- Pediatric Critical Care Medicine
Instructor, Pediatrics - Critical Care
Boards, Advisory Committees, Professional Organizations
Member, Maternal and Child Health Research Institute (MCHRI) (2018 - Present)
Member, American Academy of Pediatrics (2010 - Present)
Member, Society of Critical Care Medicine (2013 - Present)
Faculty, SCCM Critical Care Ultrasound (2014 - Present)
Residency: University of Washington Pediatric Residency (2013) WA
Medical Education: University of Missouri Kansas City School of Medicine Registrar (2010) MO
Board Certification: Pediatric Critical Care Medicine, American Board of Pediatrics (2016)
Fellowship: Johns Hopkins University Pediatric Critical Care Fellowship (2016) MD
Board Certification: Pediatrics, American Board of Pediatrics (2013)
Mitochondrial dysfunction mediated through dynamin-related protein 1 (Drp1) propagates impairment in blood brain barrier in septic encephalopathy.
Journal of neuroinflammation
2020; 17 (1): 36
Out of the myriad of complications associated with septic shock, septic-associated encephalopathy (SAE) carries a significant risk of morbidity and mortality. Blood-brain-barrier (BBB) impairment, which subsequently leads to increased vascular permeability, has been associated with neuronal injury in sepsis. Thus, preventing BBB damage is an attractive therapeutic target. Mitochondrial dysfunction is an important contributor of sepsis-induced multi-organ system failure. More recently, mitochondrial dysfunction in endothelial cells has been implicated in mediating BBB failure in stroke, multiple sclerosis and in other neuroinflammatory disorders. Here, we focused on Drp1-mediated mitochondrial dysfunction in endothelial cells as a potential target to prevent BBB failure in sepsis.We used lipopolysaccharide (LPS) to induce inflammation and BBB disruption in a cell culture as well as in murine model of sepsis. BBB disruption was assessed by measuring levels of key tight-junction proteins. Brain cytokines levels, oxidative stress markers, and activity of mitochondrial complexes were measured using biochemical assays. Astrocyte and microglial activation were measured using immunoblotting and qPCR. Transwell cultures of brain microvascular endothelial cells co-cultured with astrocytes were used to assess the effect of LPS on expression of tight-junction proteins, mitochondrial function, and permeability to fluorescein isothiocyanate (FITC) dextran. Finally, primary neuronal cultures exposed to LPS were assessed for mitochondrial dysfunction.LPS induced a strong brain inflammatory response and oxidative stress in mice which was associated with increased Drp1 activation and mitochondrial localization. Particularly, Drp1-(Fission 1) Fis1-mediated oxidative stress also led to an increase in expression of vascular permeability regulators in the septic mice. Similarly, mitochondrial defects mediated via Drp1-Fis1 interaction in primary microvascular endothelial cells were associated with increased BBB permeability and loss of tight-junctions after acute LPS injury. P110, an inhibitor of Drp1-Fis1 interaction, abrogated these defects, thus indicating a critical role for this interaction in mediating sepsis-induced brain dysfunction. Finally, LPS mediated a direct toxic effect on primary cortical neurons, which was abolished by P110 treatment.LPS-induced impairment of BBB appears to be dependent on Drp1-Fis1-mediated mitochondrial dysfunction. Inhibition of mitochondrial dysfunction with P110 may have potential therapeutic significance in septic encephalopathy.
View details for DOI 10.1186/s12974-019-1689-8
View details for PubMedID 31987040
Cardiac Dysfunction Identified by Strain Echocardiography Is Associated With Illness Severity in Pediatric Sepsis.
Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies
Sepsis-induced myocardial dysfunction has been associated with illness severity and mortality in pediatrics. Although early sepsis-induced myocardial dysfunction diagnosis could aid in hemodynamic management, current echocardiographic metrics for assessing biventricular function are limited in detecting early impairment. Strain echocardiography is a validated quantitative measure that can detect subtle perturbations in left ventricular and right ventricular function. This investigation evaluates the utility of strain echocardiography in pediatric sepsis and compares with to conventional methods.Retrospective, observational study comparing left ventricular and right ventricular strain. Strain was compared with ejection fraction and fractional shortening and established sepsis severity of illness markers.Tertiary care medical-surgical PICU from July 2013 to January 2018.Seventy-nine septic children and 28 healthy controls.None.Compared with healthy controls, patients with severe sepsis demonstrated abnormal left ventricular strain (left ventricular longitudinal strain: -13.0% ± 0.72; p = 0.04 and left ventricular circumferential strain: -16.5% ± 0.99; p = 0.046) and right ventricular (right ventricular longitudinal strain = -14.3% ± 6.3; p < 0.01) despite normal fractional shortening (36.0% ± 1.6 vs 38.1% ± 1.1; p = 0.5129) and ejection fraction (60.7% ± 2.2 vs 65.3% ± 1.5; p = 0.33). There was significant association between depressed left ventricular longitudinal strain and increased Vasotrope-Inotrope Score (r = 0.52; p = 0.034). Worsening left ventricular circumferential strain was correlated with higher lactate (r = 0.31; p = 0.03) and higher Pediatric Risk of Mortality-III score (r = 0.39; p < 0.01). Depressed right ventricular longitudinal strain was associated with elevated pediatric multiple organ dysfunction score (r = 0.44; p < 0.01) CONCLUSIONS:: Compared with healthy children, pediatric septic patients demonstrated abnormal left ventricular and right ventricular strain concerning for early signs of cardiac dysfunction. This was despite having normal ejection fraction and fractional shortening. Abnormal strain was associated with abnormal severity of illness markers. Strain echocardiography may have utility as an early indicator of sepsis-induced myocardial dysfunction in pediatric sepsis.
