Acute Kidney Injury After Pediatric Cardiac Surgery: A Secondary Analysis of the Safe Pediatric Euglycemia After Cardiac Surgery Trial

CircPICALM promotes neonatal acute kidney injury triggered by hypoxia/reoxygenation via sponging microRNA-204-5p

BACKGROUND

Circular RNAs (circRNAs) have been documented to regulate neonatal acute kidney injury (AKI). Based on previous RNA-sequence findings, circPICALM exhibited significantly disparate expression between AKI newborns and Controls. This study aimed to provide further insights into the regulatory mechanism of circPICALM in neonatal AKI.

METHODS

C57BL/6 mice born 7 days were divided into Control group and hypoxia groups (11%O2 and 8%O2 groups). Human tubule epithelial cells (HK-2) were stimulated with hypoxia/reoxygenation (H/R) to establish an AKI cell model. Through overexpression and knockdown techniques, the regulatory role of circPICALM in H/R-induced kidney injury was explored. Inflammatory cytokines, cell apoptosis, and oxidative stress were also detected to confirm the regulatory function of circPICALM in neonatal AKI.

RESULTS

RT-qPCR confirmed that circPICALM was highly expressed in the serum of AKI newborns, neonatal I/R mice and H/R-treated HK-2 cells. Functionally, circPICALM exacerbated H/R-induced HK-2 cell injury by aggravating apoptosis and mitochondrial oxidative stress, increasing the expression of inflammatory factors, including IL-6, IL-1β, and TNF-α. Conversely, inhibition of circPICALM alleviated H/R injury in the HK-2 cell line. The interaction between circPICALM and miR-204-5p was validated through RNA immunoprecipitation and luciferase assay. Finally, circPICALM functioned as a molecular sponge of miR-204-5p and promoted the upregulation of downstream IL-1β expression.

CONCLUSION

CircPICALM plays a critical role in H/R-induced neonatal AKI by sponging miR-204-5p and then activating the downstream IL-1β signaling axis. The inhibition of circPICALM and subsequent suppression of pro-inflammatory factors could serve as a promising biomarker and therapeutic target for early intervention in neonatal AKI.

Framework for Kidney Health Follow-Up Among Neonates With Critical Cardiac Disease: A Report From the Neonatal Kidney Health Consensus Workshop

Acute kidney injury is common among neonates with critical cardiac disease. Risk factors and associations with kidney-related outcomes are heterogeneous and distinct from other neonates. As survival of children with critical cardiac disease increases to adulthood, the burden of chronic kidney disease is increasing. Thirty percent to 50% of adults with congenital heart disease have impaired kidney function, even in the absence of prior kidney injury episodes. This may be related to the current standardized acute kidney injury criteria, which may not fully capture clinically meaningful kidney injury and long-term kidney health risks. An improved understanding of which neonates with critical cardiac disease should undergo kidney health follow-up is imperative. During the National Institutes of Health-supported Neonatal Kidney Health Consensus Workshop to Address Kidney Health meeting conducted in February 2024, a panel of 51 neonatal nephrology experts focused on at-risk groups: (1) preterm infants, (2) critically ill infants with acute kidney injury, and (3) infants with critical cardiac disease. The critical cardiac disease subgroup, comprising multidisciplinary experts, used a modified Delphi process to achieve consensus on recommendations for kidney health follow-up. In this report, we review available data on kidney health follow-up in critical cardiac disease and summarize the 2 consensus-based recommendations. We introduce novel diagnostic and risk-stratification tools for acute kidney injury diagnosis in neonates with cardiac disease to guide follow-up recommendations. Finally, we identify important knowledge gaps, representing areas of focus for future research. These should be prioritized to understand and improve long-term kidney health in critical cardiac disease.

Evaluation of uNGAL and TIMP-2*IGFBP7 as early biomarkers of Acute Kidney Injury in Caucasian term and preterm neonates: a prospective observational cohort study

BACKGROUND

Early diagnosis of Acute Kidney Injury (AKI) in neonates is a complex challenge. Novel urinary biomarkers such as uNGAL and TIMP-2*IGFBP7 may be helpful for predicting AKI earlier than changes in serum creatinine (sCr) and urinary output (UOP) in the neonatal period. uNGAL is a marker of tubular injury and its concentration rises immediately after AKI, while the proteins TIMP-2 and IGFBP7 jointly participate in the G1 phase cell cycle arrest processes and their tubular expression and urinary excretion increase in response to kidney damage. The aim of this study is to determine urinary concentrations of uNGAL and TIMP-2*IGFBP7 in term and preterm newborns and to evaluate their predictive role of AKI.

METHODS

Forty-two heathy term neonates and twenty-six preterm infants were prospectively recruited at the NICU of Policlinico in Bari, Italy. uNGAL and TIMP-2*IGFBP7 were measured in fresh urinary samples collected via perineal bag either before discharge (term neonates) or over the first week of life (preterm neonates).

RESULTS

In term neonates median uNGAL and TIMP-2*IGFBP7 concentrations were 41.40 ng/ml (IQR 20.25-74.5) e 0.22 (ng/ml)2/1000 (IQR 0.14-0.34), respectively. In preterm infants without AKI, uNGAL median concentrations over the first week of life ranged between 10 and 16 ng/ml, whereas median concentration of TIMP-2*IGFBP7 ranged between 0.05 and 0.08 (ng/ml)2/1000. Preterm infants who developed AKI during the first week of life had significantly higher uNGAL median concentrations compared to preterm infants without AKI (148.5 vs. 10.0, p = 0.04; 324.0 vs. 15.75, p = 0.02; 318.0 vs. 16.0 ng/ml, p = 0.04). Conversely, TIMP-2*IGFBP7 did not significantly increase in preterm infants with AKI. Preterm female neonates without AKI had significantly higher uNGAL than male neonates (46.5 vs. 10.0 ng/ml; Mann-Whitney U-test, p =0.013).

CONCLUSIONS

Our data show that uNGAL could be more useful than TIMP-2*IGFBP7 for early detection of AKI in preterm newborns. Further studies are needed to evaluate the role of both biomarkers during AKI and their relationship with gender, gestational age and birth weight.

Biomarker-based acute kidney injury sub-phenotypes refine risk assessment in children undergoing cardiac surgery

BACKGROUND

Pediatric cardiac surgery-associated acute kidney injury (CS-AKI) is common with variable association with outcomes, possibly because transient serum creatinine (SCr) elevations are unrelated to kidney disease. Sub-phenotypes of CS-AKI with biomarker integration may provide prognostic enrichment. This study aims to determine if combining early postoperative urine neutrophil gelatinase-associated lipocalin (uNGAL) and SCr into sub-phenotypes strengthens associations with AKI and outcomes. We hypothesized that patients with early subclinical (uNGAL + , SCr -) or damage (uNGAL + , SCr +) CS-AKI would have more postoperative day 2-4 KDIGO-defined AKI and worse clinical outcomes than patients with early functional AKI (uNGAL - , SCr +).

METHODS

Two-center prospective observational study evaluating combinations of early uNGAL (8-12 h from ICU admission, ≥ 150 ng/mL) and early postoperative (≤ 8 h of admission) KDIGO SCr-defined AKI to predict CS-AKI on postoperative days (POD) 2-4. Four CS-AKI phenotypes were derived (uNGAL - /SCr - ; uNGAL + /SCr - ; uNGAL - /SCr + and uNGAL + /SCr +). The primary outcome was POD2-4 KDIGO SCr-defined CS-AKI. Secondary outcomes included ventilator and intensive care unit-free days (maximum 28).

RESULTS

Four hundred seventy-six patients (median age 4.8 [IQR 1.4-30.4] months, 39% female) were included. POD2-4 AKI occurred in 44 (9.2%). 27% were uNGAL + /SCr - and 0.4% (n = 2) uNGAL + /SCr + . The adjusted odds of POD2-4 AKI was ninefold higher (aOR: 9.09, 95%CI: 3.84-21.53) in uNGAL + /SCr - when compared to uNGAL - /SCr - . uNGAL + /SCr - was associated with fewer ventilator-free (aOR: 0.30, 95%CI: 0.19-0.48) and ICU-free days (aOR: 0.41, 95%CI: 0.26-0.66) when compared to uNGAL - /SCr - .

CONCLUSION

Early postoperative uNGAL, regardless of SCr elevation, refines risk assessment for pediatric POD2-4 CS-AKI and associated morbidity, enabling earlier AKI identification and prognostics.

Recurrent acute kidney injury is associated with delayed language development in infants with Congenital Heart Disease

OBJECTIVE

Neurodevelopmental delay is common in children who undergo surgery for Congenital Heart Disease (CHD) in infancy. Cardiac surgery associated acute kidney injury (CS-AKI) occurs frequently in the paediatric cardiac Intensive care unit (ICU). Cardiac surgery associated acute kidney injury (CS-AKI) is associated with worse neurodevelopmental scores and delay in cognitive, language, and motor domains in children with CHD. No known data exist regarding the association of CS-AKI and motor and language subscales. In this study, we explored the relationship between CS-AKI and receptive and expressive language, as well as gross and fine motor delay.

METHODS

This was a single centre retrospective observational cohort study. Children who underwent surgery for CHD and developed recurrent CS-AKI in the first year of life who had follow-up neurodevelopmental testing using the Bayley Scale of Infant Development Version III were included. Neurodevelopmental delay subscales assessed included: receptive and expressive language, fine and motor skills.

RESULTS

The study cohort included 203 children. Recurrent CS-AKI was significantly associated with lower scores in receptive and expressive language, as well as fine and gross motor on unadjusted analyses. On adjusted analyses, recurrent CS-AKI was significantly associated with severe receptive language delay.

