Abstract
Introduction: Surfactant dosing in extremely premature infants is not based on rigorous human pharmacokinetic data. Beractant (Survanta®) is an animal-derived surfactant. The manufacturer's package insert suggests a dosing interval of "no sooner than 6 hours" after a preceding dose. Other animal-derived surfactant preparations are commonly dosed at 12 hour intervals. We evaluated Survanta use following a change in the re-treatment dosing interval from no less than 6 (Q6 h) to no less than 12 hours (Q12 h) in June 2007.
Method: We used a retrospective comparison of two cohorts, Q6 h and Q12 h, born at <31 weeks' gestation or with birth weights < 1100 grams treated with Survanta for respiratory distress syndrome (RDS). Infants could receive up to 4 doses, if clinically indicated.
Results: Infants in the Q12 group (n=77) and the Q6 group (n=140) had similar birth weight (mean ± SD; 1079 ± 351 vs. 1117 ± 326 g, p=0.44), birth in a tertiary center (inborn) (84% vs. 84%, p=1.0), prenatal treatment with steroids (88% vs 81%, p=0.17), Cesarean section delivery (78% vs. 73%, p=0.51), and singleton birth (64% vs. 62%, p=0.93). However, infants in the Q12 group had a slightly lower gestational age (mean ± SD; 27 ± 2 vs 28 ± 2 wk, p=0.014) and had a higher proportion of male infants (62% vs 48%, p=0.047.The Q12 group also had a higher but not statistically significant proportion of white infants (82% vs. 69%, p=0.053) than the Q6 group. Infants in the Q12 group received fewer surfactant doses per patient (mean ± SD; 1.91 ± 0.54 vs. 2.11 ± 0.63, p=0.018) and less frequently received more than two doses of surfactant (8% vs. 21%, p=0.012) compared to the Q6 group. The Q12 and the Q6 groups had similar rates of chronic lung disease (CLD) (23% vs. 18%, p=0.25), death (18% vs. 14%, p=0.44), duration of mechanical ventilation (mean ± SD; 21 ± 21 vs. 18 ± 25 days, p=0.477), and total hospital length of stay (mean ± SD; 58 ± 39 vs. 59 ± 33 days, p=0.94).
Conclusions: Administering Survanta to premature infants at 12 hour intervals was associated with using less surfactant to treat RDS compared to dosing at 6 hour intervals and similar measured respiratory parameters, including duration of hospitalization and mechanical ventilation and rates of death and CLD. We speculate that using a longer Survanta dosing interval would also result in significant cost savings.