Sonographic prediction of chronic lung disease in the premature undergoing mechanical ventilation

The aims of the study are to investigate the possible role of ultrasound (US) of the chest in predicting the development of chronic lung disease (CLD) in patients with hyaline membrane disease (HMD) and to determine the optimal age for the sonographic examination. One hundred and five consecutive prematures undergoing mechanical ventilation were prospectively studied by US of the chest. The US examinations were performed at birth and at least once a week until discharge from the neonatal unit. The sonographic patterns observed behind the diaphragm and their evolutions were recorded and correlated with the clinical and radiological data at day 28, which corresponds to the currently accepted limit for determining the presence of CLD. CLD is currently defined as oxygen dependency on day 28 with radiographic abnormalities. A diffuse retrodiaphragmatic hyperechogenicity was observed in all the patients with HMD. The hyperechogenicity resolved completely in patients with an uncomplicated clinical evolution. In contrast, in patients with CLD the hyperechogenicity resolved only partially, resulting in less diffuse and less extensive hyperechogenicity. Day 18 was the earliest day where the persistence of the abnormal retrodiaphragmatic hyperechogenicity was observed in 100 % of the patients presenting CLD at day 28. At that time, 95.2 % of the patients without abnormal hyperechogenicity showed uncomplicated evolution and no CLD. US can be a useful diagnostic tool to determine the occurrence of CLD and to predict as early as day 18 the prematures at risk for the disease.