CONCLUSION

The independent association of recurrent CS-AKI with severe language delay in children who undergo surgery for CHD in infancy is novel. Our findings may contribute to the understanding of language impairment in this population. Further studies are required to better understand this relationship and any potentially modifiable factors.

Evaluation of risk factors associated with acute kidney injury in a level IV regional NICU

BACKGROUND

Intervening on neonates at risk for developing acute kidney injury (AKI) improves safety and clinical outcomes. This study sought to evaluate risk factors associated with AKI in a level IV neonatal intensive care unit (NICU).

METHODS

Single-center, case-control study of patients with corrected gestational age (GA) ≤44 weeks from 2018 to 2022. Cases were those that developed AKI after day 4 of life. Controls were the next neonate admitted to the same NICU team that met inclusion criteria but did not develop AKI. Neonatal and maternal factors, nephrotoxic medication administration, and procedures were analyzed to identify risk factors associated with AKI using univariate and multivariate analyses.

RESULTS

A total of 94 patients were included: 47 cases and 47 controls. GA <27 weeks, birth weight <1500 grams, low APGAR score, intubation at birth, bronchopulmonary dysplasia (BPD), patent ductus arteriosus (PDA), necrotizing enterocolitis (NEC), and sepsis were associated with AKI on univariate analysis. Most cases (89.4%) had >4 risk factors, and this was associated with a 13.1-fold increase in the odds of developing AKI. Multivariate analysis identified GA <27 weeks (OR 7.7, 95% CI 1.7-34.4), vasopressor and/or inotrope administration (OR 4.4, 95% CI 1.2-23.8), and diagnosis of PDA (OR 6.9, 95% CI 1.5-31.3) as independent predictors of AKI.

CONCLUSIONS

Risk factors associated with AKI were identified, and a 13.1-fold increase in AKI was found when >4 risk factors were present. This information may be used to expand renal acuity surveillance programs focusing on high-risk medication evaluation, demographic, and clinical factors.

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.

Acute Kidney Injury in Children: A Focus for the General Pediatrician

Acute kidney injury (AKI) presents significant challenges in pediatric care, often remaining underrecognized. This paper provides an overview of pediatric AKI, highlighting its epidemiology, pathophysiology, diagnosis, predisposing conditions, and treatment. AKI in children stems from diverse causes, including renal tubular damage, vasoconstriction, and inflammation. Diagnosis relies on traditional markers such as serum creatinine and urine output, alongside emerging biomarkers such as Cystatin C, NGAL, KIM-1, IL-18, TIMP-2 and IGFBP7, urinary calprotectin, URBP4, L-FABP, and clusterin. Various pediatric conditions predispose to AKI, including type 1 diabetes, pneumonia, bronchiolitis, appendicitis, gastroenteritis, COVID-19, multisystem inflammatory syndrome, sickle cell disease, and malignancies. Treatment entails supportive care with fluid management and, in severe cases, renal replacement therapy. Timely recognition and management are essential to mitigating adverse outcomes. Enhanced awareness and integration of novel biomarkers could improve pediatric AKI care, warranting further research for better diagnosis and management.

Acute Kidney Injury Requiring Dialysis After Pediatric Heart Transplant

BACKGROUND

Acute kidney injury (AKI) is a common complication of pediatric heart transplant, with a subset of patients developing severe AKI requiring dialysis (AKI-D). We aimed to identify the epidemiology, risk factors, and outcomes of postoperative AKI-D in pediatric heart transplant recipients.

METHODS

We retrospectively identified all pediatric first-time, single-organ heart transplants at our institution from 2014 to 2022. Postoperative AKI was defined as AKI within 2 weeks of transplant. Unadjusted and adjusted logistic regression were used to identify characteristics associated with AKI-D, and unadjusted time-to-event analyses were used to determine the association between AKI-D and survival free of kidney failure.

RESULTS

Among 177 patients included, 116 (66%) developed postoperative AKI of any stage, including 13 (7%) who developed AKI-D with median time from transplant to dialysis initiation of 6 days (IQR 3-13). In adjusted models, increased cardiopulmonary bypass time (OR 1.19, 95% CI 1.04-1.37, per 15 min increase in bypass time) and higher weight at transplant were associated with higher odds of AKI-D, whereas patient demographics and pretransplant kidney function were not associated with AKI-D. AKI-D was associated with greater mortality during initial hospitalization (46% vs. 1%, p < 0.001) and a lower rate of survival free of kidney failure.

CONCLUSIONS

The incidence of AKI-D after pediatric heart transplant was 7%, with extended cardiopulmonary bypass time associated with postoperative AKI-D even in adjusted models. Further research is needed to improve the prediction and management of AKI-D in this population.

Short-Term Preconditioning with Insulin and Glucose Efficiently Protected the Kidney Against Ischemia-Reperfusion Injury via the P-AKT-Bax-Caspase-3 Signaling Pathway in Mice

Objective

Insulin attaches insulin receptor to activate the PI3-kinase/Akt signaling to maintain glucose homeostasis and inhibit apoptosis. This study determined whether preconditioning with insulin and glucose protects the kidney against ischemia-reperfusion injury (IRI).

Methods

Kidney IRI was performed in C57BL/6 mice by clamping the renal vessels for 30 min, followed by reperfusion for 24 h. A total subcutaneous 0.1 unit of insulin along with 10% glucose in drinking water was treated on the mice for 24 h before kidney IRI. The kidney function and injuries were investigated through the determination of BUN and Cr in blood plasma, as well as the apoptosis and the expression of P-AKT, BAX, and caspase-3 in the kidneys. The role of P-AKT in insulin-treated IRI kidneys was tested using an AKT inhibitor. The effects of the preconditional duration of insulin and glucose on IRI kidneys were investigated by expanding the treatment duration to 1, 3, and 6 days.

Results

Preconditioning with insulin and glucose protected the kidney against IRI as manifested by a decrease in creatinine and BUN and a reduction of kidney tubular injury. The protection effect was mediated by P-AKT-BAX-caspase-3 signaling pathway resulting in suppression of apoptotic cell death. An AKT inhibitor partially reversed the protective effects of preconditional insulin. The preconditional duration for 1, 3, and 6 days had no differences in improving kidney functions and pathology.

Conclusion

A short-term preconditioning with insulin and glucose protected the kidney from IRI through the activation of p-AKT and subsequent reduction of BAX-caspase-3-induced apoptosis. The short-term precondition provides a practicable strategy for protecting the kidney against predictable IRI, such as kidney transplant and major surgical operations with high risk of hypotension.

Acute Kidney Injury in Neonatal Intensive Care Unit: Epidemiology, Diagnosis and Risk Factors

Acute kidney injury (AKI) is associated with long-term consequences and poor outcomes in the neonatal intensive care unit. Its precocious diagnosis represents one of the hardest challenges in clinical practice due to the lack of sensitive and specific biomarkers. Currently, neonatal AKI is defined with urinary markers and serum creatinine (sCr), with limitations in early detection and individual treatment. Biomarkers and risk factor scores were studied to predict neonatal AKI, to early identify the stage of injury and not the damage and to anticipate late increases in sCr levels, which occurred when the renal function already began to decline. Sepsis is the leading cause of AKI, and sepsis-related AKI is one of the main causes of high mortality. Moreover, preterm neonates, as well as patients with post-neonatal asphyxia or after cardiac surgery, are at a high risk for AKI. Critical patients are frequently exposed to nephrotoxic medications, representing a potentially preventable cause of AKI. This review highlights the definition of neonatal AKI, its diagnosis and new biomarkers available in clinical practice and in the near future. We analyze the risk factors involving patients with AKI, their outcomes and the risk for the transition from acute damage to chronic kidney disease.

Cardiac Surgery-Associated Acute Kidney Injury in Neonates Undergoing the Norwood Operation: Retrospective Analysis of the Multicenter Neonatal and Pediatric Heart and Renal Outcomes Network Dataset, 2015-2018

OBJECTIVES

Cardiac surgery-associated acute kidney injury (CS-AKI) is associated with adverse outcomes. Single-center studies suggest that the prevalence of CS-AKI is high after the Norwood procedure, or stage 1 palliation (S1P), but multicenter data are lacking.

DESIGN

A secondary analysis of the Neonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) multicenter cohort who underwent S1P. Using neonatal modification of Kidney Disease Improving Global Outcomes (KDIGO) criteria, perioperative associations between CS-AKI with morbidity and mortality were examined. Sensitivity analysis, with the exclusion of prophylactic peritoneal dialysis (PD) patients, was performed.

SETTING

Twenty-two hospitals participating in the Pediatric Cardiac Critical Care Consortium (PC 4 ) and contributing to NEPHRON.

PATIENTS

Three hundred forty-seven neonates (< 30 d old) with S1P managed between September 2015 and January 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 347 patients, CS-AKI occurred in 231 (67%). The maximum stages were as follows: stage 1, in 141 of 347 (41%); stage 2, in 51 of 347 (15%); and stage 3, in 39 of 347 (11%). Severe CS-AKI (stages 2 and 3) peaked on the first postoperative day. In multivariable analysis, preoperative feeding was associated with lower odds of CS-AKI (odds ratio [OR] 0.48; 95% CI, 0.27-0.86), whereas prophylactic PD was associated with greater odds of severe CS-AKI (OR 3.67 [95% CI, 1.88-7.19]). We failed to identify an association between prophylactic PD and increased creatinine (OR 1.85 [95% CI, 0.82-4.14]) but cannot exclude the possibility of a four-fold increase in odds. Hospital mortality was 5.5% ( n = 19). After adjusting for risk covariates and center effect, severe CS-AKI was associated with greater odds of hospital mortality (OR 3.67 [95% CI, 1.11-12.16]). We failed to find associations between severe CS-AKI and respiratory support or length of stay. The sensitivity analysis using PD failed to show associations between severe CS-AKI and outcome.

