Dysfunction of pulmonary surfactant is one of the key pathogenic features in meconium aspiration syndrome. Surfactant function may be affected by components of meconium, by inflammatory mediators (e.g., tumor necrosis factor alpha and interleukin-1), proteolytic enzymes, phospholipase A2, reactive oxygen species, and by plasma proteins leaking into the alveolar space. Administration of exogenous surfactant may at least partially alleviate the inactivation of pulmonary surfactant present in meconium aspiration syndrome. In experimental and clinical studies, intratracheal administration of a surfactant bolus significantly improved both lung function and survival. However, some patients are non-responders and there is only transient improvement in oxygenation. A repeat dose of surfactant may be required in these patients. Bronchoalveolar lavage with diluted exogenous surfactant is another technique for surfactant administration that may be more effective in partially removing meconium from the lungs, and thereby reducing surfactant inhibition, inflammation and mechanical obstruction of the airways. There is also a growing body of evidence suggesting that exogenous surfactant may be more effective when combined with pulmonary vasodilators, anti-inflammatory and antioxidant treatment.
Keywords: Surfactant; animal models; meconium aspiration; newborns.