THE PATHOPHYSIOLOGIC CHANGES FOLLOWING BILE ASPIRATION IN A PORCINE LUNG MODEL

Aspiration of bile is an underpublicized aspiration syndrome. Using a porcine lung model, the physiologic response and the histopathology of lung tissue were evaluated after the intratracheal instillation of su blethal doses of bile. Twenty-one domestic swine (11 to 19 kg) were th e studied population. Three groups of five swine were evaluated: a con trol group received intratracheal physiologic saline (pH 7.45); study group I received strained gastric contents (pH 2.24); and study group 2 received strained bile (pH 7.19). All animals received the solutions at 0.5 ml/kg intratracheally. Lungs of six additional animals were st udied (two gastric, two bile, and two physiologic saline) after aspira tion by scanning electron microscopy (SEM). A seventh untreated animal was used as the SEM control. The physiologic data were analyzed using analysis of variance for repeated measures. The SEM and histopatholog ic results were graded by an observer blinded to the groups and were a nalyzed using the analysis of variance (ANOVA) and Scheffe tests. The group with bile aspiration was consistently characterized by significa nt deterioration of PaO2, the alveolar-arterial (A-a) gradient, shunt fraction, and static compliance (p<0.01); and the light histopathologi c and SEM findings demonstrated pathologic changes in the bile-exposed lung (p<0.05) greater than the gastric- or saline-exposed lungs. It i s concluded that bile aspiration produces a severe chemical pneumoniti s leading to noncardiac pulmonary edema.