Sevoflurane anesthesia deteriorates pulmonary surfactant promoting alveolar collapse in male Sprague-Dawley rats.

General anesthesia is frequently associated to transient hypoxemia and lung atelectasis. Although volatile anesthetics are safe and widely used, their potential role on anesthesia-induced pulmonary impairment has not been fully explored. In this study, we investigated the effect of volatile anesthetic sevoflurane on pulmonary surfactant composition and structure that could contribute to atelectasis. After 30 min of sevoflurane anesthesia, Sprague-Dawley rats showed increased levels of lyso-phosphatidylcholine and decreased levels of phosphatidylcholine associated with significant impairment in lung mechanics and alveolar collapse, but showed no deterioration of alveolar fluid reabsorption when compared to control group of rats anesthetized with pentobarbital. Exposure to sevoflurane altered the thermotropic profile of surfactant model membranes, as detected by fluorescence anisotropy. In this sense, sevoflurane-promoted fluidification of condensed phases could potentially impair the ability of surfactant films to sustain the lowest surface tensions. In conclusion, the observed changes in surfactant composition and viscosity properties suggest a direct effect of sevoflurane on surfactant function, a factor potentially involved in anesthetic-induced alterations in lung mechanics.