A simple estimate of glomerular filtration rate in full-term infants during the first year of life

Home-based inspiratory muscle training in pediatric patients after kidney transplantation: a randomized clinical trial

BACKGROUND

Chronic kidney disease (CKD) represents the irreversible stages of renal failure and is a growing worldwide public health issue associated with increases in morbidity, mortality, and decreased quality of life. Kidney transplantation is considered one of the best treatment options in this population. However, even after surgery, respiratory muscle strength is below normal values, and inspiratory muscle training (IMT) improves respiratory muscle function, strength, and endurance. This study aimed to evaluate the effects of IMT regarding respiratory muscle strength, functional capacity, and pulmonary function in pediatric kidney transplant recipients with CKD, and secondarily, to assess the biochemical profile of patients after intervention.

METHODS

This is a randomized, double-blind, placebo-controlled trial. Patients were randomized into two groups, intervention (IG) and control (CG) and performed IMT home-based training for 6 weeks. In the IG, the load was adjusted to 40% of the maximal inspiratory pressure and in the CG was adjusted to a minimum placebo load (9 cm H₂O).

RESULTS

Thirty-one patients were randomly allocated to the intervention (n = 16) or control (n = 15) groups. There were no differences at baseline between groups. Increase of 35% in the maximal inspiratory pressure predicted and 26% in the maximal expiratory pressure predicted in the IG were found, compared with 5 and 4% in the CG. There was an increase in hemoglobin and hematocrit values in the IG.

CONCLUSIONS

Home-based IMT provides a significant increase in respiratory muscle strength, without changes in functional capacity and pulmonary function. Benefits regarding biochemical markers (hemoglobin and hematocrit) were also observed.

Primary causes of kidney disease and mortality in dialysis-dependent children

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) is associated with a slower progression to end-stage renal disease (ESRD) in pre-dialysis patients. However, little is known about the associated mortality risks after transitioning to dialysis.

METHODS

This retrospective cohort study included 0-21 year-old incident dialysis patients from the United States Renal Data System starting dialysis between 1995 and 2016. We examined the association of CAKUT vs. non-CAKUT with all-cause mortality, using Cox regression adjusted for case mix variables. We also examined the mortality risk associated with 14 non-CAKUT vs. CAKUT ESRD etiologies and under stratification by estimated glomerular filtration rate (eGFR).

RESULTS

Among 25,761 patients, the median (interquartile range) age was 17 (11-19) years, and 4780 (19%) had CAKUT. CAKUT was associated with lower mortality, with an adjusted hazard ratio (aHR) of 0.72 (95%CI, 0.64-0.81) (reference: non-CAKUT). In age-stratified analyses, CAKUT vs. non-CAKUT aHRs (95%CI) were 0.66 (0.54-0.80), 0.56 (0.39-0.80), 0.66 (0.50-0.86), and 0.97 (0.80-1.18) among patients < 6, 6-< 13, 13-< 18, and ≥ 18 years at dialysis initiation, respectively. Among non-CAKUT ESRD etiologies, the risk of mortality associated with primary glomerulonephritis (aHR, 0.93; 95%CI 0.80-1.09) and focal segmental glomerulosclerosis (aHR, 0.89; 95%CI, 0.75-1.04) were comparable or slightly lower compared to CAKUT, whereas most other primary causes were associated with higher mortality risk. While the CAKUT group had lower mortality risk compared to the non-CAKUT group patients with eGFR ≥5 mL/min/1.73m², CAKUT was associated with higher mortality in patients with eGFR < 5 mL/min/1.73 m².

CONCLUSIONS

CAKUT is associated with lower mortality among children < 18 years old, but showed comparable mortality with non-CAKUT among patients ≥ 18 years old. ESRD etiology should be considered in risk assessment for children initiating dialysis.

Population Pharmacokinetics of Metoclopramide in Infants, Children, and Adolescents

Metoclopramide is commonly used for gastroesophageal reflux. The aims of the present study were to develop a pediatric population pharmacokinetic (PopPK) model, which was applied to simulate the metoclopramide exposure following dosing used in clinical practice. Opportunistic pharmacokinetic data were collected from pediatric patients receiving enteral or parenteral metoclopramide per standard of care and these data were simultaneously fitted using NONMEM. Allometric scaling with body weight was included a priori in the model. Using the final model, the steady‐state maximum concentrations (C_ss,max) and the area under the metoclopramide plasma concentration‐time curve at steady state from 0 to 6 hours (AUC_ss,0–6h) were simulated following 0.1 or 0.15 mg/kg orally every 6 hours in virtual patients, and compared with previously reported ranges associated with toxicity or the efficacy for gastroesophageal reflux in infants. A two‐compartment model with first‐order absorption best characterized 87 concentration measurements from 50 patients (median [range] postnatal age of 8.89 years [0.01–19.13]). There were 20 infants (≤ 2 years), 9 children (2 years to age ≤ 12 years), and 21 adolescents (> 12 years). Body weight was the only covariate included in the final model. For > 75% of virtual patients, simulated C_ss,max and AUC_ss,0–6h estimates were within the range associated with efficacy for gastroesophageal reflux in infants; however, slightly lower exposures were predicted in virtual patients < 2 years. Our study suggests that a metoclopramide enteral dose of 0.1 mg/kg every 6 hours, which was previously recommended for pediatric patients, results in simulated exposure generally within suggested ranges for the treatment of gastroesophageal reflux.

A randomized, double-blind, placebo-controlled, pharmacokinetic and pharmacodynamic study of a fixed-dose combination of phentermine/topiramate in adolescents with obesity

AIMS

To assess the pharmacokinetic (PK) and pharmacodynamic characteristics of VI-0521, a fixed-dose combination of immediate-release phentermine (PHEN) and extended-release topiramate (TPM) in adolescents aged 12 to 17 years with obesity, and to report weight loss and adverse events using this drug combination.

MATERIALS AND METHODS

This was a multicentre, randomized, double-blind, parallel-design, placebo-controlled study in adolescents with obesity. A total of 42 adolescents were randomly assigned in a 1:1:1 ratio to placebo, or to a mid-dose (PHEN/TPM 7.5 mg/46 mg), or a top-dose (PHEN/TPM 15 mg/92 mg) of VI-0521. A total of 26 adolescents were included in the PK analysis (14 from the mid-dose group and 12 from the top-dose group).

RESULTS

On day 56, arithmetic means of terminal elimination half-life, apparent clearance (CL/F) and apparent central volume of distribution (Vc/F) were consistent across dose levels for both PHEN and TPM. Arithmetic means of CL/F and Vc/F for PHEN and TPM administered as a combination in adolescents with obesity were within 10% to 30% of those previously assessed in adults with obesity enrolled in phase II and III studies. A higher proportion of adolescents in both the mid- and top-dose groups (13.3% and 50.0%, respectively) compared with placebo (0.0%) reached ≥5% weight loss at day 56. The least squares (LS) mean change in systolic blood pressure from baseline to day 56 was -5.2 mmHg for the placebo group, -2.5 mmHg for the mid-dose group, and - 5.5 mmHg for the top-dose group. The LS mean change in diastolic blood pressure from baseline to day 56 was -2.4 mmHg for the placebo group, +3.8 mmHg for the mid-dose group, and + 2.0 mmHg for the top-dose group. Participants in the top-dose group had increases in heart rate from baseline of 4.1 bpm, while participants in the mid-dose group experienced a mean decrease in heart rate of 4.5 bpm at day 56. Both PHEN/TPM dose combinations were safe and well tolerated.

CONCLUSIONS

Treatment of adolescents with obesity using a fixed-dose combination of PHEN/TPM for 8 weeks resulted in exposure to PHEN and TPM that was comparable to that observed in adults, statistically significant weight loss, and a tolerable safety profile. These data indicate that both mid- and top-dose levels are appropriate for longer-term safety and efficacy studies in adolescents.

Population Pharmacokinetics of Teicoplanin in Preterm and Term Neonates: Is It Time for a New Dosing Regimen?

