Impact of bronchial circulation on bronchial exudates following combined burn and smoke inhalation injury in sheep

We previously reported bronchial circulation contributes to pulmonary edema and increases shunt fraction following smoke inhalation, and bronchial blood flow significantly increases in inhalation injury. We hypothesized reduction of bronchial blood flow reduces exudation to the airway and ameliorates lung injury from combined burn and smoke insults (B&S injury). Method: Merino ewes (n = 28) randomly divided into three groups: (1) bronchial artery ligated and injured (injury + ligation group); (2) bronchial artery left intact and injured (injury + no ligation group); (3) bronchial artery ligated but not injured (no injury + ligation group) were subjected to a flame burn and inhalation injury under halothane anesthesia. Parameters were analyzed using Scheffe's post hoc test (P < 0.05). All Groups were resuscitated with Ringer lactate solution and placed on a ventilator for 48 h. Results: Pulmonary gas exchange (PaO ₂/FiO ₂) improved in injury + ligation group. Further, obstruction score, an index of airway cast formation, significantly changed between injury + no ligation group compared to both ligation groups. Conclusion: Bronchial circulation plays a significant role in lung injury after B&S injury, and reduction of bronchial blood flow by bronchial artery ligation reduces bronchial exudates, resulting in improved gas exchange.