Epidemiology and Pathogenesis of Acute Kidney Injury in the Critically Ill Patients

The Reality of Evaluating Urine Spot Sodium and Urine Spot Sodium Creatinine Ratio in Furosemide Stress Test as a New Biomarker in Diagnosing Progressive AKI in Critically Ill

How to cite this article: Chatterjee R, Gupta L. The Reality of Evaluating Urine Spot Sodium and Urine Spot Sodium Creatinine Ratio in Furosemide Stress Test as a New Biomarker in Diagnosing Progressive AKI in Critically Ill. Indian J Crit Care Med 2024;28(12):1089-1090.

Role of Spot Urine Sodium in Furosemide Stress Test in Volume-overloaded Critically Ill Patients with Acute Kidney Injury

Introduction and aims

Urine output (UO) in response to furosemide stress test (FST) can predict the progression of acute kidney injury (AKI). This study aimed to assess if changes in UO, urine spot sodium (USS), urine spot sodium creatinine ratio (USSCR) and changes in these parameters over 6 hours could differentiate between progressive and non-progressive AKI.

Materials and methods

Fifty critically ill adults with AKI in acute kidney injury network (AKIN) stages I and II with volume overload were included in this prospective study. The FST was performed with 1 mg/kg intravenous bolus. Hourly UO, USS, USSCR, maximum USS difference (USSDMAX), and maximum USSCR difference (USSCRDMAX) were documented. Any progression of AKI was noted till day 3.

Results

A total of 50 patients were recruited and n = 10 had progressive AKI (PAKI) and n = 40 had non-progressive AKI (NPAKI). Urine output at 1 and 2 h were significantly less in PAKI group. USS0, USS2, USS6, and USSDMAX were comparable between the groups. USSCR0 and USSCR6 were comparable between the groups whereas USSCR2 and USSCRDMAX were significantly less in PAKI group. USSDMAX did not correlate with UO1 (correlation coefficient 0.2, p = 0.16). However, USSCRDMAX showed a poor but significant correlation with UO1 (correlation coefficient 0.3, p = 0.03).

Conclusion

To conclude, hourly UO in the first two hours and maximum change in USSCR within 6 hours following the FST may have an important role in early differentiation of progressive AKI in critically ill patients.

How to cite this article

Suhas P, Anand RK, Baidya DK, Dehran M. Role of Spot Urine Sodium in Furosemide Stress Test in Volume-overloaded Critically Ill Patients with Acute Kidney Injury. Indian J Crit Care Med 2024;28(12):1107-1111.

Linezolid Adsorption on Filters during Continuous Renal Replacement Therapy: An In Vitro Study

Background: Renal replacement therapy (RRT), widely used in the treatment of renal injury during sepsis, aims to eliminate the toxins and proinflammatory cytokines involved in the pathomechanism underlying septic shock. Dialysis filters are characterized by a high adsorption potential for cytokines in RRT in the case of septic renal injury. For the treatment of sepsis with antibiotics, it is of key importance to achieve the desired values of PK/PD indices. Continuous renal replacement therapy (CRRT) may affect antimicrobial clearance, increasing their elimination in some cases. Methods: The aim of this study was to determine the degree of adsorption for linezolid on three different types of filters used in CRRT. In our in vitro study, a continuous veno-venous hemofiltration (CVVH) was conducted using three types of filters: polysulfone (PS), polyethyleneimine-treated polyacrylonitrile (PAN PEI), and non-PEI-treated polyacrylonitrile (PAN). Each type of filter was used in three CVVH cycles, involving the use of 600 mg of linezolid dissolved in 700 mL of bovine blood or in 700 mL of 0.9% NaCl. In each case, the total volume of the obtained solution was 1000 mL. Blood samples were collected at particular time points to measure their drug concentration. The differences in mean drug/NaCl adsorption and drug/blood adsorption were determined using a one-way ANOVA with multiple comparisons via Tukey's post hoc test; a p-value of <0.05 was considered significant. Results: A significant adsorption of linezolid was found for PAN PEI filters, both in samples obtained from bovine blood and 0.9% NaCl solutions, at the endpoint. In PAN PEI samples, the concentration of linezolid in 0.9% NaCl solutions decreased from 594.74 μg/mL to 310.66 μg/mL after 120 min (the difference was established at 52%). In blood samples, the initial concentration was 495.18 μg/mL, which then decreased to 359.84 μg/mL (73% of the beginning value). No significant adsorption was demonstrated on PAN or PS filters. Conclusion: There is a need for in vivo research to confirm the effect of filter type on linezolid concentration in patients undergoing CRRT.

