Seasonal respiratory viral infections. Impact on infants with chronic lung disease following discharge from the neonatal intensive care unit

J. S. Kinney, C. M. Robertsen, K. M. Johnson, M. Gaddis, R. Wheeler, M. A. Jackson and D. K. Daily
Section of Neonatology, Children's Mercy Hospital, University of Missouri-Kansas City.

OBJECTIVE: To determine the frequency and severity of acute respiratory infections in infants with bronchopulmonary dysplasia following discharge from the neonatal intensive care unit. DESIGN: A prospective cohort study of 30 oxygen-dependent children who were younger than 2 years (mean age, 9.8 months; range, 3 to 24 months) were studied from September 1990 through April 1991. MEASUREMENTS/RESULTS: During the study, 101 (90.2%) of 112 visits for illness were prompted by new or worsening respiratory symptoms. Diagnoses included upper respiratory tract infection (30.4%), otitis media (26.0%), pneumonia (11.1%), acute exacerbation of bronchopulmonary dysplasia (10.4%), reactive airway disease (9.6%), and bronchiolitis (5.9%). Among these children, an increase in the fraction of inspired oxygen was necessary during 43% of visits. Ten children were hospitalized on 25 occasions for a mean of 37.6 hospital days per child (range, 1 to 107 days), and mean length of stay for each hospitalization was 15 days (median, 6 days). Five children were admitted to the pediatric intensive care unit. Respiratory viruses isolated included respiratory syncytial virus (n = 7), parainfluenza 3 virus (n = 3), and adenovirus (n = 2). No isolates of influenza A or B were detected. Anthropometrics at study entry and study end were converted to z scores as descriptors of weight for age, height for age, and weight for height. Growth improved during the 8 months of the study; however, overall, the children were leaner at study end than at study entry. CONCLUSIONS: In children with bronchopulmonary dysplasia, respiratory viral infections led to significant morbidity, which included long and frequent hospitalizations during the peak of the respiratory viral season. Although weight and linear growth increased throughout the study, patients were leaner at study conclusion than at study entry.