of oleic acid-induced acute lung injury were present earlier than that of PaO. The individual differences in the experimental rabbits may lead the decrease of PaO₂ at different time points. PaO₂ decreased in all cases till 24 hours after the modeling. Pulmonary ultrasonography can be used for early imaging diagnosis of acute lung injury.