View details for DOI 10.1097/PCC.0000000000002247
View details for PubMedID 32084099
PERSEVERE Biomarkers Predict Severe Acute Kidney Injury and Renal Recovery in Pediatric Septic Shock.
American journal of respiratory and critical care medicine
Acute kidney injury (AKI), a common complication of sepsis, is associated with substantial morbidity and mortality and lacks definitive disease-modifying therapy. Early, reliable identification of at risk patients is important for targeted implementation of renal protective measures. PERSEVERE-II is a validated, multi-biomarker prognostic enrichment strategy to estimate baseline mortality risk in pediatric septic shock.To assess the association between PERSEVERE-II mortality probability and the development of severe, sepsis-associated AKI on day 3 (D3 SA-AKI) in pediatric septic shock.Secondary analysis of a prospective, observational study of children with septic shock in whom the PERSEVERE biomarkers were measured to assign a PERSEVERE-II baseline mortality risk.Among 379 patients, 65 (17%) developed severe D3 SA-AKI. The proportion of patients developing severe D3 SA-AKI increased directly with increasing PERSEVERE-II risk category, and increasing PERSEVERE-II mortality probability was independently associated with increased odds of severe D3 SA-AKI after adjustment for age and illness severity (OR 1.4, 95% CI: 1.2-1.7, p<0.001). Similar associations were found between increasing PERSEVERE-II mortality probability and the need for renal replacement therapy. Lower PERSEVERE-II mortality probability was independently associated with increased odds of renal recovery among patients with early AKI. A newly derived model incorporating the PERSEVERE biomarkers and day 1 AKI status predicted severe D3 SA-AKI with an AUROC of 0.95 (95% CI: 0.92 to 0.98).Among children with septic shock, the PERSEVERE biomarkers predict severe D3 SA-AKI and identify patients with early AKI who are likely to recover.
View details for DOI 10.1164/rccm.201911-2187OC
View details for PubMedID 31916857
ULTRASOUND-GUIDED IV PROGRAM IMPROVES FIRST STICK SUCCESS AND LONGEVITY IN CRITICALLY ILL CHILDREN
LIPPINCOTT WILLIAMS & WILKINS. 2020
View details for Web of Science ID 000530000201664
Early Use of Adjunctive Therapies for Pediatric Acute Respiratory Distress Syndrome: A PARDIE Study.
American journal of respiratory and critical care medicine
Little data exist to guide early adjunctive therapy use in pediatric acute respiratory distress syndrome (PARDS).To describe contemporary use of adjunctive therapies for early PARDS as a framework for future investigations.Pre-planned, sub-study of a prospective, international, cross-sectional observational study of children with PARDS from 100 centers over 10 study weeks.We investigated six adjunctive therapies for PARDS: continuous neuromuscular blockade (cNMB), corticosteroids, inhaled nitric oxide (iNO), prone positioning, high frequency oscillatory ventilation (HFOV), and extracorporeal membrane oxygenation (ECMO). Almost half (45%) of children with PARDS received at least one therapy. Variability was noted in the median starting oxygenation index (OI) of each therapy; corticosteroids started at the lowest OI (13.0 IQR:7.6, 22.0) and HFOV at the highest (25.7 IQR:16.7, 37.3). Continuous NMB was the most common, used in 31%, followed by iNO (13%), corticosteroids (10%), prone positioning (10%), HFOV (9%), and ECMO (3%). Steroids, iNO, and HFOV were associated with comorbidities. Prone positioning and HFOV were more common in middle-income countries and less frequently used in North America. The use of multiple ancillary therapies increased over the first 3 days of PARDS, but there was not an easily identifiable pattern of combination or order of use.The contemporary description of prevalence, combinations of therapies and oxygenation threshold for which the therapies are applied is important for design of future studies. Region of the world, income and comorbidities influence adjunctive therapy use and are important variables to include in PARDS investigations.
View details for DOI 10.1164/rccm.201909-1807OC
View details for PubMedID 32130867
Predicting Mortality in Children With Pediatric Acute Respiratory Distress Syndrome: A Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology Study.
