Biexponential pulmonary clearance of 99mTc-DTPA induced by detergent aerosol.
We measured the pulmonary clearance of technetium-99m-labeled diethylenetriamine pentaacetatic acid (99mTc-DTPA) for 3 h after perturbation of the surfactant system by administration of the detergent dioctyl sodium sulfosuccinate in aerosol. Forty-two rabbits were anesthetized with pentobarbital sodium. Tracheostomies were performed, and the rabbits were mechanically ventilated. Increasing concentrations of detergent (0.125-2%) or vehicle were given for 5 min, and clearance measurements were performed immediately or 60 min after detergent administration. No animals developed respiratory distress. After vehicle, the clearance was monoexponential with a half-life of 153 min. Detergent induced a biexponential clearance with a rapidly clearing additional pool of radioactivity with a half-life of 5-15 min. The relative amount of radioactivity clearing rapidly increased with detergent concentration. The detergent effect was partly reversible. We conclude that detergent induces a biexponential clearance of 99mTc-DTPA by accelerating the transfer of tracer across the alveolocapillary barrier in a proportion of lung units in a dose-related manner.
Evander
E
E
Department of Clinical Physiology, University of Lund, Malmö, Sweden.
Wollmer
P
P
Valind
S
S
Sörnmo
L
L
John
J
J
Jonson
B
B
D000336:Aerosols; D000818:Animals; D001784:Blood Gas Analysis; D003902:Detergents / Q000008:administration & dosage / Q000494:pharmacology*; D004143:Dioctyl Sulfosuccinic Acid / Q000008:administration & dosage / Q000494:pharmacology; D008168:Lung / Q000378:metabolism*; D008954:Models, Biological; D011817:Rabbits; D012129:Respiratory Function Tests; D013501:Surface-Active Agents / Q000008:administration & dosage / Q000494:pharmacology; D016284:Technetium Tc 99m Pentetate / Q000493:pharmacokinetics*
D000336:Aerosols; D003902:Detergents; D013501:Surface-Active Agents; D004143:Dioctyl Sulfosuccinic Acid; D016284:Technetium Tc 99m Pentetate