CONCLUSIONS

KDIGO-defined CS-AKI occurred frequently and early postoperatively in this 2015-2018 multicenter PC 4 /NEPHRON cohort of neonates after S1P. We failed to identify associations between resource utilization and CS-AKI, but there was an association between severe CS-AKI and greater odds of mortality in this high-risk cohort. Improving the precision for defining clinically relevant neonatal CS-AKI remains a priority.

Persistent acute kidney injury and fluid accumulation with outcomes after the Norwood procedure: report from NEPHRON

BACKGROUND

Cardiac surgery-associated acute kidney injury (CS-AKI) is common, but its impact on clinical outcomes is variable. Parsing AKI into sub-phenotype(s) and integrating pathologic positive cumulative fluid balance (CFB) may better inform prognosis. We sought to determine whether durational sub-phenotyping of CS-AKI with CFB strengthens association with outcomes among neonates undergoing the Norwood procedure.

METHODS

Multicenter, retrospective cohort study from the Neonatal and Pediatric Heart and Renal Outcomes Network. Transient CS-AKI: present only on post-operative day (POD) 1 and/or 2; persistent CS-AKI: continued after POD 2. CFB was evaluated per day and peak CFB during the first 7 postoperative days. Primary and secondary outcomes were mortality, respiratory support-free and hospital-free days (at 28, 60 days, respectively). The primary predictor was persistent CS-AKI, defined by modified neonatal Kidney Disease: Improving Global Outcomes criteria.

RESULTS

CS-AKI occurred in 59% (205/347) neonates: 36.6% (127/347) transient and 22.5% (78/347) persistent; CFB > 10% occurred in 18.7% (65/347). Patients with either persistent CS-AKI or peak CFB > 10% had higher mortality. Combined persistent CS-AKI with peak CFB > 10% (n = 21) associated with increased mortality (aOR: 7.8, 95% CI: 1.4, 45.5; p = 0.02), decreased respiratory support-free (predicted mean 12 vs. 19; p < 0.001) and hospital-free days (17 vs. 29; p = 0.048) compared to those with neither.

CONCLUSIONS

The combination of persistent CS-AKI and peak CFB > 10% after the Norwood procedure is associated with mortality and hospital resource utilization. Prospective studies targeting intra- and postoperative CS-AKI risk factors and reducing CFB have the potential to improve outcomes.

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.

Model-Informed Vancomycin Dosing Optimization to Address Delayed Renal Maturation in Infants and Young Children with Critical Congenital Heart Disease

Ensuring safe and effective drug therapy in infants and young children often requires accounting for growth and organ development; however, data on organ function maturation are scarce for special populations, such as infants with congenital diseases. Children with critical congenital heart disease (CCHD) often require multiple staged surgeries depending on their age and disease severity. Vancomycin (VCM) is used to treat postoperative infections; however, the standard pediatric dose (60-80 mg/kg/day) frequently results in overexposure in children with CCHD. In this study, we characterized the maturation of VCM clearance in pediatric patients with CCHD and determined the appropriate dosing regimen using population pharmacokinetic (PK) modeling and simulations. We analyzed 1,254 VCM serum concentrations from 152 postoperative patients (3 days-13 years old) for population PK analysis. The PK model was developed using a two-compartment model with allometrically scaled body weight, estimated glomerular filtration rate (eGFR), and postmenstrual age as covariates. The observed clearance in patients aged ≤ 1 year and 1-2 years was 33% and 40% lower compared with that of non-CCHD patients, respectively, indicating delayed renal maturation in patients with CCHD. Simulation analyses suggested VCM doses of 25 mg/kg/day (age ≤ 3 months, eGFR 40 mL/min/1.73 m2 ) and 35 mg/kg/day (3 months < age ≤ 3 years, eGFR 60 mL/min/1.73 m2 ). In conclusion, this study revealed delayed renal maturation in children with CCHD, could be due to cyanosis and low cardiac output. Model-informed simulations identified the lower VCM doses for children with CCHD compared with standard pediatric guidelines.

Immune urinary biomarkers predict infant cardiac surgery-associated acute kidney injury

BACKGROUND

Acute kidney injury (AKI) occurs frequently after infant cardiac surgery and is associated with poor outcomes, including mortality and prolonged length of stay. AKI mechanisms are poorly understood, limiting therapeutic targets. Emerging data implicates dysregulated immune activation in post-cardiac surgery AKI development. We sought to identify immune-mediated AKI biomarkers after infant cardiopulmonary bypass (CPB)-assisted cardiac surgery.

METHODS

A single-center prospective study of 126 infants less than 1 year old undergoing CPB-assisted surgery enrolled between 10/2017 and 6/2019. Urine samples were collected before CPB and at 6, 24, 48, and 72 h after surgery. Immune-mediated biomarkers were measured using commercial ELISA and Luminex™ multiplex kits. Based on subject age, neonatal KDIGO (< 1 month) or KDIGO criteria defined AKI. The Kruskal-Wallis rank test determined the relationship between urinary biomarker measurements and AKI.

RESULTS

A total of 35 infants (27%) developed AKI. AKI subjects were younger, underwent more complex surgery, and had longer CPB time. Subjects with AKI vs. those without AKI had higher median urinary chemokine 10 (C-X-C motif) ligand levels at 24, 48, and 72 h, respectively: 14.3 pg/ml vs. 5.3 pg/ml, 3.4 pg/ml vs. 0.8 pg/ml, and 1.15 pg/ml vs. 0.22 pg/ml (p < 0.05) post-CPB. At 6 h post-CPB, median vascular cell adhesion protein 1 (VCAM) levels (pg/mL) were higher among AKI subjects (491 pg/ml vs. 0 pg/ml, p = 0.04).

CONCLUSIONS

Urinary CXCL10 and VCAM are promising pro-inflammatory biomarkers for early AKI detection and may indicate eventual AKI therapeutic targets. A higher resolution version of the Graphical abstract is available as Supplementary information.

Biomarkers of eGFR decline after cardiac surgery in children: findings from the ASSESS-AKI study

BACKGROUND

Children who require surgery for congenital heart disease have increased risk for long-term chronic kidney disease (CKD). Clinical factors as well as urine biomarkers of tubular health and injury may help improve the prognostication of estimated glomerular filtration rate (eGFR) decline.

METHODS

We enrolled children from 1 month to 18 years old undergoing cardiac surgery in the ASSESS-AKI cohort. We used mixed-effect models to assess the association between urinary biomarkers (log2-transformed uromodulin, NGAL, KIM-1, IL-18, L-FABP) measured 3 months after cardiac surgery and cyanotic heart disease with the rate of eGFR decline at annual in-person visits over 4 years.

RESULTS

Of the 117 children enrolled, 30 (24%) had cyanotic heart disease. During 48 months of follow-up, the median eGFR in the subgroup of children with cyanotic heart disease was lower at all study visits as compared with children with acyanotic heart disease (p = 0.01). In the overall cohort, lower levels of both urine uromodulin and IL-18 after discharge were associated with eGFR decline. After adjustment for age, RACHS-1 surgical complexity score, proteinuria, and eGFR at the 3-month study visit, lower concentrations of urine uromodulin and IL-18 were associated with a monthly decline in eGFR (uromodulin β = 0.04 (95% CI: 0.00-0.09; p = 0.07) IL-18 β = 0.07 (95% CI: 0.01-0.13; p = 0.04), ml/min/1.73 m2 per month).

CONCLUSIONS

At 3 months after cardiac surgery, children with lower urine uromodulin and IL-18 concentrations experienced a significantly faster decline in eGFR. Children with cyanotic heart disease had a lower median eGFR at all time points but did not experience faster eGFR decline. A higher-resolution version of the Graphical abstract is available as Supplementary information.

Evaluation of Parenteral Potassium Supplementation in Pediatric Patients

OBJECTIVE

The primary objective was to evaluate the effect of parenteral potassium chloride (KCl) supplementation on potassium (K⁺) concentrations in a non-cardiac pediatric population. Secondary outcomes were to identify variables that may influence response to KCl supplementation (i.e., change in K⁺ concentration after KCl administration) and assess the incidence of hyperkalemia.

METHODS

This single-center, retrospective study evaluated infants and children who received parenteral KCl supplementation of 0.5 or 1 mEq/kg between January 2017 and December 2019.

RESULTS

The study included 102 patients with a median age of 1 year (IQR, 0.4-3.9) and weight of 9.1 kg (IQR, 4.9-14.2) who received 288 parenteral KCl administrations. One hundred seventy-three administrations were in the 1 mEq/kg group, and 115 administrations were in the 0.5 mEq/kg group. The median changes in K⁺ were 0.8 and 0.5 mEq/L in the 1 mEq/kg and 0.5 mEq/kg groups, respectively. Patients who had a repeat K⁺ concentration within 4 hours of the end of a 1 to 2-hour infusion had a higher median change in K⁺ compared with those who had a concentration drawn after this time frame (0.8 vs 0.6 mEq/L; p < 0.01).

CONCLUSIONS

There is a paucity of data on the correlation between parenteral KCl supplementation and change in K⁺ concentrations in pediatric patients. Our study demonstrated an association between KCl supplementation doses of 1 and 0.5 mEq/kg and changes in K⁺ of 0.8 and 0.5 mEq/L, respectively, in non-cardiac pediatric patients, with low observed incidence of hyperkalemia.

