Acute Kidney Injury Before or During ECMO Linked to Higher Mortality, Study Finds

The study, led by Clemens Wiest and colleagues from the University Hospital Regensburg in Germany, examined outcomes in 500 patients who underwent VV-ECMO between November 2014 and December 2021. The median age was 55 years, and women made up 30% of the cohort. Overall, 64% of patients developed AKI during their hospital stay. Among them, 182 patients had kidney injury before starting ECMO, while 158 developed it during ECMO therapy. A smaller subgroup experienced AKI both before ECMO and again after an initial recovery.

The key findings of the study were as follows:

• Patients with AKI before ECMO initiation had higher inflammatory marker levels and required larger doses of norepinephrine at treatment start, indicating more severe underlying illness.
• Those who developed AKI during ECMO often showed clinical signs of sepsis and unstable blood pressure, with lower mean arterial pressure and higher CRP levels in the days before diagnosis.
• Overall survival to hospital discharge was 67%, with AKI patients having significantly lower survival rates (60.9%) compared to those without AKI (77.8%).
• Severe AKI (KDIGO stage 3) was independently associated with a higher risk of in-hospital death, regardless of whether it developed before or during ECMO.
• Long-term survival among hospital survivors was 92.5%, with age being the only independent risk factor for reduced post-discharge survival.
• Propensity score matching showed that AKI onset during ECMO was more closely linked to disease severity and septic episodes rather than ECMO-specific factors such as blood flow rates or cell-free hemoglobin levels.

The authors noted that while ECMO is a life-saving intervention for severe respiratory failure, the occurrence of AKI signals a more critical underlying disease state and is an important prognostic indicator.

They wrote, “AKI onset before VV-ECMO therapy is linked to the severity of the underlying disease. AKI onset during VV-ECMO is less due to ECMO-related factors but also to the severity of the disease and septic episodes.” The findings underscore the importance of early recognition and management of AKI risk in ECMO patients, with close monitoring for signs of sepsis and hemodynamic instability. Preventive strategies, timely interventions, and tailored post-ECMO follow-up could help improve patient outcomes.

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