Describe the RIFLE classification system for Acute Kidney Injury and briefly discuss its implications and limitations.
AKI can be defined as an abrupt (1 to 7 days) and sustained (more than 24 hours) decrease in kidney function. The ADQI formulated the RIFLE criteria to allow for AKI to be objectively and uniformly defined.
The implication of this classification is that a progression down the RIFLE criteria is associated with a higher length of stay in ICU and Hospital and is associated with a higher mortality.
The limitations of this classification relate to it’s dependence on measuring urine output and creatinine which is confounded by the following:-
This question refers to the 2004 formulation of the RIFLE criteria by the ADQI.
This is a system of classification which was supposed to step in and define the seveirty of renal failure, at a time when there were over 30 different disagreeing definitions. Its real use is in predicting mortality, and it helps decisionmaking in which mortality statistics play a role.
The Acute Dialysis Quality Initiative formulated this classification. Our very own Ronco, Bellomo and Kellum published this thing in 2004. And of course, its varios advantages and disadvantages have been picked apart in the literature reviews, not the least of which comes from Life In The Fast Lane. ADQI themselves have also addressed the limitations of their system.
The table itself is quoted in the college answer:
|Risk||Creatinine x 1.5||u/o < 0.5ml/kg/hr x 6 hrs|
|Injury||Creatinine x 2||u/o < 0.5ml/kg/hr x 12 hrs|
|Failure||Creatinine x 3||u/o < 0.3ml/kg/hr x 24 hrs|
|Loss||Complete loss of function > 4 weeks|
|End-stage||Complete loss of function > 3 months|
Major complaints against this system are elaborated upon elsewhere.
The greatest criticism of this system would come from the front lines of critical care, where the definitions and their prognostic value play little role. Sure, they have some utility in epidemiology, but at the bedside there is no way to apply these criteria to make management decisions. The fact that only 2% of the candidates passed this question is telling. Cold pragmatic bastards, they never saw a point in studying something they all viewed as a research tool.
Bellomo, Rinaldo, et al. "Acute renal failure–definition, outcome measures, animal models, fluid therapy and information technology needs: the Second International Consensus Conference of the Acute Dialysis Quality Initiative (ADQI) Group." Critical care 8.4 (2004): R204.
Cruz, Dinna N., Zaccaria Ricci, and Claudio Ronco. "Clinical review: RIFLE and AKIN–time for reappraisal." Critical care 13.3 (2009): 211.