Renal aspects of the term and preterm infant: a selective update

The American Association for Thoracic Surgery (AATS) 2024 expert consensus document: Management of neonates and infants with Ebstein anomaly

OBJECTIVES

Symptomatic neonates and infants with Ebstein anomaly (EA) require complex management. A group of experts was commissioned by the American Association for Thoracic Surgery to provide a framework on this topic focusing on risk stratification and management.

METHODS

The EA Clinical Congenital Practice Standards Committee is a multinational and multidisciplinary group of surgeons and cardiologists with expertise in EA. A citation search in PubMed, Embase, Scopus, and Web of Science was performed using key words related to EA. The search was restricted to the English language and the year 2000 or later and yielded 455 results, of which 71 were related to neonates and infants. Expert consensus statements with class of recommendation and level of evidence were developed using a modified Delphi method, requiring 80% of members votes with at least 75% agreement on each statement.

RESULTS

When evaluating fetuses with EA, those with severe cardiomegaly, retrograde or bidirectional shunt at the ductal level, pulmonary valve atresia, circular shunt, left ventricular dysfunction, or fetal hydrops should be considered high risk for intrauterine demise and postnatal morbidity and mortality. Neonates with EA and severe cardiomegaly, prematurity (<32 weeks), intrauterine growth restriction, pulmonary valve atresia, circular shunt, left ventricular dysfunction, or cardiogenic shock should be considered high risk for morbidity and mortality. Hemodynamically unstable neonates with a circular shunt should have emergent interruption of the circular shunt. Neonates in refractory cardiogenic shock may be palliated with the Starnes procedure. Children may be assessed for later biventricular repair after the Starnes procedure. Neonates without high-risk features of EA may be monitored for spontaneous closure of the patent ductus arteriosus (PDA). Hemodynamically stable neonates with significant pulmonary regurgitation at risk for circular shunt with normal right ventricular systolic pressure should have an attempt at medical closure of the PDA. A medical trial of PDA closure in neonates with functional pulmonary atresia and normal right ventricular systolic pressure (>20-25 mm Hg) should be performed. Neonates who are hemodynamically stable without pulmonary regurgitation but inadequate antegrade pulmonary blood flow may be considered for a PDA stent or systemic to pulmonary artery shunt.

CONCLUSIONS

Risk stratification is essential in neonates and infants with EA. Palliative comfort care may be reasonable in neonates with associated risk factors that may include prematurity, genetic syndromes, other major medical comorbidities, ventricular dysfunction, or sepsis. Neonates who are unstable with a circular shunt should have emergent interruption of the circular shunt. Neonates who are unstable are most commonly palliated with the Starnes procedure. Neonates who are stable should undergo ductal closure. Neonates who are stable with inadequate pulmonary flow may have ductal stenting or a systemic-to-pulmonary artery shunt. Subsequent procedures after Starnes palliation include either single-ventricle palliation or biventricular repair strategies.

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.

Acute kidney injury among preterm infants receiving nonsteroidal anti-inflammatory drugs: A pilot study

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a frequently prescribed class of medications in the neonatal intensive care unit (NICU). We aimed to reveal acute kidney injury (AKI) epidemiology in NSAID-exposed premature infants admitted to the NICU using a standardized definition and determine the percentage of NSAID-exposed patients with adequate serum creatinine (SCr) monitoring.

METHODS

This retrospective study compared infants born at ≤34 weeks gestational age who received NSAID for intraventricular hemorrhage prophylaxis (prophylaxis group) or symptomatic treatment for patent ductus arteriosus (PDA; treatment group) between January and December 2014 at a tertiary NICU. All available SCr and 12-h urine output (UO) values were recorded from admission until day seven post-NSAID exposure. AKI incidence was determined using the neonatal modified Kidney Disease Improving Global Outcomes classification, defined as an increase in SCr (i.e., 1.5 fold rise from previous SCr measurement within seven days or 26.5 mmol/L increase within 48 h) or UO < 1 mL/kg/hour, excluding the first 24 h of life.

RESULTS

We identified 70 eligible subjects; 32 received prophylactic NSAIDs, and 38 received indomethacin or ibuprofen for treating symptomatic PDA. AKI incidence for the entire cohort was 23% (16/70). The prophylaxis group had a significantly lower AKI rate than the treatment group (9% vs. 34%; p = 0.014). The treatment group had a higher proportion of infants with adequate SCr monitoring during NSAID treatment than the prophylaxis group (87% vs. 13%, p < 0.001).

CONCLUSION

NSAID-associated AKI occurred in approximately one-quarter of premature infants overall, and the AKI incidence was higher in infants treated with NSAIDs for the symptomatic treatment of PDA than in those receiving prophylactic treatment during the first day of life. Standardized protocols for monitoring daily SCr and UO after exposure should be implemented for all neonates with NSAID exposure to improve early AKI recognition and management.

Gestational and Age-Specific Cystatin C Reference Intervals for Newborns

OBJECTIVE

Cystatin C (CysC) references are useful for the monitoring of renal function in neonates. However, the standard CysC references in newborn infants have not been determined. The aim of this study was to establish a useful reference range for CysC in newborns.

STUDY DESIGN

Serum CysC levels were measured in 1,919 blood samples from 1,044 newborns during their first 28 days of life. CysC levels were analyzed for associations between subgroups dichotomized by postnatal age (PA) and gestational age (GA). The serum CysC reference intervals were determined according to the PA and GA. The associations between the serum CysC level and other biochemical parameters as well as perinatal factors were also analyzed.

RESULTS

In this study, the mean GA was 35.8 ± 2.9 weeks and the birth weight (BW) was 2,614 ± 697 g. Reference ranges of serum CysC were determined, and a general decreasing trend of CysC levels was observed as the GA increased. CysC levels differed significantly among the PA and GA categories (p < 0.001). Serum CysC levels were relatively stable throughout the GA range but were impacted by the white blood cell count within the first postnatal 24 hours. Moreover, CysC levels always correlated positively with serum creatinine concentrations (p < 0.001). Serum Cr levels were influenced by multiple factors, including BW, GA, total bilirubin, direct bilirubin, white blood cell count, C-reactive protein, and blood urea nitrogen.

CONCLUSION

Reference levels of serum CysC should be determined according to the PA and GA. In contrast to Cr, serum CysC is a reliable index for assessing renal function in neonates as it is influenced by very few factors. The CysC reference levels will allow neonatologists to accurately evaluate renal function in the neonatal population.

KEY POINTS

· Cystatin C is a useful marker of the glomerular filtration rate in neonates.. · A reference range for cystatin C using 1,919 blood samples of 1,044 newborns was determined.. · In contrast to creatinine, only a few nonrenal factors influence serum cystatin C..

Serum and urinary biomarkers to predict acute kidney injury in premature infants: a systematic review and meta-analysis of diagnostic accuracy

BACKGROUND

Premature infants are at high risk for acute kidney injury (AKI) and current diagnostic criteria are flawed. The objective of this study was to determine the diagnostic accuracy of urine and serum biomarkers not currently used in routine clinical practice to predict AKI in premature infants.

METHOD

A systematic review was performed that followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Diagnostic Test Accuracy Studies (PRISMA-DTA). Data were extracted on the diagnostic accuracy of AKI biomarkers using serum creatinine or urine output as the reference standard. Quality and validity were assessed using modified Standards for Reporting Diagnostic Accuracy (STARD) criteria.

RESULTS

We identified 1024 articles, with 15 studies (791 infants) eligible for inclusion. Twenty-seven biomarkers were identified including serum cystatin C and urinary neutrophil gelatinase-associated lipocalin (uNGAL), osteopontin, kidney injury molecule-1, epidermal growth factor, and protein S100-P. However, many were only reported by one study each. A meta-analysis could only be conducted on uNGAL (288 infants from 6 studies) using a hierarchical, random-effects logistic-regression model. uNGAL had a summary sensitivity of 77% (95% CI 58-89%), specificity of 76% (95% CI 57-88%) and AUC-SROC of 0.83 (95% CI 0.80-0.86) for the diagnosis of AKI. By utilising uNGAL, the post-test probability of AKI increased to 52% (95% CI 37-66%) with a positive test and decreased to 9% (95% CI 5-16%) with a negative test if the pre-test probability was 25%.

CONCLUSION

uNGAL shows promise as a diagnostically accurate biomarker for AKI in premature infants.

Serum Cystatin C as a predictor of acute kidney injury in neonates: a meta-analysis

OBJECTIVES

The objective of this meta-analysis is to evaluate the diagnostic value of serum Cystatin C in acute kidney injury (AKI) in neonates.

