Proposal for a New Theory of Molecular Transport Across Membranes: Implications for Lung Gas Transference

Abstract

It has been proposed that water insoluble nonpolar gases are solubilized by lung surfactants. To test this hypothesis, aqueous dog lung preparations were made which contained increasing concentrations of surfactant. Solubilization was followed by placing samples in a Tonometer, admitting a nonpolar vapor, extracting gas samples and analyzing by gas chromatographic methods. Using oxygen, halothane, ether, and trichloroethylene, the results indicate that surfactant preparations in the micellar and coacervate states can readily solubilize the nonpolar gases. Little gas is dissolved by dilute aqueous lung or dilute synthetic surfactant solutions. The effect of powder particles accumulating on lung surfactant solutions was studied. The results showed that solid particles on the concentrated surfactant suspension reduced the ability to solubilize gas. From the above and from film balance studies of lung surfactant, a molecular mechanism of gas transfer across the aqueous alveolar film is proposed.