Improved Ventilation by Re-aeration of Atelectatic Regions with Exogenous Surfactant in Acute Respiratory Failure

Improved oxygenation, decreased ventilator requirements, and increased survival have been reported after tracheal administration of surfactant in premature infants with respiratory distress syndrome (RDS) [1]. It seems reasonable to assume that such improvement in gas exchange is caused by an immediate improvement in lung volumes and lung mechanics. However, studies in which respiratory compliance was calculated from tidal volumes (dynamic compliance) during mechanical ventilation in surfactant-treated infants did not show any immediate changes [2–4]. To understand the mechanisms behind the improved oxygenation after tracheal surfactant instillation, we first describe the normal function of the pulmonary surfactant system, then discuss the immediate effects of exogenous surfactant instillation on lung volume and lung mechanics by reviewing experimental and clinical findings.