SOURCES

PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), and WanFang Database were searched to retrieve the literature related to the diagnostic value of Cystatin C for neonatal AKI from inception to May 10, 2021. Subsequently, the quality of included studies was determined using the QUADAS-2 tool. Stata 15.0 statistical software was used to calculate the combined sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). Additionally, meta-regression analysis and subgroup analysis contributed to explore the sources of heterogeneity.

SUMMARY OF THE FINDINGS

Twelve articles were included. The pooled sensitivity was 0.84 (95%CI: 0.74-0.91), the pooled specificity was 0.81 (95%CI: 0.75-0.86), the pooled PLR was 4.39 (95%CI: 3.23-5.97), the pooled NLR was 0.19 (95%CI: 0.11-0.34), and the DOR was 22.58 (95%CI: 10.44-48.83). The area under the receiver operating characteristic curve (AUC) was 0.88 (95%CI: 0.85-0.90). No significant publication bias was identified (p > 0.05).

CONCLUSIONS

Serum Cystatin C has a good performance in predicting neonatal AKI; therefore, it can be used as a candidate biomarker after the optimal level is determined by large prospective studies.

Optimizing neonatal cardiac imaging (magnetic resonance/computed tomography)

Magnetic resonance imaging (MRI) and CT perform an important role in the evaluation of neonates with congenital heart disease (CHD) when echocardiography is not sufficient for surgical planning or postoperative follow-up. Cardiac MRI and cardiac CT have complementary applications in the evaluation of cardiovascular disease in neonates. This review focuses on the indications and technical aspects of these modalities and special considerations for imaging neonates with CHD.

Non-invasive continuous renal tissue oxygenation monitoring to identify preterm neonates at risk for acute kidney injury

BACKGROUND

Near-infrared spectroscopy (NIRS) is an emerging tool to identify signs of inadequate tissue oxygenation in preterm neonates with acute kidney injury (AKI). Previous studies have shown a correlation between low renal tissue oxygenation (RrSO₂) in the first 24 hours of age and the later development of AKI. In this prospective clinical trial, NIRS monitoring was used to identify changes in RrSO₂ in comparison to traditional AKI markers, serum creatinine (SCr), and urine output (UOP).

METHODS

We enrolled 35 preterm neonates born less than 32 weeks' gestation and applied neonatal NIRS sensors at less than 48 hours of age. Neonates underwent 7 days of continuous monitoring. Renal and demographic information were collected for the first 7 days of age. AKI was determined by the modified neonatal Kidney Disease: Improving Global Outcomes (KDIGO) definition including UOP.

RESULTS

Three patients experienced AKI, all based on both SCr and UOP criteria. Each neonate with AKI had decreases in RrSO₂ over 48 hours prior to changes in SCr and UOP. Patients with AKI had lower median RrSO₂ values compared to patients without AKI over the first week of age, (32.4% vs. 60%, p < 0.001).

CONCLUSION

RrSO₂ monitoring identified preterm neonates at risk for AKI. NIRS detected a decline in RrSO₂ prior to changes in SCr and UOP and was significantly lower in patients with AKI compared to those without AKI. Further studies are needed to evaluate the ability of RrSO₂ monitoring to detect signs of kidney stress prior to the diagnosis of AKI. Graphical abstract.

Can urinary biomarkers predict acute kidney injury in newborns with critical congenital heart disease?

Background/aim

Congenital heart disease (CHD) is the most common congenital malformation group and is the leading cause of newborn mortality in developed countries. Most of the infants with CHD develop preoperative or postoperative acute kidney injury (AKI). Acute kidney injury may develop before the serum creatinine rise and oliguria. Urinary biomarkers such as kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), interleukin (IL)-18, and cystatin C may predict AKI in patients with critical CHD (CCHD) before the serum creatinine rise. In this study, we aimed to determine the AKI incidence among newborn patients with CCHD and investigate the predictivity of urinary biomarkers for AKI.

Materials and methods

Newborns with a gestational age >34 weeks and birth weight >1500 g with a diagnosis of CCHD were enrolled in the study. Blood and urine samples were collected at birth, during the first 24–48 h, and in the preoperative and postoperative periods.

Results

A total of 53 CCHD patients requiring surgery during the neonatal period were enrolled in the study. The 24–48 h KIM-1 levels of the cases with exitus were higher (P = 0.007). The 24–48 h cystatin C and preoperative NGAL levels were higher in patients with postoperative AKI (P = 0.02).

Conclusion

In newborns with CCHD, high KIM-1 levels may predict mortality, whereas high cystatin C and preoperative NGAL levels may be indicative of AKI. These biomarkers deserve further investigation in larger study populations.

A New Approach to Recognize Neonatal Impaired Kidney Function

Introduction

Previous studies in term newborns with hypoxic ischemic encephalopathy showed that the rate of serum creatinine (SCr) decline during the first week of life could be used to identify newborns with impaired kidney function (IKF) who are missed by standard definitions of neonatal acute kidney injury (nAKI).

Methods

Retrospective review of the medical records of 329 critically ill newborns ≥27 weeks of gestational age (GA) admitted to a level 4 neonatal intensive care unit (NICU). We tested the hypothesis that the rate of SCr decline combined with SCr thresholds provides a sensitive approach to identify term and preterm newborns with IKF during the first week of life.

Results

Excluding neonates with nAKI, an SCr decline <31% by the seventh day of life, combined with an SCr threshold ≥0.7 mg/dl, recognized newborns of 40 to 31 weeks of GA with IKF. An SCr decline <21% combined with an SCr threshold ≥0.8 mg/dl identified newborns of 30 to 27 weeks of GA with IKF. Neonates with IKF (∼17%), like those with nAKI (7%), showed a more prolonged hospital stay and required more days of mechanical ventilation, vasoactive drugs, and diuretics, when compared with the controls. Changes in urine output did not distinguish newborns with IKF.

Conclusion

The rate of SCr decline combined with SCr thresholds identifies newborns with IKF during the first week of life. This distinctive group of newborns that is missed by standard definitions of nAKI, warrants close monitoring in the NICU to prevent further renal complications.

A retrospective study on the incidence of acute kidney injury and its early prediction using troponin-I in cooled asphyxiated neonates

Acute kidney injury (AKI) is a common complication of perinatal asphyxia and is associated with poorer short-term and long-term outcomes. This retrospective study describes the incidence of AKI in asphyxiated neonates who have received therapeutic hypothermia using the proposed modified Kidney Diseases: Improving Global Outcomes (KDIGO) definition and investigates clinical markers that would allow earlier recognition of at-risk neonates. We included asphyxiated  neonates who underwent therapeutic hypothermia between the period of January 2011 and May 2018 in our study. The serum creatinine levels within a week of birth were used in establishing AKI according to the modified KDIGO definition. Demographic data, resuscitation details, laboratory results and use of medications were collected and compared between the AKI and non-AKI groups to identify variables that differed significantly. A total of 66 neonates were included and 23 out of them (35%) were found to have AKI. The neonates with AKI had a lower gestational age (p = 0.006), lower hemoglobin level (p = 0.012), higher lactate level before and after therapeutic hypothermia (p = 0.013 and 0.03 respectively) and higher troponin-I level after therapeutic hypothermia (p < 0.001). After logistic regression analysis, elevated troponin-I after therapeutic hypothermia was independently associated with risk of AKI (OR 1.69, 95% CI 1.067–2.699, p = 0.025). The receiver operating curve showed that troponin-I after therapeutic hypothermia had an area under curve of 0.858 at the level 0.288 ng/ml. Our study concludes that the incidence of AKI among asphyxiated newborns who received therapeutic hypothermia is 35% and an elevated troponin-I level after therapeutic hypothermia is independently associated with an increased risk of AKI in asphyxiated newborns.

Cell-Cycle Arrest Biomarkers: Usefulness for Cardiac Surgery-Related Acute Kidney Injury in Neonates and Infants

OBJECTIVES

Cell cycle arrest urine biomarkers have recently been shown to be early indicators of acute kidney injury in various clinical settings in critically ill adults and children. The product of tissue inhibitor metalloproteinase -1 and insulin-like growth factor binding protein-7 concentrations/1,000 (TIMP-1) × (IGFBP-7) provides stratification of acute kidney injury-risk in adults with critical illness. The present study explores the predictive accuracy of (TIMP-1) × (IGFBP-7) measured early after cardiopulmonary bypass for cardiac surgery-related acute kidney injury in neonates and infants, a population in whom such data are not yet available.

DESIGN

Prospective, observational.

SETTING

A tertiary referral pediatric cardiac ICU.

