Nosocomial infections acquired by patients treated with extracorporeal membrane oxygenation.

BACKGROUND: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.