Our objective was to develop a population pharmacokinetic (PK) model in order to evaluate the currently recommended dosing regimen in term and preterm neonates. By using an optimal design approach, a prospective PK study was designed and implemented in 60 neonates with postmenstrual ages (PMA) of 26 to 43 weeks. A loading dose of 16 mg/kg was administered at day 1, followed by a maintenance dose of 8 mg/kg daily. Plasma concentrations were quantified by high-pressure liquid chromatography-mass spectrometry. Population PK (popPK) analysis was performed using NONMEM software. Monte-Carlo (MC) simulations were performed to evaluate currently recommended dosing based on a pharmacodynamic index of area under the concentration-time curve (AUC)/MIC ratio of ≥400. A two-compartment model with linear elimination best described the data by the following equations: clearance (CL) = 0.0227 × (weight [wt]/1,765)^0.75 × (estimated creatinine clearance [eCRCL]/22)^0.672, central compartment volume of distribution (V1) = 0.283 (wt/1,765), intercompartmental clearance (Q) = 0.151 (wt/1,765)^0.75, and peripheral compartment volume (V2) = 0.541 (wt/1,765). The interindividual variability estimates for CL, V1, and V2 were 36.5%, 45.7%, and 51.4%, respectively. Current weight (wt) and estimated creatinine clearance (eCRCL) significantly explained the observed variability. MC simulation demonstrated that, with the current dosing regimen, an AUC/MIC ratio of ≥400 was reached by only 68.5% of neonates with wt of <1 kg when the MIC was equal to 1 mg/kg, versus 82.2%, 89.7%, and 92.7% of neonates with wt of 1 to <2, 2 to <3, or ≥3 kg, respectively. Augmentation of a maintenance dose up to 10 or 11 mg/kg for preterm neonates with wt of 1 to <2 or <1 kg, respectively, increases the probability of reaching the therapeutic target; the recommended doses seem to be adequate for neonates with wt of ≥2 kg. Teicoplanin PK are variable in neonates, with wt and eCRCL having the most significant impact. Neonates with wt of <2 kg need higher doses, especially for Staphylococcus spp. with an MIC value of ≥1 mg/liter.

Pharmacokinetic and pharmacodynamic considerations of general anesthesia in pediatric subjects

Introduction: The target concentration strategy uses PKPD information for dose determination. Models have also quantified exposure-response relationships, improved understanding of developmental pharmacokinetics, rationalized dose prescription, provided insight into the importance of covariate information, explained drug interactions and driven decision-making and learning during drug development.Areas covered: The prime PKPD consideration is parameter estimation and quantification of variability. The main sources of variability in children are age (maturation) and weight (size). Model use is mostly confined to pharmacokinetics, partly because anesthesia effect models in the young are imprecise. Exploration of PK and PD covariates and their variability hold potential to better individualize treatment.Expert opinion: The ability to model drugs using computer-based technology is hindered because covariate data required to individualize treatment using these programs remain lacking. Target concentration intervention strategies remain incomplete because covariate information that might better predict individualization of dose is absent. Pharmacogenomics appear a valuable area for investigation for pharmacodynamics and pharmacodynamics. Effect measures in the very young are imprecise. Assessment of the analgesic component of anesthesia is crude. While neuromuscular monitoring is satisfactory, depth of anaesthesia EEG interpretation is inadequate. Closed loop anesthesia is possible with better understanding of EEG changes.

User-Centered Development of an Online Platform for Drug Dosing Recommendations in Pediatrics

BACKGROUND

Drug therapy in pediatric patients is a complex process. Children are subject to continuous growth and variation in drug-metabolizing enzyme activity, requiring continuous adaption of dosages. In Germany, currently no publicly available database exists that provides evidence-based information on drug dosages in pediatrics. For local drug dosing support, a prototype database has been developed within the Children's Hospital, Erlangen. A user-centered development process was initiated to establish an online platform for evidence-based dosing recommendations, as well as pharmacological and pharmaceutical drug information in pediatrics.

OBJECTIVES

The objectives of the study were to survey the demand for such a platform and to assess the usability of the different versions of the developed system.

METHODS

The developed prototype was evaluated in a pluralistic walkthrough with prospective end users. After a redesign, the second prototype of the online platform underwent an online usability testing based on a tailored questionnaire and the System Usability Scale (SUS) (n = 12).

RESULTS

Eleven of 12 participants expressed a demand for an online platform for pediatric dosing recommendations. The majority of the participants requested the integration of extended features, such as drug-drug interaction alerts, or information on adverse effects, pharmacokinetics, and pharmacodynamics. Particularly noteworthy is the demand for an online calculator; 5 of a total of 15 participants explicitly requested a calculator for dosages (based on age, weight, body surface) and glomerular filtration rate. The usability of the second prototype was rated "good to excellent" with a median SUS of 81.25.

CONCLUSION

Local domain experts demand an online platform for pediatric dosing recommendations. The application of the user-centered design approach enabled the development of a prototype suitable for practical use. Multiple additional required functionalities have been identified, whereby the importance of an online calculator for patient-individual dosing recommendations was particularly emphasized.

Renal injury and recovery in pediatric patients after ventricular assist device implantation and cardiac transplant

BACKGROUND

The use of ventricular assist devices (VADs) in children with heart failure may be of particular benefit to those with accompanying renal failure, as improved renal function is seen in some, but not all recipients. We hypothesized that persistent renal dysfunction at 7 days and/or 1 month after VAD implantation would predict chronic kidney disease (CKD) 1 year after heart transplantation (HT).

METHODS

Linkage analysis of all VAD patients enrolled in both the PEDIMACS and PHTS registries between 2012 and 2016. Persistent acute kidney injury (P-AKI), defined as a serum creatinine ≥1.5× baseline, was assessed at post-implant day 7. Estimated glomerular filtration rate (eGFR) was determined at implant, 30 days thereafter, and 12 months post-HT. Pre-implant eGFR, eGFR normalization (to ≥90 mL/min/1.73 m² ), and P-AKI were used to predict post-HT CKD (eGFR <90 mL/min/1.73 m² ).

RESULTS

The mean implant eGFR was 85.4 ± 46.5 mL/min/1.73 m² . P-AKI was present in 19/188 (10%). Mean eGFR at 1 month post-VAD implant was 131.1 ± 62.1 mL/min/1.73 m² , significantly increased above baseline (P < 0.001). At 1 year post-HT (n = 133), 60 (45%) had CKD. Lower pre-implant eGFR was associated with post-HT CKD (OR 0.99, CI: 0.97-0.99, P = 0.005); P-AKI was not (OR 0.96, CI: 0.3-3.0, P = 0.9). Failure to normalize renal function 30 days after implant was highly associated with CKD at 1 year post-transplant (OR 12.5, CI 2.8-55, P = 0.003).

CONCLUSIONS

Renal function improves after VAD implantation. Lower pre-implant eGFR and failure to normalize renal function during the support period are risk factors for CKD development after HT.

Vancomycin Treatment Failure in Children With Methicillin-Resistant Staphylococcus aureus Bacteremia

OBJECTIVES

Limited data exist regarding clinical outcomes of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in children treated with vancomycin. Treatment success in adults correlates best with an area under the curve/minimum inhibitory concentration (AUC₂₄/MIC) ratio ≥400. It is unknown if this relationship is useful in children.

METHODS

Charts of children who received vancomycin ≥5 days for MRSA bacteremia with a steady state trough were reviewed. AUC₂₄/MIC ratios were estimated using 2 different vancomycin clearance equations. Vancomycin treatment failure was defined as persistent bacteremia ≥7 days, recurrent bacteremia within 30 days, or 30-day mortality.

RESULTS

There were 67 bacteremia episodes in 65 patients. Nine (13.4%) met failure criteria: persistent bacteremia (n = 6), recurrent bacteremia (n = 2), 30-day mortality (n = 1). There were no differences between patients receiving <60 mg/kg/day and ≥60 mg/kg/day of vancomycin in median trough (11.9 versus 12.3 mg/L, p = 0.1). Troughs did not correlate well with AUC₂₄/MIC ratios (R ² = 0.32 and 0.22). Patients receiving ≥60 mg/kg/day had greater probability of achieving ratios ≥400. There were no significant differences in median dose (p = 0.8), trough (p = 0.24), or AUC₂₄/MIC ratios (p = 0.07 and p = 0.6) between patients with treatment success and failure.

CONCLUSIONS

Treatment failure was lower than previously reported in children. AUC₂₄/MIC ratios ≥400 were frequently achieved but were not associated with treatment success, dose, or troughs. Prospective studies using standard definitions of vancomycin treatment failure are needed to understand treatment failure in children with MRSA bacteremia.

