Inhaled budesonide in experimental chlorine gas lung injury: influence of time interval between injury and treatment

Objective: To examine the time window between injury and treatment during which nebulized corticosteroid lessens lung injury induced by chlorine gas inhalation. Design: An experimental laboratory study. Setting: Academic research laboratory. Subjects: Twenty-four juvenile female pigs. Interventions: Twenty-four mechanically ventilated pigs were exposed to chlorine gas (1400 PPM in air) for 20 min, then divided into four groups (six in each group). Nebulized budesonide (BUD) was given immediately (BUD 0 min), 30 min (BUD 30 min) or 60 min (BUD 60 min) after chlorine gas exposure. Six pigs receiving nebulized saline served as controls. Measurements and main results: Hemodynamics, gas exchange and lung mechanics were evaluated for 5 h after chlorine gas exposure. All animals had an immediate increase in airway and pulmonary artery pressure and a sharp drop of arterial oxygenation. The mean arterial oxygen tension of BUD 0 min and BUD 30 min animals was significantly higher than in the control and the BUD 60 min groups (p<0.001). The recovery Of lung compliance in the BUD 0 min and the BUD 30 min groups was significantly more rapid than in the control and the BUD 60 min groups (p<0.001). The pulmonary wet to dry weight ratio was greater in the control group than in the BUD-treated groups (p<0.05). Conclusion: Treatment with inhaled budesonide immediately or 30 min after chlorine gas lung injury had similar positive effects on symptoms and signs of pulmonary injury, whereas treatment delayed for 60 min was less effective.