bluuebunny/crossref_metadata_2025 huggingface dataset:
Scalp‐recorded high‐frequency oscillations in childhood sleep‐induced electrical status epilepticus
Authors: Kobayashi Katsuhiro , Watanabe Yoshiaki , Inoue Takushi , Oka Makio , Yoshinaga Harumi , Ohtsuka Yoko
Published: April 2010

Because high‐frequency oscillations (HFOs) may affect normal brain functions, we examined them using electroencephalography (EEG) in epilepsy with continuous spike‐waves during slow‐wave sleep (CSWS), a condition that can cause neuropsychological regression. In 10 children between 6 and 9 years of age with epilepsy with CSWS or related disorders, we investigated HFOs in scalp EEG spikes during slow‐wave sleep through temporal expansion of the EEG traces with a low‐cut frequency filter at 70 Hz as well as through time‐frequency power spectral analysis. HFOs (ripples) concurrent with spikes were detected in the temporally expanded traces, and the frequency of the high‐frequency peak with the greatest power in each patient’s spectra ranged from 97.7 to 140.6 Hz. This is the first report on the detection of HFOs from scalp EEG recordings in epileptic patients. We speculate that epileptic HFOs may interfere with higher brain functions in epilepsy with CSWS.
Epilepsy surgery, antiepileptic drug trials, and the role of evidence
Authors: Janszky Jozsef , Kovacs Norbert , Gyimesi Csilla , Fogarasi Andras , Doczi Tamás , Wiebe Samuel
Published: April 2010

Objective:  We assessed whether recent randomized controlled trials (RCTs) of antiepileptic drugs (AEDs) are informed by evidence about surgical effectiveness. We explored whether RCTs of AEDs consider the patients’ candidacy for surgery in their eligibility criteria, and whether the necessary investigations are requested in participating patients to determine their potential eligibility for surgery.

Methods:  We systematically analyzed RCTs published in the last 2 years investigating the efficacy of new AEDs in localization‐related epilepsy. Results from a surgical RCT and recommendations from an epilepsy surgery practice parameter were used to assess the degree to which surgical evidence informed the drug study design.

Results:  Eleven RCTs were analyzed. All were conducted in countries with access to epilepsy surgery. None of the studies required magnetic resonance imaging (MRI) with an epilepsy protocol or explicit statement of the epilepsy syndrome, which could lead to the identification of surgical candidates. Having temporal lobe epilepsy or being a potential surgical candidate were not exclusion criteria in any of the trials. The primary efficacy end point was the reduction in seizure frequency or responder rate. Seizure freedom was never the primary outcome, and it was reported in only seven studies. The pooled data analysis of these trials revealed that 1.9% of patients became seizure‐free on placebo and 4.4% on the study drug (p < 0.01).

Conclusions:  Important aspects of patient selection for new AED trials are not informed by the evidence about surgical effectiveness. Investigations that could lead to identification of patients for presurgical evaluation were not required in any of the studies.
Calibrating CAT Bonds for Mexican Earthquakes
Authors: Härdle Wolfgang Karl , Cabrera Brenda López
Published: April 2010

Abstract

This article examines the calibration of a real parametric catastrophe bond (CAT bond) for earthquakes sponsored by the Mexican government, which is of a high interest as it delivers several policy‐relevant findings. The results demonstrate that a combination of reinsurance and CAT bond is optimal in the sense that it provides coverage for a lower cost and lower exposure at default than reinsurance itself. A hybrid CAT bond for earthquakes is also priced in order to reduce the basis and moral risk borne by the sponsor and to reflect the value of the loss by several variables.
Synthesis of Nanotube Array Composed of an Amorphous Matrix Embedded with NaCl‐Type SiC Crystallites by Chemical Vapor Infiltration Techniques
Authors: Yang Wen , Su Yanjing , Araki Hiroshi , Abe Eiji , Suzuki Hiroshi , Noda Tetsuji
Published: April 2010

Highly dense oriented arrays of nanotubes were synthesized via a chemical vapor infiltration process using anodic alumina membrane as a template. The nanotubes have a unique granular structure, which is composed of SiC nanocrystals embedded in an amorphous matrix. X‐ray diffraction and high‐resolution transmission electron microscopy examinations both indicate an NaCl‐type crystalline structure of the SiC nanocrystals in the nanotubes. The process described here can be extended to the preparation of other nanomaterials that are suitable to be obtained via a vapor–solid approach.
An Optimized Composition for Making Dense Fused Silica Bodies from Highly Loaded Slurries Using Egg White and Sucrose
Authors: Mohanta Kalyani , Bhargava Parag
Published: April 2010