Abdominal and Peripheral Tissue Oxygen Supply during Selective Lower Body Perfusion for the Surgical Repair of Congenital Heart Disease: A Pilot Study

Background: Lower body perfusion (LBP) may be a strategy for maintaining organ perfusion during congenital heart disease surgery. It is hypothesized that renal and lower limb oxygen supply during LBP is superior to off-pump surgery and comparable to that of a standard cardiopulmonary bypass (CPB). Methods: in this prospective single-center study, patients aged <1 year were recruited if they were scheduled for a correction of aortic arch anomalies using antegrade cerebral perfusion and LBP (group 1), a repair of coarctation during aortic cross-clamping (group 2), or surgery under whole-body CPB (group 3). Renal (prefix “r”) and peripheral (prefix “p”) oxygen saturation (SO2), hemoglobin amount (Hb), blood velocity (Velo), and blood flow (Flow) were measured noninvasively. Results: A total of 23 patients were included (group 1, n = 9; group 2, n = 5; group 3, n = 9). Compared to the baseline values, rSO2 and pSO2 decreased significantly in group 2 compared to groups 1 and 3. Conversely, rHB significantly increased in group 2 compared to groups 1 and 3, reflecting abdominal venous stasis. Compared to group 3, group 1 showed a significantly lower pFlow during CPB; however, rFlow, pFlow, and pVelo did not differ. Conclusion: according to these observations, LBP results in an improved renal oxygen supply compared to off-pump surgery and may prove to be a promising alternative to conventional CPB.

Subphenotypes of acute kidney injury in children

PURPOSE OF REVIEW

The purpose of this review is to describe acute kidney injury (AKI) phenotypes in children.

RECENT FINDINGS

AKI is a heterogenous disease that imposes significant morbidity and mortality on critically ill and noncritically ill patients across the age spectrum. As our understanding of AKI and its association with outcomes has improved, it is becoming increasingly apparent that there are distinct AKI subphenotypes that vary by cause or associated conditions. We have also learned that severity, duration, and repeated episodes of AKI impact outcomes, and that integration of novel urinary biomarkers of tubular injury can also reveal unique subphenotypes of AKI that may not be otherwise readily apparent.

SUMMARY

Studies that further delineate these unique AKI subphenotypes are needed to better understand the impact of AKI in children. Further delineation of these phenotypes has both prognostic and therapeutic implications.

Consensus-Based Recommendations on Priority Activities to Address Acute Kidney Injury in Children: A Modified Delphi Consensus Statement

IMPORTANCE

Increasing evidence indicates that acute kidney injury (AKI) occurs frequently in children and young adults and is associated with poor short-term and long-term outcomes. Guidance is required to focus efforts related to expansion of pediatric AKI knowledge.

OBJECTIVE

To develop expert-driven pediatric specific recommendations on needed AKI research, education, practice, and advocacy.

EVIDENCE REVIEW

At the 26th Acute Disease Quality Initiative meeting conducted in November 2021 by 47 multiprofessional international experts in general pediatrics, nephrology, and critical care, the panel focused on 6 areas: (1) epidemiology; (2) diagnostics; (3) fluid overload; (4) kidney support therapies; (5) biology, pharmacology, and nutrition; and (6) education and advocacy. An objective scientific review and distillation of literature through September 2021 was performed of (1) epidemiology, (2) risk assessment and diagnosis, (3) fluid assessment, (4) kidney support and extracorporeal therapies, (5) pathobiology, nutrition, and pharmacology, and (6) education and advocacy. Using an established modified Delphi process based on existing data, workgroups derived consensus statements with recommendations.

FINDINGS

The meeting developed 12 consensus statements and 29 research recommendations. Principal suggestions were to address gaps of knowledge by including data from varying socioeconomic groups, broadening definition of AKI phenotypes, adjudicating fluid balance by disease severity, integrating biopathology of child growth and development, and partnering with families and communities in AKI advocacy.

CONCLUSIONS AND RELEVANCE

Existing evidence across observational study supports further efforts to increase knowledge related to AKI in childhood. Significant gaps of knowledge may be addressed by focused efforts.

Filtering Down to Risks and Solutions: Risk Factors and Stratification After Pediatric Cardiac Surgery

Acute kidney injury after cardiac surgery (CS-AKI) is common in neonatal and pediatric populations and is a risk factor for poor outcomes, such as mortality and increased hospital resource utilization. This review presents a summary of CS-AKI risk factors, integration of biomarkers, and the need to improve risk stratification for targeting future clinical trials. To date, studies examining CS-AKI risk factors cannot be generalized easily owing to variability in patient age, surgical complexity or population, AKI definition, and center-specific practices. However, certain risk associations, such as younger age at surgery, history of prematurity, cardiopulmonary bypass time, and surgical complexity, have been identified across multiple, but not all, studies. CS-AKI appears to have different severity and duration phenotypes, and serum creatinine is limited in its ability to identify CS-AKI early and predict CS-AKI course. Treatment strategies are largely supportive, and efforts are ongoing to use biomarkers and clinical features to risk-stratify patients, which in turn may facilitate differential CS-AKI phenotyping and management with supportive care bundles, clinical decision support techniques, and modulation of modifiable risk factors.

Evaluation of acute kidney injury after surgery for congenital heart disease in neonates: a tertiary hospital experience

PURPOSE OF THE ARTICLE

Acute kidney injury (AKI) after cardiac surgery in children with congenital heart disease (CHD) is a serious complication closely associated with high morbidity and mortality. Despite numerous studies on AKI in children, most studies have excluded neonates. We sought to characterize AKI associated with cardiac surgery in neonates, determine its incidence, perioperative and postoperative risk factors, and short-term results.

MATERIALS AND METHODS

This retrospective study included 177 neonates who were operated on for CHD in our hospital between January 2015 and December 2019. Data of the patients were analyzed according to nKDIGO (neonatal Kidney Disease Improving Global Outcomes) and nRIFLE (neonatal Risk, Injury, Failure, Loss of function, End-stage kidney disease) criteria for evaluating AKI retrospectively. Data of groups with and without AKI were analyzed.

RESULTS

The average age of 177 neonates were 8.2 ± 6.1 (1-28) days. Twenty-two (12.4%) neonates had CS-AKI defined according to nKDIGO criteria. Four (2.3%) neonates reached nKDIGO stage I, 1 (0.6%) reached stage II, 17 (9.6%) reached stage III. Thirty-eight (21.5%) neonates had CS-AKI defined according to nRIFLE criteria. Twenty-four (13.6%) neonates reached nRIFLE stage risk(R), 6 (3.4%) reached stage injury(I), 8 (4.5%) reached stage failure (F). The incidence of cardiac surgery-associated acute kidney injury (CS-AKI) in neonates was 12.5% and 21.5% for nKDIGO and nRIFLE, respectively. The percentage difference between nKDIGO and nRIFLE for AKI assessment was due to the criteria for nRIFLE stage risk(R) urine output < 1.5 mL/kg/h for 24 h. In both classifications, the duration of cardiopulmonary bypass, operation, inotropic treatment, and mechanical ventilation, length of intensive care unit (ICU), and hospital stay were significantly higher in the AKI group than those without AKI group (p˂.05). The mortality rate in the groups with AKI was found to be significantly higher (p˂.05) than in the groups without AKI. In Kappa analysis, when two classifications were compared according to AKI stages, a significant agreement was found between nKDIGO and nRIFLE classifications (p˂.05) (Kappa: 0.299).

CONCLUSION

AKI and mortality rates were similar between groups according to the nKDIGO and nRIFLE criteria. For early prediction of AKI and adverse outcomes, diagnostic reference intervals might be specified in more detail in neonates undergoing cardiac surgery for CHD.

Transient and persistent acute kidney injury phenotypes following the Norwood operation: a retrospective study

BACKGROUND

Acute kidney injury is a common complication following the Norwood operation. Most neonatal studies report acute kidney injury peaking within the first 48 hours after cardiac surgery. The aim of this study was to evaluate if persistent acute kidney injury (>48 postoperative hours) after the Norwood operation was associated with clinically relevant outcomes.

METHODS

Two-centre retrospective study among neonates undergoing the Norwood operation. Acute kidney injury was initially identified as developing within the first 48 hours after cardiac surgery and stratified into transient (≤48 hours) and persistent (>48 hours) using the neonatal modification of the Kidney Disease: Improving Global Outcomes serum creatinine criteria. Severe was defined as stage ≥2. Primary and secondary outcomes were mortality and duration of ventilation and hospital length of stay.

RESULTS

One hundred sixty-eight patients were included. Transient and persistent acute kidney injuries occurred in 24 and 17%, respectively. Cardiopulmonary bypass and aortic cross clamp duration, and incidence of cardiac arrest were greater among those with persistent kidney injury. Mortality was four times higher (41 versus 12%, p < 0.001) and mechanical ventilation duration 50 hours longer in persistent acute kidney injury patients (158 versus 107 hours; p < 0.001). In multivariable analysis, persistent acute kidney injury was not associated with mortality, duration of ventilation or length of stay. Severe persistent acute kidney injury was associated with a 59% increase in expected ventilation duration (aIRR:1.59, 95% CI:1.16, 2.18; p = 0.004).

CONCLUSIONS

Future large studies are needed to determine if risk factors and outcomes change by delineating acute kidney injury into discrete timing phenotypes.

Neurodevelopmental Outcomes in Infants with Cardiac Surgery Associated Acute Kidney Injury

BACKGROUND

Infants who undergo surgery for congenital heart disease (CHD) are at risk of neurodevelopmental delay. Cardiac surgery associated acute kidney injury (CS-AKI) is common but its association with neurodevelopment has not been explored.

METHODS

Single center retrospective observational study of infants who underwent cardiac surgery in the first year of life who had neurodevelopmental testing using the Bayley Scale for Infant Development version 3. Single and recurrent episodes of Stage 2 and 3 CS-AKI were determined.

