Early and late acute kidney injury: temporal profile in the critically ill pediatric patient

Perioperative Incidence of Acute Renal Failure in Aortic Arch Reconstruction Using Retrograde Selective Lower Body Perfusion in Neonates and Infants

OBJECTIVE

Examination of the impact of retrograde selective lower body perfusion (SLP) via a femoral arterial catheter on urine output and the incidence of acute kidney injury (AKI) during pediatric aortic arch reconstructions. The secondary objective was if the cannulation of the superficial femoral artery was associated with complications in the perfusion area.

DESIGN

A retrospective study over an 8-year period (January 2015 to December 2023).

SETTING

Pediatric heart center of a tertiary care hospital.

PARTICIPANTS

Neonates and infants (N = 104) undergoing elective aortic arch reconstruction with cardiopulmonary bypass, of whom 45 received retrograde SLP.

INTERVENTIONS

Retrograde SLP via ultrasound-guided, weight-adapted femoral artery catheters for retrograde perfusion during clamping of the descending aorta under surgery, compared to a control group with identical surgical, perfusion, and anesthesiologic management but without SLP.

MEASUREMENTS AND MAIN RESULTS

Perioperative AKI incidence was analyzed using KDIGO criteria at multiple predetermined time points, along with urinary output. The SLP group showed a significantly lower AKI incidence immediately and 6 hours postsurgery (p = 0.001). Higher urine output postoperatively until day 3 (p ≤ 0.045) in the SLP group. No vascular complications were observed until hospital discharge.

CONCLUSIONS

Retrograde SLP is associated with a reduced AKI incidence and increased postoperative urine output, without vascular complications. Further studies are needed to investigate the long-term effects of retrograde SLP on renal function.

Pediatric Considerations in Post Acute Kidney Injury Care

Acute kidney injury in children is associated with adverse outcomes. These include longer hospital stays, increased mortality, and nonrecovery of kidney function in the short term and increased health care utilization, new onset hypertension, and chronic kidney disease in the long term. Systematic post acute kidney injury care may help mitigate some of the complications that follow acute kidney injury. Patient, family, and health care team education is a key aspect of post acute kidney injury care. This includes individualized education to the patient and family, ideally prior to hospital discharge, provision of a discharge summary with details of the acute kidney injury episode and follow-up plan, and communication with the primary care provider. Given that severe acute kidney injury may often be seen in patients with other underlying medical conditions, partnership between the primary care provider, non-nephrology specialist and the nephrologist, and the use of telehealth may facilitate follow-up without increasing caregiver burden. Ongoing surveillance includes monitoring kidney function, proteinuria, and hypertension. There are no guidelines on the frequency of this evaluation or the duration of follow-up. These decisions should be individualized based on the characteristics of the index acute kidney injury episode and underlying risk factors for chronic kidney disease.

Sociodemographic Disparities in 1-Year Outcomes of Children With Community-Acquired Acute Kidney Injury

Importance

Racial disparities have been identified in pediatric community-acquired acute kidney injury (CA-AKI), and they are associated with increased risk of child mortality, morbidity, and progression of kidney disease.

Objective

To assess clinical outcomes at 1 year among children with CA-AKI, stratified by age, race, and ethnicity.

Design, Setting, and Participants

This retrospective cohort study is a population-based analysis of deidentified, aggregated electronic health record data collected by 61 large health care organizations from 2003 to 2023 and accessed through the TriNetX platform. Outcomes were assessed at 1 year after a CA-AKI episode. Participants included pediatric patients (aged <18 years) with AKI. Data were accessed in January 2024.

Exposure

A diagnosis of CA-AKI and sociodemographic factors such as race, ethnicity, and age, as reported in electronic health records.

Main Outcomes and Measures

The primary end point of this study was to assess differences in clinical outcomes within 1 year of an episode of CA-AKI, including all-cause emergency department (ED) visits, intensive care unit (ICU) admissions, mechanical intubation and ventilation, and mortality. Risk was compared between White children and Asian (including Asian, Native Hawaiian, and Other Pacific Islander), Black, and Hispanic children, stratified by age group. Measures of association, Cox proportional hazard analyses, and Kaplan-Meier survival curves were performed within the TriNetX Advanced Analytics Platform between racial and ethnic groups for each analysis.

