Acute Renal Failure with values WNL.
We have been advised that we should ask the doctor about Acute Renal Failure in patients presenting with a normal creatinine that dips down to their normal which is more than 0.3 mg/dl than the initial. In this example the initial creatinine is 1.10 but dips down to .65. This is a greater than 0.3 mg/dl change within 48 hours. The rationale is that frail debilitated patient with low protein stores have low creatinines to begin with and the elevation indicates failure in these patients. I have not been able to find information to support this coding, so am reluctant to assign failure in this instance. Do you/would you?
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Hi,
I think I will be reluctant as well based on the rationale provided.
Let’s not think about the normal creatinine levels or ARF definitions (as we know most have limitations)
The real question is the decrease in kidney function?
Then we have to take into account factors that could falsely lower or increase Cr levels or speed / decrease filtration rate in the short term. Does this truly mean the kidneys are failing?
Well I will look further…
What is the patient’s UO? What does the patient’s Cr clearance suggest? What is the patient GFR?
Does the patient have biomarkers that could further explain Cr levels such as creatine kinase levels?
In all, I think I agree with your judgement, but looking forward to read a different perspective regarding your question.
I am certainly not a Nephrologist; and, perhaps one of our physicians that reads these postings may reply? I do recall that the MD teaching our Pathophysiology DID indeed state that a 'baseline' Cr can be tricky, and for the precise reasons you cite...the baseline level can be impacted by such things as protein stores, muscle mass of the patient, age, and particularly with an elderly, debilitated patient. Granted, one should conduct a review of literature on this topic - which I am not claiming I have done with this response; I am responding with what I recall from what I was taught at the university, and also from what nephrologist have stated to me regarding protein stores and muscle mass in elderly, debilitated patients. Having said that, I posit that such an abrupt change in the Cr can very well present Acute Kidney Injury in such patient. Per KDIGO, the abrupt changes would signify changes in the renal function.
P. Evans, RHIA, CCDS
I was taught the diagnosis of acute kidney injury 'depends' upon what is 'normal' baseline for the individual patient rather than a reference range used to reflect normal values. As an allegory, my normal WBC is 3.8 to 4.0..this is my stable baseline for years. So, I'd think a new level of 10.0 for me, particularly with a left shift, would be concerning, even thought that level is within normal levels for the general population.
Paul E
Paul,
I certainly understand your point based on KDIGO definition as you stated. My point is that could it be the physicians are not documenting acute renal failure because they do not think the patient is in renal failure irrespective of the elevation in Cr levels.
Could it be possible the patient now has a new baseline 1.10 and the regression to 0.65 was insignificant
Personally, I generally do not believe physicians would routinely miss documenting a significant diagnosis which is why I would ask why is not documented and further review the entire record before deciding to query for an undocumented diagnosis especially a diagnosis that can have significant impact. KDIGO Criteria is a good starting point but does not encapsulate the entire story.
HI, Matthew
I'd ONLY issue query for AKI IF/When the Cr changes are 'abrupt' changes from a measured baseline in 48 hours or less. If the baseline at time of admit not known, I'd use the lowest SCr obtained during the episode of care. I'd also review the GFR to see if it changes at all...if there are no abrupt SCr changes indicating potential for AKI, the changes may indicate only progression to CKD. As you correctly indicate, this 'could be' AKI on CKD, AKI, only or newly diagnosed CKD. My main point is that different patients have different baseline levels of Cr, and abrupt changes from their baseline may indicate KDIGO criteria met.
P. Evans, RHIA
I would agree baselines vary for different patients. Combing through the entire clinical picture is also as important as the abrupt changes in Cr levels.
Very enlightening discussion.
I am fortunate in that SCr, in my experience, is always done if/when renal function is in question; I do not know how to use GFR for ARF. I only use GFR when trying to confirm stage of known CKD.
Perhaps you could consider Urine output if SCr not available?: personally, if I see the Cr is being ordered, I wait for those results. I tend not to use urine output as measurement is not always consistent.