Fused silica slurries with a maximum ceramic loading of 70 vol% were prepared using aqueous premixes with egg white (0.5–1.5 vol%) and/or sucrose (5–20 vol%). The egg white and sucrose content in the premix were optimized to obtain a shear‐thinning slurry. Observation indicated the existence of an optimum composition (Si70_(S+E)10_E10), for which slurry viscosity was minimum. Thermal analysis confirms the interaction between egg white and sucrose molecules, which influence interparticle interaction and slurry properties. Green samples cast from optimum slurry composition exhibited the highest mechanical properties. Linear drying and sintering shrinkage of samples were 0.5% and 1.0%, respectively.
Low‐Temperature Formation of Ultra‐High‐Temperature Transition Metal Carbides from Salt–Polymer Precursors
Authors: Adamczak Andrea D. , Spriggs Adam A. , Fitch Danielle M. , Radovic Miladin , Grunlan Jaime C.
Published: April 2010

Refractory transition metal carbides were produced via carbothermal reduction of transition metal halides in a polymer precursor at low temperatures (<1200°C). This approach was used to generate TaC (Tm=3883°C), NbC (Tm=3610°C), and WC (Tm=2870°C) from TaBr5, NbBr5, and WCl4/WCl6, respectively. Solubility of transition metal halides and polymers in the same organic solvents allows for intimate mixing on the molecular level, which reduces the synthesis temperature. Greater than 90% TaC conversion was achieved by exposing a 50:50 weight ratio mixture of TaBr5 and polyimide (or polystyrene) to 1200°C for 1 h. Even at temperatures as low as 1000°C, the major product remains TaC. The ability to process these high‐temperature materials so simply, and at relatively low temperatures, makes them accessible for different applications requiring thermal protection such as coatings for metallic components of hypersonic aircraft, rocket engine components, fibers, or refractory containers.
Estimation of the High‐Temperature R Curve for Ceramics from Strength Measurements Including Specimens with Focused Ion Beam Notches
Authors: Fünfschilling Stefan , Fett Theo , Hoffmann Michael J. , Oberacker Rainer , Özcoban Hüseyin , Schneider Gerold A. , Brenner Patrice , Gerthsen Dagmar , Danzer Robert
Published: April 2010

For failure assessment of natural cracks caused by surface treatment, the crack resistance for very small crack extensions is necessary. In ceramics with strongly rising R curves, the initial part of a few micrometer crack propagation is of special interest. For this purpose, the use of very small sharp starter notches introduced by a focused ion beam is recommended. As an example, the initial R curve for gas‐pressure‐sintered silicon nitride at high temperature will be estimated. Whereas for V‐notched bending bars a fracture toughness of about 6–6.3 MPa·m1/2 was determined, the toughness for small strength‐relevant cracks was found to be KIc≅5.1 MPa·m1/2.
Synthesis of Tungsten Oxide Powders Via Thiourea‐Assisted Route: Tailoring from Hierarchical Microspheres to Mesoporously Structured Nanoparticles
Authors: Wu Wei‐Ting , Chen Jen‐Sue , Wu Jih‐Jen
Published: April 2010

Tungsten oxide powders with controlled micro‐to‐nanoscale features, i.e. from microspheres to mesoporous structure, have been synthesized using peroxopolytungstic acid (PTA) and thiourea. Using PTA alone, elliptical tungsten oxide microspindles are hierarchically assembled from rectangular nanoparticles (NPs) after heat treatment at 450°C. With an appropriate addition of thiourea into the PTA precursor, hierarchical microspheres are obtained through the aggregation of isotropic NP unit blocks. When the thiourea content in the precursor increases further, high‐surface‐area mesoporous tungsten oxides composed of well‐dispersed isotropic NPs can be synthesized. We suggest that thiourea acts as a capping agent for forming the isotropic NP unit blocks in the precursors. Moreover, gaseous species released at high temperatures through decomposition and oxidation of nonchelated thiourea in the precursor will suppress the aggregation of NP unit blocks. As a result, tungsten oxide powders in form of microspheres or mesoporous nanostructures can be tailored by the thiourea content in the precursor.
Disease Progression in Hemodynamically Stable Patients Presenting to the Emergency Department With Sepsis
Authors: Glickman Seth W. , Cairns Charles B. , Otero Ronny M. , Woods Christopher W. , Tsalik Ephraim L. , Langley Raymond J. , Van Velkinburgh Jennifer C. , Park Lawrence P. , Glickman Lawrence T. , Fowler Vance G. , Kingsmore Stephen F. , Rivers Emanuel P.
Published: April 2010

Background:  Aggressive diagnosis and treatment of patients presenting to the emergency department (ED) with septic shock has been shown to reduce mortality. To enhance the ability to intervene in patients with lesser illness severity, a better understanding of the natural history of the early progression from simple infection to more severe illness is needed.