PATIENTS

Fifty-seven neonates and 110 infants undergoing surgery with cardiopulmonary bypass.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

(TIMP-1) × (IGFBP-7) was measured on the NephroCheck (Astute Medical, San Diego, CA) platform preoperatively, less than 1 hour of cardiopulmonary bypass and 1-3 hours of cardiopulmonary bypass. The incidence of postoperative acute kidney injury, dialysis, and/or death were compared among quintiles of postoperative (TIMP-1) × (IGFBP-7). Multivariable regression was used to assess the added predictive value for renal events of (TIMP-1) × (IGFBP-7) over clinical models. Basal (TIMP-1) × (IGFBP-7) increased with age at surgery (regression coefficient = 0.004 ± 0.001; p = 0.005). (TIMP-1) × (IGFBP-7) increased after cardiopulmonary bypass. Neonates had lower postoperative (TIMP-1) × (IGFBP-7) compared with older infants, despite undergoing longer surgeries and experiencing a higher incidence of postoperative renal events. (TIMP-1) × (IGFBP-7) was not associated with acute kidney injury, dialysis, and/or death and was not a predictor of the aforementioned events when added to a clinical acute kidney injury model including age, duration of cardiopulmonary bypass, and mechanical ventilation prior to surgery.

CONCLUSIONS

These findings question the usefulness of (TIMP-1) × (IGFBP-7) for the prediction of cardiac surgery-related acute kidney injury in neonates and infants when measured within 3 hours of cardiopulmonary bypass.

Effect of Aminophylline in Preventing Renal Dysfunction among Neonates with Prenatal Asphyxia: A Clinical Trial

BACKGROUND

As there are different views on the effects of aminophylline on neonatal renal function, we intended to observe the effects of aminophylline on renal dysfunction in neonates with prenatal asphyxia.

METHODS

This randomized trial was conducted in the Obstetrics and Gynecology Hospital, Tehran, Iran, from June 2016 to May 2017, in neonates with moderate to severe asphyxia during birth. Fifty-six neonates were divided randomly into two groups. The intervention group received one dose of 5mg/kg slow intravenous aminophylline injection and the placebo group received 2 mL/kg of intravenous 10% solution of dextrose saline during the first hour of life. They were monitored and compared for renal functional indices, electrolytes, and complications of asphyxia during the three days of life.

RESULTS

The mean of Cr (37.9 ± 8.8 vs 38.5 ± 9.4 and 20.8 ± 4.8 vs 30.1 ± 5.2 μmol/L), GFR (21.55 ± 4.7 vs 20.25 ± 4.4 and 30.8 ± 7.1 vs 20.1 ± 6.5 mL/minute/1.73 m²), Na (135.1 ± 12.4 vs134.5 ± 11.2 and 128.9 ± 11.5 vs 134.2 ± 10.9 mEq/L), and urine output (98.2 ± 25 vs 96.8 ± 23 and 148.7 ± 35 vs 108.8 ± 20 cc) were in the aminophylline treated and placebo group on the 1st and 3rd days, respectively. The mean difference of Cr (-9.3 (-8.9; -9.7) μmol/L); (P = 0.02), GFR (10.7 (10.1; 11.3) mL/minute/1.73 m²) (P = 0.009), Na (-5.3 (-5.9; -4.7) mEq/L) (P = 0.002), and urine volume (39.9 (24.9; 54.9) cc) (P = 0.001) presented statistically significant differences on the third day between the intervention and placebo group.

CONCLUSION

Aminophylline was effective in preventing renal dysfunction in neonates with asphyxia. Neonates who received aminophylline indicated a significant improvement in GFR and urine output on the first day of life.

Fetal Physiologically Based Pharmacokinetic Models: Systems Information on the Growth and Composition of Fetal Organs

BACKGROUND

The growth of fetal organs is a dynamic process involving considerable changes in the anatomical and physiological parameters that can alter fetal exposure to xenobiotics in utero. Physiologically based pharmacokinetic models can be used to predict the fetal exposure as time-varying parameters can easily be incorporated.

OBJECTIVE

The objective of this study was to collate, analyse and integrate the available time-varying parameters needed for the physiologically based pharmacokinetic modelling of xenobiotic kinetics in a fetal population.

METHODS

We performed a comprehensive literature search on the physiological development of fetal organs. Data were carefully assessed, integrated and a meta-analysis was performed to establish growth trends with fetal age and weight. Algorithms and models were generated to describe the growth of these parameter values as functions of age and/or weight.

RESULTS

Fetal physiologically based pharmacokinetic parameters, including the size of the heart, liver, brain, kidneys, lungs, spleen, muscles, pancreas, skin, bones, adrenal and thyroid glands, thymus, gut and gonads were quantified as a function of fetal age and weight. Variability around the means of these parameters at different fetal ages was also reported. The growth of the investigated parameters was not consistent (with respect to direction and monotonicity).

CONCLUSION

Despite the limitations identified in the availability of some values, the data presented in this article provide a unique resource for age-dependent organ size and composition parameters needed for fetal physiologically based pharmacokinetic modelling. This will facilitate the application of physiologically based pharmacokinetic models during drug development and in the risk assessment of environmental chemicals and following maternally administered drugs or unintended exposure to environmental toxicants in this population.

Laboratory Findings After Urinary Tract Infection and Antimicrobial Prophylaxis in Children With Vesicoureteral Reflux

It is a common practice to monitor blood tests in patients receiving long-term trimethoprim-sulfamethoxazole (TMP-SMZ) prophylaxis for recurrent urinary tract infections. This multicenter, randomized, placebo-controlled trial enrolled 607 children aged 2 to 71 months with vesicoureteral reflux diagnosed after symptomatic urinary tract infection. Study participants received TMP-SMZ (n = 302) or placebo (n = 305) and were followed for 2 years. Serum electrolytes (n ≥ 370), creatinine (n = 310), and complete blood counts (n ≥ 206) were measured at study entry and at the 24-month study conclusion. We found no significant electrolyte, renal, or hematologic abnormalities when comparing the treatment and placebo groups. We observed changes in several laboratory parameters in both treatment and placebo groups as would normally be expected with physiologic maturation. Changes were within the normal range for age. Long-term use of TMP-SMX had no treatment effect on complete blood count, serum electrolytes, or creatinine. Our findings do not support routine monitoring of these laboratory tests in children receiving long-term TMP-SMZ prophylaxis.

Preterm birth is associated with epigenetic programming of transgenerational hypertension in mice

Renal and cardiovascular complications of prematurity are well established, notably the development of hypertension in adulthood. However, the underlying molecular mechanisms remain poorly understood. Our objective was to investigate the impact of prematurity on the ontogenesis of renal corticosteroid pathways, to evaluate its implication in perinatal renal complications and in the emergence of hypertension in adulthood. Swiss CD1 pregnant mice were injected with lipopolysaccharides at 18 days of gestation (E18) to induce prematurity at E18.5. Pups were sacrificed at birth, 7 days and 6 months of life. Second (F2) and third (F3) generations, established by mating prematurely born adult females with wild-type males, were also analyzed. Former preterm males developed hypertension at M6 (P < 0.0001). We found robust activation of renal corticosteroid target gene transcription at birth in preterm mice (αENaC (+45%), Gilz (+85%)), independent of any change in mineralocorticoid or glucocorticoid receptor expression. The offspring of the preterm group displayed increased blood pressure in F2 and F3, associated with increased renal Gilz mRNA expression, despite similar MR or GR expression and plasma corticosteroid levels measured by LC-MS/MS. Gilz promoter methylation measured by methylated DNA immunoprecipitation-qPCR was reduced with a negative correlation between methylation and expression (P = 0.0106). Our study demonstrates prematurity-related alterations in renal corticosteroid signaling pathways, with transgenerational inheritance of blood pressure dysregulation and epigenetic Gilz regulation up to the third generation. This study provides a better understanding of the molecular mechanisms involved in essential hypertension, which could partly be due to perinatal epigenetic programming from previous generations.

A propensity towards high blood pressure may be passed down through several generations from adults who were born preterm. People who are born prematurely often suffer from kidney (renal) problems, high blood pressure and cardiovascular disease as they age. Recent research suggests adults born prematurely can pass dysregulated blood pressure to their children. Laetitia Martinerie at INSERM Unit 1185, Le Kremlin Bicêtre and Robert Debré Hospital in Paris, France, and co-workers studied generations of mice to explore how epigenetic alterations, DNA modifications that do not change the DNA code, affect blood pressure from birth through to adulthood. The team identified tissue-specific alterations in renal signaling pathways in premature mice. They also traced the associated overexpression of a gene called Gilz, known to play a role in blood pressure maintenance, through second and third generation mice born to the first generation preterms.

