Echo-AKI

Ultrasound assessment of venous congestion in acute kidney injury

Background

Fluid overload is associated with adverse outcomes in patients with severe acute kidney injury. It remains unclear if fluid overload is merely a marker of disease severity or if organ congestion is a direct mediator of complications. Point-of-care ultrasound could be a modality used to assess organ congestion and its clinical implications.

Objective

To determine whether ultrasound markers of organ congestions are associated with major adverse kidney events (MAKE) at 30 days. Secondary outcomes will include other clinical outcomes, initiation of RRT, and tolerance of fluid removal once RRT is initiated.

Study design

This multi-centre prospective cohort study will assess ultrasound markers of organ congestion. Repeated assessment will be performed within 12 hours of recruitment, 72 hours after recruitment, and 7 days thereafter. Clinical outcomes will be collected for up to 90 days after recruitment.

Recruitment

Adult patients admitted to the intensive care unit with severe acute kidney injury (≥ 2-fold increase in serum creatinine OR a serum creatinine ≥ 354 μmol/L with evidence of a minimum increase of 27 μmol/L OR Urine output < 6.0 mL/kg over the preceding 12 hours OR initiation of RRT within 72 hours of recruitment) are eligible for inclusion. We will recruit up to 200 patients: 100 with non-dialysis requiring AKI (Cohort 1) and 100 who have commenced RRT within 72 hours prior to screening (Cohort 2). We will be using a deferred consent model.

Patient assessment

Markers of interest include inferior vena cava distension, portal vein flow pulsatility, discontinuous intra-renal flow and pulmonary B-lines artifacts. Hemodynamic parameters, and clinical information will also be collected. The primary outcome studied will be MAKE at 30 days defined as death, renal replacement therapy or worsening kidney function (de novo chronic kidney disease or > 25% decline from baseline estimated glomerular filtration rate (eGFR)). Ultrasound examinations will be performed by Dr. Brian Buchanan (site PI) and Dr. Vince Lau. Ultrasound examinations from this study are not substitutes for comprehensive ultrasound examinations by diagnostic imaging and should be requested through EPIC order entry.

Impact

An approach targeting the resolution of organ congestion might improve the prognosis in patients with severe AKI. Identifying clinically relevant markers of organ congestion is a precursor to the design of future interventional trials investigating personalized fluid balance management.