Population Pharmacokinetic Modeling of Gentamicin in Pediatrics

The primary objective of this work was to characterize the pharmacokinetics (PK) of gentamicin across the whole pediatric age spectrum from premature neonates to young adults with a single model by identifying significant clinical predictors. A nonlinear mixed-effect population PK model was developed with retrospective therapeutic drug-monitoring data. A total of 6459 drug concentration measurements from 3370 hospitalized patients were collected for model building (n = 2357) and evaluation (n = 1013). In agreement with previously reported models, a 2-compartment model with first-order elimination best described the drug PK. Patient-specific factors significantly impacting gentamicin clearance included fat-free mass, postmenstrual age, and serum creatinine (SCr). Based on our model, the deviation of the individual SCr from the age-dependent expected mean SCr value (SCrM) can result in a 40% lower clearance in a patient with renal impairment than that in a patient with normal kidney function, with SCrM:SCr ratios between 0.16 and 3.2 in this study. Consistent with the known age-dependent changes of the proportion of extracellular water in body weight, the inclusion of the impact of extracellular water maturation on the central volume of distribution was found to improve the model fitting significantly. In comparison with other published models, model evaluation suggested the developed model was the least biased and physiologically most representative. These results will be used to inform individualized initial dosing strategies and serve as a prior PK model for Bayesian updating and forecasting as individual clinical observations become available.

Prevalence and factors associated with renal dysfunction among children with sickle cell disease attending the sickle cell disease clinic at a tertiary hospital in Northwestern Tanzania

BACKGROUND

Little is known on how the interaction between Sickle Cell Disease (SCD) and renal insults caused by other coexisting conditions in Sub Saharan Africa such as urinary schistosomiasis, malnutrition and HIV affect the prevalence of renal dysfunction in children with SCD.

OBJECTIVES

To determine the prevalence and factors associated with renal dysfunction among children with SCD aged 6 months to 12 years attended at a tertiary hospital in Northwestern Tanzania.

METHODS

A cross sectional hospital-based study with a short follow up component of 3 months for 153 children with SCD was done to document demographics, clinical characteristics and features of renal dysfunction including urine dipstick albuminuria (>20mg/l) and eGFR (<60ml/ml/min/1.73m2). Other potential renal insults such as HIV infection and Schistosomiasis were also evaluated.

RESULTS

At enrollment, 48/153(31.37%) children had renal dysfunction declining to 31(20.3%) at 3 months follow up. Acute chest syndrome (OR 3.04, 95% CI [1.08-8.96], p = 0.044), severe anemia (OR 0.44, 95% CI [0.26-0.76],p = 0.003), urinary schistosomiasis (OR 7.43, 95% CI [2.10-26.32] p<0.002) and acute malnutrition (OR 4.92, 95% CI [1.29-18.84], p = 0.020). were associated with renal dysfunction.

CONCLUSION

Where prevalent, urinary schistosomiasis and acute malnutrition increase the risk for renal dysfunction in children with SCD. We recommend albuminuria routine screening in children with SCD especially those presenting with acute chest syndrome, severe anemia and features of acute malnutrition for early detection of renal dysfunction among children with SCD.

Clinical Profile and Outcome of Children with Congenital Obstructive Uropathy

OBJECTIVES

To study the etiology and clinical profile of congenital obstructive uropathy in children, renal status and growth at diagnosis and at follow-up and to determine the predictors for development of chronic kidney disease (CKD).

METHODS

An observational (retrospective-prospective) study was conducted at a tertiary care hospital in South India from September 2014 through September 2016. Sixty children diagnosed to have congenital obstructive uropathy with a minimum follow-up period of 5 y were included and followed up prospectively for 2 more years during the study period. The data of the children at admission and follow-up was obtained from the medical records and analyzed.

RESULTS

Congenital uretero-pelvic junction obstruction followed by Posterior urethral valve were the most common etiologies identified. Male preponderance (88.3%) was observed with poor urinary stream being the most common presentation (36.6%). Forty percent of the population had elevated creatinine. Fifteen percent were hypertensive and 25% had growth failure at diagnosis. However, there was a reduction in the number of children with poor estimated glomerular filtration rate (eGFR), hypertension and growth faltering during follow-up. Among the risk factors, hypertension at diagnosis [O.R-12.8 (2.21-74.22) and p value <0.05] and frequent urinary tract infection (UTI) [O.R-14.06 (2.32-85.42) and p value <0.05] were the most important factors for CKD progression. Children with low eGFR (< 60 ml/min/1.73m²) had more height faltering and hypertension at follow-up (p value <0.05).

CONCLUSIONS

Hypertension and frequent UTI were observed to be strongly associated with progression of CKD. Estimated GFR was found to be significantly associated with faltering of height and hypertension. Preserving the renal function prevents growth faltering and development of hypertension at follow-up thereby ensuring a better quality of life.

The Growing Epidemic of Chronic Kidney Disease: Preventive Strategies to Delay the Risk for Progression to ESRD

Hypertension, obesity and metabolic syndromes are leading risk factors for the development of chronic kidney disease (CKD). Considering the high prevalence of hypertension and obesity in children and adolescents and it's risk of progression to cardiovascular disease, CKD should be considered a serious long-term health issue in children with metabolic syndrome. Prevention of CKD requires a professional teamwork consisting of primary care physicians, nephrologists, nutritionist, pharmacist, and social work to identify and manage children at risk of developing CKD in order to provide a highly valuable management strategies. This review focuses on the principles underlying the importance of a team approach for CKD prevention.

Pediatric Dosing of Ganciclovir and Valganciclovir: How Model-Based Simulations Can Prevent Underexposure and Potential Treatment Failure

Intravenous ganciclovir and oral valganciclovir are effective in the prevention and treatment of pediatric cytomegalovirus (CMV) infection but various dosing regimens are used in medical practice. Population pharmacokinetic (PopPK) model-based simulations were used to propose a new ganciclovir pediatric dosing algorithm for regulatory review and to evaluate the approved valganciclovir pediatric dosing algorithm against published dosing recommendations derived from quantitative approaches. Oral valganciclovir (mg = 7 × body surface area (BSA) × creatinine clearance according to the Schwarz formula (CrCLS) daily) and i.v. ganciclovir (mg = 3 × BSA × CrCLS daily) are effective in reaching ganciclovir target exposure for the prevention of CMV (area under the concentration-time curve (AUC)_0-24 40-60 μg ∙ hour/mL) in most pediatric patients across the full pediatric age range. In contrast, ganciclovir and valganciclovir dosing based on body weight, as commonly used in medical practice, leads to underexposure, particularly in younger pediatric patients. This example shows that model-based dosing algorithms built on clinical pharmacology and implemented using good modeling practice can prevent underexposure and reduce the risk of treatment failure in pediatric patients.

PBPK and its Virtual Populations: the Impact of Physiology on Pediatric Pharmacokinetic Predictions of Tramadol

In pediatric PBPK models, age-related changes in the body are known to occur. Given the sparsity of and the variability associated with relevant physiological parameters, different PBPK software providers may vary in their system's data. In this work, three commercially available PBPK software packages (PK-Sim®, Simcyp®, and Gastroplus®) were investigated regarding their differences in system-related information, possibly affecting clearance prediction. Three retrograde PBPK clearance models were set up to enable prediction of pediatric tramadol clearance. These models were qualified in terms of total, CYP2D6, and renal clearance in adults. Tramadol pediatric clearance predictions from PBPK were compared with a pooled popPK model covering clearance ranging from neonates to adults. Fold prediction errors were used to evaluate the results. Marked differences in liver clearance prediction between PBPK models were observed. In general, the prediction bias of total clearance was greatest at the youngest population and decreased with age. Regarding CYP2D6 and renal clearance, important differences exist between PBPK software tools. Interestingly, the PBPK model with the shortest CYP2D6 maturation half-life (PK-Sim) agreed best with the in vivo CYP2D6 maturation model. Marked differences in physiological data explain the observed differences in hepatic clearance prediction in early life between the various PBPK software providers tested. Consensus on the most suited pediatric data to use should harmonize and optimize pediatric clearance predictions. Moreover, the combination of bottom-up and top-down approaches, using a convenient probe substrate, has the potential to update system-related parameters in order to better represent pediatric physiology.

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.