Maternal and environmental risk factors for neonatal AKI and its long-term consequences

Acute kidney injury (AKI) is a common and life-threatening complication in critically ill neonates. Gestational risk factors for AKI include premature birth, intrauterine growth restriction and low birthweight, which are associated with poor nephron development and are often the consequence of pre-gestational and gestational factors, such as poor nutritional status. Our understanding of how to best optimize renal development and prevent AKI is in its infancy; however, the identification of pre-gestational and gestational factors that increase the risk of adverse neonatal outcomes and the implementation of interventions, such as improving nutritional status early in pregnancy, have the potential to optimize fetal growth and reduce the risk of preterm birth, thereby improving kidney health. The overall risk of AKI among critically ill and premature neonates is exacerbated postnatally as these infants are often exposed to dehydration, septic shock and potentially nephrotoxic medications. Strategies to improve outcomes - for example, through careful evaluation of nephrotoxic drugs - may reduce the incidence of AKI and its consequences among this population. Management strategies and updated technology that will support neonates with AKI are greatly needed. Extremely premature infants and those who survive an episode of AKI should be screened for chronic kidney disease until early adulthood. Here, we provide an overview of our current understanding of neonatal AKI, focusing on its relationship to preterm birth and growth restriction. We describe factors that prevent optimal nephrogenesis during pregnancy and provide a framework for future explorations designed to maximize outcomes in this vulnerable population.

Medication Use and Pain Management in Pregnancy: A Critical Review

BACKGROUND

Pain during pregnancy is common, and its management is complex. Certain analgesics may increase the risk for adverse fetal and pregnancy outcomes, while poorly managed pain can result in adverse maternal outcomes such as depression and hypertension. Guidelines to assist clinicians in assessing risks and benefits of exposure to analgesics for the mother and unborn infant are lacking, necessitating evidence-based recommendations for managing pain in pregnancy.

METHODS

A comprehensive literature search was conducted to assess pregnancy safety data for pharmacological and nonpharmacological pain management methods. Relevant clinical trials and observational studies were identified using multiple medical databases, and included studies were evaluated for quality and possible biases.

RESULTS

Paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs) are appropriate for mild to moderate pain, but NSAIDs should be avoided in the third trimester due to established risks. Short courses of weaker opioids are generally safe in pregnancy, although neonatal abstinence syndrome must be monitored following third trimester exposure. Limited safety data for pregabalin and gabapentin indicate that these are unlikely to be major teratogens, and tricyclic antidepressants and serotonin-norepinephrine reuptake inhibitors have limited but overall reassuring safety data. Many of the included studies were limited by methodological issues.

CONCLUSIONS

Findings from this review can guide clinicians in their decision to prescribe analgesics for pregnant women. Treatment should be tailored to the lowest therapeutic dose and shortest possible duration, and management should involve a discussion of risks and benefits and monitoring for response. Further research is required to better understand the safety profile of various analgesics in pregnancy.

Neonatal Acute Kidney Injury: A Survey of Perceptions and Management Strategies Amongst Pediatricians and Neonatologists

Background: Neonatal Acute Kidney Injury (AKI) occurs in 40-70% of critically ill newborn infants and is independently associated with increased morbidity and mortality. Understanding the practice patterns of physicians (neonatologists and pediatricians), caring for neonates in India is important to optimize care and outcomes in neonatal AKI. Aim: The aim of this study was to identify differences in physician's perception and practice variations of diagnosis, management, and follow-up of newborn infants with AKI in India. Methods: An online survey of neonatologists and pediatricians in India caring for newborn infants with AKI. Results: Out of 800 correspondents, 257 (135 neonatologists and 122 pediatricians) completed the survey, response rate being 32.1%. Resources available to the respondents included level III NICU (59%), neonatal surgery (60%), dialysis (11%), and extracorporeal membrane oxygenation (ECMO, 3%). Most respondents underestimated the risk of AKI due to various risk factors such as prematurity, asphyxia, sepsis, cardiac surgery, and medications. Less than half the respondents were aware of the AKIN or KDIGO criteria, which are the current standard criteria for defining neonatal AKI. Only half of the respondents were aware of the risk of CKD in preterm neonates and nearly half were unaware of the need to follow up with a pediatric nephrologist. Conclusions: Similar to other regions worldwide, there exists a knowledge gap in early recognition, optimal management and follow up of newborn infants with AKI amongst Indian physicians.

Glomerular Filtration Rate Estimation Formulas for Pediatric and Neonatal Use

Renal function assessment is of the utmost importance in predicting drug clearance and in ensuring safe and effective drug therapy in neonates. The challenges to making this prediction relate not only to the extreme vulnerability and rapid maturation of this pediatric subgroup but also to the choice of renal biomarker, covariates, and glomerular filtration rate (GFR) estimating formula. In order to avoid burdensome administration of exogenous markers and/or urine collection in vulnerable pediatric patients, estimation of GFR utilizing endogenous markers has become a useful tool in clinical practice. Several estimation methods have been developed over recent decades, exploiting various endogenous biomarkers (serum creatinine, cystatin C, blood urea nitrogen) and anthropometric measures (body length/height, weight, muscle mass). This article reviews pediatric GFR estimation methods with a focus on their suitability for use in the neonatal population.

Subclinical acute kidney injury is associated with adverse outcomes in critically ill neonates and children

Background

Research on acute kidney injury (AKI) has focused on identifying early biomarkers. However, whether AKI could be diagnosed in the absence of the classic signs of clinical AKI and whether the condition of subclinical AKI, identified by damage or functional biomarkers in the absence of oliguria or increased serum creatinine (sCr) levels, is clinically significant remains to be elucidated in critically ill children. The aims of the study were to investigate the associations between urinary cystatin C (uCysC) levels and AKI and mortality and to determine whether uCysC-positive subclinical AKI is associated with adverse outcomes in critically ill neonates and children.

Methods

In this prospective cohort study, uCysC levels were serially measured during the first week after intensive care unit (ICU) admission in a heterogeneous group of patients (n = 510) presenting to a tertiary neonatal and pediatric ICU. The diagnosis of neonatal AKI that developed during the first week after admission was based on neonatal KDIGO criteria or sCr >1.5 mg/dL, and pediatric AKI was based on Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The term “uCysC(−)” or “uCysC(+)”, indicating the absence or presence of tubular injury, was defined by the optimal peak uCysC cutoff value for predicting ICU mortality.

Results

The initial and peak uCysC levels were significantly associated with AKI and mortality, and had an area under the receiver operating characteristic curve of 0.76 and 0.81, respectively, for predicting mortality. At the optimal cutoff value of 1260 ng/mg uCr, the peak uCysC displayed sensitivity of 79.2% and specificity of 72.3% for predicting mortality. Among all patients, 130 (25.5%) developed uCysC(+)/AKI(−) status during the first week after admission. The adjusted odds ratio for patients with uCysC(+)/AKI(−) status in association with an increased risk of mortality compared with that for patients with uCysC(−)/AKI(−) was 9.34 (P < 0.001). Patients with uCysC(+)/AKI(−) spent 2.8 times as long in the ICU as those with uCysC(−)/AKI(−) (P < 0.001).

Conclusions

Both initial and peak uCysC levels are associated with AKI and mortality and are independently predictive of mortality in critically ill neonates and children. Subclinical AKI may occur without detectable loss of kidney function, and uCysC-positive subclinical AKI is associated with worse clinical outcomes in this population.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2193-8) contains supplementary material, which is available to authorized users.

Association of In-hospital outcome of Acute Kidney Injury (AKI) with etiology among newborns at a tertiary care unit

Objective:

To determine association of in-hospital outcome of AKI with etiology in newborns at a tertiary care hospital.

Methods:

This descriptive cross-sectional study was conducted at Department of Pediatric Neonatology, The Children's Hospital and Institute of the Child Health, Multan by using non-probability purposive sampling technique from June 2016 to June 2017. A total of 101 newborns diagnosed with acute kidney injury were registered. Etiological factors were assessed and these patients were followed till discharge to monitor in-hospital outcomes.

