Low dose methylprednisolone prophylaxis to reduce inflammation during one-lung ventilation

Background: The specific aim of this study was to examine the efficacy of a low dose of methylprednisolone in minimizing inflammatory response in juvenile piglets when given 45–60 min prior to onset of one‐lung ventilation. Methods: Twenty piglets aged 3 weeks were assigned to either the control group (n = 10) or methylprednisolone group (n = 10). The animals were anesthetized and after 30 min of ventilation, they had their left lung blocked. Ventilation was continued via right lung for 3 h. The left lung was then unblocked. Following another 30 min of bilateral ventilation, the animals were euthanized and both lungs were harvested. The methylprednisolone group had a single dose (2 mg·kg^?1) of methylprednisolone given i.v. 45–60 min prior to onset of one‐lung ventilation. Physiological parameters (PaO₂, resistance, and compliance) and markers of inflammation (tumor necrosis factor [TNF]‐α, interleukin [IL]‐1β, IL‐6, and IL‐8) were measured at baseline and every 30 min thereafter. Lung tissue homogenates from both collapsed and ventilated lungs were analyzed for TNF‐α, IL‐1β, IL‐6, and IL‐8. Results: The methylprednisolone group had higher partial pressure of oxygen (P = 0.01), lower plasma levels of TNF‐α (P = 0.03) and IL‐6 (P = 0.001) when compared with control group. Lung tissue homogenate in the methylprednisolone group had lower levels of TNF‐α (P < 0.05), IL‐1β (P < 0.05), and IL‐8 (P < 0.05) in both the collapsed and the ventilated lungs. Conclusions: In a piglet model of one‐lung ventilation, use of prophylactic methylprednisolone prior to collapse of the lung improves lung function and decreases systemic pro‐inflammatory response. In addition, in the piglets who received methylprednisolone, there were reduced levels of inflammatory mediators in both the collapsed and ventilated lungs.