Clinical factors associated with microstructural connectome related brain dysmaturation in term neonates with congenital heart disease.

Objective: Term congenital heart disease (CHD) neonates display abnormalities of brain structure and maturation, which are possibly related to underlying patient factors, abnormal physiology and perioperative insults. Our primary goal was to delineate associations between clinical factors and postnatal brain microstructure in term CHD neonates using diffusion tensor imaging (DTI) magnetic resonance (MR) acquisition combined with complementary data-driven connectome and seed-based tractography quantitative analyses. Our secondary goal was to delineate associations between mild dysplastic structural brain abnormalities and connectome and seed-base tractography quantitative analyses. These mild dysplastic structural abnormalities have been derived from prior human infant CHD MR studies and neonatal mouse models of CHD that were collectively used to calculate to calculate a brain dysplasia score (BDS) that included assessment of subcortical structures including the olfactory bulb, the cerebellum and the hippocampus. Methods: Neonates undergoing cardiac surgery for CHD were prospectively recruited from two large centers. Both pre- and postoperative MR brain scans were obtained. DTI in 42 directions was segmented into 90 regions using a neonatal brain template and three weighted methods. Clinical data collection included 18 patient-specific and 9 preoperative variables associated with preoperative scan and 6 intraoperative (e.g., cardiopulmonary bypass and deep hypothermic circulatory arrest times) and 12 postoperative variables associated with postoperative scan. We compared patient specific and preoperative clinical factors to network topology and tractography alterations on a preoperative neonatal brain MRI, and intra and postoperative clinical factors to network topology alterations on postoperative neonatal brain MRI. A composite BDS was created to score abnormal findings involving the cerebellar hemispheres and vermis, supratentorial extra-axial fluid, olfactory bulbs and sulci, hippocampus, choroid plexus, corpus callosum, and brainstem. The neuroimaging outcomes of this study included (1) connectome metrics: cost (number of connections) and global/nodal efficiency (network integration); (2) seed based tractography methods of fractional anisotropy (FA), radial diffusivity, and axial diffusivity. Statistics consisted of multiple regression with false discovery rate correction (FDR) comparing the clinical risk factors and BDS (including subcortical components) as predictors/exposures and the global connectome metrics, nodal efficiency, and seed based- tractography (FA, radial diffusivity, and axial diffusivity) as neuroimaging outcome measures. Results: A total of 133 term neonates with complex CHD were prospectively enrolled and 110 had analyzable DTI. Multiple patient-specific factors including d-transposition of the great arteries (d-TGA) physiology and severity of impairment of fetal cerebral substrate delivery (i.e., how much the CHD lesion alters typical fetal circulation such that the highest oxygen and nutrient rich blood from the placenta are not directed toward the fetal brain) were predictive of preoperative reduced cost (p < 0.0073) and reduced global/nodal efficiency (p < 0.03). Cardiopulmonary bypass time predicted postoperative reduced cost (p < 0.04) and multiple postoperative factors [extracorporeal membrane oxygenation (ECMO), seizures and cardiopulmonary resuscitation (CPR)] were predictive of postoperative reduced cost and reduced global/nodal efficiency (p < 0.05). Anthropometric measurements (weight, length, and head size) predicted tractography outcomes. Total BDS was not predictive of brain network topology. However, key subcortical components of the BDS score did predict key global and nodal network topology: abnormalities of the cerebellum predicted reduced cost (p < 0.0417) and of the hippocampus predicted reduced global efficiency (p < 0.0126). All three subcortical structures predicted unique alterations of nodal efficiency (p < 0.05), including hippocampal abnormalities predicting widespread reduced nodal efficiency in all lobes of the brain, cerebellar abnormalities predicting increased prefrontal nodal efficiency, and olfactory bulb abnormalities predicting posterior parietal-occipital nodal efficiency. Conclusion: Patient-specific (d-TGA anatomy, preoperative impairment of fetal cerebral substrate delivery) and postoperative (e.g., seizures, need for ECMO, or CPR) clinical factors were most predictive of diffuse postnatal microstructural dysmaturation in term CHD neonates. Anthropometric measurements (weight, length, and head size) predicted tractography outcomes. In contrast, subcortical components (cerebellum, hippocampus, olfactory) of a structurally based BDS (derived from CHD mouse mutants), predicted more localized and regional postnatal microstructural differences. Collectively, these findings suggest that brain DTI connectome and seed-based tractography are complementary techniques which may facilitate deciphering the mechanistic relative contribution of clinical and genetic risk factors related to poor neurodevelopmental outcomes in CHD.