Results

From the total sample of 18 152 children, those with hospital-acquired AKI, chronic kidney disease, end-stage kidney failure, or dialysis dependence were excluded, leaving a final cohort of 17 125 children (mean [SD] age, 11.2 [5.2] years; 9424 male [55.3%]). Eligible patients were divided into racial and ethnic groups as follows: non-Hispanic Asian, 1169 children (6.5%); non-Hispanic Black, 4636 children (27.3%); Hispanic, 1786 children (10.2%); and non-Hispanic White, 9534 children (55.9%). Patients were further subdivided into groups aged 0 to 9 years (546 Asian children, 1675 Black children, 689 Hispanic children, and 3340 White children) and 10 to 18 years (623 Asian children, 2961 Black children, 1091 Hispanic children, and 6104 White children). Within 1 year of CA-AKI diagnosis, compared with White children, Black children experienced greater rates of ED visits (hazard ratio [HR], 1.53; 95% CI, 1.40-1.67), ICU admissions (HR, 1.31; 95% CI, 1.16-1.47), mechanical ventilation (HR, 1.33; 95% CI, 1.13-1.56), and all-cause mortality (HR, 1.27; 95% CI, 1.09-1.48), as well as the greatest risk for composite outcomes (HR, 1.43; 95% CI, 1.33-1.53). Hispanic children experienced greater rates of ED visits (HR, 1.40; 95% CI, 1.21-1.62) and the greatest risk of all-cause mortality (HR, 1.66; 95% CI, 1.31-2.09), whereas Asian children experienced greater rates of mechanical ventilation (HR, 1.69; 95% CI, 1.26-2.27), compared with White children. Black and Hispanic children aged 0 to 9 years were at greatest risk of experiencing poor clinical outcomes. Black children had a 11.41% lower survival probability and Hispanic children had a 7.14% lower survival probability compared with White children after an initial ED encounter.

Conclusions and Relevance

Among children with an identified episode of CA-AKI diagnosed in an ED, within 1 year, Black and Hispanic children had a poorer survival probability compared with White children. Future studies are needed to understand these disparities and improve awareness and follow-up after emergency care.

Diuretic response after neonatal cardiac surgery: a report from the NEPHRON collaborative

BACKGROUND

Multicenter early diuretic response (DR) analysis of single furosemide dosing following neonatal cardiac surgery is lacking to inform whether early DR predicts adverse clinical outcomes.

METHODS

We performed a retrospective cohort study utilizing data from the NEPHRON registry. Random forest machine learning generated receiver operating characteristic-area under the curve (ROC-AUC) and odds ratios for mechanical ventilation (MV) and respiratory support (RS). Prolonged MV and RS were defined using ≥ 90th percentile of observed/expected ratios. Secondary outcomes were prolonged CICU and hospital length of stay (LOS) and kidney failure (stage III acute kidney injury (AKI), peritoneal dialysis, and/or continuous kidney replacement therapy on postoperative day three) assessed using covariate-adjusted ROC-AUC curves.

RESULTS

A total of 782 children were included. Cumulative urine output (UOP) metrics were lower in prolonged MV and RS patients, but DR poorly predicted prolonged MV (highest AUC 0.611, OR 0.98, sensitivity 0.67, specificity 0.53, p = 0.006, 95% OR CI 0.96-0.99 for cumulative 6-h UOP) and RS (highest AUC 0.674, OR 0.94, sensitivity 0.75, specificity 0.54, p < 0.001, 95% CI 0.91-0.97 UOP between 3 and 6 h). Secondary outcome results were similar. DR had fair discrimination for kidney failure (AUC 0.703, OR 0.94, sensitivity 0.63, specificity 0.71, 95% OR CI 0.91-0.98, p < 0.001, cumulative 6-h UOP).