Pharmacokinetic and Pharmacodynamic Evaluation of Intravenous Levetiracetam in Children With Epilepsy

This study aimed to evaluate the safety and tolerability of intravenous (IV) levetiracetam (LEV) as a monotherapy in children aged 1 month-16 years and to explore the pharmacokinetics (PK) of IV LEV and the time to seizure after IV then oral administration of LEV in pediatric children with epilepsy. Children diagnosed with acute unprovoked seizures requiring in-hospital IV LEV administration were included. After administration, the clinical seizure outcomes, side effects, and the Korean-Child Behavior Checklist were monitored and the PK and repeated time to seizure were analyzed via modeling using NONMEM software. Overall, 37 children with epilepsy were enrolled and underwent a PK analysis (median age, 4.6 years; median weight, 18.0 kg). Nine children (24.3%) had seizure recurrence during the follow-up period (median, 3.8 months) and 5 children (13.5%) experienced LEV-associated adverse events such as irritability (n = 2; 5.4%) and somnolence (n = 3; 8.1%). The plasma LEV concentrations after IV LEV were best described by a one-compartment linear PK model. Only body weight was associated with both the clearance and volume of distribution of LEV. The Weibull distribution model described the time to seizure recurrence well; no statistically significant predictor for the time to seizure was identified. Therefore, IV LEV was a well-tolerated and effective alternative in children with acute unprovoked seizures, and models for the PK and time to repeated seizure recurrence after LEV were successfully developed. In particular, the current use of a weight-based IV LEV dosing regimen in pediatric children is practical.

Changes in renal function after left ventricular assist device placement in pediatric patients: A Pedimacs analysis

BACKGROUND

Renal dysfunction (RD) is prevalent among pediatric patients with advanced heart failure. Data are limited regarding changes in renal function after left ventricular assist device (LVAD) placement in this population.

METHODS

Pediatric LVAD recipients enrolled in the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) between September 19, 2012 and June 30, 2016 were included. Longitudinal changes in renal function were analyzed for the entire cohort as well as subgroups stratified by patient and device characteristics. Logistic regression was used to attempt to identify factors associated with lack of improvement in renal function after LVAD placement. Post-LVAD outcomes were assessed using the Kaplan‒Meier method.

RESULTS

Data from 247 patients from 39 centers were analyzed. Baseline RD (estimated glomerular filtration rate [eGFR] <90 ml/min/1.73 m²) was present in 150 (61%) patients. Overall, eGFR improved post-LVAD, peaking at 1 month post-implant. There was an inverse relationship between baseline eGFR and the degree of improvement at 1 month. Degree of improvement in eGFR at 1 month was not impacted by device type, age, Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile, or diagnosis. Failure to normalize renal function at 1 week was correlated with persistent RD at 1 month. Post-implant outcomes did not differ among patients stratified by pre-implant renal function.

CONCLUSIONS

Renal function improves post-LVAD placement in pediatric patients regardless of age, diagnosis, illness severity, or device type, with improvement most pronounced in patients with baseline RD. Identifying patients with irreversible renal dysfunction before LVAD placement remains difficult. Pre-LVAD renal function does not appear to impact survival to transplant.

Pharmacokinetics of cefuroxime in infants and neonates undergoing cardiac surgery

AIMS

Very little data exist regarding the effect of cardiopulmonary bypass (CPB) on cefuroxime (CXM) pharmacokinetics in children less than one year of age.

METHODS

50 mg kg^-1 CXM i.v. after induction were followed by 75 mg kg^-1 into the CPB circuit. In 42 patients undergoing cardiac surgery, 15-20 samples were obtained between 5 and 360 min after the first dose. Total CXM concentrations were measured by high-performance liquid chromatography and a pharmacokinetic/pharmacodynamic (PK/PD) modelling was performed.

RESULTS

Using a fixed protein binding of 15.6% for CXM, peak plasma concentrations of unbound CXM were 229 ± 52 μg ml^-1 after the first bolus and 341 ± 86 μg ml^-1 on CPB. Nadir concentrations before CPB were 69 ± 20 μg ml^-1 and six hours later decreased to 41 ± 19 μg ml^-1 with and 24 ± 14 μg ml^-1 without CPB. A two-compartment model was fitted with the main covariates body weight, CPB and postmenstrual age (PMA). PK parameters were as follows: systemic clearance, 5.15 [95% CI 4.5-5.8] l h^-1 ; central volume of distribution, 11.25 [9.41-13.09] l; intercompartmental clearance, 18.19 [14.79-21.58] l h^-1 ; and peripheral volume, 17.07 [15.7-18.5] L. ƒT > MIC of 32 μg ml^-1 for an 8-h time period was between 70 and 100% (2.5-10 kg BW). According to our simulation, 25 mg ml^-1 CXM as a primary bolus and into the prime plus a 5 mg kg^-1  h^-1 infusion maintain CXM concentrations continuously above 32 μg ml^-1 .

CONCLUSIONS

The routine dosing regimen provided was sufficient for prophylaxis, but continuous dosing can provide a higher percentage of ƒT > MIC.

Optimizing Amikacin Dosage in Pediatrics Based on Population Pharmacokinetic/Pharmacodynamic Modeling

OBJECTIVE

Our objective was to determine the population pharmacokinetic parameters of amikacin in pediatric patients to contribute to the future development of a revised optimum dose and population-specific dosing regimens.

METHODS

We performed a retrospective chart review in non-critical pediatric patients (aged 1-12 years) who received amikacin for suspected or proven Gram-negative infection at a university hospital. The population pharmacokinetic models were developed using Monolix 4.4. Pharmacokinetic/pharmacodynamic (PK/PD) simulations were performed to explore the ability of different dosage regimens to achieve the pharmacodynamic targets.

RESULTS

The analysis included 134 amikacin plasma concentrations from 67 patients with a mean ± standard deviation age of 4.1 ± 3.9 years and bodyweight of 15 ± 8.4 kg. The patients received an amikacin total daily dose (TDD) of 23 ± 7.3 mg/kg, which resulted in peak and trough concentrations of 20.65 ± 7.6 and 2.4 ± 1.7 mg/l, respectively. The estimated pharmacokinetic parameters for amikacin were 1.2 l/h and 6.5 l for total body clearance (CL) and the volume of distribution (V), respectively. Dosing simulations showed that the standard dosing regimen (15 mg/kg/day) of amikacin achieved the PK/PD target of peak serum concentration (C_peak)/minimum inhibitory concentration (MIC) ≥ 8 for an MIC of 2 mg/l; higher doses were required to achieve higher MIC values.

CONCLUSION

The simulation results indicated that amikacin 20 mg/kg once daily provided a higher probability of target attainment with lower toxicity than dosing three times daily. In addition, combination therapy is recommended for pathogens with an MIC of ≥ 8 mg/l.

The importance of cardiovascular disease in pediatric transplantation and its link to the kidneys

Cardiovascular disease is a frequent cause of morbidity and mortality in pediatric patients following solid organ transplant. CKD is also common in pediatric patients after a solid organ transplant, and the link between CKD and cardiovascular morbidity is strong. In this review, we examine potential etiologies to explain the risk of cardiovascular morbidity and mortality in pediatric solid organ recipients and identify targets for improving outcomes.

Urinary neutrophil gelatinase-associated lipocalin (NGAL) and serum cystatin C measurements for early diagnosis of acute kidney injury in children admitted to PICU

BACKGROUND

Acute kidney injury (AKI) is common in critically ill children with significant mortality and morbidity. Serum creatinine is an insensitive and late biomarker compared to newly proposed AKI biomarkers.

METHODS

Prospective study in pediatric intensive care unit (PICU) over three months to compare between serum cystatin-C (s-Cys-C) and urinary neutrophil gelatinase-associated lipocalin (uNGAL) as AKI biomarkers at multiple time points with pediatric risk, injury, failure, loss, end-stage renal disease (pRIFLE) classification in diagnosing AKI.

RESULTS

Forty children were recruited. Of these 40 children, 22 developed AKI according to pRIFLE criteria. There was no significant difference between AKI and non-AKI in age (P = 0.29). Post cardiac surgery, renal insult was the main cause of AKI (27.3%). There was a twofold increased risk of incident AKI in those patients with high baseline uNGAL at PICU admission and almost a fourfold increased risk in patients with high baseline s-Cys-C at PICU admission. uNGAL levels were highly predictive of AKI during the follow-up period [area under the curve (AUC) = 0.76, 95% confidence interval (CI) 0.61-0.92]. The cutoff point with the highest correctly classified proportion was 223 ng/mL (≥ 12 centiles) which correctly predict 80.0% patients with AKI, with a corresponding sensitivity of 72.7% and a specificity of 89.9%. AUC for s-Cys-C was 0.86 (95% CI 0.75-0.97), and the highest correctly classified proportion was 1009 µg/L (≥ 13 centiles); 75% of patients with AKI, with a corresponding sensitivity of 63.6% and a specificity of 88.9%.

CONCLUSION

uNGAL and s-Cys-C predicts AKI early in critically ill children.

