Diagnostic Criteria for Acute Kidney Injury

Hello -  some advocate that if a patient is resuscitated successfully with fluids, then the criteria for AKI is not met.  I am reading the excellent reference published by Pinson & Tang,  2017 CDI Pocket Guide, and it does not make reference to fluid status.  I also have attended several seminars by others, such as Kennedy and Huff, and do not recall that either mentioned fluid status as something that would preclude KDIGO application.

DIAGNOSTIC CRITERIA — The definition for AKI used in clinical and epidemiologic studies is based on specific criteria that have been sequentially developed. The Kidney Disease: Improving Global Outcomes (KDIGO) definition and staging system is the most recent and preferred definition [1]. Other criteria include the RIFLE criteria [2] and a subsequent modification proposed by the Acute Kidney Injury Network (AKIN) and others [3-5]. These criteria are outlined in the table (table 1).

The KDIGO guidelines define AKI as follows [1]:

●Increase in serum creatinine by ≥0.3 mg/dL (≥26.5 micromol/L) within 48 hours, or

●Increase in serum creatinine to ≥1.5 times baseline, which is known or presumed to have occurred within the prior seven days, or

●Urine volume <0.5 mL/kg/hour for six hours

The KDIGO criteria allow for correction of volume status and obstructive causes of AKI prior to classification. Before diagnosing and classifying AKI, one should assess and optimize volume status and exclude obstruction. (See "Evaluation of acute kidney injury (acute renal failure) among hospitalized patients".)

The timeframe for an absolute increase in serum creatinine of ≥0.3 mg/dL is retained from the AKIN definition (48 hours), while the timeframe for a ≥50 percent increase in serum creatinine reverted to the seven days originally included in the Acute Dialysis Quality Initiative (ADQI) RIFLE criteria.

The RIFLE and AKIN definitions are shown in the table (table 1).


Any thoughts?  

thank you

Comments

  • edited August 2017
    It looks to me like the KDIGO criteria says just the opposite of what you are saying:"For example, a patient might receive very large quantities of intravascular fluids such that SCr is falsely lowered" (pg 31)"Nevertheless, the clinician should be cognizant of possibility that SCr may be falsely lowered by large-volume fluid resuscitation or transfusion; thus, a normal value may not rule out AKI."Page 28 details how to diagnosis AKI based on either a retrospective or prospective measurement of the SCr, and absolutely makes no mention or requirement that cases where a patient responds to IVF be excluded.  In fact, pre-renal AKI would be EXPECTED to show recovery after initiation of IVF.The system considers the lowerest SCr measured to always be the new baseline (even when lower than the previously established baseline) and the highest measured SCr is the acute state"...the lowest SCr obtained during a hospitalization is usually equal to or greater than the baseline. This SCr should be used to diagnose (and stage) AKI." (page 30).Only using the post hydration SCr effectively nullifies the entire KDIGO system!Not only that, but the event does not even have to have occured during the hospital stay (and IVF would not have been given during the time period before presentation obviously."Importantly, there is no stipulation as to when the 1-week or 48-hour time periods can occur. (for the 1.5x baseline within 7 days retrospectively or the 0.3mg/dl increase over 48 hours in SCr)  It is stated unequivocally that it does not need to be the first week or 48 hours of a hospital or ICU stay. Neither does the time window refer to duration of the inciting event." (pg. 31)Next up are cases where AKI criteria are not even met based on SCr:"Atypical AKI. A complementary problem to pseudo-AKI isthe situation where a case of AKI fails to meet the definition. These cases should be distinguished from conditions in which data are simply missing (discussed above) and refer to situations in which existing data are unreliable. For example, a patient might receive very large quantities of intravascular fluids such that SCr is falsely lowered.65 Similarly, massive blood transfusions will result in the SCr more closely reflecting the kidney function of the blood donors than the patient.It is unusual for these cases not to result in oliguria and, thus, most patients will be diagnosed with AKI even if SCr is not increased. Nevertheless, the clinician should be cognizant of possibility that SCr may be falsely lowered by large-volume fluid resuscitation or transfusion; thus, a normal value may not rule out AKI."http://kdigo.org/clinical_practice_guidelines/pdf/KDIGO AKI Guideline.pdf
  • Allan> Thank you for the timely response.  Actually, if you read my post, my view aligns with yours in regards to the role of fluids and AKI.  However,  there are some in the profession that apparently have the view that these changes in AKI that are reversed with fluids do not constitute AKI.  As I said in my post,  I can't find that any of our capable physician members have endorsed this concept.
  • Hi Paul,

    I have talked to you about this a couple years ago.

    Here is my best recall/understanding:

    AKIN in 2008 suggested adjusting RIFLE (not sure -?2005).
    2012 KDIGO made their recommendation.

    I would think the most recent recommendation would be reasonable, which I do not think called for fluid resuscitation.

    It was the AKIN that suggested this step-2008
    ".... Yet, the proposed AKIN criteria also recommend only applying the urine output criteria ‘following adequate fluid resuscitation’. Regrettably, this statement is ambiguous and may possibly just add confusion as to when to apply the urine output criteria in the diagnosis of AKI. We contend that the urine output criteria for AKI, as originally proposed by the RIFLE criteria, should be used until prospective evaluations conclude otherwise. ..."
    https://academic.oup.com/ndt/article/23/5/1569/1809429/A-comparison-of-the-RIFLE-and-AKIN-criteria-for

    Ann


  • Thank you Both, very much.   My understanding is the same as each of you state.  I do not think KDIGO mandates specific adjustments for fluid resuscitation, rather if the KDIGO criteria is met,  Acute Kidney Injury is present.   Recently,  this criteria has been challenged, and I wanted to reach out to other CDI professionals in order to ensure my current understanding is clinically current and defensible. 

    Paul Evans, RHIA, CCDS, CCS, CCS-P

  • Auditors are notorious for cherry picking parts of various criteria, including outdated criteria to try and prove their point.   

    I would point out that looking at UOP status post fluid administration is also not the same thing as looking at the creatinine status post fluid administration.    I would further point out that looking at UOP can lead to false positives in the cases of stones, bph and other obstructive scenarios.

  • Allan:  Thanks, again.  I believe many of us share some frustration in that we advocate and use vetted clinical indicators in our roles, only to have our facility-approved criteria questioned.  This seems inevitable, and is frustrating.   For myself,  I seek to ensure that Organizationally-established guidelines and clinical indicators created in collaboration with the medical staff are current so that we can uniformly attempt to define, document and defend our charting.

    I support the concept of using definitions in order to promote consistency in the CDI staff and also to determine if minimal thresholds  are present in a record so that a query may be considered clinically valid and compliant.  It is a difficult task, and I appreciate your insight, as well as that of all of our CDI peers.  This website is a great source of information!


    Paul Evans, RHIA, CCDS

Sign In or Register to comment.