CONCLUSIONS

Early DR poorly discriminated patients with prolonged MV, RS, and LOS in this cohort, though it may identify severe postoperative AKI phenotype. Future work is warranted to determine if early DR or late postoperative DR later, in combination with other AKI metrics, may identify a higher-risk phenotype.

Heterogeneity in the definition of major adverse kidney events: a scoping review

Acute kidney injury (AKI) is associated with persistent renal dysfunction, the receipt of dialysis, dialysis dependence, and mortality. Accordingly, the concept of major adverse kidney events (MAKE) has been adopted as an endpoint for assessing the impact of AKI. However, applied criteria or observation periods for operationalizing MAKE appear to vary across studies. To evaluate this heterogeneity for MAKE evaluation, we performed a systematic scoping review of studies that employed MAKE as an AKI endpoint. Four major academic databases were searched, and we identified 122 studies with increasing numbers over time. We found marked heterogeneity in applied criteria and observation periods for MAKE across these studies, with some even lacking a description of criteria. Moreover, 13 different observation periods were employed, with 30 days and 90 days as the most common. Persistent renal dysfunction was evaluated by estimated glomerular filtration rate (34%) or serum creatinine concentration (48%); however, 37 different definitions for this component were employed in terms of parameters, cut-off criteria, and assessment periods. The definition for the dialysis component also showed significant heterogeneity regarding assessment periods and duration of dialysis requirement (chronic vs temporary). Finally, MAKE rates could vary by 7% [interquartile range: 1.7-16.7%] with different observation periods or by 36.4% with different dialysis component definitions. Our findings revealed marked heterogeneity in MAKE definitions, particularly regarding component assessment and observation periods. Dedicated discussion is needed to establish uniform and acceptable standards to operationalize MAKE in terms of selection and applied criteria of components, observation period, and reporting criteria for future trials on AKI and related conditions.

An update on the role of fluid overload in the prediction of outcome in acute kidney injury

Over the past two decades, our understanding of the impact of acute kidney injury, disorders of fluid balance, and their interplay have increased significantly. In recent years, the epidemiology and impact of fluid balance, including the pathologic state of fluid overload on outcomes has been studied extensively across multiple pediatric and neonatal populations. A detailed understating of fluid balance has become increasingly important as it is recognized as a target for intervention to continue to work to improve outcomes in these populations. In this review, we provide an update on the epidemiology and outcomes associated with fluid balance disorders and the development of fluid overload in children with acute kidney injury (AKI). This will include a detailed review of consensus definitions of fluid balance, fluid overload, and the methodologies to define them, impact of fluid balance on the diagnosis of AKI and the concept of fluid corrected serum creatinine. This review will also provide detailed descriptions of future directions and the changing paradigms around fluid balance and AKI in critical care nephrology, including the incorporation of the sequential utilization of risk stratification, novel biomarkers, and functional kidney tests (furosemide stress test) into research and ultimately clinical care. Finally, the review will conclude with novel methods currently under study to assess fluid balance and distribution (point of care ultrasound and bioimpedance).

Epidemiology, Risk Factors, and Clinical Outcomes of AKI in Pediatric Hematopoietic Stem Cell Transplant Patients

Key Points

The cumulative incidence of AKI diagnosis post–hematopoietic stem cell transplantation was 12.9%. Calcineurin inhibitor use was associated with the highest cumulative incidence, 21.6%, after hematopoietic stem cell transplantation. Patients with AKI with hypertension/hypertensive disease had a 30-day survival probability of 63.9% (hazard ratio, 4.86, 95% confidence interval, 3.58 to 6.60). Patients with AKI were 2.5 times more likely to experience composite hospitalization and/or mortality at 30 days. Of patients who developed AKI, dialysis dependence has nearly tripled since 2014.

Background

AKI is a common complication in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT), with a reported prevalence ranging from 68% to 84%. Few multicenter pediatric studies comprehensively assess the epidemiologic associations and clinical outcomes associated with AKI development.

