AEROSOL CHARACTERISTICS OF TC-99M-PENTETIC ACID (DTPA) AND SYNTHETIC SURFACTANT (EXOSURF)

This study evaluated the feasibility of using Tc-99m-pentetic acid (DTPA) as a radioactive tracer for aerosolized synthetic surfactant (DPPC, cetyl alcohol, tyloxapol). The Tc-99m-DTPA was admired with surfactant and aerosolized using a nebulizer system interfaced to a ventilator with a cascade impactor attached to the endotracheal tube. Particle size distribution for DPPC, cetyl alcohol, and Tc-99m-DTPA were almost identical during the 0- to 15-, 15- to 30-, and 0- to 30-min collection periods. Tyloxapol exhibited a unique distribution pattern with increased deposition in large (>10 mu m) and small (0.65 to 1.1 mu m) particles. The mass median aerodynamic diameter for all aerosolized components was in the respirable range of 2.1 to 2.5 mu m. A mixture of Tc-99m-DTPA with synthetic surfactant appears to be a reasonable method to evaluate surfactant deposition.