Population pharmacokinetics of vancomycin and AUC-guided dosing in Chinese neonates and young infants

OBJECTIVES

To develop a population pharmacokinetic (PK) model for vancomycin in Chinese neonates and infants less than 2 months of age (young infants) with a wide gestational age range, in order to determine the appropriate dosing regimen for this population.

METHODS

We performed a retrospective chart review of patients from the neonatal intensive care unit (NICU) at Children's Hospital of Fudan University to identify neonates and young infants treated with vancomycin from May 2014 to May 2017. Vancomycin concentrations and covariates were utilized to develop a one-compartment model with first-order elimination. The predictive performance of the final model was assessed by both internal and external evaluation, and the relationship between trough concentration and AUC_0-24 was investigated. Monte Carlo simulations were performed to design an initial dosing schedule targeting an AUC_0-24 ≥ 400.

RESULTS

The analysis included a total of 330 concentration-time data points from 213 neonates and young infants with gestational age (GA) and body weight of 25-42 weeks and 0.88-5.1 kg, respectively. Body weight, postmenstrual age (PMA) and serum creatinine level were found to be important factors explaining the between-subject variability in vancomycin PK parameters for this population. Both internal and external evaluation supported the prediction of the final vancomycin PK model. The typical population parameter estimates of clearance and distribution volume for an infant weighing 2.73 kg with a PMA of 39.8 weeks and serum creatinine of 0.28 mg/dL were 0.103 L/h/kg and 0.58 L/kg, respectively. Although vancomycin serum trough concentrations were predictive of the AUC, considerable variability was observed in the achievement of an AUC_0-24/MIC of ≥400. For MIC values of ≤0.5 mg/L, AUC_0-24/MIC ≥400 was achieved for 95% of the newborn infants with vancomycin troughs of 5-10 mg/L. When the MIC increased to 1 mg/L, only 15% of the patients with troughs of 5-10 mg/L achieved AUC_0-24/MIC ≥400. For MIC values of 2 mg/L, no infants achieved the target. Simulations predicted that a dose of at least 14 and 15 mg/kg every 12 h was required to attain the target AUC_0-24 ≥ 400 in 90% of infants with a PMA of 30-32 and 32-34 weeks, respectively. This target was also achieved in 93% of simulated infants in the oldest PMA groups (36-38 and 38-40 weeks, respectively) when the dosing interval was extended to 8 h. For infants with a PMA ≥44 weeks, a dose increase to 18 mg/kg every 8 h was needed. The trough concentrations of 5-15 mg/L were highly predictive of an AUC_0-24 of ≥400 when treating invasive MRSA infections with an MIC of ≤1 mg/L.

CONCLUSIONS

The PK parameters for vancomycin in Chinese infants younger than 2 months of age were estimated using the model developed herein. This model has been used to predict individualized dosing regimens in this vulnerable population in our hospital. A large external evaluation of our model will be conducted in future studies.

Acute kidney injury in pediatric patients with rhabdomyolysis

Purpose

This study aimed to evaluate the clinical findings in pediatric rhabdomyolysis and the predictive factors for acute kidney injury (AKI) in Korean children.

Methods

Medical records of 39 Korean children, who were newly diagnosed with rhabdomyolysis from January 2008 to December 2015, were retrospectively analyzed. The diagnosis was made from the medical history, elevated serum creatinine kinase level >1,000 IU/L, and plasma myoglobin level >150 ng/mL. Patients with muscular dystrophy and myocardial infarction were excluded.

Results

The median patient age at diagnosis was 14.0 years (range, 3–18 years), and the male to female ratio was 2.5. The most common presenting symptom was myalgia (n=25, 64.1%), and 14 patients (35.9%) had rhabdomyolysis-induced AKI. Eighteen patients (46.2%) had underlying diseases, such as epilepsy and psychotic disorders. Ten of these patients showed rhabdomyolysis-induced AKI. The common causes of rhabdomyolysis were infection (n=12, 30.7%), exercise (n=9, 23.1%), and trauma (n=8, 20.5%). There was no difference in the distribution of etiology between AKI and non-AKI groups. Five patients in the AKI group showed complete recovery of renal function after stopping renal replacement therapy. The median length of hospitalization was 7.0 days, and no mortality was reported. Compared with the non-AKI group, the AKI group showed higher levels of peak creatinine kinase and myoglobin, without statistical significance.

Conclusion

The clinical characteristics of pediatric rhabdomyolysis differ from those observed in adult patients. Children with underlying diseases are more vulnerable to rhabdomyolysis-induced AKI. AKI more likely develops in the presence of a high degree of albuminuria.

Pediatric renovascular hypertension: Treatment outcome according to underlying disease

BACKGROUND

Renovascular hypertension (RVH) accounts for 5-10% of pediatric hypertension, and can be associated with underlying disease involving other organs. The purpose of this study was to evaluate the clinical characteristics and assess the treatment outcomes of Korean pediatric patients with RVH.

METHODS

The medical records of 25 Korean pediatric patients with RVH were retrospectively reviewed.

RESULTS

Twenty-four patients had underlying disease, and the most common cause was moyamoya disease (MMD; n = 10; 40%). Of 10 patients with MMD, seven had RVH prior to MMD. All patients required antihypertensive medication as the initial treatment and 22 patients subsequently underwent percutaneous transluminal angioplasty (PTA). The majority of patients with MMD had ostial lesions on angiography. Eight patients had favorable outcomes after the first PTA. One patient received nephrectomy, and two patients received bypass surgery because of restenosis after PTA and technical failure of PTA, respectively. During follow up, blood pressure was well-controlled in nine patients, but only four patients were able to discontinue medication. Eight patients had target-organ damage of the brain, heart, and retina at the time of initial diagnosis, and five patients developed chronic kidney disease during follow up.

CONCLUSION

The most common cause of RVH in Korean children is MMD, and RVH caused by MMD with an ostial lesion is associated with poor PTA outcomes. Angioplasty alone does not appear to control blood pressure effectively in MMD patients, and combined treatment is necessary to prevent target organ damage.

A prospective randomized, controlled trial of eculizumab to prevent ischemia-reperfusion injury in pediatric kidney transplantation

Ischemia-reperfusion injury has multiple effects on a transplanted allograft, including delayed or impaired graft function, compromised long-term survival, and an association with an increased incidence of rejection. Eculizumab, a monoclonal antibody blocking terminal complement activation, has been postulated to be an effective agent in the prevention or amelioration of IRI. We performed a single-center prospective, randomized controlled trial involving 57 pediatric kidney transplant recipients between 2012 and 2016. The immunosuppressive protocol included two doses of alemtuzumab; half of the patients were randomized to receive a single dose of eculizumab prior to transplantation. Maintenance immunosuppression was based on a combination of low-dose tacrolimus and mycophenolate, without steroids. Eculizumab-treated patients had a significantly better early graft function, less arteriolar hyalinosis and chronic glomerulopathy on a protocol biopsies taken on day 30, 1 year, and 3 years after transplantation. In the eculizumab group, four non-vaccinated children lost their grafts during the course of a flu-like infection. Eculizumab is associated with better early graft function and improved graft morphology; however, there was an unacceptably high number of early graft losses among the eculizumab-treated children. While a promising strategy, the best approach to complement inhibition remains to be established.

Effect of renal function on antihypertensive drug safety and efficacy in children

BACKGROUND

Hypertension and chronic kidney disease (CKD) are common comorbidities. Guidelines recommend treating hypertension in children with CKD because it is a modifiable risk factor for subsequent cardiovascular disease. Children with CKD are frequently excluded from antihypertensive drug trials. Consequently, safety and efficacy data for antihypertensive drugs are lacking in children with CKD.

METHODS

We determined the incidence of adverse events in 10 pediatric antihypertensive trials to determine the effect of renal function on antihypertensive safety and efficacy in children. These trials were submitted to the US Food and Drug Administration from 1998 to 2005. We determined the number and type of adverse events reported during the trials and compared these numbers in participants with normal renal function and those with decreased function (defined as an estimated glomerular filtration rate [eGFR] <90 mL/min/1.73 m2 calculated using the original Schwartz equation).

RESULTS

Among the 1,703 children in the 10 studies, 315 had decreased renal function. We observed no difference between the two cohorts in the incidence of adverse events or adverse drug reactions related to study drug. Only 5 participants, all with decreased renal function, experienced a serious adverse event; none was recorded by investigators to be study drug-related. Among treated participants, children with decreased renal function who received a high dose of study drug had a significantly larger drop in diastolic blood pressure compared with children with normal renal function.

CONCLUSIONS

These data show that antihypertensive treatment in children with renal dysfunction can be safe and efficacious, and consideration should be given to their inclusion in selected drug development programs.