Objectives:  The objectives were to 1) describe the clinical presentation of ED sepsis, including types of infection and causative microorganisms, and 2) determine the incidence, patient characteristics, and mortality associated with early progression to septic shock among ED patients with infection.

Methods:  This was a multicenter study of adult ED patients with sepsis but no evidence of shock. Multivariable logistic regression was used to identify patient factors for early progression to shock and its association with 30‐day mortality.

Results:  Of 472 patients not in shock at ED presentation (systolic blood pressure > 90 mm Hg and lactate < 4 mmol/L), 84 (17.8%) progressed to shock within 72 hours. Independent factors associated with early progression to shock included older age, female sex, hyperthermia, anemia, comorbid lung disease, and vascular access device infection. Early progression to shock (vs. no progression) was associated with higher 30‐day mortality (13.1% vs. 3.1%, odds ratio [OR] = 4.72, 95% confidence interval [CI] = 2.01 to 11.1; p ≤ 0.001). Among 379 patients with uncomplicated sepsis (i.e., no evidence of shock or any end‐organ dysfunction), 86 (22.7%) progressed to severe sepsis or shock within 72 hours of hospital admission.

Conclusions:  A significant portion of ED patients with less severe sepsis progress to severe sepsis or shock within 72 hours. Additional diagnostic approaches are needed to risk stratify and more effectively treat ED patients with sepsis.

ACADEMIC EMERGENCY MEDICINE 2010; 17:383–390 © 2010 by the Society for Academic Emergency Medicine
Can Computed Tomography Angiography of the Brain Replace Lumbar Puncture in the Evaluation of Acute‐onset Headache After a Negative Noncontrast Cranial Computed Tomography Scan?
Authors: McCormack Robert F. , Hutson Alan
Published: April 2010

Objectives:  The primary goal of evaluation for acute‐onset headache is to exclude aneurysmal subarachnoid hemorrhage (SAH). Noncontrast cranial computed tomography (CT), followed by lumbar puncture (LP) if the CT is negative, is the current standard of care. Computed tomography angiography (CTA) of the brain has become more available and more sensitive for the detection of cerebral aneurysms. This study addresses the role of CT/CTA versus CT/LP in the diagnostic workup of acute‐onset headache.

Methods:  This article reviews the recent literature for the prevalence of SAH in emergency department (ED) headache patients, the sensitivity of CT for diagnosing acute SAH, and the sensitivity and specificity of CTA for cerebral aneurysms. An equivalence study comparing CT/LP and CT/CTA would require 3,000 +  subjects. As an alternative, the authors constructed a mathematical probability model to determine the posttest probability of excluding aneurysmal or arterial venous malformation (AVM) SAH with a CT/CTA strategy.

Results:  SAH prevalence in ED headache patients was conservatively estimated at 15%. Representative studies reported CT sensitivity for SAH to be 91% (95% confidence interval [CI] = 82% to 97%) and sensitivity of CTA for aneurysm to be 97.9% (95% CI = 88.9% to 99.9%). Based on these data, the posttest probability of excluding aneurysmal SAH after a negative CT/CTA was 99.43% (95% CI = 98.86% to 99.81%).

Conclusions:  CT followed by CTA can exclude SAH with a greater than 99% posttest probability. In ED patients complaining of acute‐onset headache without significant SAH risk factors, CT/CTA may offer a less invasive and more specific diagnostic paradigm. If one chooses to offer LP after CT/CTA, informed consent for LP should put the pretest risk of a missed aneurysmal SAH at less than 1%.