Biochemical Predictors of Acute Kidney Injury in Critically Ill COVID-19 Patients

It is estimated that 50% of patients with coronavirus disease 2019 (COVID-19) have varying degrees of renal involvement. In this clinical biomarker development research, we examined in a retrospective study design the temporal changes in biochemical laboratory parameters in relation to the development of acute kidney injury (AKI). In a sample of 399 patients admitted from May 2020 to May 2021 to a tertiary health care intensive care unit (ICU), the incidence of AKI was 27.3%, and the median time to AKI was on 7th day of ICU admission. Most common etiology of AKI was kidney hypoperfusion. Within 72 h of developmental of low blood pressure, 63.76% developed AKI. The likelihood of AKI was higher in those with elevated serum ferritin, aspartate transaminase, and thrombocytopenia (low platelet count). A cutoff value of 750.3 ng/mL [area under the ROC curve (AUC) = 0.777] for serum ferritin, and 40.05 U/L for alanine aminotransferase (AUC = 0.677) 1 day before development of AKI displayed, respectively, a sensitivity of 76.2% and 64.3%, whereas the specificity was 69.5% and 64.1%, respectively, for these two biochemical predictors. A cutoff value of platelets (152.50 × 10⁹/L [AUC = 0.75]) measured 4 days before development of AKI, displayed 83.3% sensitivity and 16.4% specificity. Taken together, our study thoroughly examined the temporal association of various clinical and laboratory parameters with AKI and prediction models were developed as per results of the time series data. These observations in a tertiary health care setting contribute to ongoing efforts for biomarker discovery and development using routine biochemical tests so as to forecast AKI in patients with COVID-19.

Plasma proteomic characterization of the development of acute kidney injury in early sepsis patients

Acute kidney injury (AKI) develops frequently in the course of patients with sepsis and strongly associates with in-hospital mortality. However, diagnosing AKI involves a considerable lag-time because it depends on assessing an increase in serum creatinine, and offers no insight in the underlying pathophysiology. Consequently, identifying a set of proteins reflecting the development of AKI may improve earlier recognition of AKI and the understanding of its pathophysiology. A targeted plasma proteomic approach was performed in early sepsis patients with and without subsequent AKI development in a matched pair design (n = 19 each). Principal component analysis identified 53 proteins associated with development of AKI, which were further analysed using Enrichr gene ontology and pathway analysis. Nine differentially expressed proteins from the targeted proteomics were increased among patients who subsequently developed AKI and correlated with principal components, namely CALCA, CALR, CA12, CLEC1A, PTK7, KIM-1, NPPC, NUCB2 and PGF. We demonstrated the biological insight in the development of AKI in early sepsis compared to non-AKI sepsis.

Prioritization of ICU beds with renal replacement therapy support by court order and mortality in a Brazilian metropolitan area

The shortage of intensive care unit (ICU) resources, including equipment and supplies for renal replacement therapy (RRT), is a critical problem in several countries. This study aimed to assess hospital mortality and associated factors in patients treated in public hospitals of the Federal District, Brazil, who requested admission to ICU with renal replacement therapy support (ICU-RRT) in court. Retrospective cohort study that included 883 adult patients treated in public hospitals of the Federal District who requested ICU-RRT admission in court from January 2017 to December 2018. ICU-RRT was denied to 407 patients, which increased mortality (OR 3.33, 95% CI 2.39–4.56, p ≪ 0.01), especially in patients with priority level I/II (OR 1.02, 95% CI 1.01–1.04, p ≪ 0.01). Of the requests made in court, 450 were filed by patients with priority levels III/IV, and 44.7% of these were admitted to ICU-RRT. In admitted patients, priority level III priority level I/II was associated with a low mortality (OR 0.47, 95% CI 0.32–0.69, p < 0.01), and not. The admission of patients classified as priority levels III/IV to ICU-RRT considerably jeopardized the admission of patients with priority levels I/II to these settings. The results found open new avenues for organizing public policies and improving ICU-RRT triage.