Application of Physiologically Based Pharmacokinetic Modeling to Characterize the Effects of Age and Obesity on the Disposition of Levetiracetam in the Pediatric Population.

BACKGROUND: Levetiracetam is an antiseizure medication used for several seizure types in adults and children aged 1 month and older; however, due to a lack of data, pharmacokinetic (PK) variability of levetiracetam is not adequately characterized in certain populations, particularly neonates, children younger than 2 years of age, and children older than 2 years of age with obesity. OBJECTIVE: This study aimed to address the gap by leveraging PK data from two prospective standard-of-care pediatric trials (n = 88) covering an age range from 1 month to 19 years, including those with obesity (64%), and applying a physiologically based PK (PBPK) modeling framework. METHODS: A published PBPK model of levetiracetam for children aged 2 years and older was extended to pediatric patients younger than 2 years of age and patients older than 2 years of age with obesity by accounting for the obesity and age-related changes in PK using PK-Sim® software. The prospective pediatric data, along with the literature data for neonates and children younger than 2 years of age, were used to evaluate the extended PBPK models. RESULTS: Overall, 82.4% of data fell within the 90% interval of model-predicted concentrations, with an average fold error within twofold of the accepted criteria. PBPK modeling revealed that children with obesity had lower weight-normalized clearances (0.053 L/h/kg) on average than children without obesity (0.063 L/h/kg). The effect of maturation was well-characterized, resulting in comparable PBPK-simulated, weight-normalized clearances for neonates and children younger than 2 years of age reported from the literature. CONCLUSIONS: PBPK modeling simulations revealed that the current US FDA-labeled pediatric dosing regimen listed in the prescribing information can produce the required exposure of levetiracetam in these target populations with dose adjustments for children with obesity aged 4 years to younger than 16 years.

Using Real-World Data to Externally Evaluate Population Pharmacokinetic Models of Dexmedetomidine in Children and Infants.

Dexmedetomidine is a sedative used in both adults and off-label in children with considerable reported pharmacokinetic (PK) interindividual variability affecting drug exposure across populations. Several published models describe the population PKs of dexmedetomidine in neonates, infants, children, and adolescents, though very few have been externally evaluated. A prospective PK dataset of dexmedetomidine plasma concentrations in children and young adults aged 0.01-19.9 years was collected as part of a multicenter opportunistic PK study. A PubMed search of studies reporting dexmedetomidine PK identified five population PK models developed with data from demographically similar children that were selected for external validation. A total of 168 plasma concentrations from 102 children were compared with both population (PRED) and individualized (IPRED) predicted values from each of the five published models by quantitative and visual analyses using NONMEM (v7.3) and R (v4.1.3). Mean percent prediction errors from observed values ranged from -1% to 120% for PRED, and -24% to 60% for IPRED. The model by James et al, which was developed using similar "real-world" data, nearly met the generalizability criteria from IPRED predictions. Other models developed using clinical trial data may have been limited by inclusion/exclusion criteria and a less racially diverse population than this study's opportunistic dataset. The James model may represent a useful, but limited tool for model-informed dosing of hospitalized children.

Pharmacokinetics and Proposed Dosing of Levetiracetam in Children With Obesity.

OBJECTIVE: Characterize levetiracetam pharmacokinetics (PK) in children with obesity to inform dosing. METHODS: Children 2 to <21 years old receiving standard of care oral levetiracetam across two opportunistic studies provided blood samples. Levetiracetam plasma PK data were analyzed with a nonlinear mixed-effects modeling approach. Indirect measures for body size and covariates were tested for model inclusion. Individual empirical Bayesian estimates using the final model parameters were compared by obesity status. Monte Carlo simulation using total body weight was performed in children with normal estimated glomerular filtration rate to identify dosing for children with obesity that resulted in comparable exposures to normal weight adults and children after receiving label dosing. RESULTS: The population PK model was developed from 341 plasma concentrations from 169 children. A 1-compartment model best fit the data with fat-free mass as a significant covariate. Compared with children with normal weight, children with obesity had significantly lower body weight-normalized clearance (median [range], 4.77 [1.49-10.44] and 3.71 [0.86-13.55] L/h/70 kg, respectively). After label dosing with the oral formulation in children with obesity 4 to <16 years old, maximum and minimum steady-state concentrations were higher (25% and 41%, respectively [oral solution] and 27% and 19%, respectively [tablet]) compared with children with normal weight. Comparable exposures between children with and without obesity were achieved with weight-tiered dosing regimens of <75 kg or ≥75 kg. CONCLUSIONS: Weight-tiered dosing for levetiracetam oral solution and tablets for children with obesity 4 to <16 years old results in more comparable exposures to children of normal weight.