Methods

An observational, retrospective analysis was conducted using an aggregated electronic health record data platform. The study population consisted of pediatric patients (age <18 years) who underwent HSCT over a 20-year period. The study groups consisted of patients with an encounter diagnosis of AKI (n =713) and those without AKI (n =4455). Both groups were propensity matched for age, sex, race, prior cancer diagnosis, and other comorbidities. End points were incidence, mortality risk, clinical outcomes, and prevalence of dialysis dependence. Competing risks analysis, Cox proportional hazard analyses, Kaplan–Meier survival curves, and incidence/prevalence rates were calculated.

Results

After matching, 688 patients were identified. Cumulative incidence of AKI diagnosis post-HSCT was 13.7%. Hypertensive disease, calcineurin inhibitors, and vancomycin were the most prevalent risk factors for AKI, with calcineurin inhibitors showing the highest cumulative incidence (21.6%). Patients with AKI with hypertensive disease had a survival probability of 63.9% at 30 days, followed by calcineurin inhibitors (64.4%) and vancomycin (65.9%). Patients with AKI were 1.7 times more likely to experience composite hospitalization and/or mortality at 30 days. At 365 days post-HSCT, patients with AKI had higher rates of all-cause emergency department visits, intensive care unit admissions, and mechanical ventilation compared with non-AKI. Of patients who developed AKI, the prevalence of dialysis dependence has nearly tripled since 2014.

Conclusions

The findings highlight a strong association between specific risk factors, such as hypertension, calcineurin inhibitor use, and vancomycin use, with increased mortality and adverse clinical outcomes in patients with AKI after HSCT. These results emphasize the need for preventative actions such as 24-hour BP monitoring and discontinuation of potential nephrotoxic medications.

Pattern and prognostic factors for kidney function progression in survivors of children with acute kidney injury: a cohort study

OBJECTIVE

To examine the pattern of kidney function progression after acute kidney injury (AKI) and identify the associated risk factors.

DESIGN

A prospective cohort study was conducted from June 2020 to June 2021 on children aged 1 month to <18 years admitted to the paediatric intensive care unit (PICU). Acute kidney disease (AKD) was defined as AKI persisting from 7 to 90 days after diagnosis. The natural history and prognostic factors of kidney function progression were determined.

RESULTS

Among the 253 admissions with a median (IQR) age of 4.9 (9.7) years, the AKI and AKD incidence was 41.9% and 52.2% respectively. The incidence of estimated glomerular filtration rate (eGFR) <90 mL/min/1.73 m2 was 6.7% at 90 days and 11.9% at latest follow-up. Severe and prolonged AKI and higher degree of nephrotoxic medication exposure were associated with AKD development. The severity and duration of AKI and AKD significantly predicted kidney function non-recovery. Children with both entities exhibited a higher peak-to-baseline serum creatinine level ratio at 90 days (1.6 vs 1.0, p<0.001), and a more pronounced decline in eGFR (21% vs 19%, p=0.028) during the follow-up period compared with those without AKI/AKD. They also had an increased risk of having eGFR <90 mL/min/1.73 m2 at 90 days (HR 14.9 (95% CI 1.8 to 124.0)) and latest follow-up (HR 3.8 (95% CI 1.1 to 13.1)).

CONCLUSIONS

AKI and AKD are prevalent among critically ill children and pose substantial risk for non-recovery of kidney function among PICU survivors. A structural follow-up visit for AKI survivors to monitor kidney function progression is advocated.

Epidemiology of acute kidney injury in children: a report from the 26th Acute Disease Quality Initiative (ADQI) consensus conference

