Timing Acute Kidney Injury Before ECMO Initiation
Acute kidney injury timing helps clinicians assess prognosis in adults receiving veno-arterial extracorporeal membrane oxygenation, though the direct link to mortality weakens after adjusting for illness severity. A two-centre retrospective study published in Scientific Reports evaluated 172 adult patients in Thailand to determine if renal injury timing provides independent prognostic information.
Researchers classified patients using Kidney Disease: Improving Global Outcomes creatinine criteria. Among the 172 participants, 81 individuals developed acute kidney injury before extracorporeal membrane oxygenation, representing 47.1% of the cohort. Another 82 patients, or 47.7%, developed the condition after cannulation. Only nine patients, amounting to 5.2%, experienced no kidney injury during their treatment course.
Pre-Cannulation Renal Impairment Raises Mortality Risks
Patients who experienced renal impairment prior to circulatory support presented with more severe organ dysfunction. They required renal replacement therapy more frequently than those who developed kidney injury afterward. Acute liver injury also appeared more often in this pre-cannulation group.
Unadjusted intensive care unit mortality reached 82.7% for patients with pre-cannulation renal injury, compared with 69.5% for those who developed it afterward. However, that mortality association shifted during statistical analysis. After researchers accounted for age, sex, chronic kidney disease, and hospital site, the adjusted hazard ratio was 1.39. Further adjustment for overall illness severity reduced the hazard ratio to 1.28. Neither adjusted figure established a statistically significant independent association with mortality.
Evaluating Candidacy Without Restricting Access
The findings indicate that renal impairment prior to cannulation often reflects underlying pre-cannulation shock and multiple organ dysfunction rather than just isolated kidney damage. This distinction matters because observed mortality differences stem largely from a patient’s underlying condition rather than the exact timing of renal injury alone.
Clinical assessments for extracorporeal support should weigh renal function alongside overall illness severity and signs of other organ damage. While pre-cannulation injury offers useful context, it does not serve as an independent predictor of intensive care unit mortality after full statistical adjustment. Investigators concluded that renal injury timing should inform candidacy discussions rather than justify restricting treatment access.
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