Estimated Glomerular Filtration Rate; Laboratory Implementation and Current Global Status

In 2002, the Kidney Disease Outcomes Quality Initiative guidelines for identifying and treating CKD recommended that clinical laboratories report estimated glomerular filtration rate (eGFR) with every creatinine result to assist clinical practitioners to identify people with early-stage CKD. At that time, the original Modification of Diet in Renal Disease (MDRD) Study equation based on serum creatinine measurements was recommended for calculating eGFR. Because the MDRD Study equation was developed using a nonstandardized creatinine method, a Laboratory Working Group of the National Kidney Disease Education program was formed and implemented standardized calibration traceability for all creatinine methods from global manufacturers by approximately 2010. A modified MDRD Study equation for use with standardized creatinine was developed. The Chronic Kidney Disease Epidemiology Collaboration developed a new equation in 2009 that was more accurate than the MDRD Study equation at values above 60 mL/min/1.73 m². As of 2017, reporting eGFR with creatinine is almost universal in many countries. A reference system for cystatin C became available in 2010, and manufacturers are in the process to standardize cystatin C assays. Equations for eGFR based on standardized cystatin C alone and with creatinine are now available from the Chronic Kidney Disease Epidemiology Collaboration and other groups.

Renal insufficiency mimicking glutaric acidemia type 1 on newborn screening

BACKGROUND

Glutaryl carnitine (C5DC) in dried blood spots is used as a biomarker for glutaric aciduria type 1 (GA-1) screening. C5DC, however, is the only screening marker for this condition, and various pathological conditions may interfere with C5DC metabolism. Recently, C5DC elevation has been reported in cases of renal insufficiency.

METHOD

Five patients who were positive for GA-1 on newborn screening with tandem mass spectrometry between September 2012 and March 2015 at Kobe University Hospital were enrolled in this study.

RESULTS

GA-1 was not confirmed on urinary organic acids analysis in any of the patients. C5DC decreased immediately in four patients, but one patient, who had high C5DC for at least 4 months, was diagnosed with bilateral renal hypoplasia.

CONCLUSION

In the case of persistently elevated C5DC, renal insufficiency should be considered as a differential diagnosis.

Increased Risk of Acute Kidney Injury in Critically Ill Children Treated With Vancomycin and Piperacillin/Tazobactam

OBJECTIVES

Compare the rates of acute kidney injury in critically ill children treated with vancomycin and piperacillin-tazobactam versus vancomycin and ceftriaxone.

DESIGN

Retrospective cohort study.

SETTING

A large tertiary care children's hospital in an urban setting.

PATIENTS

Children greater than or equal to 2 months old admitted to the PICU who received greater than or equal to 48 consecutive hours of vancomycin and piperacillin-tazobactam or vancomycin and ceftriaxone.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Acute kidney injury was defined as a minimum 50% increase in serum creatinine, adjusted for total fluid balance, from baseline over a 48-hour period. Bivariate analysis compared treatment groups and acute kidney injury groups. A multivariable logistic regression model was fit for acute kidney injury including covariable analysis. The study included 93 children. There were no differences between treatment groups in terms of age, severity of illness, baseline renal function, vancomycin dosing, or vancomycin trough concentrations. Children who received vancomycin and piperacillin-tazobactam had a higher cumulative frequency of acute kidney injury than those who received vancomycin and ceftriaxone 915/58 [25.9%] vs 3/35 [8.6%]; p = 0.041). After controlling for vancomycin trough concentration, age, concurrent nephrotoxin exposure, and use of vasopressors, exposure to piperacillin-tazobactam significantly increased the risk of acute kidney injury (adjusted odds ratio, 4.55; 95% CI [1.11-18.7]; p = 0.035) compared with ceftriaxone. Use of vasopressors (adjusted odds ratio, 3.73 [95% CI, 1.14-12.3]) and a vancomycin trough greater than or equal to 15 mg/dL (adjusted odds ratio, 4.12 [95% CI, 1.12-15.2)] was also associated with acute kidney injury. Length of stay was longer in children with acute kidney injury (median, 18.0 days; interquartile range, 7.76-29.7) compared with those without acute kidney injury (median, 6.21 days; interquartile range, 2.92-15.6; p = 0.017).

CONCLUSIONS

In critically ill children, acute kidney injury occurred more in patients treated with vancomycin and piperacillin-tazobactam versus vancomycin plus ceftriaxone. After controlling for covariates, exposure to piperacillin-tazobactam was associated with an increased odds of acute kidney injury development.

Prevention of Chemotherapy-Induced Nephrotoxicity in Children with Cancer

Children with cancer treated with cytotoxic drugs are frequently at risk of developing renal dysfunction. The cytotoxic drugs that are widely used for cancer treatment in children are cisplatin (CPL), ifosfamide (IFO), carboplatin, and methotrexate (MTX). Mechanisms of anticancer drug-induced renal disorders are different and include acute kidney injury (AKI), tubulointerstitial disease, vascular damage, hemolytic uremic syndrome (HUS), and intrarenal obstruction. CPL nephrotoxicity is dose-related and is often demonstrated with hypomagnesemia, hypokalemia, and impaired renal function with rising serum creatinine and blood urea nitrogen levels. CPL, mitomycin C, and gemcitabine treatment cause vascular injury and HUS. High-dose IFO, streptozocin, and azacitidine cause renal tubular dysfunction manifested by Fanconi syndrome, rickets, and osteomalacia. AKI is a common adverse effect of MTX, interferon-alpha, and nitrosourea compound treatment. These strategies to reduce the cytotoxic drug-induced nephrotoxicity should include adequate hydration, forced diuresis, and urinary alkalization. Amifostine, sodium thiosulfate, and diethyldithiocarbamate provide protection against CPL-induced renal toxicity.

Tools for the Individualized Therapy of Teicoplanin for Neonates and Children

The aim of this study was to develop a population pharmacokinetic (PK) model for teicoplanin across childhood age ranges to be used as Bayesian prior information in the software constructed for individualized therapy. We developed a nonparametric population model fitted to PK data from neonates, infants, and older children. We then implemented this model in the BestDose multiple-model Bayesian adaptive control algorithm to show its clinical utility. It was used to predict the dosages required to achieve optimal teicoplanin predose targets (15 mg/liter) from day 3 of therapy. We performed individual simulations for an infant and a child from the original population, who provided early first dosing interval concentration-time data. An allometric model that used weight as a measure of size and that also incorporated renal function using the estimated glomerular filtration rate (eGFR), or the ratio of postnatal age (PNA) to serum creatinine concentration (SCr) for infants <3 months old, best described the data. The median population PK parameters were as follows: elimination rate constant (Ke) = 0.03 · (wt/70)^−0.25 · Renal (h⁻¹); V = 19.5 · (wt/70) (liters); Renal = eGFR^0.07 (ml/min/1.73 m²), or Renal = PNA/SCr (μmol/liter). Increased teicoplanin dosages and alternative administration techniques (extended infusions and fractionated multiple dosing) were required in order to achieve the targets safely by day 3 in simulated cases. The software was able to predict individual measured concentrations and the dosages and administration techniques required to achieve the desired target concentrations early in therapy. Prospective evaluation is now needed in order to ensure that this individualized teicoplanin therapy approach is applicable in the clinical setting. (This study has been registered in the European Union Clinical Trials Register under EudraCT no. 2012-005738-12.)

Intraoperative hemodynamic factors predicting early postoperative renal function in pediatric kidney transplantation

BACKGROUND

The anesthetic management of kidney transplantation in children remains somewhat empirical. The goal of the present study was to investigate intraoperative hemodynamic factors affecting posttransplantation kidney function.

METHODS

We performed a retrospective analysis of data from patients undergoing kidney transplantation in our pediatric teaching hospital from 2000 to 2014. Data collected included: donor and recipient demographic data, recipient comorbidities, fluids administered intraoperatively, and intraoperative blood pressure and central venous pressure. The main outcome of the study was the creatinine clearance at day 1 corrected to a body surface area of 1.73 m². Analysis was performed using Classification Tree Analysis with 10-fold cross-validation.

RESULTS

One hundred and two patients were included. The following predictors of increased postoperative creatinine clearance at day 1 were identified: decreasing recipient weight, mean blood pressure-to-weight ratio 10 minutes after reperfusion, reduced cold ischemia duration, and increased intraoperative albumin infusion. Increased creatinine clearance was observed when mean blood pressure-to-weight ratio 10 minutes after reperfusion was ≥4.3 in patients weighing 13-21 kg and ≥2.5 in those ≥22 kg. Overall, the model explained 64% (and at cross-validation 60%) of creatinine clearance variability at day 1.

