The chest radiograph appearances of very premature infants at 36 weeks post-conceptional age

The chest radiograph of very premature infants at 36 weeks post-conceptiona l age (PCA) was evaluated with regard to the degree of hyperinflation and c ardiomegaly, and the presence of fibrosis/interstitial shadowing, cystic el ements, air bronchograms and opacification. The evolution of abnormalities was assessed by comparing the radiograph appearance at 36 weeks PCA with th at at 28 days post-natal age (PNA). Three scoring systems were used to dete rmine how any abnormalities present could be best quantified to reflect dis ease severity as determined by chronic dependency upon supplementary oxygen status. Chest radiographs at 36 weeks PCA from 60 infants (median gestatio nal age 26 weeks (range 24-28)) were studied. 47 infants also had radiograp hs at 28 days PNA. Only three infants had no chest radiograph abnormalities at 36 weeks PCA, although 24 infants were not dependent upon supplementary oxygen. The most common abnormalities were interstitial shadowing and hype rinflation, while cystic elements and cardiomegaly were rare. The radiograp hic appearance had deteriorated from 28 days PNA to 36 weeks PCA (p<0.05); more infants at 36 weeks PCA were hyperinflated (p<0.01). The chest radiogr aph appearances of infants who were dependent upon supplementary oxygen sco red higher than those who were not (p<0.01) using all three scoring systems . The system that assessed only the presence of interstitial shadowing, cys tic elements and hyperinflation had the highest specificity in identifying oxygen dependency beyond 36 weeks PCA and had the highest area under the re spective receiver operator characteristic curve. In conclusion, the majorit y of very immature infants have an abnormal chest radiograph appearance at 36 weeks PCA. The appearance can, however, be meaningfully scored by evalua ting only three abnormalities.