Pulmonary consequences of severe tricyclic antidepressant ingestion

We prospectively studied 56 consecutive patients with severe tricyclic antidepressant ingestion to determine the incidence of associated pulmonary complications. Among the patients meeting the entrance criteria, the mean antidepressant level was 1136 ng/ml. Other characteristics were a QRS duration of greater than or equal to 0.1 seconds in 35 (63%) and seizures in 19 (34%). Seventeen patients (30%) developed 18 abnormal chest X-ray findings which included pulmonary edema in 8 cases and aspiration pneumonia in 10. Using logistic regression, we evaluated the influence of tricyclic antidepressant level, blood pressure, QRS interval, seizures, drug co-ingestion and the use of gastric lavage vs. ipecac-induced emesis on pulmonary complications. For patients with pulmonary edema, the only significantly associated factor was hypotension on emergency department presentation. For aspiration pneumonia, no significant associations were found. Co-ingestion of another drug had no apparent influence on the development of pulmonary abnormalities. Our findings suggest that pulmonary edema and aspiration pneumonia are frequent complications of severe ingestions of tricyclic antidepressants. Pulmonary edema appears to result from hypotension or its treatment. The etiology of aspiration pneumonia is unclear. A chest X-ray should be obtained in all victims of tricyclic antidepressant overdose.