[Outcome of blood gas parameters during the first 24 years after Exosurf administration]

There is now good evidence that the clinical course of infants with respiratory distress syndrome can be improved by treatment with exogenous surfactant. However, optimal methods of giving such a treatment are still debated.

The arterial blood gases and the arterial/alveolar oxygen tension ratio (a/A) were recorded during the 24 hours following artificial surfactant (Exosurf) treatment in 400 newborns aged 25 to 42 gestational weeks. A positive response was defined by an a/A ratio > 0.22 or an increase in a/A ratio up to 25%.

After administration of the first dose, a positive response was obtained in 63% of cases during the first 6 hours and 11% during the 6 following hours. The response after the second dose was favourable in 75% of cases. At 24 hours after treatment, 36% of the infants had obtained an a/A ratio > 0.22.

Because of the 18% of infants who responded positively only after the second dose, administration of this dose seems justifiable even in case of non-response to the first dose. The quality of the response is related to the severity of the pulmonary illness but is independent of the gestational age.