Pulmonary surfactant films affected by solvent vapors.
Pulmonary surfactant obtained from rabbit lung lavage was evaluated with the pulsating bubble surfactometer. Because surfactant forms a monomolecular film at the air-liquid interface consisting mainly of phospholipids, solvent vapors, which might be inhaled, could have a destructive influence on the surfactant monolayer. To assess the risk of such an inhalation, vapors from five solvents--halothane, chloroform, enflurane, acetone, and diethyl ether--were made to flow into the bubble of the surfactometer as it pulsated for 30 sec, i.e., during 10 pulsations. The vapors from halothane and chloroform, excellent solvents of dipalmitoyl-phosphatidylcholine (DPPC), had a destabilizing effect evidenced by the fact that surface tension at minimal bubble size increased from 0 to as high as 20 mN/m. When the vapors were replaced with a flow of room air, the pressure tracing promptly returned to normal. The concentration of halothane vapor, however, had to be at least 20%, a concentration much higher than that used for anesthesia, to have a destabilizing effect on pulmonary surfactant. Twenty-five percent enflurane vapor had a less pronounced yet conspicuous impact. With 25% acetone and diethyl ether vapors, poor solvents of DPPC, surface tension at minimal bubble size remained unaffected. We conclude that vapors of halothane and chloroform, if inhaled in high concentration, might instantaneously obliterate the stabilizing effect of pulmonary surfactant but that anesthetic concentrations of halothane have no effect.
D000096:Acetone / Q000494:pharmacology; D000818:Animals; D002725:Chloroform / Q000494:pharmacology; D004737:Enflurane / Q000494:pharmacology; D004986:Ether / Q000494:pharmacology; D006221:Halothane / Q000494:pharmacology; D011663:Pulmonary Surfactants / Q000502:physiology*; D011817:Rabbits; D012997:Solvents / Q000494:pharmacology*; D013500:Surface Tension; D014835:Volatilization
D011663:Pulmonary Surfactants; D012997:Solvents; D004986:Ether; D000096:Acetone; D002725:Chloroform; D004737:Enflurane; D006221:Halothane