[Exogenous surfactant therapy--what is established and what still needs to be determined].

OBJECTIVE To review well-known aspects of exogenous surfactant therapy, and to discuss controversial points regarding the current state of research. SOURCES Review of the literature, using Medline and Cochrane Database Library, in association with the authors' experience in relation to exogenous surfactant replacement therapy. SUMMARY OF THE FINDINGS The main aspects of surfactant characteristics: composition, pool, metabolism, inactivation and immediate effects after its administration are well established. However, there are some doubts related to the use of exogenous surfactants that need to be cleared up: choice of surfactant type, most appropriate length of treatment, adequate dose and number of doses, best administration route and complications associated with its use. Currently, the research about exogenous surfactant therapy focuses on two aspects: the use of surfactant in other pathologies besides the respiratory distress syndrome of the newborn, and the development of new surfactants through the addition of proteins or analogous proteins, with the aim of improving its action and reducing its inactivation. CONCLUSIONS The use of exogenous surfactant has become a routine in neonatal intensive care units, but both clinical and experimental research is still necessary.