Methods: Thirty-two male Wistar type rats weighing 280-320 g were divided into four groups of eight rats each. In the control group rats were only anaesthetized. In thoracotomy group an automatic retractor was inserted for a 30-minute period after left thoracotomy. In the pneumoperitoneum group, 5 ml of room air was injected intraperitoneally. In the thoracotomy + pneumoperitoneum group, thoracotomy was performed and 5 ml of room air was injected intraperitoneally. Blood and lung tissue samples were taken at the 24th hour in all groups and were stored at -80 °C.

Results: In the thorocotomy group, the tumor necrosis factor-alfa, interleukin-6 and protein carbonyl levels were significantly higher than in the control group but no difference was found between the pneumoperitoneum and the thoracotomy + pneumoperitoneum groups.

Conclusion: Pneumoperitoneum performed after thoracotomy does not increase the inflammatory reaction and oxidative stress caused by thoracotomy. Pneumoperitoneum is an effective and easily performed method.