7 results on '"Dennis W. Simon"'
Search Results
2. Association of Thromboelastography with Progression of Hemorrhagic Injury in Children with Traumatic Brain Injury
- Author
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Elissa Abou Khalil, Barbara A. Gaines, Robert G. Kellogg, Dennis W. Simon, Katrina M. Morgan, Ward M. Richardson, and Christine M. Leeper
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Neurology (clinical) ,Critical Care and Intensive Care Medicine - Abstract
Progression of hemorrhagic injury (PHI) in children with traumatic brain injury portends poor outcomes. The association between thromboelastography (TEG), functional coagulation assays, and PHI is not well characterized in children.This was a retrospective cohort study of children presenting with PHI at a pediatric level I academic trauma center from 2015 to 2020. Inclusion criteria were as follows: age less than 18 years, intracranial hemorrhage on admission head computed tomography scan, and admission rapid TEG assay and conventional coagulation tests. PHI was defined by the following radiographic criteria: any expansion of or new intracranial hemorrhage on subsequent head computed tomography scan. Rapid TEG values included Activated Clotting Time (ACT), alpha angle, maximum amplitude, and lysis at 30 min. Wilcoxon rank-sum test was used to assess baseline differences between groups with PHI and without PHI, including laboratory assays. Univariate analysis was performed to examine the association between variables of interest and PHI. Patients were dichotomized on the basis of this cut point to generate a "low ACT" group and a "high ACT" group. These variables were included in a multivariable logistic regression model to determine independent association with traumatic brain injury progression.In total, 219 patients met criteria for analysis. In this cohort, the median (interquartile range [IQR]) age = 6 (2-12) years, median (IQR) Injury Severity Score = 21 (11-27), 68% were boys, and 69% sustained blunt injury. The rate of PHI was 25% (54). Median (IQR) time to PHI was 1 (0-4) days. Children with PHI had a higher Injury Severity Score (p 0.001), lower Glasgow Coma Scale (p 0.001), greater incidence of shock (p = 0.04), and lower admission hemoglobin (p = 0.02) compared with those without PHI. Children with PHI had a higher International Normalized Ratio (INR) and longer TEG-ACT; other TEG values (alpha angle, maximum amplitude, and lysis at 30 min) were not associated with PHI. In the logistic regression model accounting for other covariates associated with PHI, elevated ACT remained an independent predictor of progression (odds ratio = 2.25, 95% confidence interval 1.09-4.66; p = 0.03; area under the receiver operating characteristic curve = 0.76). After adjusting for confounders, INR fell out of the model and was not an independent predictor of progression (odds ratio = 1.32, 95% confidence interval 0.60-2.93; p = 0.49).Although INR was elevated in children with PHI and has been associated with poor clinical outcomes, only admission TEG-ACT was independently associated with PHI. Further study is warranted to determine whether TEG-ACT reflects an actionable therapeutic target.
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- 2022
3. Temporal Patterns in Brain Tissue and Systemic Oxygenation Associated with Mortality After Severe Traumatic Brain Injury in Children
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Jaskaran, Rakkar, Justin, Azar, Jonathan H, Pelletier, Alicia K, Au, Michael J, Bell, Dennis W, Simon, Patrick M, Kochanek, Robert S B, Clark, and Christopher M, Horvat
- Abstract
Brain tissue hypoxia is an independent risk factor for unfavorable outcomes in traumatic brain injury (TBI); however, systemic hyperoxemia encountered in the prevention and/or response to brain tissue hypoxia may also impact risk of mortality. We aimed to identify temporal patterns of partial pressure of oxygen in brain tissue (PbtOData were extracted from the electronic medical record of a quaternary care children's hospital with a level I trauma center for patients ≤ 18 years old with severe TBI and the presence of PbtOA total of 138 intracranial pressure-monitored patients with TBI (median 5.0 [1.9-12.8] years; 65% boys; admission Glasgow Coma Scale score 4 [3-7]; mortality 18%), 71 with PbtOLower PbtO
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- 2022
4. Targeting 'Natural Born Killers' to Modulate Immune Suppression in Neurocritical Care
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Patrick M. Kochanek, Dennis W. Simon, and Mandy J. McGeachy
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medicine.medical_specialty ,Neurology ,Immune system ,business.industry ,medicine ,Neurointensive care ,Neurology (clinical) ,Neurosurgery ,Critical Care and Intensive Care Medicine ,Intensive care medicine ,business - Published
- 2021
5. Assessment of Dynamic Intracranial Compliance in Children with Severe Traumatic Brain Injury: Proof-of-Concept
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Michael S. Wolf, Dennis W. Simon, Christopher M. Horvat, Gilles Clermont, Patrick M. Kochanek, Robert S. B. Clark, and Jaskaran Rakkar
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Male ,medicine.medical_specialty ,Intracranial Pressure ,Traumatic brain injury ,Critical Care and Intensive Care Medicine ,03 medical and health sciences ,0302 clinical medicine ,Brain Injuries, Traumatic ,medicine ,Humans ,Glasgow Coma Scale ,Cerebral perfusion pressure ,Child ,Intracranial pressure ,Monitoring, Physiologic ,business.industry ,musculoskeletal, neural, and ocular physiology ,Head injury ,Pressure–volume index ,Neurointensive care ,Cerebral blood volume ,030208 emergency & critical care medicine ,medicine.disease ,nervous system diseases ,CO2 reactivity ,Brain Injuries ,Cerebrovascular Circulation ,Conventional PCI ,Emergency medicine ,Neurology (clinical) ,Neurosurgery ,business ,030217 neurology & neurosurgery ,Original Work - Abstract
