Surfactant replacement in severe RDS: effects of perinatal acidosis on therapeutic response

Respiratory distress syndrome (RDS) is still a major cause of morbidity and mortality in the neonatal period. Apart from immaturity of the surfactant system there are numerous conditions that can put infants at risk of developing RDS. From the clinical point of view it is virtually impossible to differentiate between RDS based on primary surfactant deficiency and RDS triggered or aggravated by other clinical conditions. It seems that some patients that we consider to have neonatal RDS really suffer from adult RDS even in the neonatal period [1–4].