The nephrology and critical care communities have seen an increase in studies exploring acute kidney injury (AKI) epidemiology in children. As a result, we now know that AKI is highly prevalent in critically ill neonates, children, and young adults. Furthermore, children who develop AKI experience greater morbidity and higher mortality. Yet knowledge gaps still exist that suggest a more comprehensive understanding of AKI will form the foundation for future efforts designed to improve outcomes. In particular, the areas of community acquired AKI, AKI in non-critically ill children, and cohorts from low-middle income countries have not been well studied. Longer-term functional outcomes and patient-centric metrics including social determinants of health, quality of life, and healthcare utilization should be the foci of the next phase of scholarship. Current definitions identify AKI-based upon evidence of dysfunction which serves as a proxy for injury; biomarkers capable of identifying injury as it occurs are likely to more accurately define populations with AKI. Despite the strength of the association, the causal and mechanistic relationships between AKI and poorer outcomes remain inadequately examined. A more robust understanding of the relationship represents a potential to identify therapeutic targets. Once established, a more comprehensive understanding of AKI epidemiology in children will allow investigation of preventive, therapeutic, and quality improvement interventions more effectively.

Acute kidney injury and renal recovery following Fontan surgery

Objectives

Acute kidney injury has been described after Fontan surgery, but the duration and outcomes are unknown. We sought to describe the incidence of and risk factors for acute kidney injury and the phenotype of renal recovery, and evaluate the impact of renal recovery phenotype on outcomes.

Methods

All children who underwent a Fontan operation at a single center between 2009 and 2022 were included. Data collected included Fontan characteristics, vasopressor use, all measures of creatinine, and postoperative outcomes. Logistic regression models were used to assess predictors of acute kidney injury and the association between acute kidney injury and outcomes.

Results

We enrolled 141 children (45% female). Acute kidney injury occurred in 100 patients (71%). Acute kidney injury duration was transient (<48 hours) in 77 patients (55%), persistent (2-7 days) in 15 patients (11%), more than 7 days in 4 patients (3%), and unknown in 4 patients (3%). Risk factors for acute kidney injury included higher preoperative indexed pulmonary vascular resistance (odds ratio, 3.90; P = .004) and higher postoperative inotrope score on day 0 (odds ratio, 1.13, P = .047). Risk factors for acute kidney injury duration more than 48 hours included absence of a fenestration (odds ratio, 3.43, P = .03) and longer duration of cardiopulmonary bypass (odds ratio, 1.22 per 15-minute interval, P = .01). Acute kidney injury duration more than 48 hours was associated with longer length of stay compared with transient acute kidney injury (median 18 days [interquartile range, 9-62] vs 10 days [interquartile range, 8-16], P = .006) and more sternal wound infections (17% vs 4%, P = .049).

Conclusions

Acute kidney injury after the Fontan operation is common. The occurrence and duration of acute kidney injury have significant implications for postoperative outcomes.

Subphenotypes of Pediatric Acute Kidney Injury

Acute kidney injury (AKI) is seen frequently in hospitalized patients and is associated with increased risk of mortality and adverse short- and long-term renal and systemic complications. Emerging data suggest that AKI is a heterogenous syndrome with a variety of underlying causes, predisposing illnesses, and range of clinical trajectories and outcomes. This mini-review aims to discuss emerging AKI subphenotype classifications as our understanding of the heterogeneity and underlying pathophysiology has improved.

Acute Kidney Injury and Sepsis after Cardiac Surgery: The Roles of Tissue Inhibitor Metalloproteinase-2, Insulin-like Growth Factor Binding Protein-7, and Mid-Regional Pro-Adrenomedullin

BACKGROUND

Identifying a panel of markers detecting kidney injury before the glomerular filtration rate reduction is a challenge to improving the diagnosis and management of acute kidney injury (AKI) in septic patients. This study evaluated the roles of tissue inhibitor metal proteinase-2, insulin growth factor binding protein-7 (TIMP2*IGFBP7), and mid-regional pro-adrenomedullin (MR-proADM) in patients with AKI.

PATIENTS AND METHODS

This study was prospectively conducted in an intensive care unit (ICU) enrolling 230 patients who underwent cardiac surgery. Biomarkers were evaluated before and after 4 h of the cardiac surgery.