Results:

Of these 101 newborns, 75 (74.3%) were boys while 26 (25.7%) were girls. Mean age of these newborns was 7.59 ± 6.13 days (range; 1 day to 28 days). Mean age of the boys was 5.73 ± 7.20 days while that of girls was 6.77 ± 6.16 days. (p=0.515). Mean weight of these neonates was 2545.05 ± 600.42 grams (range; 1000 grams to 4000 grams). Mean serum potassium level was 4.94 ± 0.92 mgEq/L ranging from 3.1 mgEq/L to 7.0 mgEq/L. Mean urea level was 73.35 ± 27.65 mg/dl ranging from 18 mg/dl to 206 mg/dl. Mean serum creatinine level was 1.98 ± 0.27 mg/dl, ranging from 1.6 mg/dl to 2.8 mg/dl. Mean serum sodium level was 145.72 ± 12.64 mgEq/L ranging from 126 to 166 mEq/L. Eighty one (80.2%) were term babies while 20 (19.8%) were pre-term babies. Of these 101 study cases, 29 (28.7%) delivered vaginally while 72 (71.3%) through cesarean section. Delayed crying was noted in 48 (47.5%), dehydration 13 (12.9%), sepsis in 36 (35.6%) and renal malformation in only 4%. Neonatal mortality in these patients was 15 (14.9%) while 86 (85.1%) were discharged from hospital after recovery.

Conclusion:

Acute kidney disease in newborns is associated with significant disease morbidity and mortality with asphyxia and sepsis are the main etiological factors responsible. It is predominantly more common in boys compared with girls. Mortality rate was high in our study and it was significantly associated with female gender. Mortality was also associated with elevated serum sodium and urea level.

Outcome of extremely low birth weight infants with a history of neonatal acute kidney injury

OBJECTIVE

To study the outcome of extremely low birth weight (ELBW) infants with a history of acute kidney injury (AKI).

METHOD

In a retrospective, case control study, medical records of all ELBW infants admitted to the neonatal intensive care unit (NICU) between Jan 2002 and Dec 2011 were reviewed. Medical records were reviewed for infants' demographics, blood pressure (BP) at NICU discharge and at ≥3 years, and estimated glomerular filtration rate (eGFR) at ≥2 years.

RESULTS

During the study period, 222 patients met the inclusion criteria, of whom 10% (23 out of 222) had AKI stage 2 and 3, 39% (87 out of 222) had AKI stage 1, and the rest did not have AKI. At NICU discharge, there was a difference in diastolic BP (DBP) among infants who had AKI stages 2 and 3, those who had stage 1, and those who did not have AKI (53 ± 12 vs 46 ± 9 vs 46 ± 11 mmHg respectively; p = 0.007), and 11% (23 out of 209) had hypertension (HTN). Although there was a significant correlation between the rise in SCr and DBP at NICU discharge in infants with AKI (R = 0.304; p = 0.004), there was no difference in HTN between infants with and those without AKI. At ≥2 years of age, 4% (5 out of 120) across all groups had an eGFR < 90 ml/min/1.73m² or chronic kidney disease (CKD). At ≥3 years of age, 5% (11 out of 222) had HTN.

CONCLUSION

At NICU discharge, infants with AKI stages 2 and 3 have a higher DBP than infants with stage 1 AKI and those who did not have AKI. However, there is no difference in the rate of HTN between the two groups. At ≥2 years ELBW infants are at risk for CKD independently of whether or not they develop neonatal AKI.

Acute kidney injury in the fetus and neonate

Acute kidney injury (AKI) is an under-recognized morbidity of neonates; the incidence remains unclear due to the absence of a unified definition of AKI in this population and because previous studies have varied greatly in screening for AKI with serum creatinine and urine output assessments. Premature infants may be born with less than half of the nephrons compared with term neonates, predisposing them to chronic kidney disease (CKD) early on in life and as they age. AKI can also lead to CKD, and premature infants with AKI may be at very high risk for long-term kidney problems. AKI in neonates is often multifactorial and may result from prenatal, perinatal, or postnatal insults as well as any combination thereof. This review focuses on the causes of AKI, the importance of early detection, the management of AKI in neonates, and long-term sequela of AKI in neonates.

Clinical Profile and Outcome of Newborns with Acute Kidney Injury in a Level 3 Neonatal Unit in Western India

INTRODUCTION

Acute Kidney Injury (AKI) is a serious condition in neonatal care. It complicates the management necessitating the restrictive use of medications.

AIM

To evaluate clinical profile, identify associated and prog-nostic factors in newborns with AKI.

MATERIALS AND METHODS

This was a case control study done between January 2008 to January 2010. Total 1745 newborns were admitted, of which 74 babies had AKI. It was defined as serum creatinine >1.5mg/dl. Control group was selected randomly from the hospital numbers of the newborns derived from the electronic registry with serum creatinine below 1.5 mg/dl. Demographic variables like birth weight, gender, gestational age, admission age, growth restriction, Apgar scores, electrolyte levels; and common clinical conditions like asphyxia, sepsis, meningitis, persistent pulmonary hypertension, Necrotizing Enterocolitis (NEC), mechanical ventilation, congenital heart disease; were compared amongst the two groups. Information was obtained from the admission register, admission files, labor register of obstetrics and gynaecology department and electronic registry. Chi square/independent sample t-test as applicable and logistic regression were used to establish an association of various factors and outcome with AKI.

RESULTS

The incidence of AKI in our study was 4.24%. Demographic variables more common in AKI group were inborn (p=0.011), male gender (p=0.032), term gestation (p=0.001), Appropriate for gestational age (0.001), higher birth weight (p<0.001), full term (p<0.001), sepsis (p<0.001), NEC (p=0.042), low ApGAR scores at one minute (p=0.011) and five minute (p=0.003). However, on multivariate logistic regression only male gender [Odds Radio (OR)=2.84, Confidence Interval (CI)=1.12-7.21] and Sepsis (OR=14.46, CI=4.5-46.46) were associated with AKI. Respiratory distress syndrome was more prevalent in the control group (p<0.003). No need of mechanical ventilation and absence of shock, improved the survival.

CONCLUSIONS

AKI continues to be of clinical significance in neonatal intensive care. Further studies are needed to evaluate newer associations (like male gender and low APGAR scores).

Biochemical parameters of renal impairment/injury and surrogate markers of nephron number in intrauterine growth-restricted and preterm neonates at 30-40 days of postnatal corrected age

BACKGROUND

Premature and/or intrauterine growth-restricted neonates have an increased risk of developing postnatal renal injuries in later life. Studies on renal physiology in these neonates at a corrected age of 30-40 days are scarce and mostly relate to preterm infants. The data from these studies often lack the results of correlation analyses between biochemical parameters and nephron number-data which could provide additional insight and/or improve recognition of individuals at higher risk of renal failure.

METHODS

Urinary total protein and albumin levels and N-acetyl-β-D-glucosaminidase and cathepsin B activity were evaluated in preterm and intrauterine growth-restricted infants at a corrected age of 30-40 days and compared to data from a healthy control neonate population. The data were then associated with predominant susceptibility factors of renal damage related to low nephron number, such as gestational age, birth weight, total renal volume and renal cortex volume.

RESULTS

Compared to the control neonate population, we found significantly increased levels of all biochemical parameters tested in the intrauterine growth-restricted neonates, whereas in the preterm infants we observed a significant increase in cathepsin B activity, total protein level and, to a lesser extent, albumin level. Cathepsin B activity showed a significant, strong and inverse correlation with all surrogate markers of nephron number and was also strongly and positively correlated with urinary albumin level.

CONCLUSIONS

At this postnatal age, we found that lower nephron number in low birth weight neonates was associated to tubular impairment/injury that could be concurrent with a dysfunction of glomerular permeability. Urinary cathepsin B activity may be a candidate marker for the early prediction of renal susceptibility to damage in low birth weight neonates.

Non-dialytic management of acute kidney injury in newborns

Treating acute kidney injury (AKI) in newborns is often challenging due to the functional immaturity of the neonatal kidney. Because of this physiological limitation, renal replacement therapy (RRT) in this particular patient population is difficult to execute and may lead to unwanted complications. Although fluid overload and electrolyte abnormalities, as seen in neonatal AKI, are indications for RRT initiation, there is limited evidence that RRT initiated in the first year of life improves long-term outcome. The underlying cause of AKI in a newborn patient should determine the treatment strategies to restore appropriate renal function. However, our understanding of this common clinical condition remains limited, as no standardized, evidence-based definition of neonatal AKI currently exists. Non-dialytic management of AKI in these patients may restore appropriate renal function to these patients without exposure to complications often encountered with RRT.

Pharmacokinetics and Safety of Macrocyclic Gadobutrol in Children Aged Younger Than 2 Years Including Term Newborns in Comparison to Older Populations

OBJECTIVES

This clinical study evaluated the pharmacokinetics (PK) and safety data of macrocyclic extracellular contrast agent gadobutrol in pediatric subjects aged younger than 2 years.

MATERIALS AND METHODS

Pediatric subjects (term newborns to those aged younger than 2 years) with normal renal function undergoing magnetic resonance imaging with gadobutrol (0.1 mmol/kg body weight [BW]) were prospectively enrolled in this open-label, multicenter clinical trial to evaluate PK as a primary end point. Plasma PK was analyzed using a population-based PK approach. Safety and qualitative efficacy (evaluation of images) were secondary end points. Safety and tolerability were assessed throughout study participation (approximately 7 days). Imaging efficacy variables were assessed by investigators.

