Predictions are difficult…especially about AKI

Excerpt

Acute kidney injury (AKI) has been recognised as a major public health problem. Identifying patients at high risk of AKI and diagnosing AKI early are major goals worldwide. The definition of AKI is based on oliguria and elevated serum creatinine levels, two functional markers that are notoriously imperfect [1, 2]. Oliguria is neither sensitive nor specific [1, 3]. It can occur as result of renal injury but may also simply reflect an adaptive physiological response to both intracellular dehydration and hypovolemia [1]. Indeed, only a small proportion of patients in the intensive care unit (ICU) with oliguria have a sustained drop in glomerular filtration rate that leads to a rise in serum creatinine [1]. Serum creatinine is a late marker of renal function. Even when looking at a small rise in serum creatinine of 0.3 mg/dl, which would classify as AKI stage 1 according to current Kidney Disease/Improving Global Outcomes (KDIGO) criteria, acute deterioration in renal function may not be noticeable for >24 h, especially in critically ill patients with fluid accumulation and reduced creatinine generation [4]. These limitations and delays in diagnosis may explain why results from various intervention trials were negative and therapies for AKI are still lacking [5]. …