A study evaluated the prevalence, risk factors, and prognosis of fungal infections in adults on ECMO. Patients on extracorporeal membrane oxygenation (ECMO) are often among the most severely ill in the intensive care unit. They are often receiving broad-spectrum antibiotics; they have multiple entry points for pathogens, and their immune system is impaired by blood circuit interaction. These factors are thought to predispose them to fungal infections.
They conducted a retrospective cohort study using the Extracorporeal Life Support Organization registry, which compiles data on ECMO use from hundreds of international centres. They included all adult patients from 2006 to 2016 on any mode of ECMO with either a diagnosis of fungal infection or a positive fungal culture. Our study comprised 2129 adult patients (10.8%) with fungal colonization or infection.
Aspergillus involvement (colonization or infection) was present in 272 patients (1.4%), of whom 35.7% survived to hospital discharge. There were 245 patients (1.2%) with Candida invasive bloodstream infection, with 35.9% survival. Risk factors for Aspergillus involvement included solid organ transplant (OR 1.83; p = 0.008), respiratory support (OR 2.75; p < 0.001), and influenza infection (OR 2.48; p < 0.001).
Risk factors for candidemia included sepsis (OR 1.60; p = 0.005) and renal replacement therapy (OR 1.55; p = 0.007). In multivariable analysis, Aspergillus involvement (OR 0.40; p < 0.001) and candidemia (OR 0.47; p < 0.001) were both independently associated with decreased survival. Multiple hospitals across the globe in very different settings participate in the ELSO registry. These centres collect data on all their ECMO cases.
This confers strong external validity to our study. However, the internal validity of the study is affected by multiple factors partly inherent to its retrospective nature. For instance, microbiological sampling was nonsystematic. Furthermore, many patients had a respiratory failure with already abnormal chest imaging results before developing IA. Newer tests such as galactomannan and PCR of serum or bronchoalveolar lavage specimens have been developed to improve the diagnostic yield for IA.
The prevalence of Aspergillus involvement and Candida invasive bloodstream infection were not higher in patients on ECMO than what has been reported in the general intensive care population. Both were independently associated with a reduced survival. Aspergillus involvement was strongly associated with ECMO for respiratory support and influenza.
Patients on ECMO do not seem to develop fungal colonization or infection more frequently than other critically ill patients. Aspergillus involvement and CBSI were independently associated with decreased survival. CBSI mortality was higher than described in the general ICU population. Aspergillus involvement was associated with respiratory ECMO and influenza. Clinicians should maintain a high index of suspicion in this subgroup, and efforts should be made to establish an early diagnosis.