Critical care medicine
Pediatric acute respiratory distress syndrome is heterogeneous, with a paucity of risk stratification tools to assist with trial design. We aimed to develop and validate mortality prediction models for patients with pediatric acute respiratory distress syndrome.Leveraging additional data collection from a preplanned ancillary study (Version 1) of the multinational Pediatric Acute Respiratory Distress syndrome Incidence and Epidemiology study, we identified predictors of mortality. Separate models were built for the entire Version 1 cohort, for the cohort excluding neurologic deaths, for intubated subjects, and for intubated subjects excluding neurologic deaths. Models were externally validated in a cohort of intubated pediatric acute respiratory distress syndrome patients from the Children's Hospital of Philadelphia.The derivation cohort represented 100 centers worldwide; the validation cohort was from Children's Hospital of Philadelphia.There were 624 and 640 subjects in the derivation and validation cohorts, respectively.None.The model for the full cohort included immunocompromised status, Pediatric Logistic Organ Dysfunction 2 score, day 0 vasopressor-inotrope score and fluid balance, and PaO2/FIO2 6 hours after pediatric acute respiratory distress syndrome onset. This model had good discrimination (area under the receiver operating characteristic curve 0.82), calibration, and internal validation. Models excluding neurologic deaths, for intubated subjects, and for intubated subjects excluding neurologic deaths also demonstrated good discrimination (all area under the receiver operating characteristic curve ≥ 0.84) and calibration. In the validation cohort, models for intubated pediatric acute respiratory distress syndrome (including and excluding neurologic deaths) had excellent discrimination (both area under the receiver operating characteristic curve ≥ 0.85), but poor calibration. After revision, the model for all intubated subjects remained miscalibrated, whereas the model excluding neurologic deaths showed perfect calibration. Mortality models also stratified ventilator-free days at 28 days in both derivation and validation cohorts.We describe predictive models for mortality in pediatric acute respiratory distress syndrome using readily available variables from day 0 of pediatric acute respiratory distress syndrome which outperform severity of illness scores and which demonstrate utility for composite outcomes such as ventilator-free days. Models can assist with risk stratification for clinical trials.
View details for DOI 10.1097/CCM.0000000000004345
View details for PubMedID 32271186
Western diet regulates immune status and the response to LPS-driven sepsis independent of diet-associated microbiome.
Proceedings of the National Academy of Sciences of the United States of America
2019; 116 (9): 3688–94
Sepsis is a deleterious immune response to infection that leads to organ failure and is the 11th most common cause of death worldwide. Despite plaguing humanity for thousands of years, the host factors that regulate this immunological response and subsequent sepsis severity and outcome are not fully understood. Here we describe how the Western diet (WD), a diet high in fat and sucrose and low in fiber, found rampant in industrialized countries, leads to worse disease and poorer outcomes in an LPS-driven sepsis model in WD-fed mice compared with mice fed standard fiber-rich chow (SC). We find that WD-fed mice have higher baseline inflammation (metaflammation) and signs of sepsis-associated immunoparalysis compared with SC-fed mice. WD mice also have an increased frequency of neutrophils, some with an "aged" phenotype, in the blood during sepsis compared with SC mice. Importantly, we found that the WD-dependent increase in sepsis severity and higher mortality is independent of the microbiome, suggesting that the diet may be directly regulating the innate immune system through an unknown mechanism. Strikingly, we could predict LPS-driven sepsis outcome by tracking specific WD-dependent disease factors (e.g., hypothermia and frequency of neutrophils in the blood) during disease progression and recovery. We conclude that the WD is reprogramming the basal immune status and acute response to LPS-driven sepsis and that this correlates with alternative disease paths that lead to more severe disease and poorer outcomes.
View details for PubMedID 30808756
Drp1/Fis1 interaction mediates mitochondrial dysfunction in septic cardiomyopathy.
Journal of molecular and cellular cardiology
Mitochondrial dysfunction is a key contributor to septic cardiomyopathy. Although recent literature implicates dynamin related protein 1 (Drp1) and its mitochondrial adaptor fission 1 (Fis1) in the development of pathologic fission and mitochondrial failure in neurodegenerative disease, little is known about the role of Drp1/Fis1 interaction in the context of sepsis-induced cardiomyopathy. Our study tests the hypothesis that Drp1/Fis1 interaction is a major driver of sepsis-mediated pathologic fission, leading to mitochondrial dysfunction in the heart.H9C2 cardiomyocytes were treated with lipopolysaccharide (LPS) to evaluate changes in mitochondrial membrane potential, oxidative stress, cellular respiration, and mitochondrial morphology. Balb/c mice were treated with LPS, cardiac function was measured by echocardiogaphy, and mitochondrial morphology determined by electron microscopy (EM). Drp1/Fis1 interaction was inhibited by P110 to determine whether limiting mitochondrial fission can reduce LPS-induced oxidative stress and cardiac dysfunction.LPS-treated H9C2 cardiomyocytes demonstrated a decrease in mitochondrial respiration followed by an increase in mitochondrial oxidative stress and a reduction in membrane potential. Inhibition of Drp1/Fis1 interaction with P110 attenuated LPS-mediated cellular oxidative stress and preserved membrane potential. In vivo, cardiac dysfunction in LPS-treated mice was associated with increased mitochondrial fragmentation. Treatment with P110 reduced cardiac mitochondrial fragmentation, prevented decline in cardiac function, and reduced mortality.Sepsis decreases cardiac mitochondrial respiration and membrane potential while increasing oxidative stress and inducing pathologic fission. Treatment with P110 was protective in both in vitro and in vivo models of septic cardiomyopathy, suggesting a key role of Drp1/Fis1 interaction, and a potential target to reduce its morbidity and mortality.