RESULTS

203 children with median age at first surgery of 12 days. 31% had ≥ 1 episode of severe CS-AKI; of those, 16% had recurrent CS-AKI. Median age at neurodevelopmental assessment was 20 months. The incidence of delay was similar in patients with and without CS-AKI but all children with recurrent CS-AKI had a delay in ≥1 domain and had significantly lower scores in all 3 domains (cognitive, language, motor).

CONCLUSIONS

This is the first study to assess the association of CS-AKI with neurodevelopmental delay after surgery for CHD in infancy. Infants who develop recurrent CS-AKI in the first year of life were more likely to be delayed and have lower neurodevelopmental scores.

Risk factors for acute kidney injury after pediatric cardiac surgery: a meta-analysis

BACKGROUND

Cardiac surgery-associated acute kidney injury (AKI) is associated with increased morbidity and mortality in both adults and children.

OBJECTIVES

This study aimed to identify clinical risk factors for AKI following cardiac surgery in the pediatric population.

DATA SOURCES

PubMed/MEDLINE, Embase, Scopus, and reference lists of relevant articles were searched for studies published by August 2020.

STUDY ELIGIBILITY CRITERIA

Studies were included if (1) the population consisted of pediatric patients (< 18 years old), (2) patients underwent cardiac surgery, (3) risk factors were compared between patients who developed AKI and those who did not, and (4) studies were prospective or retrospective observational studies or randomized controlled trials.

PARTICIPANTS AND INTERVENTIONS

Children undergoing pediatric cardiac surgery.

STUDY APPRAISAL AND SYNTHESIS METHODS

Random-effects meta-analysis was performed, comparing potential risk factors between pediatric patients who developed CS-AKI and those who did not.

RESULTS

Sixty-one publications including a total of 19,680 participants (AKI: 7257 participants; no AKI: 12,423 participants) were included from studies published between 2008 and 2020. The pooled estimated incidence of AKI was 34.3% (95% confidence interval 30.0-38.8%, I² = 96.8%). Binary risk factors that were significantly and consistently associated with AKI were the presence of pulmonary hypertension, cyanotic heart disease, univentricular heart, risk adjustment for congenital heart surgery 1 (RACHS-1) score ≥ 3, vasopressor use, cardiopulmonary bypass use, reoperation, and sepsis. Significant continuous risk factors included younger age, lower body weight, lower preoperative creatinine, higher preoperative estimated glomerular filtration rate (eGFR), higher RACHS-1 score, longer surgery time, longer cardiopulmonary bypass time, longer aortic cross-clamp time, and higher red blood cell transfusion volume.

LIMITATIONS

Results are limited by heterogeneity and potential residual confounding.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Our meta-analysis identified clinical risk factors that are associated with AKI in children undergoing cardiac surgery. This might help clinicians anticipate and manage more carefully this population and implement standardized preventive strategies.

SYSTEMATIC REVIEW REGISTRATION NUMBER

CRD42021262699. A higher resolution version of the Graphical abstract is available as Supplementary information.

Postoperative Acute Kidney Injury in Williams Syndrome Compared With Matched Controls

OBJECTIVES

Cardiovascular manifestations occur in over 80% of Williams syndrome (WS) patients and are the leading cause of morbidity and mortality. One-third of patients require cardiovascular surgery. Renal artery stenosis (RAS) is common in WS. No studies have assessed postoperative cardiac surgery-related acute kidney injury (CS-AKI) in WS. Our objectives were to assess if WS patients have higher risk of CS-AKI postoperatively than matched controls and if RAS could contribute to CS-AKI.

DESIGN

This was a retrospective study of all patients with WS who underwent cardiac surgery at our center from 2010 to 2020. The WS study cohort was compared with a group of controls matched for age, sex, weight, and surgical procedure.

SETTING

Patients underwent cardiac surgery and postoperative care at Lucile Packard Children's Hospital Stanford.

PATIENTS

There were 27 WS patients and 43 controls (31% vs 42% female; p = 0.36). Median age was 1.8 years (interquartile range [IQR], 0.7-3.8 yr) for WS and 1.7 years (IQR, 0.8-3.1 yr) for controls.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Postoperative hemodynamics, vasopressor, total volume input, diuretic administration, and urine output were collected in the first 72 hours. Laboratory studies were collected at 8-hour intervals. Multivariable analysis identified predictors of CS-AKI.Controlled for renal perfusion pressure (RPP) and vasoactive inotrope score (VIS), compared with controls, the odds ratio (OR) of CS-AKI in WS was 4.2 (95% CI, 1.1-16; p = 0.034). Higher RPP at postoperative hours 9-16 was associated with decreased OR of CS-AKI (0.88 [0.8-0.96]; p = 0.004). Increased VIS at hour 6 was associated with an increased OR of CS-AKI (1.47 [1.14-1.9]; p = 0.003). Younger age was associated with an increased OR of CS-AKI (1.9 [1.13-3.17]; p = 0.015).

CONCLUSIONS

The OR of CS-AKI is increased in pediatric patients with WS compared with controls. CS-AKI was associated with VIS at the sixth postoperative hour. Increases in RPP and mean arterial pressure were associated with decreased odds of CS-AKI.

Are outcomes in congenital cardiac surgery better than ever?

BACKGROUND AND AIM OF THE STUDY

Congenital heart disease is the most common congenital defect among infants born in the United States. Within the first year of life, 1 in 4 of these infants will need surgery. Only one generation removed from an overall mortality of 14%, many changes have been introduced into the field. Have these changes measurably improved outcomes?

METHODS

The literature search was conducted through PubMed MEDLINE and Google Scholar from inception to October 31, 2021. Ultimately, 78 publications were chosen for inclusion.

RESULTS

The outcome of overall mortality has experienced continuous improvements in the modern era of the specialty despite the performance of more technically demanding surgeries on patients with complex comorbidities. This modality does not account for case-mix, however. In turn, clinical outcomes have not been consistent from center to center. Furthermore, variation in practice between institutions has also been documented. A recurring theme in the literature is a movement toward standardization and universalization. Examples include mortality risk-stratification that has allowed direct comparison of outcomes between programs and improved definitions of morbidities which provide an enhanced framework for diagnosis and management.

CONCLUSIONS

Overall mortality is now below 3%, which suggests that more patients are surviving their interventions than in any previous era in congenital cardiac surgery. Focus has transitioned from survival to improving the quality of life in the survivors by decreasing the incidence of morbidity and associated long-term effects. With the transformation toward standardization and interinstitutional collaboration, future advancements are expected.

The comparison of three different acute kidney injury classification systems after congenital heart surgery

BACKGROUND

We aimed to compare the frequency of acute kidney injury (AKI) and its effects on mortality and morbidity with different classification systems in pediatric patients who had surgery under cardiopulmonary bypass for congenital heart disease.

METHODS

This study included children younger than 18 years old who were followed up in the pediatric cardiac intensive care unit between September 1 and December 1, 2020, after congenital heart surgery with cardiopulmonary bypass. Each case was categorized postoperatively in terms of AKI using Pediatric-Modified Risk, Injury, Failure, Loss, and End-Stage (pRIFLE), Acute Kidney Injury Network (AKIN), and Kidney Disease: Improving Global Outcomes (KDIGO). Hospital mortality (developed within the first 30 days postoperatively) and morbidity (longer than 7 days intensive care unit stay) were compared by three model classes. Results were evaluated statistically.

RESULTS

One hundred patients were included in the study. The median age was 3 months (1 day-180 months). Acute kidney injury was diagnosed in 49% of the cases according to the pRIFLE classification. It was diagnosed in 31% of the patients by AKIN classification. It was diagnosed in 41% of the patients with the KDIGO criteria. Morbidity was observed in 25% (n = 25) of all cases. The morbidity predictor was 0.800 for pRIFLE, 0.747 for AKIN and 0.853 for KDIGO by receiver operating characteristics analysis. All three categories predicted morbidity significantly (P < 0.001). Mortality was 10% (n = 10) for all groups. The mortality predictor was 0.783 for pRIFLE, 0.717 for AKIN and 0.794 for KDIGO by receiver operating characteristics analysis, and all three categories predicted mortality significantly (P < 0.001).

CONCLUSIONS

Regardless of the three methods used, AKI was commonly detected in pediatric patients undergoing congenital heart surgery. pRIFLE classification diagnosed more patients with AKI than AKIN and KDIGO. The KDIGO and pRIFLE classifications were better in predicting hospital mortality.

Fluid Restriction Contributes to Poor Nutritional Adequacy in Patients With Congenital Heart Disease Receiving Renal Replacement Therapy

OBJECTIVES

Critically ill patients receiving renal replacement therapy (RRT) in the pediatric cardiac intensive care unit (CICU) are at high risk for inadequate nutrition delivery. The objective of this study is to evaluate barriers to adequate energy and protein delivery in critically ill patients with congenital heart disease receiving RRT.

METHODS

This is a single-center retrospective cohort study of patients receiving RRT in the CICU from 2011 to 2019. Energy and protein adequacy was recorded over the first 7 days of RRT. Adequacy was defined as delivery of >80% of the energy and protein targets during this time period. Patients who achieved adequacy were compared to those who did not. Multivariable logistic regression models were constructed to determine factors independently associated with energy and protein adequacy while receiving RRT.

