Respiratory distress syndrome in VLBW infants: changes in management and outcomes observed by the NICHD neonatal research network

Abstract

This article examines the impact of major changes in the prevention and management of respiratory distress syndrome on survival and respiratory morbidities in very low birth weight infants by examination of obstetric and neonatal variables from 15 years of National Institute of Child Health and Human Development (NICHD) Neonatal Network data on 14,494 infants of ≤ 30 weeks gestational age and ≤1500 g. Survival and bronchopulmonary dysplasia were plotted by gestational age and year to show changes coincident with the use of antenatal steroids and postnatal surfactant. Recent trends in bronchopulmonary dysplasia were examined with respect to changes in neonatal respiratory management and the incidence of other pulmonary complications. Surfactant use has steadily increased in infants ≤30 weeks gestational age since its widespread availability in 1990. Antenatal steroids were not widely used until after the 1994 National Institutes of Health (NIH) consensus statement. The percentage of infants receiving a full course of antenatal steroids increased after 1994, but appears to plateau after 1998; coincident with a marked decrease in the use of tocolytics. The proportion of infants 29–30 weeks’ gestation requiring no support increased after 1994, with fewer babies needing mechanical ventilation. This trend ended in 1999. Survival of infants ≥24 weeks improved steadily until 1997. The proportion of survivors requiring oxygen at 36 weeks postmenstrual age has increased since 1993–1994 in infants 24–28 weeks, and infants 29–30 weeks since 1998. There has been a steady increase in the diagnosis of PDA across all gestational ages since 1992. Pulmonary hemorrhage has shown an increased trend since 1998 in infants ≤28 weeks. Pneumothorax decreased in infants 25–30 weeks, from 1987 to 1998, with no clear trend beyond 1998. Postnatal steroid use peaked from 1995–1998, with markedly decreased use after 1998 in 24–26 week infants. The most dramatic improvement in survival and respiratory morbidity have occurred coincident with increased surfactant use since its availability in 1990. There were further improvements coincident with increased antenatal steroid use in 1994. These improvements have shown a plateau since 1998 and oxygen use at 36 weeks in survivors appears to be increasing across all gestational ages. These trends need to be examined further and standardized methods for determining oxygen requirement are needed.