Harmonization of Multi-Center Diffusion Tensor Tractography in Neonates with Congenital Heart Disease: Optimizing Post-Processing and Application of ComBat.

Advanced brain imaging of neonatal macrostructure and microstructure, which has prognosticating importance, is more frequently being incorporated into multi-center trials of neonatal neuroprotection. Multicenter neuroimaging studies, designed to overcome small sample sized clinical cohorts, are essential but lead to increased technical variability. Few harmonization techniques have been developed for neonatal brain microstructural (diffusion tensor) analysis. The work presented here aims to remedy two common problems that exist with the current state of the art approaches: 1) variance in scanner and protocol in data collection can limit the researcher's ability to harmonize data acquired under different conditions or using different clinical populations. 2) The general lack of objective guidelines for dealing with anatomically abnormal anatomy and pathology. Often, subjects are excluded due to subjective criteria, or due to pathology that could be informative to the final analysis, leading to the loss of reproducibility and statistical power. This proves to be a barrier in the analysis of large multi-center studies and is a particularly salient problem given the relative scarcity of neonatal imaging data. We provide an objective, data-driven, and semi-automated neonatal processing pipeline designed to harmonize compartmentalized variant data acquired under different parameters. This is done by first implementing a search space reduction step of extracting the along-tract diffusivity values along each tract of interest, rather than performing whole-brain harmonization. This is followed by a data-driven outlier detection step, with the purpose of removing unwanted noise and outliers from the final harmonization. We then use an empirical Bayes harmonization algorithm performed at the along-tract level, with the output being a lower dimensional space but still spatially informative. After applying our pipeline to this large multi-site dataset of neonates and infants with congenital heart disease (n= 398 subjects recruited across 4 centers, with a total of n=763 MRI pre-operative/post-operative time points), we show that infants with single ventricle cardiac physiology demonstrate greater white matter microstructural alterations compared to infants with bi-ventricular heart disease, supporting what has previously been shown in literature. Our method is an open-source pipeline for delineating white matter tracts in subject space but provides the necessary modular components for performing atlas space analysis. As such, we validate and introduce Diffusion Imaging of Neonates by Group Organization (DINGO), a high-level, semi-automated framework that can facilitate harmonization of subject-space tractography generated from diffusion tensor imaging acquired across varying scanners, institutions, and clinical populations. Datasets acquired using varying protocols or cohorts are compartmentalized into subsets, where a cohort-specific template is generated, allowing for the propagation of the tractography mask set with higher spatial specificity. Taken together, this pipeline can reduce multi-scanner technical variability which can confound important biological variability in relation to neonatal brain microstructure.

The role of machine learning applications in diagnosing and assessing critical and non-critical CHD: a scoping review.

Machine learning uses historical data to make predictions about new data. It has been frequently applied in healthcare to optimise diagnostic classification through discovery of hidden patterns in data that may not be obvious to clinicians. Congenital Heart Defect (CHD) machine learning research entails one of the most promising clinical applications, in which timely and accurate diagnosis is essential. The objective of this scoping review is to summarise the application and clinical utility of machine learning techniques used in paediatric cardiology research, specifically focusing on approaches aiming to optimise diagnosis and assessment of underlying CHD. Out of 50 full-text articles identified between 2015 and 2021, 40% focused on optimising the diagnosis and assessment of CHD. Deep learning and support vector machine were the most commonly used algorithms, accounting for an overall diagnostic accuracy > 0.80. Clinical applications primarily focused on the classification of auscultatory heart sounds, transthoracic echocardiograms, and cardiac MRIs. The range of these applications and directions of future research are discussed in this scoping review.

Hospital-Acquired Infection in Pediatric Subjects With Congenital Heart Disease Postcardiotomy Supported on Extracorporeal Membrane Oxygenation.

