探讨肺部超声诊断足月儿急性肺损伤(ALI)/急性呼吸窘迫综合征(ARDS)的临床价值。

选择2016年1月至2018年6月，成都市妇女儿童中心医院新生儿科收治的59例ALI/ARDS足月儿为研究对象，纳入研究组。按照罹患ALI或者ARDS，进一步将研究组受试儿分别纳入ALI亚组(n＝21)与ARDS亚组(n＝38)。选择同期于本院出生的健康足月儿62例，纳入对照组。对所有足月儿进行动脉血气分析，了解其动脉血氧分压与吸入氧气分数比(Pa_O2/Fi_O2)，并对其进行肺部超声检查，观察其肺部超声表现，并采用肺部超声评分评估其肺损伤程度。研究组与对照组受试儿肺部超声表现结果异常发生率[A线消失、彗星尾征、肺水肿、肺实变、胸腔积液、肺泡-间质综合征(AIS)]比较，采用χ²检验。ALI亚组、ARDS亚组和对照组足月儿的Pa_O2/Fi_O2值、肺部超声评分比较，分别采用Kruskal-Wallis H秩和检验和单因素方差分析。计算肺部超声表现及肺部超声评分诊断足月儿ARDS的敏感度、特异度等，并采用Kappa值评价肺部超声评分与ARDS诊断金标准，对所有足月儿的ARDS诊断结果的一致性。研究组与对照组足月儿的性别构成比、胎龄、出生体重等一般临床资料比较，差异均无统计学意义(P>0.05)。本研究遵循的程序符合成都市妇女儿童中心医院人体试验委员会所制定的伦理学标准，得到该委员会批准(批准文号：伦理审字[2014]5号)，分组征得足月儿监护人知情同意，并与其签署临床研究知情同意书。

①研究组患儿A线消失、彗星尾征、肺水肿、肺实变、胸腔积液、AIS发生率分别为84.7%(50/59)、100.0%(59/59)、67.8%(40/59)、96.6%(57/59)、91.5%(54/59)、88.1%(52/59)，均显著高于对照组的0(0/62)、6.5%(4/62)、0(0/62)、0(0/62)、4.8%(3/62)、8.1%(5/62)，并且差异均有统计学意义(χ²＝89.544、106.007、62.791、113.245、91.176、77.790，P<0.001)。②ALI亚组、ARDS亚组与对照组足月儿Pa_O2/Fi_O2值、肺部超声评分分别总体比较，差异均有统计学意义(χ²＝76.992，P<0.001；F＝78.721，P<0.001)，进一步两两比较的结果显示，ARDS亚组足月儿的Pa_O2/Fi_O2值显著低于ALI亚组和对照组，ALI亚组足月儿的Pa_O2/Fi_O2值显著低于对照组，ARDS亚组足月儿的肺部超声评分显著高于ALI亚组和对照组，ALI亚组足月儿的肺部超声评分显著高于对照组，并且差异均有统计学意义(P<0.017)。③与足月儿ARDS诊断金标准比较，彗星尾征、胸腔积液、肺实变这3种肺部超声表现联合诊断足月儿ARDS的敏感度和特异度均为100.0%。④采用肺部超声评分法对本研究121例足月儿进行ARDS诊断的结果显示，肺部超声评分法对ARDS诊断的敏感度为78.9%，特异度为95.2%，阳性似然比为16.4，阴性似然比为0.2; Kappa值为0.764，诊断一致性较高。

肺部超声检查对足月儿ARDS诊断具有重要意义，而且具有敏感度高、特异度强、及时、无场地限制等优势，有望成为临床诊断足月儿ARDS的有效检查手段。

To evaluate the clinical values of lung ultrasound in diagnosis of acute lung injury (ALI) / acute respiratory distress syndrome (ARDS) in full-term infants.

A total of 59 cases of full-term infants with ALI/ARDS who were admitted into the Department of Neonatology of Chengdu Women′s and Children′s Central Hospital were consecutively recruited into study group over a 30-month period from January 2016 to June 2018. And they were divided in ALI subgroup (n=21) and ARDS subgroup (n=38), respectively according to ALI or ARDS. Another 62 cases of healthy full-term infants who were born in our hospital during the same period were selected as control group. All the infants underwent arterial blood gas analysis to obtain the ratio of arterial oxygen partial pressure to fraction of inspired oxygen (Pa_O2/Fi_O2). All the infants were examined by lung ultrasound to observe the ultrasonic manifestations, and lung ultrasound score was conducted to evaluate the degree of lung injury. The incidence of lung ultrasonic abnormal manifestations such as A-line disappearance, comet tail sign, lung edema, lung consolidation, pleural effusion, and alveolar-interstitial syndrome (AIS) between study group and control group was compared chi-square test. Pa_O2/Fi_O2 values and lung ultrasound scores of the infants in ALI subgroup, ARDS subgroup and control group were compared by Kruskal-Wallis H rank sum test and one-way ANOVA, respectively. The sensitivity and specificity of lung ultrasonic manifestations and lung ultrasound scores in diagnosis of ARDS in full-term infants were calculated, and Kappa value was used to evaluate the consistency of diagnostic results of lung ultrasound scores with golden diagnostic criteria of ARDS. There were no significant differences between two groups in gender ratio, gestational age and birth weight (P>0.05). The procedures followed in this study were in line with the ethical standards formulated by the Human Trials Committee of Chengdu Women′s and Children′s Central Hospital, and were approved by the committee (Approval No. [2014]5). The informed consent for clinical research was signed with the guardians of every infant.

①The incidences of A-line disappearance, comet tail sign, lung edema, lung consolidation, pleural effusion, and AIS in the study group were 84.7% (50/59), 100.0% (59/59), 67.8% (40/59), 96.6% (57/59), 91.5% (54/59), 88.1% (52/59), respectively, which were significantly higher than those in control group 0 (0/62), 6.5% (4/62), 0 (0/62), 0 (0/62), 4.8% (3/62), 8.1% (5/62), and all the differences were statistically significant (χ²=89.544, 106.007, 62.791, 113.245, 91.176, 77.790; all P<0.001). ②There were statistically significant differences among ALI subgroup, ARDS subgroup and control group in Pa_O2/Fi_O2 values and lung ultrasound scores (χ²=76.992, P<0.001; F=78.721, P<0.001). The results of further comparison showed that the Pa_O2/Fi_O2 value of ARDS subgroup was significantly lower than those of ALI subgroup and control group, and Pa_O2/Fi_O2 value of ALI subgroup was significantly lower than that of control group, while lung ultrasound score of ARDS subgroup was significantly higher than those of ALI subgroup and control group, and lung ultrasound score of ALI subgroup was significantly higher than that of control group, and the above differences were statistically significant (P<0.017). ③Compared with the golden diagnostic criteria of ARDS, the sensitivity and specificity of the combination of comet tail sign, pleural effusion, and lung consolidation these three lung ultrasonic manifestations in diagnosis of full-term infants with ARDS both were 100.0%. ④The sensitivity and specificity of lung ultrasound score for diagnosis of ARDS were 78.9% and 95.2%, respectively. The positive likelihood ratio was 16.4 and the negative likelihood ratio was 0.2. Kappa value was 0.764, indicating high diagnostic consistency.

Lung ultrasound plays an important role in the diagnosis of ARDS in full-term infants. It has the advantages of high sensitivity and specificity, timeliness and without site limitation. It is expected to be an effective method for clinical diagnosis of ARDS in full-term infants.