A placebo-controlled experimental study of steroid inhalation therapy in ammonia-induced lung injury

Background: The use of corticosteroids in toxic lung injury caused by expos ure to an irritating gas such as ammonia has not been adequately studied. O bjective: To evaluate the effects of budesonide inhalation in a rabbit mode l of toxic lung injury induced by ammonia. Design: Randomized, blind placeb o-controlled laboratory investigation employing 16 New Zealand White rabbit s. Lung injury was induced by inhalation of a defined amount of aerosolized ammonia. Thirty minutes later, the rabbits were randomized to receive eith er inhalation therapy with 0.5 mg budesonide or placebo. After another 2 ho urs, a second treatment inhalation, identical to the first one, was adminis tered. Results: Airway pressures, hemodynamics, and gas exchange were measu red at baseline, 5, and 15 minutes after ammonia administration and every 3 0 minutes during a 6-hour period after the first blind inhalation of cortic osteroids or placebo. Tbe ammonia inhalation resulted in an acute severe lu ng injury, detected after 15 minutes tps a decrease in PaO2 from 23.3 (+/-3 .6) to 11.0 (+/-3.6) kPa (p<0.005) and an increase in peak airway pressure from 13 (+/-2) to 17 (+/-2) cm H2O (p<0.005). During the 6-hour observation period, the blood gas parameters improved gradually in all rabbits. In com parison with placebo, budesonide did not result in improved gas exchange or reduced airway pressure levels during the observation period. Conclusion: In this animal model corticosteroid inhalation therapy had no effect on amm onia-induced lung injury.