Effect of meconium on the surface properties of perflubron

Objective: Meconium passage with pulmonary aspiration in utero is associated with surfactant inactivation and is a major cause of neonatal morbidity and mortality. Ventilation with low surface tension perfluorocarbon in animal models of meconium aspiration has been shown to improve both oxygenation and lung compliance. Exogenously administered surfactant is inactivated by meconium. We wished to determine whether meconium would alter the surface properties of perfluorooctyl bromide (perflubron). Design: Biophysical analysis using novel methods. Setting: University research laboratory. Subjects: Healthy newborns. Interventions: First pass meconium was obtained from healthy newborns. Measurements and Main Results: We evaluated the surfaceactive properties of perflubron after exposure to meconium-saline dilutions using the de Noüy ring distraction technique to measure interfacial tension and the sessile contact angle of meconiumsaline suspensions. Both were assessed in the absence and presence of perflubron. Meconium-saline suspensions inhibited surfactant activity. In contrast, the surface properties of perflubron were unaffected by the presence of meconium-saline suspensions. Conclusions: These data are consistent with reported observations of increased lung compliance in perfluorocarbon-treated animals with meconium aspiration. In addition to these clinical implications, the novel interfacial tension technique described here could prove useful for assessing the interfacial properties of other poorly miscible biological fluids.