Lung ultrasonography of pulmonary complications in preterm infants with respiratory distress syndrome

Abstract

Aim: To evaluate the diagnostic possibilities of lung ultrasonography (LUS) in detecting pulmonary complications in preterm infants with respiratory distress syndrome (RDS).

Material and methods: A prospective study included 120 preterm infants with clinical and radiographic signs of RDS. LUS was performed using both a transthoracic and a transabdominal approach within the first 24 h of life, and, after that, follow-up LUS examinations were performed. In 47 detected pulmonary complications of RDS (hemorrhage, pneumothorax, pneumonia, atelectasis, bronchopulmonary dysplasia), comparisons between LUS and chest X-ray (CXR) were made. Also, 90 subpleural consolidations registered during LUS examinations were analysed. Statistical analysis included MANOVA and discriminant analysis, t-test, confidence interval, and positive predictive value.

Results: In 45 of 47 instances the same diagnosis of complication was detected with LUS as with CXR, indicating a high reliability of the method in premature infants with RDS. The only two false negative findings concerned partial pneumothorax. The positive predictive value of LUS was 100%. A statistically significant difference of LUS findings between the anterior and posterior lung areas was observed in both right and left hemithoraces.

Conclusions: LUS enables the detection of pulmonary complications in preterm infants with RDS and has the potential to reduce the number of CXRs. The specific guidelines for its use should be provided in a more extensive study.

Figure 1.

Normal lung US finding in a longitudinal section.

Figure 2.

Dichotomous branching of the peripheral bronchioles within the subpleural consolidation.

Figure 3.

Two microabscesses (dotted arrows) with the greatest diameter of 7 mm.

Figure 4.

Parallel air bronchogram (arrows) within the pulmonary consolidation (C) of passive atelectasis due to large amount of pleural effusion (PE).

Figure 5.

Four basic patterns of the lung US findings (IE = interstitial edema; AIE = alveolar-interstitial edema).

Figure 6.

Examined lung areas in supine (A) and lateral decubitus (B) positions (H = transhepatic approach; S = transsplenic approach; Ar = anterior right, Al = anterior left, Lr = lateral right, Ll = lateral left, Pr = posterior right, and Pl = posterior left lung areas).

Figure 7.

Inability of the US to differentiate between subpleural consolidations stemming from: pneumonia (left image), atelectasis (middle image), and hemorrhage (right image).