CONCLUSION

Intraoperative hemodynamics during kidney transplantation should be optimized in order to increase mean blood pressure according to values indicated by our analyses. Cold ischemia duration should be shortened as far as possible.

Development of tandem mass spectrometry-based creatinine measurement using dried blood spot for newborn mass screening

BackgroundCongenital anomalies of the kidney and urinary tract (CAKUT) are the most prevalent etiologies of pediatric chronic kidney disease (CKD). However, no robust mass screening methods have been developed to detect patients with CAKUT, making early intervention to prevent progressive renal failure challenging.MethodsWe applied tandem mass spectrometry (MS/MS) to measure the creatinine (Cr) value from dried blood spot (DBS) analysis, which has been used for newborn mass screening. Subsequently, we evaluated the correlation between DBS Cr measured by MS/MS and serum Cr measured by the conventional method in pediatric patients with CKD. Finally, DBS Cr was measured in 190 full-term, healthy newborns on days 4-6 after birth.ResultsWe established a system of MS/MS-based measurement of Cr from DBS. Measured DBS Cr in the pediatric patients showed a strong association with serum Cr (r=0.86; P<0.01). The median DBS Cr value in newborns was 0.222 (interquartile range: 0.189, 0.269) mg/dl. No significant correlations were found between DBS Cr values and body weight, Apgar score, gestational age, and sex in newborns.ConclusionWe successfully established a method for MS/MS-based measurement of Cr for newborn screening and determined normal reference values for full-term newborns.

Follow-up of Acute kidney injury in Neonates during Childhood Years (FANCY): a prospective cohort study

BACKGROUND

Very low birth weight (VLBW) neonates commonly experience acute kidney injury (AKI) in the neonatal intensive care unit (NICU). We hypothesize that VLBW neonates exposed to AKI in the NICU might be at a higher risk of renal dysfunction during childhood.

METHODS

In this cohort study, VLBW children (aged 3-7 years) completed a kidney health evaluation and were stratified according to AKI status in the NICU. The primary outcome was renal dysfunction defined as any of the following: estimated glomerular filtration rate (eGFR) <90 mL/min/1.73 m2, urine protein/creatinine >0.2 or blood pressure ≥95th percentile.

RESULTS

Thirty-four subjects completed the study. Twenty subjects had a history of neonatal AKI (stage 1, n = 8; stage 2, n = 9; and stage 3, n = 3). At a median age of 5 years, the AKI group had a higher risk of renal dysfunction compared with the group without AKI (65% vs 14%, relative risk 4.5 (1.2-17.1), p = 0.01). Overall, 26% of the total cohort had an eGFR <90 mL/min/1.73 m2 using serum cystatin C (35% of AKI subjects, 14% of no AKI subjects, p = 0.25).

CONCLUSIONS

Evidence of renal dysfunction in neonates born VLBW can be found early in childhood. Further work is necessary to determine how to reduce renal disease in this vulnerable population.

The incidence of pediatric acute kidney injury is increased when identified by a change in a creatinine-based electronic alert

A prospective national cohort study was undertaken to collect data on all cases of pediatric (under 18 yrs of age) acute kidney injury (AKI) identified by a biochemistry-based electronic alert using the Welsh National electronic AKI reporting system. Herein we describe the utility and limitation of using this modification of the KDIGO creatinine-based system data set to characterize pediatric AKI. Of 1,343 incident episodes over a 30-month period, 34.5% occurred in neonates of which 83.8% were AKI stage 1. Neonatal 30-day mortality was 4.1%, with 73.3% of this being accounted for by patients treated in an Intensive Care Unit. In the non-neonatal group, 76.1% were AKI stage 1. Hospital-acquired AKI accounted for 40.1% of episodes while community-acquired AKI represented 29.4% of cases within which 33.9% were admitted to hospital and 30.5% of cases were unclassified. Non-neonatal 30-day mortality was 1.2%, with half of this accounted for by patients treated in the Intensive Care Unit. Nonrecovery of renal function at 30 days occurred in 28% and was significantly higher in patients not admitted to hospital (45% vs. 20%). The reported incidence of AKI in children was far greater than previously reported in studies reliant on clinical identification of adult AKI or hospital coding data. Mortality was highest in neonates and driven by those in the Intensive Care Unit. Nonrecovery of renal function and persistent renal impairment was more common in non-neonates and was especially high in patients with community-acquired AKI who were not hospitalized.

Incidence and outcome of acute kidney injury by the pRIFLE criteria for children receiving extracorporeal membrane oxygenation after heart surgery

BACKGROUND

Acute kidney injury (AKI) is common in patients treated with extracorporeal membrane oxygenation (ECMO). The RIFLE criteria demonstrate clinical relevance for diagnosing AKI and classifying its severity.

OBJECTIVES

To systematically define the incidence, clinical course and outcome of AKI using the pediatric pRIFLE criteria.

DESIGN

Retrospective, medical records review.

SETTINGS

Pediatric cardiac surgical intensive care units at a tertiary care hospital in Riyadh.

PATIENTS AND METHODS

We reviewed the records of all pediatric patients that underwent cardiac surgery and required ECMO postoperatively between 1 January 2011 and 1 January 2016. AKI was classified according to the pRIFLE criteria 48 hours after ECMO initiation. Demographics and concomitant therapies for all patients were collected.

MAIN OUTCOME MEASURE(S)

Outcome was assessed by recovery from AKI at time of discharge, ICU stay and mortality.

RESULTS

Fifty-nine patients needed ECMO after cardiac surgery during the study period. Their mean (SD) age and weight was 11.0 (16.5) month and 5.5 (3.6) kg, respectively. All patients had a central venoarterial ECMO inserted. Fifty-three patients (90%) developed AKI after ECMO initiation. The majority of patients (57%) were categorized as pRIFLE-Failure, having a higher mortality rate (28/34 patients, 82%) in comparison to the pRIFLE-Injury and pRIFLE-Risk groups. Twenty-nine patients (49%) required either peritoneal dialysis (PD), or renal replacement therapy (RRT) or both. For AKI vs non-AKI patients, there was a statistically significant difference between mean (SD) ECMO duration (9.0 [8.00] vs 6.0 [2.0] days; P=.02) and ICU stay (37.0 [41.0] vs 21.0 [5.0] days; P=.03), respectively. The overall mortality rate was 58%, with a significant difference (P=.03) between AKI and non-AKI groups. All the patients who survived had normal creatinine clearance at hospital discharge.

CONCLUSION

There is a high incidence of AKI in pediatric patients requiring ECMO after cardiac surgery, and it is associated with higher mortality, increased ECMO duration, and increased ventilator days.

LIMITATIONS

Single-center retrospective analysis and the small sample size limited the precision of our estimates in sub-populations.

Tolerability of up to 200 days of prophylaxis with valganciclovir oral solution and/or film-coated tablets in pediatric kidney transplant recipients at risk of cytomegalovirus disease

This multicenter, open-label study evaluated the tolerability of extended prophylaxis with valganciclovir in pediatric kidney transplant recipients at risk of CMV disease. Fifty-six patients aged 4 months to 16 years received once-daily valganciclovir oral solution and/or tablets, dosed by BSA and renal function, for up to 200 days. The most common AEs on treatment were upper respiratory tract infection (33.9%), urinary tract infection (33.9%), diarrhea (32.1%), leukopenia (25.0%), neutropenia (23.2%), and headache (21.4%). There were fewer AEs during days 101-228 vs days 1-100. Twenty-seven patients (48.2%) had treatment-related AEs during valganciclovir treatment, most commonly leukopenia (21.4%), neutropenia (19.6%), anemia (7.1%), and tremor (5.4%). Treatment-related serious AEs were reported for nine patients (16.1%) and six withdrew due to AEs. Viremia was centrally confirmed in 10 patients; there was no confirmed CMV disease. One patient tested positive for a resistance mutation (UL97 L595F). Biopsy-proven acute rejection occurred in six patients (10.7%), but no graft loss or deaths occurred. In conclusion, up to 200 days of valganciclovir prophylaxis in pediatric kidney allograft recipients showed a safety profile consistent with that established in adult transplant patients.

