Pleurodesis by autologous blood, doxycycline, and talc in a rabbit model

Background. Management of recurrent spontaneous pneumothorax or symptomatic pleural effusion often uses thoracoscopic pleurodesis, about which many qu estions remain. Both effectiveness and toxicity of agents currently used fo r pleurodesis were evaluated in a rabbit model. Methods. Agents administered were autologous blood 1 mL/kg, talc slurry (70 mg . mL(-1) . kg(-1)), and doxycycline 10 mg/mL, given through a chest tub e to 30 rabbits. Controls had only chest tubes inserted. At 30 days surface s were graded by gross observation and histologic examination. Blood and lu ng tissue from all animals were analyzed for enzymes and blood chemistries. Results. Gross observations showed mediastinal thickening and adhesions wit h doxycycline, and threadlike adhesions with talc. Autologous blood was onl y slightly more effective than a chest tube alone. Talc significantly incre ased angiotensin converting enzyme activity in serum, whereas doxycycline c hanged liver function enzymes and produced tissue toxicity. Conclusions. Doxycycline produced effective pleurodesis but yielded remarka bly severe local effects. The distant sequelae of talc and doxycycline pleu rodesis-histologic changes in the contralateral lung and serum enzyme eleva tions-suggests undesirable systemic effects for the commonly used agents, a nd autologous blood exhibited no significant pleurodesis, short-term. The s earch for the ideal agent for chemical pleurodesis continues. (Ann Thorac S urg 1999;67:917-21) (C) 1999 by The Society of Thoracic Surgeons.