Surfactant therapy failure identifies infants at risk for pulmonary mortality
A. Hamvas, T. Devine and F. S. Cole
Department of Pediatrics, Washington University School of Medicine, St. Louis, MO.
OBJECTIVE--To characterize the clinical features of infants who do not
respond to surfactant therapy. DESIGN--Patient series, chart review.
SETTING--Academic referral neonatal intensive care unit.
PATIENTS/SELECTION--Ninety-nine consecutive infants with respiratory
distress syndrome who received surfactant therapy and 107 infants from the
2 years prior to initiation of surfactant therapy matched for birth weight,
race, sex, gestational age, chronological age, and disease severity.
MEASUREMENTS/RESULTS--Oxygen index was used to quantitate response to
surfactant therapy. A 25% decrease in oxygen index 6 hours after the first
surfactant dose was significantly different from that of the matched
historical cohort (P = .04). Oxygen index decreased 25% or more in 49
infants, the response group, while oxygen index decreased less than 25% or
increased following therapy in the remaining 50 infants, the nonresponse
group. Pulmonary interstitial emphysema occurred more frequently in the
nonresponse group. The only deaths from pulmonary causes at 10 days of age
or younger occurred in the nonresponse group (n = 11).
CONCLUSIONS--Pulmonary processes unresponsive to surfactant therapy
contribute to morbidity and mortality in newborn respiratory distress
syndrome. Classifying respiratory distress syndrome as "surfactant
responsive" or "surfactant unresponsive" offers a scheme by which to
investigate alternative explanations and interventions for newborn
respiratory distress syndrome.