View details for PubMedID 30981733
Prospective clinical testing and experimental validation of the Pediatric Sepsis Biomarker Risk Model.
Science translational medicine
2019; 11 (518)
Sepsis remains a major public health problem with no major therapeutic advances over the last several decades. The clinical and biological heterogeneity of sepsis have limited success of potential new therapies. Accordingly, there is considerable interest in developing a precision medicine approach to inform more rational development, testing, and targeting of new therapies. We previously developed the Pediatric Sepsis Biomarker Risk Model (PERSEVERE) to estimate mortality risk and proposed its use as a prognostic enrichment tool in sepsis clinical trials; prognostic enrichment selects patients based on mortality risk independent of treatment. Here, we show that PERSEVERE has excellent performance in a diverse cohort of children with septic shock with potential for use as a predictive enrichment strategy; predictive enrichment selects patients based on likely response to treatment. We demonstrate that the PERSEVERE biomarkers are reliably associated with mortality in mice challenged with experimental sepsis, thus providing an opportunity to test precision medicine strategies in the preclinical setting. Using this model, we tested two clinically feasible therapeutic strategies, guided by the PERSEVERE-based enrichment, and found that mice identified as high risk for mortality had a greater bacterial burden and could be rescued by higher doses of antibiotics. The association between higher pathogen burden and higher mortality risk was corroborated among critically ill children with septic shock. This bedside to bench to bedside approach provides proof of principle for PERSEVERE-guided application of precision medicine in sepsis.
View details for DOI 10.1126/scitranslmed.aax9000
View details for PubMedID 31723040
Deciphering the Effects of Performing Ultrasound on Critically Ill Emergency Department Patients
Critical Care Explorations
View details for DOI 10.1097/CCE.0000000000000048
Low Left Atrial Strain Is Associated With Adverse Outcomes in Hypertrophic Cardiomyopathy Patients.
Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography
Paroxysmal atrial fibrillation (PAF) and left atrial (LA) structural remodeling are common in hypertrophic cardiomyopathy (HCM) patients, who are also at risk for adverse cardiovascular outcomes.We assessed whether PAF and/or LA remodeling was associated with adverse outcomes in HCM.We retrospectively studied 45 HCM patients with PAF (PAF group) and 59 HCM patients without atrial fibrillation (AF; no-AF group). LA/left ventricular (LV) function and mechanics were assessed by echocardiography. Patients were followed for development of the composite endpoint comprising heart failure, stroke, and death.Clinical/demographic characteristics, degree of LV hypertrophy, and E/e' were similar in the two groups The PAF group had significantly higher LA volume, but lower LA ejection fraction (LAEF), LA contractile, and reservoir strain/strain rate than the no-AF group. During follow-up, 27 patients developed the composite endpoint. Incidence of the composite endpoint was similar in the two groups. Absolute values of 23.8% for reservoir strain and 10.2% for conduit strain were the best cutoffs for the composite endpoint, using receiver operating characteristic analysis. Kaplan-Meier survival analysis showed lower event-free survival in patients with reservoir strain ≤23.8% or conduit strain ≤10.2%. Univariate Cox analysis revealed an association between female sex, LAEF, LA reservoir/conduit strain, and LV global longitudinal strain with the composite endpoint. The association between LA reservoir/conduit strain and the composite endpoint persisted after controlling for age, sex, LAEF, and LV global longitudinal strain.In this pilot HCM patient study, PAF was associated with a greater degree of LA myopathy, and low LA reservoir and conduit strain were associated with higher risk for adverse cardiovascular outcomes.
View details for PubMedID 30904367
ROLE OF DRP1/FIS1-MEDIATED MITOCHONDRIAL FRAGMENTATION IN SEPSIS-INDUCED MYOCARDIAL DYSFUNCTION
Society of Critical Care Medicine Congress
View details for DOI 10.1097/01.ccm.0000550833.50487.ba
INFRASTRUCTURE AND PRACTICE CHARACTERISTICS OF PEDIATRIC ECMO PROGRAMS ACROSS NORTH AMERICA
LIPPINCOTT WILLIAMS & WILKINS. 2019
View details for Web of Science ID 000498593402110
ROLE OF DRP1/FIS1-MEDIATED MITOCHONDRIAL FRAGMENTATION IN SEPSIS-INDUCED MYOCARDIAL DYSFUNCTION
LIPPINCOTT WILLIAMS & WILKINS. 2019
View details for Web of Science ID 000498593400042
Fragmented mitochondria released from microglia trigger A1 astrocytic response and propagate inflammatory neurodegeneration.