RESULTS

Forty-four subjects were evaluated for safety and efficacy; 43 subjects were eligible for PK evaluation including 9 term newborns and infants aged younger than 2 months. Gadobutrol PK in pediatric subjects aged younger than 2 years were adequately described by a linear 2-compartmental model with elimination from the central compartment. Total median systemic exposure (area under the curve) of gadobutrol was estimated at 776 μmol · h/L (range, 544-1470 μmol · h/L). Simulated median concentration at 20 minutes after injection of gadobutrol (C20) was 339 μmol/L (range, 230-456 μmol/L). Safety and tolerability profile were similar to older populations. In 1 subject (2.3%), vomiting was reported as a mild adverse event related to gadobutrol, and there were no reported serious adverse events. The evaluation of gadobutrol-enhanced images provided improved diagnosis, increased confidence in diagnosis, and contributed to subject clinical management.

CONCLUSIONS

The PK profile of gadobutrol in children aged younger than 2 years including newborns is similar to that in older children and adults. At the dose of 0.1 mmol/kg BW, gadobutrol had a favorable safety profile and was well tolerated with similar profile across the age range 0 to younger than 2 years and compared with older children and adults. Extrapolation of efficacy data from adults to the younger pediatric population, including term newborns, is justified. The recommended standard dose of gadobutrol (0.1 mmol/kg BW), as used in the population aged 2 years and older, is also appropriate in children aged younger than 2 years.

A new approach to define acute kidney injury in term newborns with hypoxic ischemic encephalopathy

BACKGROUND

Current definitions of acute kidney injury (AKI) are not sufficiently sensitive to identify all newborns with AKI during the first week of life.

METHODS

To determine whether the rate of decline of serum creatinine (SCr) during the first week of life can be used to identify newborns with AKI, we reviewed the medical records of 106 term neonates at risk of AKI who were treated with hypothermia for hypoxic ischemic encephalopathy (HIE).

RESULTS

Of the newborns enrolled in the study, 69 % showed a normal rate of decline of SCr to ≥50 % and/or reached SCr levels of ≤0.6 mg/dl before the 7th day of life, and therefore had an excellent clinical outcome (control group). Thirteen newborns with HIE (12 %) developed AKI according to an established neonatal definition (AKI-KIDGO group), and an additional 20 newborns (19 %) showed a rate of decline of SCr of <33, <40, and <46 % from birth to days 3, 5, or 7 of life, respectively (delayed rise in estimated SCr clearance group). Compared to the control group, newborns in the other two groups required more days of mechanical ventilation and vasopressor drugs and had higher gentamicin levels, more fluid overload, lower urinary epidermal growth factor levels, and a prolonged length of stay.

CONCLUSIONS

The rate of decline of SCr provides a sensitive approach to identify term newborns with AKI during the first week of life.

Structural equation modelling exploration of the key pathophysiological processes involved in cardiac surgery-related acute kidney injury in infants

Background

Uncertainties about the pathophysiological processes resulting in cardiac surgery-related acute kidney injury (AKI) in infants concern the relative impact of the most prominent risk factors, the clinical relevance of changes in glomerular filtration rate vs tubular injury, and the usefulness of available diagnostic tools. Structural equation modelling could allow for the assessment of these complex relationships.

Methods

A structural model was specified using data from a prospective observational cohort of 200 patients <1 year of age undergoing cardiopulmonary bypass surgery. It included four latent variables: AKI, modelled as a construct of perioperative creatinine variation, of oliguria and of urine neutrophil gelatinase-associated lipocalin (uNGAL) concentrations; the cardiopulmonary bypass characteristics; the occurrence of a post-operative low cardiac output syndrome and the post-operative outcome.

Results

The model showed a good fit, and all path coefficients were statistically significant. The bypass was the most prominent risk factor, with a path coefficient of 0.820 (95 % CI 0.527–0.979), translating to a 67.2 % explanation for the risk of AKI. A strong relationships was found between AKI and early uNGAL excretion, and between AKI and the post-operative outcome, with path coefficients of 0.611 (95 % CI 0.347–0.777) and 0.741 (95 % CI 0.610–0.988), respectively. The path coefficient between AKI and a >50 % increase in serum creatinine was smaller, with a path coefficient of 0.443 (95 % CI 0.273–0.596), and was intermediate for oliguria, defined as urine output <0.5 ml kg⁻¹ h⁻¹, with a path coefficient of 0.495 (95 % CI 0.250–0.864). A path coefficient of −0.229 (95 % CI −0.319 to 0.060) suggested that the risk of AKI during the first year of life did not increase with younger age at surgery.

Conclusions

These findings suggest that cardiac surgery-related AKI in infants is a translation of tubular injury, predominately driven by the cardiopulmonary bypass, and linked to early uNGAL excretion and to post-operative outcome.

Trial registration

ClinicalTrials.gov identifier NCT01219998. Registered 11 October 2010.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1350-1) contains supplementary material, which is available to authorized users.

Urinary Neutrophil Gelatinase-Associated Lipocalin Levels in Neonates

BACKGROUND

Acute kidney injury (AKI) is common in preterm infants and is associated with high mortality and morbidity. New biomarkers for the early detection of AKI have been identified. Specifically, urinary neutrophil gelatinase-associated lipocalin (uNGAL) is a new and powerful biomarker for AKI and sepsis. Our study evaluated the reference range of uNGAL in healthy neonates in Taiwan.

METHODS

This study examined 24 preterm and 38 term infants without clinical complications. Urine samples were collected and the uNGAL values were measured at postnatal age (PNA) 3 days, 7 days, 14 days, and 21 days in the preterm infants and at PNA 3 days in the term infants. The uNGAL values were tested using enzyme-linked immunosorbent assay.

RESULTS

The median uNGAL values in the preterm infants at PNA 3 days, 7 days, 14 days, and 21 days were 41.52 ng/mL, 35.82 ng/mL, 43.79 ng/mL, and 30.85 ng/mL, respectively. The median value at PNA 3 days in the term infants was 88.1 ng/mL. No significant differences associated with gestational age, birth body weight, or PNA were observed among the preterm infants. However, the uNGAL values in the female term infants were higher than those in the male term infants (p = 0.003).

CONCLUSION

This study presents preliminary data on uNGAL levels in neonates in Taiwan. A large-scale study investigating the correlations between uNGAL and with gestational age, birth body weight, sex, and PNA is recommended.

Reference intervals for renal injury biomarkers neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 in young infants

BACKGROUND

Reliable reference intervals for two novel urinary biomarkers of renal injury, neutrophil gelatinase-associated lipocalin (uNGAL) and kidney injury molecule-1 (uKIM-1) are lacking for infants. Therefore, the aim of our study was to establish reference intervals for urinary NGAL and KIM-1 absolute concentrations as well as normalized to urinary creatinine in young infants categorized in small age intervals.

METHODS

From June 2010 to March 2014, serum and urine samples of 106 basically healthy infants (born between 37 and 42 weeks of gestation) aged 1 day to 1 year were collected. Blood samples were assayed for serum creatinine levels to confirm a healthy renal status. Urine samples were assayed for creatinine, uNGAL (ng/mL) and uKIM-1 (ng/mL).

RESULTS

Two thirds of the study cohort were boys. uNGAL concentrations declined with increasing age (likelihood ratio test, p=0.001). Also, uNGAL concentrations were higher in girls (50th centile uNGAL was 27.1 ng/mL) than boys (50th centile uNGAL was 14.3 ng/mL) (two tailed Wald test, p<0.001) NGAL concentrations were not related to ethnicity. uKIM-1 concentrations were extremely low in almost all 106 subjects [median uKIM-1 was 0.08 (IQR 0.08-0.08) ng/mL] and not related with age, gender or ethnicity (all p>0.05).

CONCLUSIONS

Our data uniquely provide uNGAL and uKIM-1 reference intervals for the first year of life. Notably, only uNGAL levels decreased with increasing age and were higher in girls. These reference intervals enable future studies to evaluate the performance of both biomarkers in detecting early kidney tubular injury, particularly in the setting of critical care.

Renal effects of angiotensin II in the newborn period: role of type 1 and type 2 receptors

BACKGROUND

Evidence suggests a critical role for the renin-angiotensin system in regulating renal function during postnatal development. However, the physiological relevance of a highly elevated renin-angiotensin system early in life is not well understood, nor which angiotensin receptors might be involved. This study was designed to investigate the roles of angiotensin receptors type 1 (AT1R) and type 2 (AT2R) in regulating glomerular and tubular function during postnatal development.

