Infections after cardiac surgery common, with many avoidable

Practices and procedures do influence postsurgical infection outcomes, according to a study published July 29 in the Journal of the American College of Cardiology. The research team found as many as 79 percent of patient infections occurred due to modifiable risks for bloodstream infections, pneumonia or C. difficile colitis.

Over a seven-month span in 2010, patients treated in sites in the Cardiothoracic Surgical Trials Network were followed. Almost 5 percent of 5,158 patients experienced postsurgical infections; 4.6 percent experienced major infections, while 8 percent of patients experienced minor infections with some overlap.

Lead author Annetine C. Gelijns, PHD, of the International Center for Health Outcomes and Innovation Research (InCHOIR) at the Ichan School of Medicine at Mount Sinai in New York, and colleagues found that prolonged ventilation (2.45 hazard ratio [HR]), intubation time (1.49 HR), stress hyperglycemia (1.32 HR) and prolonged postoperative antibiotic use (1.92 HR) increased the risks for postsurgical infection. Prolonged postoperative antibiotic use in particular was directly related to increased risks for C. difficile colitis, an infection that made up 80 percent of the infections seen over the course of the study.

The research team found a dose dependent relationship between risk for infection and red blood cell use (13 percent per each additional unit used).

C. difficile colitis occurred both before and after discharge. Forty-five percent of infections occurred postdischarge and were predominantly related to device-related site infections, deep surgical site infections or endocarditis. Pneumonia and bloodstream infections occurred most frequently while the patient was still in the hospital.

Gelijns et al wrote that patients with infections had a 14 percent 30-day readmission rate and a 19 percent overall readmission rate. Major infection had a significant impact (10.2 HR) on mortality.

However, pre- and perioperative procedures also helped shape outcomes. Patients scrubbed with chlorhexidine preparations prior to surgery made up 82 percent of patients and were less likely to have postoperative infections. Eighty-six percent of patients were dosed with prophylactic antibiotics per a surgical care improvement project and readministered antibiotics during surgery that lasted longer than six hours. Prophylactic use of second-generation cephalosporin decreased the risk of infection by a third. Processes that reduced the need to use blood products or extra lines decreased infection risks.

With hospital reimbursement for procedures at risk due to policies like those from the Centers for Medicare & Medicaid Services, Gelijins et al emphasized the importance of this information. “These findings suggest that—in a dynamic environment of evolving interventions, patients and offending microbes—we need to create an infrastructure for frequent re-evaluation of the incidence of healthcare-acquired infections, effectiveness of management practices, and adequacy of management guidelines,” wrote Gelijns et al.

“This is especially critical in an era that emphasizes early post-operative discharge and reduction of preventable readmissions, which are both heavily influenced by infection.”