Pediatric extracorporeal life support for refractory status asthmaticus: ELSO Registry trends from the past decade.

BACKGROUND: Extracorporeal life support (ECLS) for status asthmaticus (SA) is rare. Increased safety and experience may increase utilization of ECLS for SA. METHODS: We reviewed pediatric (<18 years old) patients requiring ECLS for SA between 1998 and 2019 within the Extracorporeal Life Support Organization (ELSO) Registry and Nemours Children's Health (NCH) system. We compared patient characteristics, pre-ECLS medications, clinical data, complications, and survival to discharge between Early (1988-2008) and Late (2009-2019) eras. RESULTS: From the ELSO Registry, we identified 173 children, 53 in Early and 120 in Late eras, with primary diagnosis of SA. Pre-ECLS hypercarbic respiratory failure was similar between eras (median pH 7.0 and pCO2 111 mm Hg). Venovenous mode (79% vs. 82%), median ECLS time (116 vs. 99 h), time to extubation (53 vs. 62 h), and hospital survival (89% vs. 88%) also remained similar. Intubation to cannulation time significantly decreased (20 vs. 10 h, p = 0.01). ECLS without complication occurred more in the Late era (19% vs. 39%, p < 0.01), with decreased hemorrhagic (24% vs. 12%, p = 0.05) and noncannula-related mechanical (19% vs. 6%, p = 0.008) complications. Within NCH, we identified six Late era patients. Pre-ECLS medication favored intravenous beta agonists, bronchodilators, magnesium sulfate, and steroids. One patient died from neurological complications following pre-ECLS cardiac arrest. CONCLUSIONS: Collective experience supports ECLS as a rescue therapy for pediatric SA. Survival to discharge remains good, and complication rates have improved. Pre-ECLS cardiac arrest may potentiate neurologic injury and impact survival. Further study is needed to evaluate causal relationships between complications and outcomes.

Single-Center Experience Using the Cardiohelp System for Neonatal and Pediatric Extracorporeal Membrane Oxygenation.

OBJECTIVES: Extracorporeal membrane oxygenation (ECMO) systems have continued to evolve and improve with the development of smaller and portable systems. The Cardiohelp (Maquet Getinge Cardiopulmonary AG, Rastatt, Germany) portable life support device is a compact ECMO system used widely in adults and for ECMO transport. Reports of its use in neonatal and pediatric centers remain limited. In this single-center retrospective review, we describe our institutional experience with the Cardiohelp. DESIGN: Single-center retrospective review. SETTING: Neonatal ICUs and PICUs in a tertiary-care children's hospital. PATIENTS: Seventeen pediatric patients on ECMO. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Median (interquartile range, IQR) of patient age was 0.5 years (0-7 yr). Eleven of 17 patients were on veno-arterial ECMO, five on veno-venous ECMO, and one on veno-venoarterial ECMO. All veno-venous and veno-venoarterial runs ( n = 6) were accomplished with bicaval, dual-lumen cannulae. Median duration on Cardiohelp was 113 hours (IQR 50-140 hr). Median anti-Xa level for patients was 0.43 IU/mL (IQR 0.35-0.47 IU/mL), with median heparin dose of 23.6 U/kg/hr (IQR 17.6-28.1 U/kg/hr). Median plasma-free hemoglobin was 41.4 mg/dL (IQR 30-60 mg/dL). Circuit change was required in three cases. Fourteen patients survived ECMO, with 13 patients surviving to discharge. CONCLUSIONS: We have used the Cardiohelp system to support 17 neonatal and pediatric ECMO patients, without complications. Further studies are warranted to compare complications, outcomes, and overall cost with other institutions and other existing ECMO systems.

How educational are 'educational' apps for young children? App store content analysis using the Four Pillars of Learning framework.

Experts have expressed concerns about the lack of evidence demonstrating that children's "educational" applications (apps) have educational value. This study aimed to operationalize Hirsh-Pasek, Zosh, et al.'s (2015) Four Pillars of Learning into a reliable coding scheme (Pillar 1: Active Learning, Pillar 2: Engagement in the Learning Process, Pillar 3: Meaningful Learning, Pillar 4: Social Interaction), describe the educational quality of commercially-available apps, and examine differences in educational quality between free and paid apps. We analyzed 100 children's educational apps with the highest downloads from Google Play and Apple app stores, as well as 24 apps most frequently played by preschool-age children in a longitudinal cohort study. We developed a coding scheme in which each app earned a value of 0-3 for each Pillar, defining lower-quality apps as those scoring ≤ 4, summed across the Four Pillars. Overall scores were low across all Pillars. Free apps had significantly lower Pillar 2 (Engagement in Learning Process) scores (t-test, p < .0001) and overall scores (t-test, p < .0047) when compared to paid apps, due to the presence of distracting enhancements. These results highlight the need for improved design of educational apps guided by developmental science.

