Simple blood and urinary parameters measured at ICU admission may sign for AKI development in the early postoperative period: a retrospective, exploratory study

Abstract

Recent studies have suggested that some blood physicochemical and urinary biochemical parameters have a standardized behavior during acute kidney injury (AKI) development. The changes in these parameters frequently begin to occur before significant rises in serum creatinine (sCr) and may help in identifying patients with more subtle decreases in glomerular filtration rate (GFR). Surgical patients have an increased risk of AKI but renal impairment is usually not evident at ICU admission. We hypothesized that the surgical patients who have AKI diagnosed in the early postoperative period have an impaired GFR since ICU admission, indirectly inferred by alterations in these blood physicochemical and urinary biochemical parameters even in the presence of a still normal sCr. We retrospectively evaluated 112 surgical patients who were categorized according to AKI development during the first 3 ICU days. Twenty-eight patients developed AKI, most of them in the first day (D1) after ICU admission (D0). AKI patients had, at D0, lower serum pH and albumin, higher C -reactive protein (CRP), lower urine sodium (NaU) and fractional excretion of urea (FEUr). Fractional excretion of potassium (FEK) was high in both groups at D0 but remained high in the subsequent days only in AKI patients. Very low CRP and high serum albumin, high NaU and FEUr values at ICU admission had a significant negative predictive value for AKI. We concluded that some easily assessed parameters in blood and urine may help to identify patients with indirect signs of increased inflammatory response and decreased GFR at ICU admission, which could help to predict the risk of postoperative AKI development. ARTICLE HISTORY

Acute Kidney Injury Induced by Bothrops Venom: Insights into the Pathogenic Mechanisms

“…FE K was analyzed in patients with different diagnoses in an intensive care unit, with No-AKI, transient and persistent AKI without renal replacement therapy. It was not altered by diuretic use [41]. In our study, FE K showed the highest accuracy by the AUC-ROC in predicting AKI diagnosis.…”

“…Although FE Ur and FE Na may be useful in differentiating between functional (pre-renal) and structural AKI (secondary to ischemia, toxins or both), the interpretation of these parameters remains conflicting [38,39,40,41]. Few studies have reported the performance of FE K in predicting AKI [40,41]. FE K was analyzed in patients with different diagnoses in an intensive care unit, with No-AKI, transient and persistent AKI without renal replacement therapy.…”

“…Most urinary K can be accounted by electrogenic secretion, mediated by principal cells in the initial and cortical collecting duct, leading to greater and more evident variations in FE K than FE Na or FE urea [42]. K secretion is partially dependent on the luminal tubular flow rate, which was not measured between the groups; however, urinary volume is not included in FE K, which goes against this idea [41]. FE Na was higher than 1% and FE urea was higher than 35% in the AKI group, which could represent impairment of the tubular capacity to retain sodium and urea.…”

Association between Urinary Potassium Excretion and Acute Kidney Injury in Critically Ill Patients

“…Similarly, biomarkers have their own limitations in predicting AKI as they are costly, and no single marker is specific and has slow turnaround time, making the diagnosis of AKI challenging in ICUs. 19 …”

Acute Kidney Injury in the Intensive Care Unit: The Most Reliable Way to Predict the Future is to Create It

“… 18 The same group demonstrated, in a retrospective analysis of postoperative patients, that while serum creatinine increases two days after ICU admission, higher fractional excretion of potassium values may appear as early as the day of admission, indicating patients at a higher risk of AKI. 19 Smyth et al estimated 24 hours urinary sodium and potassium excretion in 28,879 participants at high cardiovascular risk to conclude that urinary potassium excretion predicted clinically significant renal outcomes better than UNa. 20 …”