2019; 22 (10): 1635–48
In neurodegenerative diseases, debris of dead neurons are thought to trigger glia-mediated neuroinflammation, thus increasing neuronal death. Here we show that the expression of neurotoxic proteins associated with these diseases in microglia alone is sufficient to directly trigger death of naive neurons and to propagate neuronal death through activation of naive astrocytes to the A1 state. Injury propagation is mediated, in great part, by the release of fragmented and dysfunctional microglial mitochondria into the neuronal milieu. The amount of damaged mitochondria released from microglia relative to functional mitochondria and the consequent neuronal injury are determined by Fis1-mediated mitochondrial fragmentation within the glial cells. The propagation of the inflammatory response and neuronal cell death by extracellular dysfunctional mitochondria suggests a potential new intervention for neurodegeneration-one that inhibits mitochondrial fragmentation in microglia, thus inhibiting the release of dysfunctional mitochondria into the extracellular milieu of the brain, without affecting the release of healthy neuroprotective mitochondria.
View details for DOI 10.1038/s41593-019-0486-0
View details for PubMedID 31551592
Interaction of mitochondrial fission factor with dynamin related protein 1 governs physiological mitochondrial function in vivo.
2018; 8 (1): 14034
Mitochondria form a dynamic network governed by a balance between opposing fission and fusion processes. Because excessive mitochondrial fission correlates with numerous pathologies, including neurodegeneration, the mechanism governing fission has become an attractive therapeutic strategy. However, targeting fission is a double-edged sword as physiological fission is necessary for mitochondrial function. Fission is trigged by Drp1 anchoring to adaptors tethered to the outer mitochondrial membrane. We designed peptide P259 that distinguishes physiological from pathological fission by specifically inhibiting Drp1's interaction with the Mff adaptor. Treatment of cells with P259 elongated mitochondria and disrupted mitochondrial function and motility. Sustained in vivo treatment caused a decline in ATP levels and altered mitochondrial structure in the brain, resulting in behavioral deficits in wild-type mice and a shorter lifespan in a mouse model of Huntington's disease. Therefore, the Mff-Drp1 interaction is critical for physiological mitochondrial fission, motility, and function in vitro and in vivo. Tools, such as P259, that differentiate physiological from pathological fission will enable the examination of context-dependent roles of Drp1 and the suitability of mitochondrial fission as a target for drug development.
View details for PubMedID 30232469
Clinical Outcomes in Patients With Nonobstructive, Labile, and Obstructive Hypertrophic Cardiomyopathy.
Journal of the American Heart Association
View details for DOI 10.1161/JAHA.117.006657.
Drp1/Fis1-mediated mitochondrial fragmentation leads to lysosomal dysfunction in cardiac models of Huntington's disease.
Journal of molecular and cellular cardiology
2018; 127: 125–33
Huntington's disease (HD) is a fatal hereditary neurodegenerative disorder, best known for its clinical triad of progressive motor impairment, cognitive deficits and psychiatric disturbances, is caused by CAG-repeat expansion in exon 1 of Huntingtin (HTT). However, in addition to the neurological disease, mutant HTT (mHTT), which is ubiquitously expressed in all tissues, impairs other organ systems. Not surprisingly, cardiovascular dysautonomia as well as the deterioration of circadian rhythms are among the earliest detectable pathophysiological changes in individuals with HD. Mitochondrial dysfunction in the brain and skeletal muscle in HD has been well documented, as the disease progresses. However, not much is known about mitochondrial abnormalities in the heart. In this study, we describe a role for Drp1/Fis1-mediated excessive mitochondrial fission and dysfunction, associated with lysosomal dysfunction in H9C2 expressing long polyglutamine repeat (Q73) and in human iPSC-derived cardiomyocytes transfected with Q77. Expression of long polyglutamine repeat led to reduced ATP production and mitochondrial fragmentation. We observed an increased accumulation of damaged mitochondria in the lysosome that was coupled with lysosomal dysfunction. Importantly, reducing Drp1/Fis1-mediated mitochondrial damage significantly improved mitochondrial function and cell survival. Finally, reducing Fis1-mediated Drp1 recruitment to the mitochondria, using the selective inhibitor of this interaction, P110, improved mitochondrial structure in the cardiac tissue of R6/2 mice. We suggest that drugs focusing on the central nervous system will not address mitochondrial function across all organs, and therefore will not be a sufficient strategy to treat or slow down HD disease progression.
View details for DOI 10.1016/j.yjmcc.2018.12.004
View details for PubMedID 30550751
Diagnostic Bedside Ultrasound Program Development in Pediatric Critical Care Medicine: Results of a National Survey.
Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies
To assess current diagnostic bedside ultrasound program core element (training, credentialing, image storage, documentation, and quality assurance) implementation across pediatric critical care medicine divisions in the United States.Cross-sectional questionnaire-based needs assessment survey.Pediatric critical care medicine divisions with an Accreditation Council of Graduate Medical Education-accredited fellowship.Divisional leaders in education and/or bedside ultrasound training.None.Fifty-five of 67 pediatric critical care medicine divisions (82%) with an Accreditation Council of Graduate Medical Education-accredited fellowship provided responses. Overall, 63% of responding divisions (34/54) were clinically performing diagnostic bedside ultrasound studies with no difference between divisions with large versus small units. Diagnostic bedside ultrasound training is available for pediatric critical care medicine fellows within 67% of divisions (35/52) with no difference in availability between divisions with large versus small units. Other core elements were present in less than 25% of all divisions performing clinical studies, with a statistically significant increase in credentialing and documentation among divisions with large units (p = 0.048 and 0.01, respectively). All core elements were perceived to have not only high impact in program development but also high effort in implementation. Assuming that all structural elements could be effectively implemented within their division, 83% of respondents (43/52) agreed that diagnostic bedside ultrasound should be a core curricular component of fellowship education.Diagnostic bedside ultrasound is increasingly prevalent in training and clinical use across the pediatric critical care medicine landscape despite frequently absent core programmatic infrastructural elements. These core elements are perceived as important to program development, regardless of division unit size. Shared standardized resources may assist in reducing the effort in core element implementation and allow us to measure important educational and clinical outcomes.
View details for PubMedID 30113518
- EVALUATION OF STRAIN ECHOCARDIOGRAPHY IN PEDIATRIC SEPSIS LIPPINCOTT WILLIAMS & WILKINS. 2018: 742
Certification in Critical Care Echocardiography: The Evolution of an Emerging PICU Practice
PEDIATRIC CRITICAL CARE MEDICINE
2018; 19 (1): 88
View details for PubMedID 29303901
E/e' ratio and outcome prediction in hypertrophic cardiomyopathy: the influence of outflow tract obstruction.
European heart journal cardiovascular Imaging
2018; 19 (1): 101–7
Diastolic dysfunction is thought to be an important pathophysiologic component of hypertrophic cardiomyopathy (HCM). However, there are conflicting data on the potential value of the mitral E/e' ratio. We examined whether left ventricular outflow tract (LVOT) obstruction influences the value of E/e' in predicting outcomes in HCM.Patients who met diagnostic criteria for HCM were enrolled. Diastolic function was assessed with complete two-dimensional and Doppler echocardiography. A composite clinical outcome including new onset atrial fibrillation, sustained ventricular tachycardia/fibrillation, heart failure, transplantation, and death was examined over a mean follow-up period of 4.2 years. Among 604 patients, 206 patients had an E/e' level ≥20. Patients with higher septal E/e' level were older, with more severe NYHA class, and more severe LVOT obstruction. Higher E/e' was associated with worse event-free survival in non-obstructive group and total HCM cohort. In addition, E/e' and LVOT pressure gradient were highly correlated in non-obstructive and total HCM, but not in labile or obstructive group. During follow-up period, 95 patients underwent myectomy. Post-op E/e' correlated significantly with LVOT pressure gradient (R = 0.306, P = 0.004). In these patients, post-op E/e' was associated with worse event-free survival (log-rank P = 0.030).Assessment of E/e' is useful for risk stratification in HCM patients. Nevertheless, the predictive power is confounded by dynamic LVOT obstruction. Higher E/e' predicts worse clinical outcomes in non-obstructive HCM and in labile/obstructive after myectomy.
View details for DOI 10.1093/ehjci/jex134
View details for PubMedID 28977350
- Left Atrial Strain Predicts Adverse Outcomes in Hypertrophic Cardiomyopathy Circulation, American Heart Association's 2018 Scientific Sessions 2018: A17186
- EVALUATION OF THE TEMPORAL CHANGES IN CARDIAC BIOENERGETICS IN THE SETTING OF SEPSIS LIPPINCOTT WILLIAMS & WILKINS. 2018: 742
Certification in Critical Care Echocardiography: The Evolution of an Emerging PICU Practice.
Pediatr Crit Care Med.
2018 ; 19 ((1))
View details for DOI 10.1097/PCC.0000000000001381
Myocardial oxidative stress correlates with left ventricular dysfunction on strain echocardiography in a rodent model of sepsis.
Intensive care medicine experimental
2017; 5 (1): 21-?
