SILENT ASPIRATION AFTER CORONARY-ARTERY BYPASS-GRAFTING

Background. ''Silent'' aspiration was recognized to be a more frequent complication at this hospital in patients who have had coronary arter y bypass grafting than in the general surgical population. Methods. A case-control retrospective study covering a 4.5-year period was conduc ted to determine risk factors for pharyngeal dysfunction resulting in silent aspiration. Results. Significant predictors of silent aspiratio n were age, history of cerebral vascular disease, insulin-dependent di abetes mellitus, myocardial infarction, and chronic obstructive pulmon ary disease. Intraaortic balloon pump and number of units of fresh-fro zen plasma were the only independent intraoperative factors associated with silent aspiration in a model using continuous variables directly . Cold fibrillation was used in 7 of 53 study cases but no control pat ients, so it could not be modeled. Postoperative complications occurri ng with greater frequency included neurologic complications, adverse p ulmonary outcomes, repeat surgical interventions, infection, and death . Using an Aspiration Risk Profile developed from the retrospective st udy, in a detailed prospective study of 10 patients, 3 of 4 patients w ith postoperative dysphagia had objective evidence of stroke. Conclusi ons. These findings suggest that postoperative coronary artery bypass graft dysphagia may be the result of intraoperative cerebral injury, a nd that careful postoperative clinical evaluation of coronary artery b ypass graft patients with risk factors may result in early diagnosis o f pharyngeal dysfunction with the goals of preventing silent aspiratio n and reducing morbidity, mortality, and hospital cost. (C) 1998 by Th e Society of Thoracic Surgeons.