Permissive hypofiltration

Lakhmir S Chawla, John A Kellum, Claudio Ronco

ABSTRACT: Acute kidney injury (AKI) is a syndrome with a multitude of causes and is associated with high mortality and a permanent loss of renal function. Our current understanding of the most common causes of AKI is limited, and thus a silver bullet therapy remains elusive. A change in the approach to AKI that shifts away from the primary composite endpoint of death/dialysis, and instead focuses on improving survival and mitigating permanent renal damage, is likely to be more fruitful. We suggest that the current approach of augmenting renal function by increasing the renal blood flow or glomerular filtration rate during AKI may actually worsen outcomes. Analogous to the approach towards adult respiratory distress syndrome that limits ventilator-induced lung injury, we propose the concept of permissive hypofiltration. The primary goals of this approach are: resting the kidney by providing early renal replacement therapy, avoiding the potentially injurious adverse events that occur during AKI (for example, fluid overload, hypophosphatemia, hypothermia, and so forth), and initiating therapies focused on improving survival and mitigating permanent loss of kidney function.