Recognition of cardiomyopathy in sepsis can be challenging due to the limitations of conventional measures such as ejection fraction (EF) and fractional shortening (FS) in the context of variable preload and afterload conditions. This study correlates myocardial function using strain echocardiography (SE) with cardiomyocyte oxidative stress in a murine model of sepsis.C57BL/6J mice were randomized into control (n = 10), sham (n = 25), and a cecal ligation and puncture (CLP) (n = 33) model of sepsis. Echocardiography was performed pre-, 12, 24, and 48 h post-injury. Cardiac pro-inflammatory cytokines and mitochondrial redox scavenger expression were evaluated in a subset of each arm. To evaluate the influence of redox scavenger upregulation on oxidative injury and cardiac function, CLP was performed on mitochondrial catalase-upregulated C57BL/6J MCAT(+/+) mice (n = 12) and wild-type (WT) animals for comparison.Septic C57BL/6J mice exhibited depressed longitudinal strain (LS) when compared to sham and control at 24 h (p < 0.01) and 48 h (p = 0.04) post-CLP despite having a preserved EF. Furthermore, there was a significant association between increased odds of mortality and depressed LS (OR = 1.23, p = 0.04). Septic C57BL/6J mice concomitantly demonstrated increased expression of cardiomyocyte pro-inflammatory cytokines and decreased expression of redox scavengers at 24 and 48 h. When comparing C57Bl/6 MCAT (+/+) mice and C57BL/6J WT mice, a significant decrease in LS was identified in the WT mice at 24 h (MCAT = -23 ± 5% vs. WT = -15 ± 4% p < 0.01) and 48 h (MCAT = -23 ± 7% vs. WT = -15 ± 4.3% p = 0.04) post-CLP which correlated with significant increase in the level of cardiac oxidative stress following CLP.In this sepsis model, SE identified cardiomyopathy despite normal EF. SE depression temporally coincides with upregulation of inflammatory cytokines and decreases expression of key mitochondrial ROS scavengers. Upregulation of redox scavenger (CAT) abrogates oxidative stress and cardiac dysfunction in this sepsis model.
View details for DOI 10.1186/s40635-017-0134-5
View details for PubMedID 28405943
Role of Global Longitudinal Strain in Predicting Outcomes in Hypertrophic Cardiomyopathy.
The American journal of cardiology
2017; 120 (4): 670–75
Global longitudinal strain (GLS) is a sensitive indicator of global left ventricular function particularly in those with normal ejection fraction. We examined the potential value of GLS in predicting outcomes in hypertrophic cardiomyopathy (HC). Conventional and strain echocardiography was performed in 400 patients with HC followed for a median 3.1 years (interquartile range 1.2 to 5.6). Peak systolic strain from 3 apical views was averaged to calculate GLS. Patients were divided based on a previously published cutoff value of -16%. Additionally, we identified 4 HC subgroups based on GLS: GLS ≤ -20%, -20% < GLS ≤ -16%, -16% < GLS ≤ -10%, and GLS > -10%. The primary end point was a composite of new-onset sustained ventricular tachycardia/fibrillation, heart failure, cardiac transplantation, and all-cause death. Patients with GLS > -16% had significantly more events (17% vs 7%, p = 0.002). In the 4-group analysis, event rates increased with worsening GLS (5%, 7%, 14%, and 33%, respectively, p = 0.001). Event-free survival was significantly superior in those with GLS ≤ -16% versus GLS > -16% (p = 0.004); similarly, GLS > -10% portended a significantly worse event-free survival compared with each of the other 3 groups (p <0.01 for all pairwise comparisons). By univariate and multivariate Cox regression analysis, GLS remained significantly associated with the composite end point. GLS > -10% had 4 times the risk of events compared with GLS ≤ -16% (p = 0.006). In conclusion, echo-based GLS is independently associated with outcomes in HC. Patients with GLS > -10% have significantly higher event rates.
View details for DOI 10.1016/j.amjcard.2017.05.039
View details for PubMedID 28687124
Impact of peak provoked left ventricular outflow tract gradients on clinical outcomes in hypertrophic cardiomyopathy.
International journal of cardiology
2017; 243: 290–95
Hypertrophic cardiomyopathy (HCM) is traditionally classified based on a left ventricular outflow tract (LVOT) pressure gradient of 30mmHg at rest or with provocation. There are no data on whether 30mmHg is the most informative cut-off value and whether provoked gradients offer any information regarding outcomes.Resting and provoked peak LVOT pressure gradients were measured by Doppler echocardiography in patients fulfilling guidelines criteria for HCM. A composite clinical outcome including new onset atrial fibrillation, ventricular tachycardia/fibrillation, heart failure, transplantation, and death was examined over a median follow-up period of 2.1years.Among 536 patients, 131 patients had resting LVOT gradients greater than 30mmHg. Subjects with higher resting gradients were older with more cardiovascular events. For provoked gradients, a bi-modal risk distribution was found. Patients with provoked gradients >90mmHg (HR 3.92, 95% CI 1.97-7.79) or <30mmHg (HR 2.15, 95% CI 1.08-4.29) have more events compared to those with gradients between 30 and 89mmHg in multivariable analysis. The introduction of two cut-off points for provoked gradients allowed HCM to be reclassified into four groups: patients with "benign" latent HCM (provoked gradient 30-89mmHg) had the best prognosis, whereas those with persistent obstructive HCM had the worst outcome.Provoked LVOT pressure gradients offer additional information regarding clinical outcomes in HCM. Applying cut-off points at 30 and 90mmHg to provoked LVOT pressure gradients further classifies HCM patients into low-, intermediate- and high-risk groups.
