Objective: To evaluate the pleurodesis and the lung damage caused by intrapleural silver nitrate or talc in an experimental model in rabbits to consider the use in human beings. Design: 112 rabbits were randomized to receive intrapleural 0.5% silver nitrate or 400 mg/kg talc slurry in 2 ml saline. Eight rabbits in each group were sacrificed 1, 2, 4, 6, 8, 10, or 12 months post injection. The degree of pleurodesis (gross pleural fibrosis and inflammation), lung damage (collapse and edema), and cellular infiltrates were graded on a 0 to 4 scale. Results: The intrapleural injection of silver nitrate produced a better pleurodesis than did the intrapleural injection of talc slurry. The lung damage was moderate 1 month after silver nitrate and greater than after talc. They were similar as from the second month. Conclusions: The better pleurodesis induced by silver nitrate persists for at least one year. The more evident lung damage after silver nitrate was mild with reversible changes which show a clear tendency to normalize with time. For these reasons, the efficacy of silver nitrate as a sclerosing agent in humans should be evaluated.

Keywords: Pleurodesis. Talc. Silver nitrate. Pleural effusion.