Does this patient have acute kidney injury? An AKI checklist.

Abstract

Imagine receiving a call from a colleague asking for some help evaluating a patient in the emergency department. The patient is 66 years old and apart from some osteoarthritis is in excellent health. She has not seen a physician for several years. She now has fever, cough, and a right lower lobe infiltrate. The doctor has started antibiotics and given some IV fluid but he is concerned about a serum creatinine of 1.3 mg/dl and oliguria (voided only 20 ml in the last 2 h). The serum creatinine gives her an estimated glomerular filtration rate (eGFR) of 44 ml/min [1]. Thus, although it may be unclear if she has acute kidney injury (AKI) or chronic kidney disease (CKD) or both, what is clear is that she has some form of kidney disease. Your colleague wants advice on how to determine whether this patient has developed or is developing AKI. How can you help? The modified RIFLE criteria adopted by the Kidney Disease Improving Global Outcomes (KDIGO) workgroup [2] harmonize pediatric and adult criteria and include both relative and absolute changes in serum creatinine as well as criteria for urine output. However, as explained in the KDIGO guideline, AKI remains a clinical diagnosis. The purpose of the guideline is simply to standardize the objective criteria, but clinical judgment is still required to apply such criteria to a patient. For example, a patient with oliguria for 5 h and 59 min does not suddenly ‘‘develop AKI’’ 1 min later. Similarly, in a patient receiving high-volume fluid resuscitation, the serum creatinine will not reflect acute changes in GFR the same way it will in other patients. Clinicians are not just free to use their judgment in the diagnosis of AKI, they are required to. Large epidemiological studies of AKI may misclassify some patients in one direction or another but overall results will not change; conversely, misdiagnosing a single patient may have significant clinical implications for that patient. To help clinicians make the correct diagnosis, a checklist may be helpful.