Extracorporeal Membrane Oxygenation in a Pediatric Patient with Hepatopulmonary Syndrome and Interrupted Inferior Vena Cava After Living Related Liver Donation.

Extracorporeal membrane oxygenation (ECMO) is used for cardiopulmonary dysfunction. Hepatopulmonary syndrome (HPS) occurs in the setting of liver failure and may cause hypoxemia. Previous reports have described the use of ECMO for HPS after liver transplant. Our patient is a 19-month-old female with biliary atresia, an interrupted inferior vena cava, and HPS on 8 liters per minute of high-flow oxygen. Following liver transplantation, her postoperative course was complicated by severe hypoxemia requiring ECMO. Due to her interrupted inferior vena cava, our standard bi-caval cannula could not be used. Hence, a 16-French double lumen venovenous right internal jugular to right atrial cannula was used to provide extracorporeal life support. She was decannulated after 17 days, remained intubated for 2 days, and weaned to room air over the next 3 weeks. This is the third pediatric liver transplant patient supported with ECMO identified in the literature, and the youngest and smallest of those reported. This approach to cannulation is unique because of the use of a double lumen venovenous cannula for HPS in a child, selected due to complex anatomy. Posttransplant ECMO may provide pediatric patients with HPS and posttransplant hypoxemia a period of support for their pulmonary remodeling and recovery from HPS.

Advertising in Young Children's Apps: A Content Analysis.

OBJECTIVE: Young children use mobile devices on average 1 hour/day, but no studies have examined the prevalence of advertising in children's apps. The objective of this study was to describe the advertising content of popular children's apps. METHODS: To create a coding scheme, we downloaded and played 39 apps played by children aged 12 months to 5 years in a pilot study of a mobile sensing app; 2 researchers played each app, took detailed notes on the design of advertisements, and iteratively refined the codebook (interrater reliability 0.96). Codes were then applied to the 96 most downloaded free and paid apps in the 5 And Under category on the Google Play app store. RESULTS: Of the 135 apps reviewed, 129 (95%) contained at least 1 type of advertising. These included use of commercial characters (42%); full-app teasers (46%); advertising videos interrupting play (e.g., pop-ups [35%] or to unlock play items [16%]); in-app purchases (30%); prompts to rate the app (28%) or share on social media (14%); distracting ads such as banners across the screen (17%) or hidden ads with misleading symbols such as "$" or camouflaged as gameplay items (7%). Advertising was significantly more prevalent in free apps (100% vs 88% of paid apps), but occurred at similar rates in apps labeled as "educational" versus other categories. CONCLUSION: In this exploratory study, we found high rates of mobile advertising through manipulative and disruptive methods. These results have implications for advertising regulation, parent media choices, and apps' educational value.

NAD(P)H quinone oxidoreductase 1 regulates neutrophil elastase-induced mucous cell metaplasia.

Mucous cell metaplasia (MCM) and neutrophil-predominant airway inflammation are pathological features of chronic inflammatory airway diseases. A signature feature of MCM is increased expression of a major respiratory tract mucin, MUC5AC. Neutrophil elastase (NE) upregulates MUC5AC in primary airway epithelial cells by generating reactive oxygen species, and this response is due in part to upregulation of NADPH quinone oxidoreductase 1 (NQO1) activity. Delivery of NE directly to the airway triggers inflammation and MCM and increases synthesis and secretion of MUC5AC protein from airway epithelial cells. We hypothesized that NE-induced MCM is mediated in vivo by NQO1. Male wild-type and Nqo1-null mice (C57BL/6 background) were exposed to human NE (50 µg) or vehicle via oropharyngeal aspiration on days 1, 4, and 7. On days 8 and 11, lung tissues and bronchoalveolar lavage (BAL) samples were obtained and evaluated for MCM, inflammation, and oxidative stress. MCM, inflammation, and production of specific cytokines, granulocyte-macrophage colony-stimulating factor, macrophage inflammatory protein-2, interleukin-4, and interleukin-5 were diminished in NE-treated Nqo1-null mice compared with NE-treated wild-type mice. However, in contrast to the role of NQO1 in vitro, we demonstrate that NE-treated Nqo1-null mice had greater levels of BAL and lung tissue lipid carbonyls and greater BAL iron on day 11, all consistent with increased oxidative stress. NQO1 is required for NE-induced inflammation and MCM. This model system demonstrates that NE-induced MCM directly correlates with inflammation, but not with oxidative stress.