RESULTS

Sixty patients were included for analysis. Fifty-five patients (92%) achieved energy adequacy and 37 patients (62%) achieved protein adequacy. A higher weight-for-age z-score (WAZ) on admission to the CICU was the only independent predictor of inadequate energy intake (odds ratio 0.07, 95% confidence interval 0.01-0.58, P = .014); median WAZ was -1.17 versus +1.24 for those with adequate versus inadequate energy intake, respectively. Fluid restriction to <80% of maintenance fluid at the time of RRT initiation was more likely in patients with higher WAZ. Fluid restriction was the only independent predictor of inadequate protein intake (odds ratio 0.13, 95% confidence interval 0.02-0.7, P = .018); 5% versus 30% were fluid restricted in those with adequate versus inadequate protein intake, respectively. Azotemia was not associated with inadequate protein intake. Initiation of RRT did not allow for liberalization of fluid intake over the time period evaluated.

CONCLUSIONS

Protein delivery was inadequate in 38% of children undergoing RRT in the CICU. Fluid restriction was associated with inadequate protein intake and higher WAZ was associated with inadequate energy intake.

Epidemiology of Acute Kidney Injury After Neonatal Cardiac Surgery: A Report From the Multicenter Neonatal and Pediatric Heart and Renal Outcomes Network

OBJECTIVES

Cardiac surgery-associated acute kidney injury occurs commonly following congenital heart surgery and is associated with adverse outcomes. This study represents the first multicenter study of neonatal cardiac surgery-associated acute kidney injury. We aimed to describe the epidemiology, including perioperative predictors and associated outcomes of this important complication.

DESIGN

This Neonatal and Pediatric Heart and Renal Outcomes Network study is a multicenter, retrospective cohort study of consecutive neonates less than 30 days. Neonatal modification of The Kidney Disease Improving Global Outcomes criteria was used. Associations between cardiac surgery-associated acute kidney injury stage and outcomes (mortality, length of stay, and duration of mechanical ventilation) were assessed through multivariable regression.

SETTING

Twenty-two hospitals participating in Pediatric Cardiac Critical Care Consortium.

PATIENTS

Twenty-two-thousand forty neonates who underwent major cardiac surgery from September 2015 to January 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Cardiac surgery-associated acute kidney injury occurred in 1,207 patients (53.8%); 983 of 1,657 in cardiopulmonary bypass patients (59.3%) and 224 of 583 in noncardiopulmonary bypass patients (38.4%). Seven-hundred two (31.3%) had maximum stage 1, 302 (13.5%) stage 2, 203 (9.1%) stage 3; prevalence of cardiac surgery-associated acute kidney injury peaked on postoperative day 1. Cardiac surgery-associated acute kidney injury rates varied greatly (27-86%) across institutions. Preoperative enteral feeding (odds ratio = 0.68; 0.52-0.9) and open sternum (odds ratio = 0.76; 0.61-0.96) were associated with less cardiac surgery-associated acute kidney injury; cardiopulmonary bypass was associated with increased cardiac surgery-associated acute kidney injury (odds ratio = 1.53; 1.01-2.32). Duration of cardiopulmonary bypass was not associated with cardiac surgery-associated acute kidney injury in the cardiopulmonary bypass cohort. Stage 3 cardiac surgery-associated acute kidney injury was independently associated with hospital mortality (odds ratio = 2.44; 1.3-4.61). No cardiac surgery-associated acute kidney injury stage was associated with duration of mechanical ventilation or length of stay.

CONCLUSIONS

Cardiac surgery-associated acute kidney injury occurs frequently after neonatal cardiac surgery in both cardiopulmonary bypass and noncardiopulmonary bypass patients. Rates vary significantly across hospitals. Only stage 3 cardiac surgery-associated acute kidney injury is associated with mortality. Cardiac surgery-associated acute kidney injury was not associated with any other outcomes. Kidney Disease Improving Global Outcomes criteria may not precisely define a clinically meaningful renal injury phenotype in this population.

Post Cardiac Surgery

INTRODUCTION

The long-term renal outcomes of survivors of pediatric acute kidney injury (AKI) are varied within the current literature, and we aim to establish long-term renal outcomes for pediatric patients after cardiac surgery. We studied long-term renal outcomes and markers of kidney injury in pediatric patients after congenital cardiac surgery.

METHODS

In a prospective case-control observational study (the Renal Outcomes in Children with acute Kidney injury post cardiac Surgery [ROCKS] trial) we reviewed all children who underwent cardiac surgery on cardiopulmonary bypass (December 2010-2017).

RESULTS

During the study period, 2035 patients underwent cardiac surgery, of whom 9.8% developed AKI postoperatively. Forty-four patients who had postoperative AKI had a long-term follow-up, met our inclusion criteria, and were compared with 49 control subjects. We conducted a univariate analysis of reported parameters. At a median follow-up of 41 months, the cases had significantly higher urine levels of neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), and kidney injury molecule-1 (KIM-1). The biomarkers remained higher after adjusting for the urine creatinine, and the ratio of urine KIM-1/urine creatinine was significantly higher among cases. None of the patients had proteinuria or hypertension on follow-up. The presence of AKI, AKI stage, and younger age were not associated with the occurrence of low glomerular filtration rate (GFR) at follow-up.

CONCLUSIONS

Urinary biomarker abnormalities persist years after a congenital cardiac surgery in children, who may have a low GFR on follow-up. The presence of AKI, AKI stage, and younger age at surgery are not associated with the occurrence of low GFR at follow-up. Children with a higher surgical complexity score have lower GFR on follow-up.

Diagnosis and incidence of acute kidney injury in a mixed paediatric intensive care unit: Retrospective analysis, 2005 and 2015

Acute kidney injury (AKI) is common in intensive care patients. While creatinine definitions for AKI have been validated, oliguria criteria are less well evaluated in children. Our study compared the validity and agreement of creatinine and oliguria criteria for diagnosing AKI in a large mixed medical, surgical and cardiac paediatric intensive care unit (PICU), and assessed the significance of their independent and combined effects on predicted mortality relative to paediatric index of mortality (PIM risk of death) on admission. Creatinine measurements during PICU admissions in 2005 and 2015 were obtained from the electronic medical record. Urine output was reviewed to identify periods of oliguria of more than eight hours. We used the PIM3 model for predicted risk of death. AKI based on creatinine rise occurred in 23.6% of the total 2203 admissions (10.0%, 8.2% and 5.6% for mild, moderate and severe categories, respectively). Oliguria occurred in 11.4% (8.4%, 1.8% and 1.2% for mild, moderate and severe categories, respectively) and overlapped only partially with creatinine criteria. Mortality relative to predicted mortality increased with increasing creatinine and oliguria severity, but was lower than predicted where oliguria occurred without creatinine rise. AKI by creatinine criteria and/or oliguria are common in the PICU, but criteria overlap only partially. Increasing severity of creatinine rise and oliguria confers increasing risk-adjusted mortality, especially for admissions with low PIM3 risk of death. The mortality of patients with AKI defined by oliguria alone is low. Defining AKI by oliguria alone has less clinical utility and may not represent true AKI.

Incidence, Predictors, and Impact of Postoperative Acute Kidney Injury Following Fontan Conversion Surgery in Young Adult Fontan Survivors

Acute kidney injury (AKI) is a common complication following single ventricle congenital heart surgery. Data regarding AKI following Fontan conversion (FC) surgery are limited. This study evaluated the incidence, predictors of, and prognostic value of AKI following FC. Single-center retrospective cohort study, including consecutive FC patients from December 1994 to December 2016. Medical records were reviewed. AKI was classified into AKI-1/AKI-2/AKI-3 using Kidney Disease: Improving Global Outcomes criteria. Multivariable logistic regression identified risk factors for AKI≥2. Chi-square and 2-sample t-tests assessed associations between AKI≥2 and postoperative outcomes. Mid-term heart-transplant-free survival among AKI0-1 vs AKI2-3 groups was compared using Kaplan-Meier curves and log-rank test. We included 139 FC patients: age at FC 24 (25th-75th, 19-31) years; 81% initial atrio-pulmonary Fontan; follow-up 8.3 ± 5.3 years following FC. Post-FC, 63 patients (45%) developed AKI (AKI-1 = 37 [27%]; AKI-2 = 10 [7%]; AKI-3 = 16 [11%]). AKI recovered by hospital discharge in 86%, 80%, and 19% of patients with AKI-1/AKI-2/AKI-3, respectively. Independent risk factors for AKI≥2 included older age (OR 1.07, 95%CI 1.01-1.15; P = 0.027); ≥3 prior sternotomies (OR = 6.11; 95%CI = 1.59-23.47; P = 0.009); greater preoperative right atrial pressure (OR 1.19; 1.02-1.38; P = 0.024), and prior catheter ablation procedure (OR 3.45; 1.17-10.18; P = 0.036). AKI≥2 was associated with: longer chest tube duration (9 [5-57] vs 7 [3-28] days; P = 0.01); longer mechanical ventilation time (2 [1-117] vs 1 [1-6] days; P = 0.01); greater need for dialysis (31% v s0%; P < 0.001); and longer postoperative length of stay (18 [8-135] vs 10 [6-58] days; P < 0.001). AKI 2-3 patients had worse mid-term heart-transplant-free survival. Half of the patients undergoing FC develop AKI. AKI 2-3 is associated with worse early postoperative outcomes and reduced mid-term transplant-free survival following FC. Knowledge of AKI predictors may allow for improved FC risk stratification, patient selection, and perioperative management in this high-risk population.

Effect of alprostadil in the treatment of intensive care unit patients with acute renal injury

BACKGROUND

Acute kidney injury (AKI) is a sudden or rapid decline in the filtration function of the kidneys which is marked by increased serum creatinine or blood urea nitrogen.

AIM

To examine the value of alprostadil-assisted continuous venous-venous hemofiltration (CVVH) in the treatment of severe AKI in severely ill patients.

