PS-280Surface Film Fromation in Vitro By Infant And Therapeutic Surfactants: Role Of Surfactant Protein B

BackgroundEssential surfactant properties include transfer to gas-liquid interface, reduction of surface tension and film replenishment during respiratory cycles.ObjectiveTo compare component-specific film formation properties of infant and therapeutic surfactants.Design/methodsUsing a multiwell fluorescence assay, we compared maximal fluorescence (Max), time to reach Max (tMax) and phospholipid concentration for 1/2 maximal signal (1/2Max) for calfactant (CAL), poractant (POR), beractant (BER), colfosceryl palmitate (COL), with surfactant from immature infants with RDS. Dose-response studies were performed for addition of SP-B, albumin and budesonide.ResultsMax and 1/2Max values for CAL were higher/similar to those of rat surfactant. There were significant differences between CAL and other therapeutic surfactants for Max (CAL >COL >POR >BER) whereas 1/2Max were similar except for COL.In surfactant from 39 infant tracheal aspirates, 1/2Max was inversely correlated with SP-B content (p = 0.001). Addition of SP-B to samples with low endogenous content (