The aim of this study was to demonstrate that administration of the second dose of beractant 2 h after the first one is more effective than 6 h after the initial dose. The inclusion criteria for the recruitment of newborn infants were: age < or = 8 h, birthweight 600-2000 g, gestational age 23-36 wk, need for mechanical ventilation with inspiratory oxygen fraction (FiO2) > or = 0.4 and mean airway pressure (MAP) > or = 7 cmH2O to obtain arterial oxygen tension (PaO2) values between 70 and 80 mmHg, and thoracic X-ray compatible with hyaline membrane disease (HMD). Newborns with major congenital malformations, hydrops fetalis or severe pulmonary hypoplasia, or being treated with high-frequency oscillatory ventilation were excluded. In total, 57 premature newborns were studied, 20 of them below 1000 g, who received 100 mg kg-1 of beractant in 2 aliquots and showed an inadequate response, i.e. after 2 h of the first dose the newborn still needed a FiO2 > or = 0.4 and a MAP > or = 7 cmH2O to achieve a PaO2 > 70 mmHg. The second dose was randomly administered 2 or 6 h from the first one.
Conclusion: The 2 study groups were comparable except for a higher need of dopamine and seroalbumin in 2-h group. Evolution and complications were similar. Twelve hours after the first dose, the percentage improvement in the arteriolar/alveolar ratio (a/ADO2) in the 2-h group was similar to that in the 6-h group. However, in newborns below 1000 g, 12 h after the first dose the a/ADO2 percentage improvement in the 2-h group was greater than in 6-h group (median of 103.6% vs 16.3%; p = 0.035). In premature infants below 1000 g, it seems reasonable to advance the second dose of beractant if needed.