METHODS

This was a retrospective study and the inclusion criteria were as follows: (1) Age of patients (≥ 18 years); (2) Admission to intensive care unit due to non-renal primary disease, APACHE II score (≥ 18 points); (3) The diagnostic criteria of AKI guidelines were formulated with reference to the Global Organization for the Improvement of Prognosis in Kidney Diseases, with AKI grades of II-III; (4) All patients were treated with CVVH; and (5) Complete basic data were obtained for all patients.

RESULTS

The clinical effect of alprostadil administered in the treatment group was better than that observed in the control group (P < 0.05). The urine output of patients in the alprostadil group returned to normal time (9.1 ± 2.0 d) and was lower than that in the control group (10.6 ± 2.5 d), the difference was statistically significant (P < 0.05); adverse reactions occurred in the alprostadil group compared with the control group, but the difference was not statistically significant (P > 0.05).

CONCLUSION

Alprostadil-assisted CVVH in the treatment of severely ill patients with AKI can effectively improve the renal resistance index and partial pressure of urine oxygen, and has a positive effect on improving renal function.

Cardiorenal Syndrome

Cardiorenal syndrome (CRS) describes a specific acute and chronic clinical picture in which the heart or the kidney are primarily dysfunctioning and secondarily affect each other. CRS is divided into five classes: acute and chronic CRS, acute and chronic renocardiac syndromes, and secondary dysfunction of heart and kidneys. This article specifically details the classification and the epidemiology, some risk factors, and the pathophysiology of CRS. Some emerging aspects of CRS are also discussed, such as CRS in patients with end-stage heart failure, with mechanical ventricular assistance, and after heart transplantation. Finally, some aspects of pediatric CRS are detailed.

In-Hospital Outcomes of Acute Kidney Injury After Pediatric Cardiac Surgery: A Meta-Analysis

Background: Cardiac surgery-associated acute kidney injury (CS-AKI) is associated with increased morbidity and mortality in both adults and children. This study aimed to investigate the in-hospital outcomes of CS-AKI in the pediatric population. Methods: PubMed/MEDLINE, Embase, Scopus, and reference lists of relevant articles were searched for studies published by August 2020. Random-effects meta-analysis was performed, comparing in-hospital outcomes between patients who developed CS-AKI and those who did not. Results: Fifty-eight publications between 2008 and 2020 consisting of 18,334 participants (AKI: 5,780; no AKI: 12,554) were included. Higher rates of in-hospital mortality (odds ratio [OR] 7.22, 95% confidence interval [CI] 5.27-9.88), need for renal replacement therapy (RRT) (OR 18.8, 95% CI 11.7-30.5), and cardiac arrhythmias (OR 2.67, 95% 1.86-4.80) were observed in patients with CS-AKI. Furthermore, patients with AKI had longer ventilation times (mean difference [MD] 1.76 days, 95% CI 1.05-2.47), pediatric intensive care unit (PICU) length of stay (MD 3.31, 95% CI 2.52-4.10), and hospital length of stay (MD 5.00, 95% CI 3.34-6.67). Conclusions: CS-AKI in the pediatric population is associated with a higher risk of mortality, cardiac arrhythmias and need for RRT, as well as greater mechanical ventilation time, PICU and hospital length of stay. These results might help improve the clinical care protocols prior to cardiac surgery to minimize the disease burden of CS-AKI in children. Furthermore, etiology-specific approaches to AKI are warranted, as outcomes are likely impacted by the underlying cause.

Acute Kidney Injury and Risk of CKD and Hypertension after Pediatric Cardiac Surgery

BACKGROUND AND OBJECTIVES

The association of AKI after pediatric cardiac surgery with long-term CKD and hypertension development is unclear. The study objectives were to determine whether AKI after pediatric cardiac surgery is associated with incident CKD and hypertension.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a prospective cohort study of children of 1 month to 18 years old who were undergoing cardiac surgery at two tertiary care centers (Canada, United States). Participants were recruited before cardiac surgery and were followed during hospitalization and at 3, 12, 24, 36, and 48 months after discharge. Exposures were postoperative AKI, based on the Kidney Disease Improving Global Outcomes (KDIGO) definition, and age <2 years old at surgery. Outcomes and measures were CKD (low eGFR or albuminuria for age) and hypertension (per the 2017 American Academy of Pediatrics guidelines) at follow-up, with the composite outcome of CKD or hypertension.

RESULTS

Among 124 participants, 57 (46%) developed AKI. AKI versus non-AKI participants had a median (interquartile range) age of 8 (4.8-40.8) versus 46 (6.0-158.4) months, respectively, and higher preoperative eGFR. From the 3- to 48-month follow-up, the cohort prevalence of CKD was high (17%-20%); hypertension prevalence was also high (22%-30%). AKI was not significantly associated with the development of CKD throughout follow-up. AKI was associated with hypertension development at 12 months after discharge (adjusted relative risk, 2.16; 95% confidence interval, 1.18 to 3.95), but not at subsequent visits. Children aged <2 years old at surgery had a significantly higher prevalence of hypertension during follow-up than older children (40% versus 21% at 3-month follow-up; 32% versus 13% at 48-month follow-up).

CONCLUSIONS

CKD and hypertension burden in the 4 years after pediatric cardiac surgery is high. Young age at surgery, but not AKI, is associated with their development.

A meta-analysis of the incidence rate of postoperative acute kidney injury in patients with congenital heart disease

Background

Acute kidney injury (AKI) is a common complication of cardiac surgery. However, the incidence rate of AKI in patients with congenital heart disease (CHD) greatly varies between reports owing to the different definitions used for AKI. Therefore, this study was designed as a meta-analysis aimed at summarizing the incidence rate of AKI in patients with congenital heart disease (CHD) on the basis of different AKI criteria.

Methods

Studies published till April 24, 2020, on the incidence rate of AKI in patients with CHD, were retrieved from electronic databases and printed literature. To pool data from the included studies, the effect size, a combined statistics, was chosen and presented with the incidence rate and 95% confidence interval (CI). Heterogeneity was evaluated using I² statistics and Cochran Q test. The incidence rates obtained from the subgroup analysis according to study location, type of surgery, type of cohort, age, and AKI criteria) were also evaluated to determine the correlation of AKI with these factors. Publication bias was estimated using the Egger test.

Results

Thirty studies, comprising 9925 patients with AKI who had CHD, were included. Overall, the pooled incidence rate of AKI in the patients with CHD was 38.4% (95% CI, 32.0–44.7%). However, the incidence rate was not significantly affected by gender, study location, type of surgery, type of cohort, and AKI criteria. Moreover, age was significantly associated with the incidence of AKI, and the incidence rate was higher in the patients aged < 1 month than in those aged 1 month to 18 years, < 18 years, and ≥ 18 years (P < 0.05).

Conclusions

In this study, the estimated incidence rate of AKI in patients with CHD was 38.4% and may be influenced by age. These findings highlight the importance of further investigation of the specific causes of and effective preventive measures for AKI.

Prevalence and predictors of postoperative peritoneal dialysis in infants

BACKGROUND

Data regarding predictors of the eventual need for postoperative peritoneal dialysis in infants undergoing open heart surgery is still limited. We aimed to determine whether prolonged cardiopulmonary bypass time, surgical complexity classified according to Risk Adjustment for Congenital Heart Surgery category, younger age, and lower body weight increase the probability of requiring postoperative peritoneal dialysis.

METHODS

We retrospectively analyzed data of 181 infants who underwent open heart surgery at our institution from January 1 to December 31, 2018. Cardiopulmonary bypass time, Risk Adjustment for Congenital Heart Surgery category, age, body weight, and the need for postoperative peritoneal dialysis were recorded and analyzed.

RESULTS

Thirteen (7.2%) of the 181 patients required postoperative peritoneal dialysis. This group was found to have a longer cardiopulmonary bypass time, younger age, and lower body weight. Longer cardiopulmonary bypass time (p = 0.001), higher Risk Adjustment for Congenital Heart Surgery category (p = 0.018), younger age (p < 0.001), and lower body weight (p < 0.001) significantly increased the risk of postoperative peritoneal dialysis.

CONCLUSION

Longer cardiopulmonary bypass time, more complex surgery, younger age, and lower body weight increase the probability of requiring postoperative peritoneal dialysis in infants undergoing open heart surgery.

Acute Kidney Injury after Congenital Heart Disease Surgery: A Single-Center Experience in a Low- to Middle-Income Country

Background Acute kidney injury (AKI) is a commonly recognized clinical problem after congenital heart disease (CHD) surgery. Increased perioperative morbidity, development of chronic kidney disease, and increased mortality are the major concerns. We investigated frequency, risk factors, and outcomes of AKI after CHD surgery at our hospital. Methods This study was a retrospective analytic review conducted from January 2013 to October 2016 on patients aged between 1 month and 45 years who underwent cardiopulmonary bypass (CPB) for CHD surgery. The modified Kidney Disease Improving Global Outcomes criteria based on serum creatinine value was adopted to diagnose AKI. We assessed AKI frequency and its staging, and outcomes as AKI resolution, length of stay, and mortality. Stages II and III (plasma creatinine level two or more times the baseline) were labeled as severe AKI. Univariate and multivariate logistic regression analyses were conducted, and results were reported as mean with standard deviation and as frequencies with percentage. Odds ratios (ORs) with 95% confidence intervals (CIs) were reported for factors associated with the development of AKI. Results Of the 840 patients who underwent CHD surgery, 237 (28%) developed AKI. AKI stages II1 and III were seen in 101 (42%) and 103 (43%) patients, respectively. Prolonged CPB time > 120 minutes (adjusted OR [AOR]: 1.87; 95% CI: 1.22-2.88; p = 0.004) and hemoglobin > 16 gm/dL (AOR: 1.80; 95% CI: 1.16-2.78; p = 0.008) were associated with the development of AKI on multivariate analysis. AKI resolved spontaneously in 222 (94%) patients, and 10 (4%) patients who developed AKI died. Conclusions Most patients with AKI showed spontaneous resolution. Prolonged CPB time and increased hemoglobin were found to be significant risk factors. Our study found spontaneous resolution of AKI in most cases. However, preplanning and careful monitoring in patients with expected prolonged CPB time and increased baseline hemoglobin can prevent and identify AKI at an early stage.

