Experimental acute lung injury. Effects of methylprednisolone and lidocaine on histopathology and neutrophils

OBJECTIVE: Methylprednisolone and lidocaine are commonly used in acute lung injury caused by acid aspiration. The aim of this study is to demonstrate if these 2 agents, given at an early stage, can reduce lung damage and improve oxygenation.

METHODS: The study was carried out at the animal laboratories of Ataturk University, Medical Faculty, Erzurum, Turkey during the year 2002, and performed on a rabbit acid aspiration model. At an early stage, the controls were given saline solution, the second group was given lidocaine, and the third group was given methylprednisolone. The neutrophil count was determined hourly. After 6 hours of mechanical ventilation, lung biopsy was performed for histopathology.

RESULTS: Neutrophils increased with time. The controls showed much more severe histopathological changes than the 2 treatment groups. Methylprednisolone was more effective than lidocaine at reducing lung damage.

CONCLUSION: Histopathology suggests that acid aspiration induced acute lung injury can be effectively treated by lidocaine and methylprednisolone, if applied early. The latter appears to be the more effective.