RESULTS

Whereas urine and creatinine alterations appeared at 23.2 (12.7-36.5) hours after cardiac surgery, urinary TIMP2*IGBP7 levels were higher at 4 h in AKI patients (1.1 ± 0.4 mg/L vs. 0.08 ± 0.02 mg/L; p < 0.001). Its concentration > 2 mg/L increases AKI risk within the following 24 h, clearly identifying the population at high risk of renal replacement therapy (RRT). In patients with sepsis, MR-proADM levels were 2.3 nmol/L (0.7-7.8 nmol/L), with the highest values observed in septic shock patients (5.6 nmol/L (3.2-18 nmol/L)) and a better diagnostic profile than procalcitonin and C-reactive protein to identify septic patients. MR-proADM values > 5.1 nmol/L and urine TIMP2*IGBP7 levels > 2 mg/L showed a significantly faster progression to RRT, with a mean follow-up time of 1.1 days.

CONCLUSIONS

TIMP2*IGBP7 and MR-proADM precociously diagnose AKI in septic patients after cardiac surgery, giving prognostic information for RRT requirement.

Outcomes associated with unrecognized acute kidney injury in postoperative pediatric cardiac patients

BACKGROUND

The present retrospective study was carried out to determine the incidence of unrecognized cardiac surgery-associated acute kidney injury (CSA-AKI) due to infrequency of serum creatinine (SCr) measurements in pediatric cardiac patients and to assess the association between unrecognized CSA-AKI and clinical outcomes.

METHODS

This study was a single-center, retrospective study of pediatric patients who underwent cardiac surgery. Patients were diagnosed with CSA-AKI based on SCr measurements, and unrecognized CSA-AKI was defined under the assumptions that there had been only one or two SCr measurements within 48 h after surgery: CSA-AKI unrecognized by one SCr measurement (AKI-URone), CSA-AKI unrecognized by two SCr measurements (AKI-URtwo), and CSA-AKI recognized by one and two SCr measurements (AKI-R). The change of SCr from baseline to postoperative day 30 (delta SCr30d) was assessed as a surrogate of kidney recovery.

RESULTS

In a total of 557 cases, 313 patients (56.2%) were diagnosed with CSA-AKI, 188 (33.8%) of whom had unrecognized CSA-AKI. Delta SCr30d in the AKI-URtwo group and delta SCr30d in the AKI-URone group was not significantly different from delta SCr30d in the non-AKI group (p = 0.67 and p = 0.79, respectively). There were significant differences in the durations of mechanical ventilation, serum B-type natriuretic peptide levels, and lengths of stay in hospital between the non-AKI group and the AKI-URtwo group and between the non-AKI group and the AKI-URtwo group.

CONCLUSIONS

Unrecognized CSA-AKI due to infrequent SCr measurements is not rare and is associated with prolonged mechanical ventilation, high postoperative BNP level, and prolonged length of stay in hospital. A higher resolution version of the Graphical abstract is available as Supplementary information.

Fluid Overload Precedes and Masks Cryptic Kidney Injury in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

Given the complex interrelatedness of fluid overload (FO), creatinine, acute kidney injury (AKI), and clinical outcomes, the association of AKI with poor outcomes in critically ill children may be underestimated due to definitions used. We aimed to disentangle these temporal relationships in a large cohort of children with acute respiratory distress syndrome (ARDS).

DESIGN

Retrospective cohort study.

SETTING

Quaternary care PICU.

PATIENTS

Seven hundred twenty intubated children with ARDS between 2011 and 2019.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Daily fluid balance, urine output (UOP), and creatinine for days 1-7 of ARDS were retrospectively abstracted. A subset of patients had angiopoietin 2 (ANGPT2) quantified on days 1, 3, and 7. Patients were classified as AKI by Kidney Disease Improving Global Outcomes (KDIGO) stage 2/3 then grouped by timing of AKI onset (early if days 1-3 of ARDS, late if days 4-7 of ARDS, persistent if both) for comparison of PICU mortality and ventilator-free days (VFDs). A final category of "Cryptic AKI" was used to identify subjects who met KDIGO stage 2/3 criteria only when creatinine was adjusted for FO. Outcomes were compared between those who had Cryptic AKI identified by FO-adjusted creatinine versus those who had no AKI. Conventionally defined AKI occurred in 26% of patients (early 10%, late 3%, persistent 13%). AKI was associated with higher mortality and fewer VFDs, with no differences according to timing of onset. The Cryptic AKI group (6% of those labeled no AKI) had higher mortality and fewer VFDs than patients who did not meet AKI with FO-adjusted creatinine. FO, FO-adjusted creatinine, and ANGPT2 increased 1 day prior to meeting AKI criteria in the late AKI group.

