CHARACTERISTICS OF INFANTS WITH THREE PATTERNS OF NEONATAL CHRONIC LUNG DISEASE: A PRELIMINARY STUDY. † 1187

Neonatal chronic lung disease(CLD) has been defined as a compatible x-ray plus O₂ requirement at the latter of 28 days following birth or 36 weeks postmenstrual age. However, this definition recognizes neitherseverity of CLD, nor distinctly different patterns of this disorder in the post surfactant era. We believe these patterns are distinct and have significance for understanding the mechanisms of lung injury, and pathophysiology leading to the development of CLD.

Three patterns of CLD development were defined for research purposes and their frequency determined in 564 surviving infants of <2.0kg birthweight. Classic-CLD infants had acute respiratory distress within hrs of birth and continued to have a varying O₂ requirement to at least 28 days. RD-resolved-CLD infants had respiratory distress with an O₂ requirement for at least 4 hrs, recovered to room air for at least 72 hrs and required O₂ again after 7 days of age, continuing to at least 28 days. Delayed-CLD infants had no initial respiratory distress (O₂ less than 4 hrs on the day of birth), remained on room air until after 7 days and developed a persistent O₂ requirement until past 28 days.Table

Table 1

Late CLD without preceding respiratory distress, or following recovery from respiratory distress accounted for 27% of the CLD cases in <1kg infants, and 48% of the CLD cases in 1.0-1.25kg infants. These data suggest that oxygen therapy and surfactant deficiency are not the sole determinants of neonatal CLD, and that later events contribute to some forms of neonatal CLD.