OBJECTIVE: To determine prevalence of and risk factors for infection in pediatric subjects with congenital heart disease status postcardiotomy supported on extracorporeal membrane oxygenation, as well as outcomes of these subjects. DESIGN: Retrospective cohort from the Extracorporeal Life Support Organization. SETTING: U.S. and international medical centers providing care to children with congenital heart disease status postcardiotomy. PATIENTS: Critically ill pediatric subjects less than 8 years old admitted to medical centers between January 1, 2013, and December 31, 2015, who underwent cardiac surgery for congenital heart disease and required extracorporeal membrane oxygenation support within the first 14 postoperative days. Subjects were excluded if they underwent orthotopic heart transplantation, required preoperative extracorporeal membrane oxygenation, and had more than one postoperative extracorporeal membrane oxygenation run. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 1,314 extracorporeal membrane oxygenation subject encounters in the Extracorporeal Life Support Organization registry met inclusion criteria. Neonates comprised 53% (n = 696) of the cohort, whereas infants made up 33% (n = 435). Of the 994 subjects with Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery categorizable surgery, 33% (n = 325) were in Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category 4 and 23% (n = 231) in Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category 5. While on extracorporeal membrane oxygenation, 229 subjects (17%) acquired one or more extracorporeal membrane oxygenation-related infections, which represents an occurrence rate of 67 infections per 1,000 extracorporeal membrane oxygenation days. Gram-negative (62%) and Gram-positive (42%) infections occurred most commonly. Forty percent had positive blood cultures. Infants and children were at higher infection risk compared with neonatal subjects; subjects undergoing less complex surgery had higher infection rates. Unadjusted survival to hospital discharge was lower in infected subjects compared with noninfected subjects (43% vs 51%; p = 0.01). After adjusting for confounders via propensity matching, we identified no significant mortality difference between infected and noninfected subjects. CONCLUSIONS: Neonatal and pediatric subjects in this study have a high rate of acquired infection. Infants and children were at higher infection risk compared with neonatal subjects. There was not, however, a significant association between extracorporeal membrane oxygenation-related infection and survival to hospital discharge after propensity matching.

A National Survey on Physician Trainee Participation in Pediatric Interfacility Transport.

OBJECTIVES: To ascertain the national experience regarding which physician trainees are allowed to participate in pediatric interfacility transports and what is considered adequate education and training for physician trainees prior to participating in the transport of children. DESIGN: Self-administered electronic survey. SETTING: Pediatric transport teams listed with the American Academy of Pediatrics Section on Transport Medicine. SUBJECTS: Leaders of U.S. pediatric transport teams. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Forty-four of the 90 U.S. teams surveyed (49%) responded. Thirty-nine (89%) were university hospital-affiliated. Most programs (26/43, 60%) allowed trainees to participate in pediatric transport in some capacity. Mandatory transport rotations were reported for pediatric critical care (PICU) fellows (9/42, 21%), neonatology (neonatal ICU) fellows (6/42, 14%), pediatric emergency medicine fellows (4/41, 10%), emergency medicine residents (3/43, 7%), and pediatric residents (2/43, 5%). Fellow participation was reported by 19 of 28 programs (68%) with PICU fellowships, 12 of 25 programs (48%) with pediatric emergency medicine fellowships, and 10 of 34 programs (29%) with neonatal ICU fellowships. Transport programs with greater than or equal to 1,000 annual incoming transports were more likely to include PICU and pediatric emergency medicine fellows as providers (p = 0.04; 95% CI, 1.04-25.71 and p = 0.02; 95% CI, 1.31-53.75). Most commonly, trainees functioned as medical control physicians (86%), provided minute-to-minute medical direction for critically ill patients (62%), performed intubations (52%), and were code leaders for patients undergoing cardiopulmonary resuscitation during transport (52%). Most transport programs required pediatric residents, PICU, and pediatric emergency medicine fellows to complete a PICU rotation prior to participating in pediatric transports. The majority of transport programs did not use any metrics to determine airway proficiency of physician trainees. CONCLUSIONS: There is heterogeneity with regard to the types of physician trainees allowed to participate in pediatric interfacility transports, the roles played by physician trainees during pediatric transport, and the training (or lack thereof) provided to physician trainees prior to their participating in pediatric transports.