Measuring and estimating glomerular filtration rate in children

Glomerular filtration rate (GFR) is the best index for kidney function in health and disease. Knowledge of the GFR is essential for the detection (diagnosis) and monitoring of renal function during disease progression and for ensuring correct medication doses. Inulin clearance (plasma or urine) is currently considered to be the gold standard for measuring GFR, but in clinical practice the measurement of other exogenous filtration markers from the plasma often replaces that of inulin clearance. Different protocols can be used to determine the area under the plasma disappearance curve, and an understanding of these methods is important. GFR can also be estimated by GFR equations (eGFR), which are most often used in clinical practice because they only require a knowledge of the serum creatinine or cystatin C level and demographic information. eGFR equations are easy to use but they do have their limitations, and it is important to know how these equations were derived and in which circumstances they can be used most accurately. The aim of this review is to explain how GFR can be measured using the renal clearance and the plasma clearance method and which eGFR equations can be applied to children, as well as how and when these equations can be used in clinical practice.

Vancomycin AUC/MIC and Corresponding Troughs in a Pediatric Population

OBJECTIVES

Adult guidelines suggest an area under the curve/minimum inhibitory concentration (AUC/MIC) > 400 corresponds to a vancomycin trough serum concentration of 15 to 20 mg/L for methicillin-resistant Staphylococcus aureus infections, but obtaining these troughs in children are difficult. The primary objective of this study was to assess the likelihood that 15 mg/kg of vancomycin every 6 hours in a child achieves an AUC/MIC > 400.

METHODS

This retrospective chart review included pediatric patients >2 months to <18 years with a positive S aureus blood culture and documented MIC who received at least two doses of vancomycin with corresponding trough. Patients were divided into two groups: group 1 initially receiving ≥15 mg/kg every 6 hours, and group 2 initially receiving any other dosing ranges or intervals. AUCs were calculated four times using three pharmacokinetic methods.

RESULTS

A total of 36 patients with 99 vancomycin trough serum concentrations were assessed. Baseline characteristics were similar between groups. For troughs in group 1 (n = 55), the probability of achieving an AUC/MIC > 400 ranged from 16.4% to 90.9% with a median trough concentration of 11.4 mg/L, while in group 2 (n = 44) the probability of achieving AUC/MIC > 400 ranged from 15.9% to 54.5% with mean trough concentration of 9.2 mg/L. The AUC/MICs were not similar between the different pharmacokinetic methods used; however, a trapezoidal equation (Method A) yielded the highest correlation coefficient (r² = 0.59). When dosing every 6 hours, an AUC/MIC of 400 correlated to a trough serum concentration of 11 mg/L.

CONCLUSIONS

The probability of achieving an AUC/MIC > 400 using only a trough serum concentration and an MIC with patients receiving 15 mg/kg every 6 hours is variable based on the method used to calculate the AUC. An AUC/MIC of 400 in children correlated to a trough concentration of 11 mg/L using a trapezoidal Method to calculate AUC.

Pharmacokinetics and Safety of Valganciclovir in Pediatric Heart Transplant Recipients 4 Months of Age and Younger

BACKGROUND

Valganciclovir (VGCV) effectively prevents cytomegalovirus disease in adult and pediatric solid organ transplant recipients. A dosing algorithm for VGCV for pediatric patients, based on body surface area and renal function, provides a personalized dose using age-appropriate formulations. The suitability of this dosing algorithm has not been assessed specifically in infants and neonates 4 months of age and younger receiving a solid organ transplant.

METHODS

This multicenter prospective study evaluated the pharmacokinetics (PK) and safety of VGCV oral solution in 17 heart transplant recipients 4 months of age and younger who received 2 doses of VGCV on consecutive days using the pediatric dosing algorithm. Plasma concentrations of ganciclovir (GCV) were analyzed at specified times up to 24 hours post VGCV administration.

RESULTS

GCV concentration data were available from 16 patients. The combined data from this study and historic study datasets were used to establish a 2-compartment population PK model with first-order formation to describe the PK of GCV after oral VGCV administration in patients across all pediatric age ranges, including those younger than 4 months of age. Estimated mean area under the curve during the 0-24 hours dosing interval for these patients was 68.1 μg·h/mL.

CONCLUSIONS

The pediatric dosing algorithm for VGCV (utilizing individuals' body surface area and renal function) provides systemic GCV exposures in patients younger than 4 months that are similar to those observed in older pediatric populations. The data indicate that this dosing algorithm is appropriate across the entire pediatric age range, including this youngest age group.

Population pharmacokinetics and pharmacodynamics of teicoplanin in neonates: making better use of C-reactive protein to deliver individualized therapy

OBJECTIVES

There is uncertainty about the optimal teicoplanin regimens for neonates. The study aim was to determine the population pharmacokinetics (PK) of teicoplanin in neonates, evaluate currently recommended regimens and explore the exposure-effect relationships.

METHODS

An open-label PK study was conducted. Neonates from 26 to 44 weeks post-menstrual age were recruited (n = 18). The teicoplanin regimen was a 16 mg/kg loading dose, followed by 8 mg/kg once daily. Therapeutic drug monitoring and dose adjustment were not conducted. A standard two-compartment PK model was developed, followed by models that incorporated weight. A PK/pharmacodynamic (PD) model with C-reactive protein serial measurements as the PD input was fitted to the data. Monte Carlo simulations (n = 5000) were performed using Pmetrics. The AUCs at steady state and the proportion of patients achieving the recommended drug exposures (i.e. Cmin >15 mg/L) were determined. The study was registered in the European Clinical Trials Database Registry (EudraCT: 2012-005738-12).

RESULTS

The PK allometric model best accounted for the observed data. The PK parameters medians were: clearance = 0.435 × (weight/70)0.75 (L/h); volume = 0.765 (L); Kcp = 1.3 (h-1); and Kpc = 0.629 (h-1). The individual time-course of C-reactive protein was well described using the Bayesian posterior estimates for each patient. The simulated median AUC96-120 was 302.3 mg·h/L and the median Cmin at 120 h was 12.9 mg/L; 38.8% of patients attained a Cmin >15 mg/L by 120 h.

CONCLUSIONS

Teicoplanin population PK is highly variable in neonates, weight being the best descriptor of PK variability. A low percentage of neonates were able to achieve Cmin >15 mg/L. The routine use of therapeutic drug monitoring and improved knowledge on the PD of teicoplanin is required.

Pharmacokinetic considerations when prescribing in children

Before prescribing, the pediatrician typically considers recommended dosing guidelines and issues related to safety. Rarely does (s)he consider the impact of normal growth and development on drug disposition and by extension drug action. This paper reviews how the processes of absorption, distribution, metabolism and elimination differ between healthy children and adults and briefly discusses considerations for medication prescribing in children where these processes are altered secondary to comorbidities.

Bottom-up Meets Top-down: Complementary Physiologically Based Pharmacokinetic and Population Pharmacokinetic Modeling for Regulatory Approval of a Dosing Algorithm of Valganciclovir in Very Young Children

Population pharmacokinetic (PopPK) and physiologically based pharmacokinetic (PBPK) models are frequently used to support pediatric drug development. Both methods have strengths and limitations and we used them complementarily to support the regulatory approval of a dosing algorithm for valganciclovir (VGCV) in children <4 months old. An existing pediatric PBPK model was extended to neonates and showed that potential physiological differences compared with older children are minor. The PopPK model was used to simulate ganciclovir (GCV) exposures in children with population typical combinations of body size and renal function and to assess the effectiveness of an alternative dosing algorithm suggested by the US Food and Drug Administration. PBPK and PopPK confirmed that the proposed VGCV dosing algorithm achieves similar GCV exposures in children of all ages and that the alternative dosing algorithm leads to underexposure in a substantial fraction of patients. Our approach raised the confidence in the VGCV dosing algorithm for children <4 months old and supported the regulatory approval.

Predictive Performance of Physiologically Based Pharmacokinetic and Population Pharmacokinetic Modeling of Renally Cleared Drugs in Children

Predictive performance of physiologically based pharmacokinetic (PBPK) and population pharmacokinetic (PopPK) models of drugs predominantly eliminated through kidney in the pediatric population was evaluated. After optimization using adult clinical data, the verified PBPK models can predict 33 of 34 drug clearance within twofold of the observed values in children 1 month and older. More specifically, 10 of 11 of predicted clearance values were within 1.5‐fold of those observed in children between 1 month and 2 years old. The PopPK approach also predicted 19 of 21 drug clearance within twofold of the observed values in children. In summary, our analysis demonstrated both PBPK and PopPK adult models, after verification with additional adult pharmacokinetic (PK) studies and incorporation of known ontogeny of renal filtration, could be applied for dosing regimen recommendation in children 1 month and older for renally eliminated drugs in a first‐in‐pediatric study.