Different Causes of Respiratory Distress in Neonates at Different Gestational Ages

Abstract

Background: Surfactant replacement therapy has been widely used for the treatment of neonatal respiratory distress syndrome (NRDS). However, not all infants, especially near-term and term infants, with respiratory distress can achieve a satisfactory outcome despite intensive care and surfactant replacement therapy. Few studies have attempted to distinguish and analyze the causes of respiratory distress according to gestational age. Methods: A retrospective multicenter study was performed in 26 neonatal intensive care units (NICU) in China from 2011 to 2016. The therapeutic effect of surfactant therapy in infants at different gestational ages was compared. By comparing the differences in risk factors that are closely related to the severity of NRDS at different gestational ages, the cause of respiratory distress at different gestational ages was further analyzed. Results: In total, 1240 infants with NRDS were included in this study. Surfactant therapy was less effective in the near-term and term infants than that in the early preterm infants. Further analysis of the causes of respiratory distress at different gestational ages revealed that a gestational age of less than 30 weeks and a lack of prenatal corticosteroid use were closely related to the severity of NRDS in the early preterm infants. However, perinatal infection- and perinatal hypoxia-associated risk factors were closely related to the severity of NRDS in the near-term and term infants. Conclusion: The cause of respiratory distress in near-term and term infants differs from that in early preterm infants. Some newborn infants with respiratory distress may not have NRDS. Respiratory distress in early preterm infants is mostly due to primary surfactant deficiency, which belongs in the category of NRDS. However, respiratory distress in near-term and term infants is more likely related to perinatal infection and perinatal hypoxia and may belong to the category of NARDS. Trial Registration Number: NCT03385863 Funding: This trial was designed, organized and implemented by the first author and the corresponding author’s research center. Public funding was obtained from the Emergency Project of the National Science Foundation of China (No. 81741065) and Scientific Research Projects Unit of Chongqing (Project-cstc2016shms-ztzx13001) (Project-cstc2015shmszx1201114) Conflict of Interest: None of the authors have conflicts of interest to disclose. Ethical Approval Statement: See link in PDF.