Antenatal modes of surfactant administration for RDS prevention: a review.
OBJECTIVE: To review the body of international literature regarding lung surfactant supplements in order to determine: 1) the current knowledge of the antenatal routes of administration of surfactant supplements; 2) in-utero, antenatal, endotracheal surfactant treatment; 3) if antenatal, intraamniotic or oral administration of surfactant supplements has an equal therapeutic effect in the prevention of respiratory distress syndrome as endotracheal, postnatal administration. STUDY DESIGN: The appropriate medical subject heading terms were selected and applied in a search of the Medline and ACOG online databases. Articles focusing on fetal breathing, the fetal swallowing mechanism of amniotic fluid and the route of supplementary surfactant administration in both animal and human studies were reviewed. RESULTS: This review determined that an antenatal approach to supplementary surfactant administration has been attempted in both animal and human studies. Recent endeavors included attempts at antenatal routes of administration involving delivery into the mouth of the fetus or into the intraamniotic fluid around the mouth or nostrils. The therapeutic effect has proven inconclusive in its benefits. CONCLUSION: In-utero, oral delivery of surfactant supplements has been documented; however, the mechanism of absorption from the gastrointestinal tract by the lung tissue is difficult to determine, and the level of postnatal surfactant in the endotracheal fluid was not assessed. In-utero, intraamniotic surfactant installation was noted in the literature; however, the level of surfactant in endotracheal fluid was also not documented postnatally. No study or technique presented a description or model for antenatal, endotracheal surfactant supplement administration.