Pleurodesis is a useful therapeutic tool when local treatment of a recurrent malignant pleural effusion or pneumothorax is needed. We have previously demonstrated that the intrapleural injection of 0.5% silver nitrate (SN) produces a significant pleurodesis, while 0.25% SN has no sclerosing effect in a rabbit model. The objective of this study was to determine the minimum concentration of SN needed to induce pleurodesis in our experimental model. One hundred twenty male New Zealand white rabbits received 0.3, 0.4, or 0.5% SN (40 animals per group) in a total volume of 2 mL instilled intrapleurally. These animals were sacrificed 3, 7, 14 or 28 days after the intrapleural injection (n = 10 animals per group), and the pleural spaces were then assessed grossly for evidence of pleurodesis and microscopically for evidence of fibrosis and inflammation. By 28 days, all concentrations of SN had produced a pleurodesis. There was evidence of a gross pleurodesis 7 days post-injection in animals that received 0.5% SN (score of 2.8 +/- 0.2 on a scale of 0-4). After 14 days, significant pleural adhesions were evident in the groups that received 0.4 or 0.5% SN. We conclude that SN concentrations as low as 0.3% can effectively produce a pleurodesis within 28 days of intrapleural injection. However, the precocious pleurodesis development observed 7 days after the intrapleural injection of 0.5% SN suggests that this concentration may be optimal when a fast result is necessary.
SUMMARY: The ideal agent for producing pleurodesis has not been identified. Talc, the most commonly used, poses several problems. Another possibility is silver nitrate, which was widely used in the past.Purpose: To determine the influence of the intrapleural instillation of lidocaine in producing a pleurodesis with silver nitrate, to define the effect of lidocaine in the maturation of the collagen fibers, and to confirm that the pleurodesis after silver nitrate is stronger than after talc.Methods: We studied three groups of 8 rabbits. Two groups received 0.5% silver nitrate; in one we had previously injected 0.5 ml of 2% lidocaine. The third group received 400 mg/kg talc (2 ml). The animals were sacrificed 28 days after the injection, and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of inflammation and fibrosis. The total amount of pleural collagen and the distribution of thick and thin collagen fibers were quantified. Collagen was identified using picrosirius red stain.Results: In the two groups that received silver nitrate (without lidocaine: 3.5 + 03 and with lidocaine: 3.2 + 0.3), the macroscopic pleurodesis (scale 0 -4) was significantly (p = 0.001) better than that resulting from talc (1.6 + 0.2). The mean degree of pleural fibrosis induced by silver nitrate (3.5 + 0.2) was significantly (p = 0.004) higher than that induced by talc (1.9 + 0.1). The previous instillation of lidocaine resulted in a tendency for decreased amounts of fibrosis (3.1 + 0.4). The mean amount (10 3 mm 2 ) of pleural collagen was significantly (p = 0.009) greater in the rabbits that received silver nitrate (116.9 + 22.7) than in those that received talc (10.7 + 3.4). The injection of lidocaine slightly reduced the collagen (80.1 + 30.3). The distribution of collagen fibers did not differ among the groups.Conclusion: This rabbit model clearly confirms that intrapleural silver nitrate is more effective than talc for producing pleurodesis. The previous intrapleural instillation of lidocaine results in a decreasing trend in the amount of collagen, but does not change the effectiveness of the pleural fusion or modify the process of collagen maturation.
<span style="font-family: Helvetica; font-size: xx-small;"><span style="font-family: Helvetica; font-size: xx-small;"><p>O objetivo desse estudo foi comparar o perfil audiométrico de Operadores de Tráfego que trabalham nas áreas urbanas de São Paulo indicadas pela literatura como sendo as que apresentam o maior e o menor nível de ruído, 83,4 dB (A) e 79 dB (A) respectivamente. Além disso, a existência de associação entre perdas auditivas e outras variáveis (idade, tempo de trabalho na função, exposição extra-ocupacional ao ruído, uso de equipamento de proteção individual e queixa de zumbido) foi verificada. Utilizaram-se dados de 73 Operadores de Tráfego, previamente submetidos a exames audiométricos e a um questionário, disponíveis em banco de dados do Serviço de Saúde Ocupacional da Universidade de São Paulo. Os resultados sugerem que a exposição extra-ocupacional a ruído, mas não a exposição ocupacional a ruído urbano, tem efeito no aparecimento das perdas auditivas.</p></span></span>
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