ACADEMIC EMERGENCY MEDICINE 2010; 17:444–451 © 2010 by the Society for Academic Emergency Medicine
Cardiovascular and Metabolic Effects of High‐dose Insulin in a Porcine Septic Shock Model
Authors: Holger Joel S. , Dries David J. , Barringer Kelly W. , Peake Benjamin J. , Flottemesch Thomas J. , Marini John J.
Published: April 2010

Objectives:  High‐dose insulin (HDI) has inotropic and vasodilatory properties in various clinical conditions associated with myocardial depression. The authors hypothesized that HDI will improve the myocardial depression produced by severe septic shock and have beneficial effects on metabolic parameters. In an animal model of severe septic shock, this study compared the effects of HDI treatment to normal saline (NS) resuscitation alone.

Methods:  Ten pigs were randomized to an insulin (HDI) or NS group. All were anesthetized and instrumented to monitor cardiovascular function. In both arms, Escherichia coli endotoxin lipopolysaccharide (LPS) and NS infusions were begun. LPS was titrated to 20 μg/kg/hour over 30 minutes and continued for 5 hours, and saline was infused at 20 mL/kg/hour throughout the protocol. Dextrose (50%) was infused to maintain glucose in the 60–150 mg/dL range, and potassium was infused to maintain a level greater than 2.8 mmol/L. At 60 minutes, the HDI group received an insulin infusion titrated from 2 to 10 units/kg/hour over 40 minutes and continued at that rate throughout the protocol. Survival, heart rate (HR), mean arterial pressure (MAP), pulmonary artery and central venous pressure, cardiac output, central venous oxygen saturation (SVO2), and lactate were monitored for 5 hours (three pigs each arm) or 7 hours (two pigs each arm) or until death. Cardiac index, systemic vascular resistance (SVR), pulmonary vascular resistance (PVR), O2 delivery, and O2 consumption were derived from measured data. Outcomes from the repeated‐measures analysis were modeled using a mixed‐effects linear model that assumed normally distributed errors and a random effect at the subject level.

Results:  No significant baseline differences existed between arms at time 0 or 60 minutes. Survival was 100% in the HDI arm and 60% in the NS arm. Cardiovascular variables were significantly better in the HDI arm: cardiac index (p < 0.001), SVR (p < 0.003), and PVR (p < 0.01). The metabolic parameters were also significantly better in the HDI arm: SVO2 (p < 0.01), O2 delivery (p < 0.001), and O2 consumption (p < 0.001). No differences in MAP, HR, or lactate were found.

Conclusions:  In this animal model of endotoxemic‐induced septic shock that results in severe myocardial depression, HDI is associated with improved cardiac function compared to NS resuscitation alone. HDI also demonstrated favorable metabolic, pulmonary, and peripheral vascular effects. Further studies may define a potential role for the use of HDI in the resuscitation of septic shock.

ACADEMIC EMERGENCY MEDICINE 2010; 17:429–435 © 2010 by the Society for Academic Emergency Medicine
Thirty‐day Outcomes of Emergency Department Patients Undergoing Electrical Cardioversion for Atrial Fibrillation or Flutter
Authors: Xavier Scheuermeyer Frank , Grafstein Eric , Stenstrom Rob , Innes Grant , Poureslami Iraj , Sighary Maziar
Published: April 2010

Objectives:  While the short‐term (<7‐day) safety and efficiency of electrical cardioversion for emergency department (ED) patients with atrial fibrillation or flutter have been established, the 30‐day outcomes with respect to stroke, thromboembolic events, or death have not been investigated.

Methods:  A two‐center cohort of consecutive ED patients undergoing cardioversion for atrial fibrillation or flutter between January 1, 2000, and September 30, 2007, was retrospectively investigated. This cohort was probabilistically linked with both a regional ED database and the provincial health registry to determine which patients had a subsequent ED visit or hospital admission, stroke, or thromboembolic event or died within 30 days. In addition, trained reviewers performed a detailed chart abstraction on 150 randomly selected patients, with emphasis on demographics, vital signs, medical treatment, and predefined adverse events. Hemodynamically unstable patients or those whose condition was the result of an underlying acute medical diagnosis were excluded. Data were analyzed by descriptive methods.

Results:  During the study period, 1,233 patients made 1,820 visits for atrial fibrillation or flutter to the ED. Of the 400 eligible patients undergoing direct‐current cardioversion (DCCV), no patients died, had a stroke, or had a thromboembolic event in the following 30 days (95% confidence interval [CI] = 0.0 to 0.8% for all outcomes). A total of 141 patients were included in the formal chart review, with five patients (3.5%, 95% CI = 0.5% to 6.6%) failing cardioversion, six patients (4.3%, 95% CI = 0.9% to 7.6%) having a minor adverse event that did not change disposition, and five patients (3.5%, 95% CI = 0.5% to 6.6%) admitted to hospital at the index visit.

