Fluid Overload and Mortality in Patients with Severe Acute Kidney Injury and Extracorporeal Membrane Oxygenation

Abstract

Background: Volume overload is increasingly being understood as an independent risk factor for increased mortality in the setting of acute kidney injury (AKI) and critical illness, but little is known about its impact in the setting of extracorporeal membrane oxygenation (ECMO). We sought to evaluate the incidence of AKI and volume overload and their impact on all-cause mortality in adults following ECMO cannulation. Methods: We identified all adult patients who underwent ECMO cannulation at the University of Chicago between January 2015 and March 2017. We evaluated the incidence of KDIGO defined AKI, renal replacement therapy (RRT) and volume overload. Volume overload was defined as achieving a positive fluid balance of 10% above admission weight over the first 72 hours following ECMO cannulation. The primary outcome collected was 90 day all-cause mortality. Secondary outcomes included 30 day mortality, duration of ECMO and RRT therapy, length of stay and dialysis independence at 90 days. Results: There were 98 eligible patients, 83 of whom developed AKI (85%); with 48 (49%) requiring RRT and 19 (19%) developing volume overload at 72 hours. Patients with volume overload had increased risk of death at 90 days compared to those without volume overload (HR 2.3(1.3, 4.2); p=0.004). Patients with AKI-D had increased risk of death at 90 days compared to those without AKI-D (HR 2.2(1.3, 3.8); p=0.004). Volume overload remained an independent predictor of 90 day mortality when adjusting for RRT, APACHE score, weight (kg), diabetes, and heart failure (HR 2.9(1.4, 6.0); p=0.003). Conclusions: Volume overload and AKI are common and have significant prognostic value in patients treated with ECMO. Initiating RRT may help to control the deleterious effects of volume overload and improve mortality.

Timing of Initiation of Kidney Replacement Therapy in Acute Kidney Injury in the Critically Ill Patient

“…In cases of significant FO, acute pulmonary edema refractory to diuretics with PaO2/FiO2 < 300 mmHg, a resource in this clinical scenario, is Slow Continuous Ultrafiltration (SCUF) and/or CKRT depending on the clinical requirement, and these are alternatives that have been extensively studied with conflicting results. In a retrospective cohort study of 98 critically ill patients who required ECMO, 85% of them developed AKI, and of these, 49% required CKRT; in those who had FO > 10% 72 hours after connection to ECMO and developed severe AKI, 90-day mortality was higher when compared to those who did not develop AKI (HR 2.2; 95% CI, 1.3 to 3.8; p = 0.004) and those in the subgroup requiring CKRT had higher mortality (p = 0.029), and it is observed that CKRT does not ensure a negative fluid balance, but helps to achieve a less positive balance [97].…”

Controversial Efficacy of Early Timing of Prone Positioning for Severe Acute Respiratory Distress Syndrome During Venovenous Extracorporeal Membrane Oxygenation

“…The authors evaluated the association between the timing of PP during ECMO and the prognosis and respiratory mechanics using various covariates. However, fluid balance (4) and the use of neuromuscular blockade during PP were not included as potential confounders. Because these covariates may have affected survival and respiratory mechanics, their effect needs to be assessed.…”