Feasibility and Perceptions of PICU Diaries.

OBJECTIVES: To determine the feasibility of implementing an ICU diary in the pediatric critical care setting and to understand the perceptions held by family members who receive the diaries after PICU discharge. DESIGN: Observational pilot study. SETTING: PICU in a tertiary academic hospital in the United States. PARTICIPANTS: Critically ill pediatric patients admitted to the PICU and their families. INTERVENTIONS: The addition of a PICU diary to a patient's routine care. MEASUREMENTS AND MAIN RESULTS: Twenty families of critically ill children admitted to the PICU were enrolled in the PICU diary pilot study between May 2017 and March 2018. Patients who had an anticipated length of stay of at least 3 days and whose families were English-speaking were included. The median age of patients was 6 years, ranging from newborns to 18 years old, and the median length of stay was 11.5 days (interquartile range, 8.5-41 d). A total of 453 diary entries were written in 19 diaries over 433 PICU days, the majority of which were composed by bedsides nurses (63%). Follow-up surveys sent to parents 2 weeks after PICU discharge revealed that of the parents who had contributed to the diary, most enjoyed doing so (7/8). Nine of 12 parents had reviewed the diary at least once since discharge, and all parent respondents found the diary to be a beneficial aspect of their experience after PICU discharge. CONCLUSIONS: The use of ICU diaries in the PICU setting is feasible and perceived as beneficial by families of critically ill children. Future studies are needed to better understand if PICU diaries may objectively improve psychologic outcomes of patients and family members after PICU admission.

Characteristics of postintensive care syndrome in survivors of pediatric critical illness: A systematic review.

AIM: To synthesize the available evidence focusing on morbidities in pediatric survivors of critical illness that fall within the defined construct of postintensive care syndrome (PICS) in adults, including physical, neurocognitive and psychological morbidities. METHODS: A comprehensive search was conducted in MEDLINE, EMBASE, the Cochrane Library, PsycINFO, and CINAHL using controlled vocabulary and key word terms to identify studies reporting characteristics of PICS in pediatric intensive care unit (PICU) patients. Two reviewers independently screened all titles and abstracts and performed data extraction. From the 3176 articles identified in the search, 252 abstracts were identified for full text review and nineteen were identified for inclusion in the review. All studies reporting characteristics of PICS in PICU patients were included in the final synthesis. RESULTS: Nineteen studies meeting inclusion criteria published between 1995 and 2016 were identified and categorized into studies reporting morbidities in each of three categories-physical, neurocognitive and psychological. The majority of included articles reported prospective cohort studies, and there was significant variability in the outcome measures utilized. A synthesis of the studies indicate that morbidities encompassing PICS are well-described in children who have survived critical illness, often resolving over time. Risk factors for development of these morbidities include younger age, lower socioeconomic status, increased number of invasive procedures or interventions, type of illness, and increased benzodiazepine and narcotic administration. CONCLUSION: PICS-related morbidities impact a significant proportion of children discharged from PICUs. In order to further define PICS in children, more research is needed using standardized tools to better understand the scope and natural history of morbidities after hospital discharge. Improving our understanding of physical, neurocognitive, and psychological morbidities after critical illness in the pediatric population is imperative for designing interventions to improve long-term outcomes in PICU patients.

Evaluation of the Safety of Quetiapine in Treating Delirium in Critically Ill Children: A Retrospective Review.

OBJECTIVE: Quetiapine is an atypical antipsychotic that has been used off-label for the treatment of intensive care unit (ICU) delirium in the adult population, with studies demonstrating both efficacy and a favorable safety profile. Although there is a potential role for quetiapine in the treatment of pediatric ICU delirium, there has been no systematic reporting to date of safety in this patient population. METHODS: Pharmacy records were used to identify 55 consecutive pediatric ICU patients who were diagnosed with delirium and received quetiapine. A comprehensive retrospective medical chart review was performed to collect data on demographics, dosing, and side effects. RESULTS: Fifty patients treated between January 2013 and November 2014 were included, and five patients were excluded from the study. Subjects ranged in age from 2 months to 20 years. Median daily dose was 1.3 mg/kg/day, and median duration of treatment was 12 days. There were three episodes of QTc prolongation that were clinically nonsignificant with no associated dysrhythmia: Two resolved over time without intervention, and one resolved with decrease in quetiapine dosage. There were no episodes of extrapyramidal symptoms or neuroleptic malignant syndrome. CONCLUSIONS: In this population of critically ill youth, short-term use of quetiapine as treatment for delirium appears to be safe, without serious adverse events. Further research is required to assess efficacy and evaluate for long-term effects. A prospective, randomized, placebo-controlled study of quetiapine in managing pediatric delirium is necessary.

