EFFECTIVENESS OF SODIUM-HYDROXIDE AS A PLEURAL SCLEROSING AGENT IN RABBITS - INFLUENCE OF CONCOMITANT INTRAPLEURAL LIDOCAINE

The two agents that have been used most commonly to produce a pleurode sis are tetracycline and bleomycin. Tetracycline is no longer generall y available because of more stringent requirements on the manufacturin g process. Bleomycin is very expensive. Therefore, alternative agents are necessary particularly in developing countries. The objective of t his project was to determine whether 0.5% sodium hydroxide is an effec tive sclerosant in an experimental model in rabbits. Sodium hydroxide (NaOH) (2 ml of 0.5%) was instilled intrapleurally in 24 anesthetized male rabbits. Half the rabbits received 1 ml of 2% lidocaine 3-5 min b efore the NaOH. Twenty-eight days after the instillation, the animals were sacrificed, and the pleural spaces were assessed grossly for evid ence of pleurodesis and microscopically for evidence of fibrosis and i nflammation. The results indicated that the intrapleural injection of NaOH was effective in creating a pleurodesis only if the animals were not premedicated with lidocaine. The mean (+/-S.D.) degree of gross pl eurodesis after NaOH alone 2.8 (1.0) was significantly (p < 0.001) gre ater than after that following the combination 1.3 (0.5). We conclude that NaOH is an effective pleural sclerosant but that it is ineffectiv e if it is injected concomitantly with lidocaine.