Low dose methylprednisolone prophylaxis to reduce inflammation during one-lung ventilation
Part of this work was presented at the American Society for Anesthesiology in October (San Francisco) 2007.
Summary
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.