SCr increased >3x baseline or GFR decreased 75% or
SCr>mg/dL; acute rise >0.5mg/dL
<0.3mL/kg/h for 24 hrs
or anuria for 12 hrs
Hi. I missed your citation here that the Cr changed from .79 to .45...per KDIGO, that does support Acute Kidney Injury. Sorry, I missed that in all of these messages! I can only tell you we use KDIGO and your case does indicate criteria has been met.
Paul
His GFR went from a low of 84 to a high of 181.
The relationship between Cr and GFR in inverse so increase filtration rate could decrease Cr. I would want to see more chemistry to determine if I would query.
I understand you don’t have Cr clearance but
What is NA levels? How much IVF received and pt’s output?
Patient presented dehydrated so am suspecting aggressive fluid resuscitation was implemented. Again could 0.79 be the patient's baseline and may be due to aggressive treatment Cr decrease 0.45 due to increase filtration rate?
So if 0.45 is the lowest during admission or the assumed baseline then 0.79 would meet KDIGO criteria for an AKI. (.45*1.5=.675, so anything over that value would qualify for an AKI).
There's medical literature out there supporting prompt recognition of an AKI in a pregnant patient with pre-eclampsia (for example). SCr falls in pregnancy due to increased filtration by the kidneys. These ladies can be in trouble renal wise with a "normal" SCr, most often demonstrated by a decreased UOP.
Thanks, Jeff
excellent discussion and good points. Pocket Guide also provides an example (pg 59) in which patient admitted with baseline 0.4 with increase to 0.8 in 36 hours, stating this meets both the >0.3 criteria and the 1.5x criteria. "AKI creatinine criteria are applied to baseline with regard to the reference range', per the 2017 Pocket Guide.
Paul
A few points.
By criteria only...we all know there is more to a diagnosis than critiera.
1) KDIGO says you can have AKI even if your measured levels are in the normal range because as Paul stated, baseline is more important than reference range.
2) KDIGO says the lowest measured criteria taken during a stay can be used as the baseline. I am not aware of the severity of the dilutional effect that being severely fluid overloaded might here but I assume it is a real issue, this is why clinical correlation must be applied.
3) The fact that a patient is dehydrated, is not in itself exculpatory of a diagnosis of AKI under modern standards. It used to be, until the renal experts of the world elected to identify such cases as AKI even when the kidneys are technically functioning perfectly with no true intra-renal pathology. AKA "pre-renal" aki.
4) It is also correct that you cannot use the aggressive 0.3mg/dl threshold unless you have a prospective measurement. Otherwise you need a criteria of 1.5x the baseline for retrospective measurements, but the time frame is extended out for about 7 days as opposed to using a prospective criteria of 0.3mg wish must have been measured over a 48 hour max delta.
5) GFR can certainly be used for AKI and the threshold is fairly simple. As pointed out a decrease by 50% of the assumed baseline. In the example above going from 84 to 181 represents a 46% increase without knowing the Scr. One problem with the example is it does not say how quickly the onset was, or how rapidly the recovery was. A shrewed auditor may try and deny if there is wasn't a Scr. Using the Scr of 0.79 and 0.45 you meet the absolute 0.3 threshold, but you don't know the time frame it occurred as the example does not state if it was prospective but as Jeff pointed out it works out to well over 1.5x baseline so as a retrospective measurement, it doesn't have to have been observed and could have developed over 7 days instead of 48 hours. It still meets.
6) Also as Jeff pointed out it becomes more important to measure UOP in pediatrics, the elderly, pregnancy, shock, or pre-existing intra renal pathology as the UOP standard my be what gets observed well before the SCR of GFR.
To note this is all criteria and lab based assessment. AKI should never be ruled in without clinical correlation. It should also never be denied based on a laboratory standard by a payer without clinical correlation either (but it happens all the time).
aariley. Thank you for sharing your clinical insight on this topic.
Paul E.