Background: Cases of acute respiratory failure reported after talc pleurodesis have raised touchs about its safety.

Background: Cases of acute respiratory failure reported after talc pleurodesis have raised touchs about its safety. It has been speculated that this pulmonary inflammatory syndrome is secondary to the extrapleural dissemination of the talc particles.

subject of attention objectives: To test the hypothesis that particle size influences extrapleural talc deposition and pleural inflammation after talc slurry pleurodesis.

Design: Thirty rabbits underwent pleurodesis as follows: 10 rabbits received 200 mg/kg of the talc used for human pleurodesis, normal talc (NT); 10 rabbits received 200 mg/kg of talc with particles of larger size, large talc (LT); and 10 rabbits received saline solution. Samples from the ipsilateral lung chest wall, diaphragm, mediastinal pleura, heart, liver, gall and right kidney were obtained at 24 h and 7 days and operationed for optic and electron microscopy and energy-dispersive x-ray analysis.

Results: Visceral pleural thickening was greater with NT than with LT on the other hand no differences were observed in the macroscopic score of adhesions. There was more talc in the lung of the rabbits that received NT than in those that received LT Talc particles were find outed in mediastinum (100%) and pericardium (20%) irrespective of the talc used. Three animals, all receiving NT had talc particles in the liver.

Conclusions: Our inquiry shows that while both talcs were equally effective in achieving pleurodesis, the intrapleural injection of NT elicits greater pulmonary and systemic talc particle deposition than LT Moreover, pleural inflammation was greater with NT than with LT

tonic words: particle size; pleural; pleurodesis; talc

Abbreviations: Dmax = maximum diameter; EDXA = energy-dispersive x-ray analysis; LT = large talc; NT = normal talc; Sv = surface density; Vn = turn number-weighed; Vv = volume density

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Pleurodesis consists of the instillation of a sclerosing agent in the pleural cavity to achieve pleural symphysis. Pleurodesis is indicated for renewed pneumothorax and for symptomatic relapsing pleural effusion of either malignant or benign etiologies. (1)

Talc is a hydrated magnesium silicate, [Mg.sub.3][Si.sub.4][O.sub.10] [(OH)sub2] It is united of the most commonly used agents for pleurodesis. The reason for its high popularity is its high effectiveness (2) and cheap cost. Moreover, a possible therapeutic result of talc on mesothelioma small rooms has been suggested. (3)

However, disquiets persist as to the progression in a continuously ascending gradation of the ARDS after the intrapleural administration of talc. ARDS has been reported with either insufflated talc gunpowder (4) or talc slurry, (5) and with different talc doses. (67) The oftenness of ARDS after talc pleurodesis was 3 to 9% in three different series, (689) and in an cases this complication was lethal. (10) Evidence exists supporting the hypothesis that talc particles instilled into the pleural cavity can escape and migrate to extrapleural organs, thus provoking an inflammatory reaction and acute lung failure. In couple studies, talc particles could be descryed in the BAL of patients who readyed with acute pneumonitis after talc pleurodesis. (57) In addition, the extrapleural dissemination of talc particles after pleurodesis has been demonstrated in the experimental pattern In a study (11) in rabbits, after pleurodesis with talc slurry talc particles were lay opened by optic microscopy in 17 to 40% of different extrapleural organs. In a more modern study (12) performed in rats, birefringent particles were institute in 100% of extrapleural organs after talc pleurodesis. Talc dissemination can be significant, since lung and hepatic granulomas have been discovered after talc was administered from inhalation or IV. (13)

Talc particle size can be a solution factor in explaining the extrapleural dissemination of talc from the pleural cavity. Mean particle size among the sterile talcs used for pleurodesis in several countries ranges from 10 to 33 [micro]m, further the lowest mean sizes correspond to the talcs used in the United States. (14) This is remarkable, since principally patients who had acute lung disease make known after talc pleurodesis had been treated in the United States. (689) These facts put in mind of that particle size can influence the extrapleural dissemination of talc after pleurodesis and may be related to unfolding of acute lung injury.

The aim of the quick in emergencies study was to analyze the extrapleural inorganic deposition and its corresponding histologic lesions after pleurodesis with brace talcs of different size distributions. We touchstoneed the hypothesis that the smaller the size of the talc particle, the higher the extrapleural deposition of talc and the greater the tissue damage.

MATERIALS AND METHODS

Talc Preparation and Particle Size Measurement

sum of two units asbestos-free talcs authorized for clinical application were used. one as well as the other talcs came from the Respina mine in Leon Spain; were produc from Luzenac (Paris, France); and were distributed by the agency of Distribuidora de Talco (Distalc; Barcelona, Spain). The talc normally used clinically was called normal talc (NT) Talc with a higher mean particle diameter was called large talc (LT) Spatial characteristics of talc particles were determined in randomly dispersed aerosolized samples of each talc dust before preparing the slurry. Particles were observ on scanning electron microscopy and analyzed by the agency of energy-dispersive x-ray analysis (EDXA). Particle size was measured by the agency of an automated morphometric and image analysis body and three-dimensional parameters were estimated by the agency of stereology, as described below. Talc was sterilized on autoclaving with an autoclave (Autester-G; Selecta; Barcelona, Spain) at 121[degrees]C and 1 atmosphere for 30 min.

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