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 artery bypass grafting than in the general surgical population. Methods. A case-control retrospective study covering a 4.5-year period was conducted to determine risk factors for pharyngeal dysfunction resulting in silent aspiration. Results. Significant predictors of silent aspiration were age, history of cerebral vascular disease, insulin-dependent diabetes mellitus, myocardial infarction, and chronic obstructive pulmonary disease. Intraaortic balloon pump and number of units of fresh-frozen 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 patients, so it could not be modeled. Postoperative complications occurring with greater frequency included neurologic complications, adverse pulmonary outcomes, repeat surgical interventions, infection, and death. Using an Aspiration Risk Profile developed from the retrospective study, in a detailed prospective study of 10 patients, 3 of 4 patients with postoperative dysphagia had objective evidence of stroke. Conclusions. These findings suggest that postoperative coronary artery bypass graft dysphagia may be the result of intraoperative cerebral injury, and that careful postoperative clinical evaluation of coronary artery bypass graft patients with risk factors may result in early diagnosis of pharyngeal dysfunction with the goals of preventing silent aspiration and reducing morbidity, mortality, and hospital cost. (C) 1998 by The Society of Thoracic Surgeons.