Clinical use and efficacy of porcine surfactant for the treatment of RDS in infants with birth weight ≤1000 g: Experience of three years

Objective: Evaluate the clinical response to the first and subsequent doses of natural surfactant for the treatment of respiratory distress syndrome (RDS) in extremely low birth weight infants (ELBWI). Methods: Retrospective chart review of all ELBWI admitted to Neonatal Intensive Care Unit of Padova from July 1995 to December 1998 who received porcine surfactant for the treatment of RDS. Data collection included: (a) standard clinical variables (birth weight, gestational age, material steroid treatment, etc) (b) surfactant dosing), and (c) response to surfactant treatment as assessed by changes in the fraction of inspiratory oxygen (F102) and by the Oxygenation Index (OI). Outcome data (d) which included: death, duration of mechanical ventilation, duration of oxygen therapy, days in hospital stay, OI at 3,7 and 21 days of age, oxygen dependency at 28 days and at 36 week post conception were also collected. Data were analyzed by group comparison tests when comparing the groups that received one (S1), two (S2) or Three (S3) surfactant doses and by multiple regression for the "predictors" of the response to surfactant treatment and for the "predictors" of outcome. Results: Ninety-four ELBWI were evaluated. F1O2 at 12 hours after surfactant was reduced by more than one/third in 62% of the infants after the first dose, in 54% of the second doses and 61% of the third doses (non significant). S1, S2 and S3 groups had similar demographics and birth characteristics but the OI differed at 3 and 7 days (1.73±1.39, 3.34±2.15 and 6.45±5.23 at day 3 and 1.42±1.27, 1.98±1.83 and 4.03±3.91 at day 6 for S1, S2 and S3 respectively, p=0.003). The response of exogenous was not found to be a significant predictor in our multiple regression model for major outcome variables such as oxygen dependency at 28 d or 36 wk. Conclusions: In ELBWI in spite of the high percentages of good clinical response to the first, to the second and even to the third surfactant dose, response to surfactant treatment did not predict major general and respiratory outcomes.