Efficacy of hyperthermia pleurodesis: A comparative experimental study on serous membrane of abdominopelvic and thoracic cavities of rats.

Background: Pleurodesis is a common technique for treating the accumulation of air or liquid in the pleural space caused by pneumothorax or pleural effusion, it is based on the bounding of pleural layers through induced inflammatory lesions. There are several pleurodesis procedures.

Objectives: To test and describe the inflammatory effect of hyperthermia on the pleural and peritoneal mesothelia of rats, with the aim of testing the effectiveness of this process for inducing pleurodesis.

Methods: 35 Sprague-Dawley (male/female) rats were randomized into four treatment groups: Group A (Talc, 10 individuals); group B (control, 5 individuals); group C (hyperthermic isotonic saline, 10 individuals); and group D (filtrate air at 50°, 10 individuals). Inflammatory effect of hyperthermia was the primary outcome parameter.

Results: In the talc group, minimal adhesions between both pleural and peritoneal layers were observed in seven rats. Talc produced peritoneal mesothelium inflammation and fibrosis associated to foreign body giant cells in 80% (8/10) of the sample. Furthermore, clear evidence of a granulomatous foreign-body reaction was detected. No macroscopic and/or microscopic damage was registered in the remaining three groups (control, hyperthermic, and filtrate air).

Conclusions: Talc is an excellent method for producing pleuro-peritoneal inflammatory lesions. On the contrary, hyperthermia apparently does not induce the macroscopic and microscopic damage that is required for efficient pleurodesis. Therefore, hyperthermia should not be used for pleurodesis procedures.