Nosocomial infections acquired by patients treated with extracorporeal membrane oxygenation

Infectious complications in patients treated with extracorporeal membrane oxygenation (ECMO) are a frequent contributor to morbidity and mortality in this group. Defining the characteristics of ECMO-related infections may inform treatment decisions, including antimicrobial therapy.

A retrospective observational study in an Australian intensive care unit, including adult patients treated with ECMO for at least 48 hours, over a 3-year period. Medical records were analysed for evidence of bloodstream infections (BSIs) and wound infections (WIs) at the ECMO cannulation site or the sternum. Demographic, ECMO-related and clinical data were collected, including inpatient antibiotic usage.

We included 98 patients in the study. The median age was 50 years (IQR, 39-57 years). The median duration of ECMO treatment was 6.6 days (IQR, 4.0-12.8 days). Twenty-four infections were diagnosed in 21 patients; eight patients were diagnosed with BSIs on ECMO, 14 developed cannulation-site WIs, and two patients developed sternal wound infections. On multivariate analysis, we found that factors that increased infection risk included immunosuppression (OR, 2.9; P = 0.04) and treatment with venoarterial (VA) ECMO (OR, 14.7; P = 0.01). Infected patients had a significantly longer duration of hospital admission than patients without BSI or WI (55 days v 30 days; P = 0.03). Prior antibiotic use did not appear to be protective against subsequent infection.

Infectious complications are common in ECMO patients and are associated with longer durations of hospital admission. Isolated pathogens were predominantly hospital-acquired Gram-negative bacteria and yeasts. Immunosuppression and treatment with VA ECMO were found to be specific risk factors for infection.