Factors influencing the clinical response to surfactant replacement therapy in babies with severe respiratory distress syndrome

Abstract

Clinical data from a total of 164 babies with severe respiratory distress syndrome treated with a single dose of porcine surfactant (Curosurf, 200 mg/kg body weight) were subjected to multiple regression analysis in order to identify factors influencing the response to replacement therapy. At entry all babies were being treated with artificial ventilation, requiring at least 60% oxygen; the first 77 babies were part of a controlled trial, and an additional 87 babies were treated without controls once the benefit of surfactant therapy had been established. Both series of patients showed a sustained doubling of the mean arterial/alveolar oxygen tension ratio (a/APO2) after treatment with surfactant. Mortality was only 15% in the new series of treated patients, and the number of survivors without evidence of chronic lung disease after 28 days remained twice as high as that of the control group in the randomized study (55% vs. 26%; P less than 0.001). High fraction of inspired oxygen requirement at entry had a negative impact on a/APO2 6 h and 24 h after treatment. The duration of artificial ventilation and total time in greater than 21% oxygen were lower in heavier babies, who also had a lower mortality. Male and outborn babies had a higher mortality. Perinatal asphyxia (Apgar score less than 7 at 5 min) and high airway pressure requirement at entry were associated with increased mortality. Hospital allocation had a significant impact on all dependent variables. We also analysed the incidence of complications in relation to the therapeutic response pattern.(ABSTRACT TRUNCATED AT 250 WORDS)