METHODS

The renal effects of the selective antagonist to AT1R, ZD 7155 and to AT2R, PD 1233319 were evaluated in two groups of conscious chronically instrumented lambs aged ~ one week (N = 8) and ~ six weeks (N = 10). Two experiments were carried out in each animal and consisted of the assessment of renal variables including glomerular and tubular function, for 30 min before (Control) and 60 min after infusion of ZD 7155 and PD 123319, respectively. Statistical significance was determined using parametric testing (Student t-test, analysis of variance ANOVA) as appropriate.

RESULTS

ZD 7155 infusion was associated with a significant decrease in glomerular filtration rate and filtration fraction at one but not six weeks; urinary flow rate decreased significantly in older animals, whereas sodium excretion and free water clearance were not altered. There was an age-dependent effect on potassium handling along the nephron, potassium excretion decreasing after ZD 7155 infusion in younger but not in older lambs. PD 123319 had no significant effects on glomerular filtration rate and tubular function in either age group.

CONCLUSIONS

These results provide evidence to support an important role for AT1Rs in mediating the renal effects of angiotensin II during postnatal maturation in conscious developing animals. In contrast to a role for AT2Rs later in life, there appears to be no role for AT2Rs in influencing the renal effects of Angiotensin II in the postnatal period.

Effect of vitamin A supplementation on the urinary retinol excretion in very low birth weight infants

Despite high-dose vitamin A supplementation of very low birth weight infants (VLBW, <1500 g), their vitamin A status does not improve substantially. Unknown is the impact of urinary retinol excretion on the serum retinol concentration in these infants. Therefore, the effect of high-dose vitamin A supplementation on the urinary vitamin A excretion in VLBW infants was investigated. Sixty-three VLBW infants were treated with vitamin A (5000 IU intramuscular, 3 times/week for 4 weeks); 38 untreated infants were classified as control group. On days 3 and 28 of life, retinol, retinol-binding protein 4 (RBP4), glomerular filtration rate, proteinuria, and Tamm-Horsfall protein were quantified in urine. On day 3 of life, substantial retinol and RBP4 losses were found in both groups, which significantly decreased until day 28. Notwithstanding, the retinol excretion was higher (P < 0.01) under vitamin A supplementation as compared to infants of the control group. On day 28 of life, the urinary retinol concentrations were predictive for serum retinol concentrations in the vitamin A treated (P < 0.01), but not in the control group (P = 0.570).

CONCLUSION

High urinary retinol excretion may limit the vitamin A supplementation efficacy in VLBW infants. Advanced age and thus postnatal kidney maturation seems to be an important contributor in the prevention of urinary retinol losses.

Prostaglandin Availability and Association with Outcomes for Infants with Congenital Heart Disease

Data regarding availability of prostaglandin E1 (PGE) and its impact on the stabilization, transport, critical care course, and surgical outcome of infants with ductal-dependent congenital heart disease in the current pediatric healthcare environment are unknown. We sought to determine the proportion of hospitals in Texas that stock PGE and to investigate associations between PGE availability and clinical outcomes. All birth institutions listed with the Texas Department of Health and Human Services were contacted to determine PGE availability as of 2011. Outcomes of all infants admitted to our institution from 2007 to 2012 who received PGE for ductal-dependent lesions were evaluated. PGE was stocked in 50 % (n = 139) of hospitals that performed deliveries in Texas in 2011 representing 79.1 % (303, 481) of births. Hospitals that did not stock PGE had less annual births and were located a further distance from a center that provided pediatric cardiac surgical services. Patients born at a hospital that did not stock PGE had significantly greater serum lactate and creatinine (p = 0.002) and serum lactate on admission (p < 0.001). The PGE availability was not associated with hospital length of stay, postoperative length of stay, or mortality. When stratifying in TGA and HLHS subgroups, lack of PGE availability remained associated with higher creatinine, higher lactate, lower glucose, and lower pH. PGE is not universally available in all healthcare institutions providing obstetrical services. Lack of availability of PGE at an outlying hospital was associated with increased morbidity, but was not associated with mortality or length of stay.

Neonatal Acute Kidney Injury

In recent years, there have been significant advancements in our understanding of acute kidney injury (AKI) and its impact on outcomes across medicine. Research based on single-center cohorts suggests that neonatal AKI is very common and associated with poor outcomes. In this state-of-the-art review on neonatal AKI, we highlight the unique aspects of neonatal renal physiology, definition, risk factors, epidemiology, outcomes, evaluation, and management of AKI in neonates. The changes in renal function with gestational and chronologic age are described. We put forth and describe the neonatal modified Kidney Diseases: Improving Global Outcomes AKI criteria and provide the rationale for its use as the standardized definition of neonatal AKI. We discuss risk factors for neonatal AKI and suggest which patient populations may warrant closer surveillance, including neonates <1500 g, infants who experience perinatal asphyxia, near term/ term infants with low Apgar scores, those treated with extracorporeal membrane oxygenation, and those requiring cardiac surgery. We provide recommendations for the evaluation and treatment of these patients, including medications and renal replacement therapies. We discuss the need for long-term follow-up of neonates with AKI to identify those children who will go on to develop chronic kidney disease. This review highlights the deficits in our understanding of neonatal AKI that require further investigation. In an effort to begin to address these needs, the Neonatal Kidney Collaborative was formed in 2014 with the goal of better understanding neonatal AKI, beginning to answer critical questions, and improving outcomes in these vulnerable populations.

Early urinary angiotensinogen excretion in critically ill neonates

INTRODUCTION

Urinary angiotensinogen is considered a reliable biomarker for intrarenal renin-angiotensin system activity. The aims of this study were to assess the urinary angiotensinogen level during the first day of life and to evaluate its correlation with renal function in critically ill neonates.

METHODS

Urinary angiotensinogen concentration during the first 24 hours of life was measured in 98 critically ill neonates. Neonatal renal function was assessed by urinary levels of cystatin-C, albumin and α1-microglobulin and urinary electrolyte excretion.

RESULTS

Urinary angiotensinogen level decreased with increasing gestational age and body weight in critically ill neonates (P<0.001). After adjustment for gestational age, urinary angiotensinogen level correlated with urinary fractional excretion of sodium and urinary levels of cystatin-C and α1-microglobulin. Multivariate linear regression identified a significant impact of urinary cystatin-C on urinary angiotensinogen level (P<0.001). Furthermore, urinary angiotensinogen was significantly increased in neonates with a urinary cystatin-C-to-creatinine ratio ⩾2500 ng/mg, which was the optimal cut-off value to predict acute kidney injury in our previous study.

CONCLUSIONS

The urinary angiotensinogen level correlates with the overall maturity of renal function during the early postnatal period in critically ill neonates and an increased urinary angiotensinogen level might reflect renal injury in immature neonates.

Reliability of reagent strips for semi-quantitative measurement of glucosuria in a neonatal intensive care setting

BACKGROUND

Glucosuria in preterm infants is often measured using a visually readable reagent strip, e.g., when monitoring total parenteral nutrition or during sepsis or when treating with corticosteroids. However, the specific circumstances in a neonatal intensive care unit (NICU), such as the use of diapers and the high temperature in incubators, could affect its reliability.

OBJECTIVES

To evaluate the reliability of the semi-quantitative measurement of glucosuria under the specific circumstances of a NICU setting.

METHODS

Nine hundred assessments of artificially supplemented (contrived) urine samples, intended to simulate pathological specimens, were performed under the following varying conditions: environmental temperature (21°C and 34°C); different times of contact of the urine with the diaper; and using two different methods of collecting urine from the diaper. Each reagent strip was read independently by three observers. The test strips scores were categorized as 0, 1+, 2+, 3+, or 4+ in ascending degree of glucosuria.

RESULTS

Agreement was excellent under all the different conditions (temperature, weighted kappa (κ(w)) = 0.92; method of urine collection, κ(w) = 0.88; time, p = 0.266). Inter-observer reliability was very good (multi-rater κ = 0.81). The deviation between the different conditions was seldom larger than one category (2.9%). The reagent strip readings were concordant with the true urinary glucose concentrations in 79.0% of assessments. The discordance was never larger than one category.

CONCLUSION

The reliability of the semi-quantitative measurement of glucosuria in newborn infants using reagent strips is good, even under the conditions of a NICU. Changes in the rating of reagent strips of more than one category are most likely to be beyond measurement error.

