Comparisons of pleurodesis induced by talc with or without thymol iodide in rabbits

At the present time, talc administered either as a slurry or an aerosol is a popular agent for producing pleurodesis. Some investigators use iodized talc while others use plain talc. The purpose of the present study was to determine if iodized talc slurry produced a better pleurodesis in animals than did plain talc.

New Zealand white male rabbits were randomly assigned to receive talc slurry, 200 mg/kg, with or without the addition of 50 mg iodide intrapleurally. Approximately 10 rabbits in each group were killed 1, 2, 4, 7, 14, and 28 days after the injection. The amount and character of pleural fluid, the degree of pleural adhesions, and the microscopic changes were compared in the two different groups.

The pleural fluid findings, the gross adhesion score for the pleura, and the microscopic changes in the visceral pleura were essentially identical for the rabbits that received iodized talc and those that received plain talc. The injection of both plain talc and iodized talc produced a normoglycemic exudative pleural effusion that had, for the most part, disappeared by the fourth day postinjection. The amount of pleural fluid at 48 h was 3.3+/-0.6 mL in the plain talc and 2.2+/-0.5 mL in the iodized talc group. At 28 days, the mean degree of gross pleurodesis in the talc group was 2.6+/-0.2 compared with 2.3+/-0.2 in the iodized group, while the mean degree of microscopic fibrosis was 1.4+/-0.3 in the plain talc group compared with 2.0+/-0.3 in the iodized talc group.

From this study, we conclude that the addition of 50 mg of iodide does not improve the results with talc slurry pleurodesis in rabbits.