PATHOLOGY OF THE LUNG IN SURFACTANT-TREATED NEONATES

Respiratory distress syndrome (RDS) is associated with prematurity-rel ated deficiency of surfactant. Surfactant replacement therapy has been used in premature infants to Prevent RDS or reduce its severity. In t his study we describe the pathology of the lungs after surfactant repl acement therapy. All the neonatal autopsies during the years 1989 and 1990 (n = 235) were examined. Infants greater-than-or-equal-to 31 week s gestation, with congenital anomalies or who lived more than 2 weeks were excluded from the study. Infants who had received intratracheal S urvanta, a modified surfactant extracted from cow lung (n = 14), were compared with infants who did not receive exogenous surfactant (n = 20 ). The two groups were statistically comparable in terms of weight, ge stational and postnatal age, and clinical management. H&E-stained lung sections were examined independently by two pathologists without know ledge of surfactant treatment status; any discrepancies in histologica l evaluation were resolved by joint review. Nine histological features were evaluated including hyaline membranes, necrosis of the epitheliu m, hemorrhage, edema, inflammation, metaplasia, arteriolar muscular hy perplasia interstitial fibrosis, and pulmonary interstitial emphysema (PIE). Histological changes were graded from 0 to 3+. When it was pres ent, cerebral periventricular-intraventricular hemorrhage (PVH-IVH) wa s graded 1-4. The presence or absence of sepsis and necrotizing entero colitis (AEC) were also determined. Comparisons between patient groups were performed using the Mann-Whitney U, Student's t and chi2 tests. The severity of hyaline membrane disease, PIE, and epithelial necrosis was less severe in the surfactant-treated group than in the untreated group. There were no differences between the two groups in the degree of pulmonary hemorrhage or in the incidence of PVH-IVH, sepsis, or NE C.