Effects of early bronchoalveolar lavage fluid collected from dogs with smoke inhalation injury on the lungs of rats

Objective: Whether early massive bronchoalveolar lavage can remove the harmful substances from the lungs injured with smoke inhalation remains uncertain. This study was designed to observe the effects of early massive bronchoalveolar lavage fluid (BALF) on the healthy lungs in rats. Methods: Mongrel dogs were inflicted with severe smoke inhalation injury. The injured lungs were lavaged with large amount of normal saline in the first hour after injury and the BALF was collected. The BALF was injected into the healthy lungs of 30 rats (group C) in the dosage of 5 ml/kg. The functions and pathological changes of the lungs were observed 24 h after perfusion with the BALF. The data were compared with those of 23 rats (group B) whose lungs were perfused with the BALF collected from normal dogs and those of 21 rats (group A) whose lungs were perfused with normal saline. Results: The mortality rate 24 h after lung perfusion was higher in group C than in groups A and B. The survivors of group C exhibited fluctuation of respiratory rate (RR), remarkable decrease of PaO 2, significantly higher content of lung water, decrease of total static pulmonary compliance and pulmonary expansion index, and increasse of inflammatory cytokines in the tissues of lungs. Only slight mechanic obstructive effect on the airway was observed in rats of group A and B. The pathological changes of the lungs of the rats in group C were similar to those of the dogs with actual smoke inhalation injury. Conclusion: Our findings indicate that the BALF collected from dogs with acute severe smoke inhalation injury in the early stage after injury injured the normal lungs of rats with the bioactive substances in the BALF. These findings show us that it is a valuable therapeutic procedure to apply massive bronchoalveolar fluid lavage in the early stage after inhalation injury.