Antenatal steroid exposure and pulmonary outcomes in adolescents born with very low birth weight.

OBJECTIVE: To compare asthma history and pulmonary function in adolescents born prematurely with very low birth weight with and without antenatal steroid exposure. STUDY DESIGN: We studied 188 fourteen-year olds (94 exposed, 84 male). We used parent report to ascertain asthma and asthma-related symptoms and spirometry to assess pulmonary function. Steroid-exposed and -unexposed groups were compared using Mann-Whitney U-tests (continuous variables), χ(2) analysis (categorical variables) and logistic regression (multivariate analyses). RESULT: The steroid-exposed group had greater prevalence of larger airway obstruction (35% vs 21%), and steroid-exposed adolescents with birth weights <1000 g had 4.5-fold higher odds of larger airway obstruction. Wheezing in the past 12 months was two times as prevalent in steroid-exposed adolescents with birth weights between 1000 and 1500 g. CONCLUSION: Antenatal steroid exposure does not provide long-term benefits for pulmonary outcomes in adolescents born prematurely with very low birth weight in the era of surfactant therapy.

The cytologic evaluation of lipid-laden alveolar macrophages as an indicator of aspiration pneumonia in young children.

Gastroesophageal reflux with aspiration of feedings in infants and young children may be involved in the development of chronic lung damage. Our laboratory has utilized tracheal aspirates stained with oil red O to identify and quantitate lipid-laden alveolar macrophages as a marker of such aspiration. During the last 10 years, we have evaluated 244 tracheal aspiration smears in children. Although a few patients were up to 3 years old, the vast majority were infants. The cytologist looked for the presence of and the number of oil red O-positive macrophages on tracheal aspirate smears. The specimens were easily assigned grades of absent (grade = 0), low positive (grade 1: 1-25 lipid-laden macrophages), moderate positive (grade 2: 26-50 lipid-laden macrophages), and high positive (grade 3: > 50 lipid-laden macrophages). The grade was then correlated with the positive or negative clinical diagnosis of gastroesophageal reflux with aspiration. We believe the cytologic evaluation and grading of oil red O-stained tracheal aspirates for lipid-laden macrophages is valuable in identifying these patients with gastroesophageal reflux and aspiration.

Response to Haemophilus influenzae type b conjugate vaccine in chronically ill premature infants.

Twenty-two premature infants with chronic lung disease (median gestational age 28 weeks) received polyribosylribitol phosphate-outer membrane protein conjugate Haemophilus vaccine at 2 and 4 months of chronologic age. The proportions with antibodies to polyribosylribitol phosphate at levels > 1 microgram/ml after doses 1 and 2 were 27% and 55%; geometric mean titers were 0.43 and 0.73 microgram/ml, significantly lower than values for term infants.

Effect of elevated atrial pressure on plasma renin activity in hypotensive fetal lambs.

In adults, renin secretion is stimulated by reductions in arterial pressure and inhibited by increases in atrial pressure. In the late gestation fetus, a fall in arterial pressure stimulates renin secretion, but it is unknown whether elevation of atrial pressure will alter such an increase. Therefore we studied the effect of elevated atrial pressure on renin secretion in the presence of nitroprusside-induced arterial hypotension. Thirteen fetal lambs at 127.9 +/- 0.9 days of gestation were prepared 5 days before study with inflatable pulmonary artery occluders and right atrial, vascular, and amniotic catheters. Each fetus underwent two protocols (hypotension and hypotension with occlusion) using a randomized block design. Nitroprusside reduced arterial pressure by 34% in both groups. Right atrial pressure during the course of hypotension was significantly higher in the occlusion group (F = 14.2, P = 0.001). Plasma renin activity increased similarly in both groups during hypotension (F = 6.0, P = 0.003). Elevated right atrial pressure did not alter hypotension-induced renin secretion in the fetus.