Direct interactions between nitrous oxide and exogenous pulmonary surfactant in vitro.

During inhalation anesthesia, lung alveolar and Clara cells are exposed directly to volatile anesthetic. Porcine-derived natural lung surfactant (Curosurf) was used for in vitro measurements of surface activity under exposure to N2O mixed with air at concentration used in prolonged anesthesia. The study suggests that prolonged use of N2O may be associated with increased value of the minimum surface tension and reduction of surface tension-bubble radius hysteresis obtained in the pulsating bubble surfactometer used in the experiments. These phenomena indicate the physicochemical inactivation of surfactant.