Background and Aims Intracranial compliance refers to the relationship between a change in intracranial volume and the resultant change in intracranial pressure (ICP). Measurement of compliance is useful in managing cardiovascular and respiratory failure; however, there are no contemporary means to assess intracranial compliance. Knowledge of intracranial compliance could complement ICP and cerebral perfusion pressure (CPP) monitoring in patients with severe traumatic brain injury (TBI) and may enable a proactive approach to ICP management. In this proof-of-concept study, we aimed to capitalize on the physiologic principles of intracranial compliance and vascular reactivity to CO2, and standard-of-care neurocritical care monitoring, to develop a method to assess dynamic intracranial compliance. Methods Continuous ICP and end-tidal CO2 (ETCO2) data from children with severe TBI were collected after obtaining informed consent in this Institutional Review Board-approved study. An intracranial pressure-PCO2 Compliance Index (PCI) was derived by calculating the moment-to-moment correlation between change in ICP and change in ETCO2. As such, “good” compliance may be reflected by a lack of correlation between time-synched changes in ICP in response to changes in ETCO2, and “poor” compliance may be reflected by a positive correlation between changes in ICP in response to changes in ETCO2. Results A total of 978 h of ICP and ETCO2 data were collected and analyzed from eight patients with severe TBI. Demographic and clinical characteristics included patient age 7.1 ± 5.8 years (mean ± SD); 6/8 male; initial Glasgow Coma Scale score 3 [3–7] (median [IQR]); 6/8 had decompressive surgery; 7.1 ± 1.4 ICP monitor days; ICU length of stay (LOS) 16.1 ± 6.8 days; hospital LOS 25.9 ± 8.4 days; and survival 100%. The mean PCI for all patients throughout the monitoring period was 0.18 ± 0.04, where mean ICP was 13.7 ± 2.1 mmHg. In this cohort, PCI was observed to be consistently above 0.18 by 12 h after monitor placement. Percent time spent with PCI thresholds > 0.1, 0.2, and 0.3 were 62% [24], 38% [14], and 23% [15], respectively. The percentage of time spent with an ICP threshold > 20 mmHg was 5.1% [14.6]. Conclusions Indirect assessment of dynamic intracranial compliance in TBI patients using standard-of-care monitoring appears feasible and suggests a prolonged period of derangement out to 5 days post-injury. Further study is ongoing to determine if the PCI—a new physiologic index, complements utility of ICP and/or CPP in guiding management of patients with severe TBI. Electronic supplementary material The online version of this article (10.1007/s12028-020-01004-3) contains supplementary material, which is available to authorized users.
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- 2020
6. Targeting 'Natural Born Killers' to Modulate Immune Suppression in Neurocritical Care
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Dennis W, Simon, Mandy J, McGeachy, and Patrick M, Kochanek
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- 2021
7. Cerebrospinal Fluid NLRP3 is Increased After Severe Traumatic Brain Injury in Infants and Children
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Jessica Wallisch, Michael J. Bell, Dennis W. Simon, Robert S. B. Clark, Patrick M. Kochanek, and Hülya Bayır
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Male ,0301 basic medicine ,medicine.medical_specialty ,Neurology ,Adolescent ,Traumatic brain injury ,NLR Proteins ,Critical Care and Intensive Care Medicine ,Article ,03 medical and health sciences ,0302 clinical medicine ,Cerebrospinal fluid ,Brain Injuries, Traumatic ,NLR Family, Pyrin Domain-Containing 3 Protein ,medicine ,Humans ,Child ,Neuroinflammation ,Adaptor Proteins, Signal Transducing ,integumentary system ,medicine.diagnostic_test ,Lumbar puncture ,business.industry ,Glasgow Coma Scale ,Infant ,Hypothermia ,medicine.disease ,030104 developmental biology ,Child, Preschool ,Anesthesia ,Biomarker (medicine) ,Female ,Neurology (clinical) ,medicine.symptom ,Apoptosis Regulatory Proteins ,business ,Biomarkers ,030217 neurology & neurosurgery - Abstract
Inflammasome-mediated neuroinflammation may cause secondary injury following traumatic brain injury (TBI) in children. The pattern recognition receptors NACHT domain-, Leucine-rich repeat-, and PYD-containing Protein 1 (NLRP1) and NLRP3 are essential components of their respective inflammasome complexes. We sought to investigate whether NLRP1 and/or NLRP3 abundance is altered in children with severe TBI.Cerebrospinal fluid (CSF) from children (n = 34) with severe TBI (Glasgow coma scale score [GCS] ≤8) who had externalized ventricular drains (EVD) placed for routine care was evaluated for NLRP1 and NLRP3 at 0-24, 25-48, 49-72, and72 h post-TBI and was compared to infection-free controls that underwent lumbar puncture to rule out CNS infection (n = 8). Patient age, sex, initial GCS, mechanism of injury, treatment with therapeutic hypothermia, and 6-month Glasgow outcome score were collected.CSF NLRP1 was undetectable in controls and detected in 2 TBI patients at only24 h post-TBI. CSF NLRP3 levels were increased in TBI patients compared with controls at all time points, p 0.001. TBI patients ≤4 years of age had higher peak NLRP3 levels versus patients4 (15.50 [3.65-25.71] vs. 3.04 [1.52-8.87] ng/mL, respectively; p = 0.048). Controlling for initial GCS in multivariate analysis, peak NLRP36.63 ng/mL was independently associated with poor outcome at 6 months.In the first report of NLRP1 and NLRP3 in childhood neurotrauma, we found that CSF NLRP3 is elevated in children with severe TBI and independently associated with younger age and poor outcome. Future studies correlating NLRP3 with other markers of inflammation and response to therapy are warranted.
- Published
- 2017
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