Conclusions:  Cardioversion of patients with atrial fibrillation or flutter in the ED appears to have a very low rate of long‐term complications.

ACADEMIC EMERGENCY MEDICINE 2010; 17:408–415 © 2010 by the Society for Academic Emergency Medicine
Prospective Multicenter Study of Bronchiolitis: Predictors of an Unscheduled Visit After Discharge From the Emergency Department
Authors: Norwood Agatha , Mansbach Jonathan M. , Clark Sunday , Waseem Muhammad , Camargo Carlos A.
Published: April 2010

Objectives:  There is little evidence about which children with bronchiolitis will have worsened disease after discharge from the emergency department (ED). The objective of this study was to determine predictors of post‐ED unscheduled visits.

Methods:  The authors conducted a prospective cohort study of patients discharged from 2004 to 2006 at 30 EDs in 15 U.S. states. Inclusion criteria were diagnosis of bronchiolitis, age <2 years, and discharge home; the exclusion criterion was previous enrollment. Unscheduled visits were defined as urgent visits to an ED/clinic for worsened bronchiolitis within 2 weeks.

Results:  Of 722 patients eligible for the current analysis, 717 (99%) had unscheduled visit data, of whom 121 (17%; 95% confidence interval [CI] = 14% to 20%) had unscheduled visits. Unscheduled visits were more likely for children age <2 months (11% vs. 6%; p = 0.04), males (70% vs. 57%; p = 0.007), and those with history of hospitalization (27% vs. 18%; p = 0.01). The two groups were similar in other demographic and clinical factors (all p > 0.10). Using multivariable logistic regression, independent predictors of unscheduled visits were age <2 months, male, and history of hospitalization.

Conclusions:  In this study of children age younger than 2 years with bronchiolitis, one of six children had unscheduled visits within 2 weeks of ED discharge. The three predictors of unscheduled visits were age under 2 months, male sex, and previous hospitalization.

ACADEMIC EMERGENCY MEDICINE 2010; 17:376–382 © 2010 by the Society for Academic Emergency Medicine
Surface Cooling for Rapid Induction of Mild Hypothermia After Cardiac Arrest: Design Determines Efficacy
Authors: Uray Thomas , Haugk Moritz , Sterz Fritz , Arrich Jasmin , Richling Nina , Janata Andreas , Holzer Michael , Behringer Wilhelm
Published: April 2010

Objectives:  Recently, a novel cooling pad was developed for rapid induction of mild hypothermia after cardiac arrest. The aim of this study was to evaluate the cooling efficacy of three different pad designs for in‐hospital cooling.

Methods:  Included in this prospective interventional study were patients with esophageal temperature (Tes) > 34°C on admission. The cooling pad consists of multiple cooling units, filled with a combination of graphite and water, which is precooled to –18°C (design A) or to –9°C (designs B and C) before use. The designs of the cooling pad differed in number, shape, and thickness of the cooling units, with weights of 9.7 kg (design A), 5.3 kg (design B), and 6.2 kg (design C). All three designs were tested in sequential order and were changed according to the results found in the previous trial. Cooling was started after admission until Tes = 34°C, when the cooling pad was removed. The target temperature of Tes = 32–34°C was maintained for 24 hours. Data are presented as medians and interquartile ranges (IQRs = 25%–75%) or proportions.

Results:  Cooling rates were 3.4°C/hour (IQR = 2.5–3.7) with design A (n = 12), 2.8°C/hour (IQR = 1.6–3.3) with design B (n = 7), and 2.9°C/hour (IQR = 1.9–3.6) with design C (n = 10; p = 0.5). To reach 34°C, the cooling pad had to be exchanged with a new one due to melting and therefore depleting cooling capacity in three patients with design A, in five patients with design B, and in no patient with design C (p = 0.004).

Conclusions:  With adequate design and storage temperature, the cooling pad proved to be efficient for rapid in‐hospital cooling of patients resuscitated from cardiac arrest.

ACADEMIC EMERGENCY MEDICINE 2010; 17:360–367 © 2010 by the Society for Academic Emergency Medicine
Tissue Oxygenation Does Not Predict Central Venous Oxygenation in Emergency Department Patients With Severe Sepsis and Septic Shock
Authors: Napoli Anthony M. , Machan Jason T. , Forcada Ahteri , Corl Keith , Gardiner Fenwick
Published: April 2010

Objectives:  This study sought to determine whether tissue oxygenation (StO2) could be used as a surrogate for central venous oxygenation (ScVO2) in early goal‐directed therapy (EGDT).