Assessment of the Independent and Synergistic Effects of Fluid Overload and Acute Kidney Injury on Outcomes of Critically Ill Children

OBJECTIVES

Evaluate the independent and synergistic associations of fluid overload and acute kidney injury with outcome in critically ill pediatric patients.

DESIGN

Secondary analysis of the Acute Kidney Injury in Children Expected by Renal Angina and Urinary Biomarkers (NCT01735162) prospective observational study.

SETTING

Single-center quaternary level PICU.

PATIENTS

One-hundred forty-nine children 3 months to 25 years old with predicted PICU length of stay greater than 48 hours, and an indwelling urinary catheter enrolled (September 2012 to March 2014). Acute kidney injury (defined by creatinine or urine output on day 3) and fluid overload (≥ 20% on day 3) were used as outcome variables and risk factors for ICU endpoints assessed at 28 days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Acute kidney injury and fluid overload occurred in 19.4% and 24.2% respectively. Both acute kidney injury and fluid overload were associated with longer ICU length of stay but neither maintained significance after multivariate regression. Delineation into unique fluid overload/acute kidney injury classifications demonstrated that fluid overload patients experienced a longer ICU and hospital length of stay and higher rate of mortality compared with fluid overload patients, regardless of acute kidney injury status. Fluid overload/acute kidney injury patients had increased odds of death (p = 0.013). After correction for severity of illness, ICU length of stay remained significantly longer in fluid overload/acute kidney injury patients compared with patients without both classifications (17.4; 95% CI, 11.0-23.7 vs 8.8; 95% CI, 7.3-10.9; p = 0.05). Correction of acute kidney injury classification for net fluid balance led to acute kidney injury class switching in 29 patients and strengthened the association with increased mechanical ventilation and ICU length of stay on bivariate analysis, but reduced the increased risk conferred by fluid overload for mortality.

CONCLUSIONS

The current study suggests the effects of significant fluid accumulation may be delineable from the effects of acute kidney injury. Concurrent fluid overload and acute kidney injury significantly worsen outcome. Correction of acute kidney injury assessment for net fluid balance may refine diagnosis and unmask acute kidney injury associated with deleterious downstream sequelae. The unique effects of fluid overload and acute kidney injury on outcome in critically ill patients warrant further study.

Incidence and Risk Factors of Acute Kidney Injury after Kasai Operation for Biliary Atresia: A Retrospective Study

Background: Biliary atresia is a progressive, inflammatory, and destructive pathology of the bile ducts. Patients who undergo surgery for correction of biliary atresia (Kasai operation) are at risk of acute kidney injury (AKI) because of their young age at the time of surgery, long operation time, and liver fibrosis or failure as complication of biliary atresia. Conversely, AKI is associated with poor outcomes after surgery. This study therefore aimed to evaluate the incidence, risk factors, and outcomes of AKI after Kasai operation. Methods: All consecutive patients who underwent Kasai operation between March 2006 and December 2015 in a single tertiary-care university hospital were enrolled. AKI was defined based on the Acute Kidney Injury Network criteria. Multivariate logistic regression models were used to assess risk factors for AKI. Results: One hundred sixty-six patients received Kasai operation during study period. Of these, AKI occurred in 37 of 166 patients (22.3%). In multivariate logistic regression analysis, age older than 30 days, higher preoperative estimated glomerular filtration rate, and preoperative contrast use within 7 days were associated with the development of AKI. Perioperative packed red blood cells transfusion was related to reduced occurrence of AKI. AKI was associated with longer ICU stay (OR = 1.015, p = 0.016). More patients with AKI were also found to receive additional surgery except liver transplantation within 1 year compared to those without AKI (10.8 % vs. 2.3 %, p = 0.045). Conclusions: Increased age is strongly associated with the development of AKI after Kasai operation. These findings indicate a rational basis for early corrective surgery for biliary atresia, early screening for AKI, and intervention to improve the results of Kasai operation.

Near-Infrared-Based Cerebral Oximetry for Prediction of Severe Acute Kidney Injury in Critically Ill Children After Cardiac Surgery

Supplemental Digital Content is available in the text.

Cerebral oximetry by near-infrared spectroscopy is used frequently in critically ill children but guidelines on its use for decision making in the PICU are lacking. We investigated cerebral near-infrared spectroscopy oximetry in its ability to predict severe acute kidney injury after pediatric cardiac surgery and assessed its additional predictive value to routinely collected data.

Acute Kidney Injury and Fluid Overload in Pediatric Cardiac Surgery

PURPOSE OF REVIEW

Acute kidney injury (AKI) and fluid overload affect a large number of children undergoing cardiac surgery, and confers an increased risk for adverse complications and outcomes including death. Survivors of AKI suffer long-term sequelae. The purpose of this narrative review is to discuss the short and long-term impact of cardiac surgery associated AKI and fluid overload, currently available tools for diagnosis and risk stratification, existing management strategies, and future management considerations.

RECENT FINDINGS

Improved risk stratification, diagnostic prediction tools and clinically available early markers of tubular injury have the ability to improve AKI-associated outcomes. One of the major challenges in diagnosing AKI is the diagnostic imprecision in serum creatinine, which is impacted by a variety of factors unrelated to renal disease. In addition, many of the pharmacologic interventions for either AKI prevention or treatment have failed to show any benefit, while peritoneal dialysis catheters, either for passive drainage or prophylactic dialysis may be able to mitigate the detrimental effects of fluid overload.

SUMMARY

Until novel risk stratification and diagnostics tools are integrated into routine practice, supportive care will continue to be the mainstay of therapy for those affected by AKI and fluid overload after pediatric cardiac surgery. A viable series of preventative measures can be taken to mitigate the risk and severity of AKI and fluid overload following cardiac surgery, and improve care.

Incidence and Risk Factors of Early Onset Neonatal AKI

BACKGROUND AND OBJECTIVES

Neonatal AKI is associated with poor short- and long-term outcomes. The objective of this study was to describe the risk factors and outcomes of neonatal AKI in the first postnatal week.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The international retrospective observational cohort study, Assessment of Worldwide AKI Epidemiology in Neonates (AWAKEN), included neonates admitted to a neonatal intensive care unit who received at least 48 hours of intravenous fluids. Early AKI was defined by an increase in serum creatinine >0.3 mg/dl or urine output <1 ml/kg per hour on postnatal days 2-7, the neonatal modification of Kidney Disease: Improving Global Outcomes criteria. We assessed risk factors for AKI and associations of AKI with death and duration of hospitalization.

RESULTS

Twenty-one percent (449 of 2110) experienced early AKI. Early AKI was associated with higher risk of death (adjusted odds ratio, 2.8; 95% confidence interval, 1.7 to 4.7) and longer duration of hospitalization (parameter estimate: 7.3 days 95% confidence interval, 4.7 to 10.0), adjusting for neonatal and maternal factors along with medication exposures. Factors associated with a higher risk of AKI included: outborn delivery; resuscitation with epinephrine; admission diagnosis of hyperbilirubinemia, inborn errors of metabolism, or surgical need; frequent kidney function surveillance; and admission to a children's hospital. Those factors that were associated with a lower risk included multiple gestations, cesarean section, and exposures to antimicrobials, methylxanthines, diuretics, and vasopressors. Risk factors varied by gestational age strata.

CONCLUSIONS

AKI in the first postnatal week is common and associated with death and longer duration of hospitalization. The AWAKEN study demonstrates a number of specific risk factors that should serve as "red flags" for clinicians at the initiation of the neonatal intensive care unit course.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Assessment of Worldwide AKI Epidemiology in Neonates (AWAKEN), NCT02443389.

Renal replacement therapy in the pediatric cardiac intensive care unit

OBJECTIVE

There is an increased risk of mortality in patients in whom acute kidney injury and fluid accumulation develop after cardiothoracic surgery, and the risk is especially high when renal replacement therapy is needed. However, renal replacement therapy remains an essential intervention in managing these patients. The objective of this study was to identify risk factors for mortality in surgical patients requiring renal replacement therapy in a pediatric cardiac intensive care unit.

METHODS

We performed a retrospective review of patients requiring renal replacement therapy for acute kidney injury or fluid accumulation after cardiothoracic surgery between January 2009 and December 2017. Survivors and nonsurvivors were compared with respect to multiple variables, and a multivariable logistic regression analysis was performed to identify independent risk factors associated with mortality.

RESULTS

The mortality rate for the cohort was 75%. Nonsurvivors were younger (nonsurvivors: 0.8 years; interquartile range, 0.1-8.2; survivors: 14.6 years; interquartile range, 4.2-19.7; P = .002) and had a lower weight-for-age z-score (nonsurvivors: -1.5; interquartile range, -3.1 to -0.4; survivors: -0.5; interquartile range, -0.9 to 0.3; P = .02) compared with survivors. There was no difference with respect to fluid accumulation. In multivariable analysis, a longer duration of stage 3 acute kidney injury before initiation of renal replacement therapy was independently associated with mortality (adjusted odds ratio, 1.39; 95% confidence interval, 1.05-1.83; P = .021).

CONCLUSIONS

Mortality in patients requiring renal replacement therapy after congenital heart disease surgery is high. A longer duration of acute kidney injury before renal replacement therapy initiation is associated with increased mortality.