Management Practices and the Risk of Infection Following Cardiac Surgery

Hospital-acquired infections represent the main non-cardiac complication after heart surgery. They are associated with substantial morbidity and higher mortality, as they often require prolonged hospitalization and additional surgery. The proportion of cardiac surgery patients at high-risk for infection is increasing because of the increased prevalence of co-morbid conditions such as obesity and diabetes mellitus in the general (and especially the elderly) population. In addition to increased morbidity and mortality, infectious complications also result in greater economic burden. A past study estimated that the incremental cost of treating Medicare beneficiaries who suffered from septicemia after coronary artery bypass grafting (CABG) to be $59,204. These patients stayed in the hospital 21.3 days longer than those who did not experience any serious adverse events. Of great relevance to treating hospitals, the Centers for Medicare and Medicaid Services (CMS) announced in the fall of 2007 that they would no longer pay for care related to preventable complications. CMS specifically mentioned excluding reimbursements for mediastinitis after CABG, and catheter associated infections. Thus, there is a crucial need to identify variables that mitigate infections post cardiac surgery and to develop effective preventative treatment strategies. Prior studies have examined the relationship between patient baseline (preoperative) characteristics (e.g., co-morbid conditions) and hospital-acquired infections post cardiac surgery. The STS database, for example, has led to the identification of predictive factors of post-operative CABG infections. Much of the variations in outcomes seen at different institutions, however, cannot be explained by differences in preoperative patient characteristics alone. How care is delivered also plays an essential role in determining infection rates and is therefore likely to explain some of the differences in these rates observed at different institutions. The literature has not sufficiently examined the relationship between treatment/management practices (e.g., line management, ventilator management, etc) and postoperative infection risk. In this study we seek to better understand management practices that put patients at high risk for infections post-cardiac surgery.