CONCLUSIONS

AKI was associated with higher mortality and fewer VFDs in pediatric ARDS, irrespective of timing. FO-adjusted creatinine captures a group of patients with Cryptic AKI with outcomes approaching those who meet AKI by traditional criteria. Increases in FO, FO-adjusted creatinine, and ANGPT2 occur prior to meeting conventional AKI criteria.

Impact of the Magnitude and Timing of Fluid Overload on Outcomes in Critically Ill Children: A Report From the Multicenter International Assessment of Worldwide Acute Kidney Injury, Renal Angina, and Epidemiology (AWARE) Study

OBJECTIVES

With the recognition that fluid overload (FO) has a detrimental impact on critically ill children, the critical care nephrology community has focused on identifying clinically meaningful targets for intervention. The current study aims to evaluate the epidemiology and outcomes associated with FO in an international multicenter cohort of critically ill children. The current study also aims to evaluate the association of FO at predetermined clinically relevant thresholds and time points (FO ≥ 5% and FO ≥ 10% at the end of ICU days 1 and 2) with outcomes.

DESIGN

Prospective cohort study.

SETTING

Multicenter, international collaborative of 32 pediatric ICUs.

PATIENTS

A total of 5,079 children and young adults admitted consecutively to pediatric ICUs as part of the Assessment of the Worldwide Acute Kidney Injury, Renal Angina and Epidemiology Study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The FO thresholds at the time points of interest occurred commonly in the cohort (FO ≥ 5%Day1 in 38.1% [ n = 1753], FO ≥ 10%Day1 in 11.7% [ n = 537], FO ≥ 5%Day2 in 53.3% [ n = 1,539], FO ≥ 10%Day2 in 25.1% [ n = 724]). On Day1, multivariable modeling demonstrated that FO ≥ 5% was associated with fewer ICU-free days, and FO ≥ 10% was associated with higher mortality and fewer ICU and ventilator-free days. On multivariable modeling, FO-peak, Day2 FO ≥ 5%, and Day2 FO ≥ 10% were associated with higher mortality and fewer ICU and ventilator-free days.

CONCLUSIONS

This study found that mild-to-moderate FO as early as at the end of ICU Day1 is associated with adverse outcomes. The current study fills an important void in the literature by identifying critical combinations of FO timing and quantity associated with adverse outcomes (FO ≥ 5%Day1, FO ≥10%Day1, FO ≥ 5%Day2, and FO ≥ 10%Day2). Those novel findings will help guide the development of interventional strategies and trials targeting the treatment and prevention of clinically relevant FO.

The Neglected Price of Pediatric Acute Kidney Injury: Non-renal Implications

Preclinical models and emerging translational data suggest that acute kidney injury (AKI) has far reaching effects on all other major organ systems in the body. Common in critically ill children and adults, AKI is independently associated with worse short and long term morbidity, as well as mortality, in these vulnerable populations. Evidence exists in adult populations regarding the impact AKI has on life course. Recently, non-renal organ effects of AKI have been highlighted in pediatric AKI survivors. Given the unique pediatric considerations related to somatic growth and neurodevelopmental consequences, pediatric AKI has the potential to fundamentally alter life course outcomes. In this article, we highlight the challenging and complex interplay between AKI and the brain, heart, lungs, immune system, growth, functional status, and longitudinal outcomes. Specifically, we discuss the biologic basis for how AKI may contribute to neurologic injury and neurodevelopment, cardiac dysfunction, acute lung injury, immunoparalysis and increased risk of infections, diminished somatic growth, worsened functional status and health related quality of life, and finally the impact on young adult health and life course outcomes.