title: Low dose methylprednisolone prophylaxis to reduce inflammation during one-lung ventilation.
abstract: 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 x 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]-alpha, interleukin [IL]-1beta, 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-alpha, IL-1beta, IL-6, and IL-8.
  
  
  RESULTS
  The methylprednisolone group had higher partial pressure of oxygen (P = 0.01), lower plasma levels of TNF-alpha (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-alpha (P < 0.05), IL-1beta (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.
authors.affiliation: Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA. mtheroux@nemours.org
authors.forename: Mary C
authors.initials: MC
authors.lastname: Theroux
authors.forename: Alicia
authors.initials: A
authors.lastname: Olivant
authors.forename: Doyle
authors.initials: D
authors.lastname: Lim
authors.forename: John P
authors.initials: JP
authors.lastname: Bernardi
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Costarino
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Shaffer
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Miller