Distribution of calibrated talc after intrapleural administration - An experimental study in rats

Study objective: Many reports have shown that tale is the most effective and least expensive agent for the creation of a pleural symphysis. However, its use still remains controversial due to severe acute respiratory side effects possibly related to the systemic dissemination of tale particles. The purpose of this study was to assess the distribution of calibrated talc after intrapleural administration in rats. Material and methods: Thirty-seven Wistar male rats were randomly assigned to undergo pleurodesis by tale slurry (33 rats) or by simple chest tube drainage (control group; 4 rats). Forty milligrams of calibrated tale suspended in 1 mL sterile saline solution was injected into rats in the treated group. The animals were randomly assigned for autopsy at 24 or 72 h after pleural injection. Lungs, parietal pleura, diaphragm, liver, kidneys, spleen, pericardium, brain, and blood were assessed by polarized light for birefringent tale particle detection and counting. Results: No deaths were observed. The autopsies showed no pleurodesis at 24 and 72 h. Despite high doses of tale (extrapolated from the dose of 10 g in a 70-kg adult man), few talc particles were found in the liver of two rats, in the spleen of one rat, and only one particle of tale was observed at the brain surface of the rat studied by scanning electron microscopy. No particles were found in the other organs, in particular in the contralateral lung and blood, contrasting with previously published results using nonealibrated tale particles. Conclusions: The lack of systemic dispersion of tale particles, with the packaging talc we currently use in our clinical practice, is probably due to the size of the talc particles, which are larger than the other tale preparations. Calibrated tale is required in case of intrapleural administration for pleurodesis to avoid systemic dissemination and potential secondary acute respiratory failures.