View details for DOI 10.1016/j.ijcard.2017.04.039
View details for PubMedID 28747034
Strain Echocardiography Parameters Correlate With Disease Severity in Children and Infants With Sepsis
PEDIATRIC CRITICAL CARE MEDICINE
2016; 17 (5): 383-390
In the progression of severe sepsis, sepsis-induced myocardial dysfunction contributes to severity of illness and ultimate mortality. Identification of sepsis-induced myocardial dysfunction causing depressed cardiac function during critical illness has implications for ongoing patient management. However, assessing pediatric cardiac function traditionally relies on echocardiographic qualitative assessment and measurement of left ventricular ejection fraction or fractional shortening. These metrics are often insensitive for detecting early or regional myocardial dysfunction. Strain echocardiography is a contemporary echocardiographic modality that may be more sensitive to perturbations in cardiac function. This investigation hypothesizes that strain echocardiography metrics correlate with severity of illness in pediatric sepsis despite normal fractional shortening.Single-center retrospective observational study.Tertiary 36-bed medical/surgical PICU.Pediatric patients admitted with sepsis.None.Twenty-three children with sepsis received an echocardiogram in the study period. Patients with sepsis demonstrated abnormal peak systolic longitudinal strain for age (mean = -0.13 ± 0.07; p < 0.01) and low normal peak systolic circumferential strain (mean = -0.17 ± 0.14; p = 0.02) compared with internal controls as well as previously published normal values. Depressed strain was demonstrated in the septic patients despite having normal fractional shortening (mean = 0.41; 95% CI, 0.38-0.43). On initial echocardiographic imaging, worsening peak systolic longitudinal strain was associated with increasing lactate (p = 0.04).Pediatric patients with sepsis demonstrate evidence of depressed strain echocardiography parameters not shown by fractional shortening that correlate with clinical indices of sepsis severity. Whether strain echocardiography could eventually assist in grading pediatric sepsis severity and affect management is an area for potential future investigation.
View details for DOI 10.1097/PCC.0000000000000683
View details for Web of Science ID 000379595900008
View details for PubMedID 26963758
View details for PubMedCentralID PMC4856561
Oropharyngeal dermoid cyst in an infant with intermittent airway obstruction. A case report.
The neuroradiology journal
2014; 27 (5): 627-631
Dermoid cysts are benign epithelial inclusions and cystic lesions that may occur in several locations including the oropharynx. We describe the case of a two-month-old baby girl who presented with progressive respiratory distress, hypoxemia, and feeding difficulties because of an oropharyngeal dermoid cyst. The child had an airway work-up that included laryngoscopy. However, the mass remained undetected. This is most likely explained by the mobile nature of the lesion, prolapsing into the high nasopharynx in supine position. In our patient, magnetic resonance imaging (MRI), initially performed to rule out brainstem pathology, revealed an oropharyngeal dermoid cyst. This case shows the potential role of neuroimaging in the diagnostic work-up of a young child presenting with respiratory distress by excluding a central nervous system lesion and diagnosing an "unexpected" nasopharyngeal mass lesion. In addition, MRI allowed exclusion of skull base lesions of neural origin such as an anterior meningoencephalocele or heterotopic neuroglial tissue which would be managed differently from pharyngeal masses.
View details for DOI 10.15274/NRJ-2014-10085
View details for PubMedID 25260210
View details for PubMedCentralID PMC4237111
Fat Embolism: Evolution of Histopathological Changes in the Rat Lung
JOURNAL OF ORTHOPAEDIC RESEARCH
2010; 28 (2): 191-197
The pathophysiology of Fat Embolism Syndrome (FES) is poorly understood and subject to some controversy. Evaluation of the evolution of histological changes in the lungs of patients with FES is impractical. The current theories of FES were established through acute clinical observations and acute animal experiments, but sequential changes in the histology of lungs over a prolonged period have not been made. The progressive effects of fat embolization of the lungs were examined in a rat model over a period of 11 days. Triolein, a major bone marrow fat, was administered to conscious Sprague-Dawley rats via the caudal vein. Rats were euthanized at 24, 48, 96 h, and 11 days, but some died within a few hours. Histomorphometric evaluations of lung tissue were made, including stains for fat, collagen, and smooth muscle actin. Arterial and arteriolar patency decreased progressively up to 96 h, but returned toward normal after 11 days. A striking finding was the very early presence of inflammation and fibrosis after only several hours, persisting up to 11 days. The results of this study provide evidence of both very early and prolonged changes due to fat embolization.
View details for DOI 10.1002/jor.20963
View details for Web of Science ID 000273675700008
View details for PubMedID 19688870