Surgical Site Infection: Chronic Medications Predispose Patients

Medical sternotomy is a highly accessible route of entry into the chest cavity but apt to introduce infectious microbes.

Previous studies exploring surgical site infection (SSI) prevention have focused on antibiotic prophylaxis, and a small number of trials have focused on immunosuppressed surgical patients.

Few, if any, studies have investigated if patients’ medications contribute to SSI risk. However, the impact of the large array of medications commonly prescribed to cardiovascular surgery patients is largely unknown.

An article published ahead-of-print in Surgical Infections indicated that pre-operative immunosuppressive medications, corticosteroids, and alpha-blocker antihypertensives increase SSI risk.

The researchers conducted a retrospective cohort study of 1,077 adult cardiac surgery patients undergoing median sternotomy at Jewish General Hospital in Montreal, Canada between April 1, 2011 and October 31, 2013.

The researchers collected SSI risk-increasing surgical information on median sternotomy patients. They followed patients for 90 days to monitor for SSI. The researchers surveyed patients’ profiles for common cardiovascular medications including antihypertensives, nitroglycerin, vasopressors, proton pump inhibitors (PPIs), bronchodilators, immunosuppressive medications, steroids, antidiabetics, and antiplatelet agents.

The incidence of SSI varies widely between institutions due to varying surgical methods. In this study, the incidences of sternal site and harvest site infections in the cohort were 5.8 and 2.5 per 100 procedures. Most SSIs (80%) were diagnosed post-discharge (consistent with other studies), underscoring the importance of post-discharge monitoring.

Patients receiving immunosuppressive medications, steroids, and α-blocker antihypertensives were more likely to develop SSIs. Age, gender, smoking, pre-existing diabetes mellitus, congestive heart failure, obesity, or past SSI history did not predict SSI risk.

ACE inhibitors and β-blockers have been associated with increased risk of sepsis in previous trials, possible because they change the hemodynamic response to infection.

Immunosuppressing medications and α-blocker antihypertensives increase the risk of surgical site infections in patients undergoing median sternotomy. The researchers recommend larger multicenter studies to better understand the impact of patient medications on surgical site infections.