Bacterial lipoprotein TLR2 agonists broadly modulate endothelial function and coagulation pathways in vitro and in vivo.

TLR2 activation induces cellular and organ inflammation and affects lung function. Because deranged endothelial function and coagulation pathways contribute to sepsis-induced organ failure, we studied the effects of bacterial lipoprotein TLR2 agonists, including peptidoglycan-associated lipoprotein, Pam3Cys, and murein lipoprotein, on endothelial function and coagulation pathways in vitro and in vivo. TLR2 agonist treatment induced diverse human endothelial cells to produce IL-6 and IL-8 and to express E-selectin on their surface, including HUVEC, human lung microvascular endothelial cells, and human coronary artery endothelial cells. Treatment of HUVEC with TLR2 agonists caused increased monolayer permeability and had multiple coagulation effects, including increased production of plasminogen activator inhibitor-1 (PAI-1) and tissue factor, as well as decreased production of tissue plasminogen activator and tissue factor pathway inhibitor. TLR2 agonist treatment also increased HUVEC expression of TLR2 itself. Peptidoglycan-associated lipoprotein induced IL-6 production by endothelial cells from wild-type mice but not from TLR2 knockout mice, indicating TLR2 specificity. Mice were challenged with TLR2 agonists, and lungs and plasmas were assessed for markers of leukocyte trafficking and coagulopathy. Wild-type mice, but not TLR2 mice, that were challenged i.v. with TLR2 agonists had increased lung levels of myeloperoxidase and mRNAs for E-selectin, P-selectin, and MCP-1, and they had increased plasma PAI-1 and E-selectin levels. Intratracheally administered TLR2 agonist caused increased lung fibrin levels. These studies show that TLR2 activation by bacterial lipoproteins broadly affects endothelial function and coagulation pathways, suggesting that TLR2 activation contributes in multiple ways to endothelial activation, coagulopathy, and vascular leakage in sepsis.

MyD88-dependent and MyD88-independent pathways in synergy, priming, and tolerance between TLR agonists.

TLRs sense components of microorganisms and are critical host mediators of inflammation during infection. Different TLR agonists can profoundly alter inflammatory effects of one another, and studies suggest that the sequence of exposure to TLR agonists may importantly impact on responses during infection. We tested the hypothesis that synergy, priming, and tolerance between TLR agonists follow a pattern that can be predicted based on differential engagement of the MyD88-dependent (D) and the MyD88-independent (I) intracellular signaling pathways. Inflammatory effects of combinations of D and I pathway agonists were quantified in vivo and in vitro. Experiments used several D-specific agonists, an I-specific agonist (poly(I:C)), and LPS, which acts through both the D and I pathways. D-specific agonists included: peptidoglycan-associated lipoprotein, Pam3Cys, flagellin, and CpG DNA, which act through TLR2 (peptidoglycan-associated lipoprotein and Pam3Cys), TLR5, and TLR9, respectively. D and I agonists were markedly synergistic in inducing cytokine production in vivo in mice. All of the D-specific agonists were synergistic with poly(I:C) in vitro in inducing TNF and IL-6 production by mouse bone marrow-derived macrophages. Pretreatment of bone marrow-derived macrophages with poly(I:C) led to a primed response to subsequent D-specific agonists and vice versa, as indicated by increased cytokine production, and increased NF-kappaB translocation. Pretreatment with a D-specific agonist augmented LPS-induced IFN-beta production. All D-specific agonists induced tolerance to one another. Thus, under the conditions studied here, simultaneous and sequential activation of both the D and I pathways causes synergy and priming, respectively, and tolerance is induced by agonists that act through the same pathway.