Aspiration pneumonia: Physiologic data following experimental aspiration

Previously, it was found that the immediate use of positive pressure ventilation markedly decreased the mortality rate in a dog model of aspiration pneumonia. In the current study, physiologic measurements were carried out in dogs following hydrochloric acid instillation into the left main stem bronchus in an attempt to identify factors important for survival. It was found that positive pressure ventilation did not affect the hemodynamic response following aspiration, nor the change in pulmonary mechanics that occurred. It did, however, initially decrease the amount of intrapulmonary shunting. These results were correlated with other studies that demonstrated thrombosis of pulmonary vessels early following aspiration in dogs not treated with positive pressure ventilation.