Evaluation of urinary prostaglandin E2 metabolite as a biomarker in infants with fever due to viral infection

We have investigated the clinical feasibility of the major urinary metabolite of prostaglandin (PG) E2, tetranor-PGEM, as a biomarker of inflammation in infants with fever. We tested two different and clinically relevant sampling methods, using self-adhesive urinary bags or gauze pads, with respect to stability of tetranor-PGEM and ease of sampling from infants. Liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis was used to quantify tetranor-PGEM in urine, and different normalization parameters, i.e., urinary creatinine and body surface area, were investigated. To study inflammation, infants (1 month-1 year) that were hospitalized with fever of unknown origin at admittance (n=14) were compared to age-matched healthy controls (n=14). Levels of urinary tetranor-PGEM in infants with viral induced fever were increased compared to controls (102.4±56.2 vs. 37.0±21.6pmol/ml/m(2) body surface area, p<0.001). We conclude that urinary tetranor-PGEM is a potential non-invasive biomarker of inflammation in infants.

Gadolinium and nephrogenic systemic fibrosis: an update

Nephrogenic systemic fibrosis (NSF) is a multisystem disease seen exclusively in patients with renal impairment. It can be severely debilitating and sometimes fatal. There is a strong association with gadolinium-based contrast agents used in magnetic resonance imaging (MRI). Risk factors include renal impairment and proinflammatory conditions, e.g. major surgery and vascular events. Although there is no single effective treatment for NSF, the most successful outcomes are seen following restoration of renal function, either following recovery from acute kidney injury or following renal transplantation. There have been ten biopsy-proved pediatric cases of NSF, with no convincing evidence that children have a significantly altered risk compared with the adult population. After implementation of guidelines restricting the use of gadolinium-based contrast agents in at-risk patients, there has been a sharp reduction in new cases and no new reports in children. Continued vigilance is recommended: screening for renal impairment, use of more stable gadolinium chelates, consideration of non-contrast-enhanced MRI or alternative imaging modalities where appropriate.

Factors associated with bacteremia in young infants with urinary tract infection

BACKGROUND

Urinary tract infection (UTI) is the most frequent severe bacterial infection in infants. Up to 31% of infants with UTI have bacteremia.

METHODS

We retrospectively identified all infants aged 0-2 months who were managed in our hospital with UTI during a 1-year period. Those with bacteremia were compared with those without bacteremia, according to the following variables: ethnicity, age, gender, white blood cell and polymorphonuclear counts, C-reactive protein, urinalysis and blood creatinine values as related to age-appropriate norms, imaging and outcome.

RESULTS

We identified 81 infants with 82 episodes of UTI. Most occurred in males (72.8%) and 35 (42.7%) were in infants of non-Jewish origin. In 14/81 (17.3%) of episodes, Escherichia coli was cultured from blood. In multivariate analysis, increased blood creatinine levels (P = 0.004) and non-Jewish origin (P = 0.006) were associated with bacteremia. Time to defervescence was significantly longer in bacteremic versus nonbacteremic children (P = 0.018). Duration of hospitalization was longer in bacteremic infants-10 (7-17) days in bacteremic versus 7 (1-14) days in nonbacteremic children (P < 0.001).

CONCLUSIONS

In infants aged 0-2 months with UTI, increased blood creatinine value at admission was associated with bacteremia. This value provides an additional clue on admission, independent of personal judgment, to help identify infants at higher risk for bacteremia, prolonged hospitalization and possible complications.

Management during the first 72 h of age of the periviable infant: an evidence-based review

After NICU admission the extremely immature newborn (EIN) requires evaluation and support of each organ system, and the integration of all those supports in a comprehensive plan of care. In this review, I attempt to analyze the evidence for treatment options after the initial transition, during the first 3 days of life, which have been shown to improve survival or short- or long-term morbidity. This review revealed several things: there is little available evidence from studies that have included significant numbers of EINs; interventions affecting different organ systems need to be co-ordinated as any intervention will have multiple effects; and future advances in treatment of this group of patients will require the installation of permanent research networks to have enough power to perform many studies needed to improve outcomes.

Limitations of early serum creatinine variations for the assessment of kidney injury in neonates and infants with cardiac surgery

Background

Changes in kidney function, as assessed by early and even small variations in serum creatinine (ΔsCr), affect survival in adults following cardiac surgery but such associations have not been reported in infants. This raises the question of the adequate assessment of kidney function by early ΔsCr in infants undergoing cardiac surgery.

Methodology

The ability of ΔsCr within 2 days of surgery to assess the severity of kidney injury, accounted for by the risk of 30-day mortality, was explored retrospectively in 1019 consecutive neonates and infants. Patients aged ≤ 10 days were analyzed separately because of the physiological improvement in glomerular filtration early after birth. The Kml algorithm, an implementation of k-means for longitudinal data, was used to describe creatinine kinetics, and the receiver operating characteristic and the reclassification methodology to assess discrimination and the predictive ability of the risk of death.

Results

Three clusters of ΔsCr were identified: in 50% of all patients creatinine decreased, in 41.4% it increased slightly, and in 8.6% it rose abruptly. Mortality rates were not significantly different between the first and second clusters, 1.6% [0.0–4.1] vs 5.9% [1.9–10.9], respectively, in patients aged ≤ 10 days, and 1.6% [0.5–3.0] vs 3.8% [1.9–6.0] in older ones. Mortality rates were significantly higher when creatinine rose abruptly, 30.3% [15.1–46.2] in patients aged ≤ 10 days, and 15.1% [5.9–25.5] in older ones. However, only 41.3% of all patients who died had an abrupt increase in creatinine. ΔsCr improved prediction in survivors, but not in patients who died, and did not improve discrimination over a clinical mortality model.

Conclusions

The present results suggest that a postoperative decrease in creatinine represents the normal course in neonates and infants with cardiac surgery, and that early creatinine variations lack sensitivity for the assessment of the severity of kidney injury.

A novel urinary biomarker profile to identify acute kidney injury (AKI) in critically ill neonates: a pilot study

BACKGROUND

The goal of this study was to assess the value of a urinary biomarker profile comprised of neutrophil gelatinase-associated lipocalin (NGAL), fibroblast growth factor-2 (FGF-2), and epidermal growth factor (EGF), to detect acute kidney injury (AKI) in critically ill neonates.

METHODS

We conducted a prospective cohort pilot study of at-risk neonates treated in a level IIIC neonatal intensive care unit (NICU) with therapeutic hypothermia (HT) (n = 25) or extracorporeal membrane oxygenation (ECMO) (n = 10). Urine was collected at baseline, 48 h of illness, and > 24 h post-recovery of their corresponding treatments. Control samples were collected from 27 healthy newborns. The data were expressed as urinary concentrations and values normalized for urinary creatinine. AKI was defined as the presence of oliguria >24 h and/or elevated serum creatinine (SCr), or the failure to improve the estimated creatinine clearance (eCCL) by >50% post-recovery. Non-parametric statistical tests and ROC analyses were used to interpret the data.

RESULTS

Fifteen at-risk newborns had AKI. In the first 48 h of illness, the urinary levels of NGAL and FGF-2 had high sensitivity but poor specificity to identify neonates with AKI. At recovery, low urinary EGF levels identified neonates with AKI with a sensitivity of 74% and specificity of 84%. Overall, in the early stages of a critical illness, the urinary levels of NGAL and FGF-2 were sensitive, but not specific, to identify neonates at risk of AKI. Low EGF levels post-recovery identified critically ill neonates with AKI.

CONCLUSIONS

These findings require validation in larger prospective studies.

Early initiation of peritoneal dialysis in neonates and infants with acute kidney injury following cardiac surgery is associated with a significant decrease in mortality

Association between early renal replacement therapy and better survival has been reported in adults with postoperative kidney injury, but not in children undergoing cardiac surgery. We conducted a retrospective cohort study of 146 neonates and infants requiring peritoneal dialysis following cardiac surgery in a tertiary referral hospital. A propensity score was used to limit selection bias due to timing of dialysis, and included baseline and intraoperative characteristics, requirement for postoperative extracorporeal membrane oxygenation, and creatinine clearance variation. Inverse probability of treatment weighting resulted in good balance between groups for all baseline and intraoperative variables. After weighting, 30-day and 90-day mortality were compared between the 109 patients placed on dialysis early, within the first day of surgery, and those with delayed dialysis, commencing on the second day of surgery or later, using logistic regression and survival analysis. Mortality was 28.1% at 30 days, and was 36.3% during follow-up. Early dialysis was associated with a 46.7% decrease in the 30-day and a 43.5% decrease in the 90-day mortality rate when compared with delayed dialysis. All other short-term outcome variables were similar. Thus, initiation of peritoneal dialysis on the day of or the first day following surgery was associated with a significant decrease in mortality in neonates and infants with acute kidney injury.