Methods:  The study enrolled a prospective convenience sample of patients aged ≥18 years with sepsis and systolic blood pressure <90 mm Hg after 2 L of normal saline or lactate >4 mmol, who received a continuous central venous oximetry catheter. StO2 and ScVO2 were measured at 15‐minute intervals. Data were analyzed using a random coefficients model, correlations, and Bland‐Altman plots.

Results:  There were 284 measurements in 40 patients. While a statistically significant relationship existed between StO2 and ScVO2 (F(1,37) = 10.23, p = 0.002), StO2 appears to systematically overestimate at lower ScVO2 and underestimate at higher ScVO2. This was reflected in the fixed effect slope of 0.49 (95% confidence interval [CI] = 0.266 to 0.720) and intercept of 34 (95% CI = 14.681 to 50.830), which were significantly different from 1 and 0, respectively. The initial point correlation (r = 0.5) was fair, but there was poor overall agreement (bias = 4.3, limits of agreement = −20.8 to 29.4).

Conclusions:  Correlation between StO2 and ScVO2 was fair. The two measures trend in the same direction, but clinical use of StO2 in lieu of ScVO2 is unsubstantiated due to large and systematic biases. However, these biases may reflect real physiologic states. Further research may investigate if these measures could be used in concert as prognostic indicators.

ACADEMIC EMERGENCY MEDICINE 2010; 17:349–352 © 2010 by the Society for Academic Emergency Medicine
The Association Between Hypothermia, Prehospital Cooling, and Mortality in Burn Victims
Authors: Singer Adam J. , Taira Breena R. , Thode Jr Henry C. , McCormack Jane E. , Shapiro Mark , Aydin Ani , Lee Christopher
Published: April 2010

Objectives:  Hypothermia is associated with increased morbidity and mortality in trauma victims. The prognostic value of hypothermia on emergency department (ED) presentation in burn victims is not well known. The objective of this study was to determine the incidence of hypothermia in burn victims and its association with mortality and hospital length of stay (LOS). The study also examined the potential causative role of prehospital cooling in hypothermic burn patients.

Methods:  This was a retrospective review of a county trauma registry. The county was both suburban and rural, with a population of 1.5 million and with one burn center. Burn patients between 1994 and 2007 who met trauma registry criteria were included. Demographic and clinical data including prehospital cooling, burn size and depth, and presence of inhalation injury were collected. Hypothermia was defined as a core body temperature of less than or equal to 35°C. Data analysis consisted of univariate associations between patient characteristics and hypothermia.

Results:  There were 1,215 burn patients from 1994 to 2007. Mean age (±standard deviation [±SD]) was 29 (±24) years, 67% were male, 248 (26.7%) had full‐thickness burns, and 24 (2.6%) had inhalation injury. Only 17 (1.8%) had a burn larger than 70% total body surface area (TBSA). A total of 929 (76%) patients had an initial ED temperature recorded. Only 15/929 (1.6%) burn patients had hypothermia on arrival, and all were mild (lowest temperature was 32.6°C). There was no association between sex, year, and presence of inhalation injury with hypothermia. Hypothermic patients were older (44 years vs. 29 years, p = 0.01), and median Injury Severity Score (ISS) was higher (25 vs. 4, p = 0.002) than for nonhypothermic patients. Hypothermia was present in 6/17 (35%) patients with a TBSA of 70% or greater and in 8/869 (0.9%) patients with a TBSA of <70% (p < 0.001). Mortality was higher in hypothermic patients (60% vs. 3%, p < 0.001). None of the hypothermic patients received prehospital cooling.

Conclusions:  Hypothermia on presentation to the ED was noted in 1.6% of all burn victims in this trauma registry. Hypothermia was more common in very large burns and was associated with high mortality. In this series, prehospital cooling did not appear to contribute to hypothermia.

ACADEMIC EMERGENCY MEDICINE 2010; 17:456–459 © 2010 by the Society for Academic Emergency Medicine
Prevalence of Herniation and Intracranial Shift on Cranial Tomography in Patients With Subarachnoid Hemorrhage and a Normal Neurologic Examination
Authors: Baraff Larry J. , Byyny Richard L. , Probst Marc A. , Salamon Noriko , Linetsky Michael , Mower William R.
Published: April 2010

Objectives:  Patients frequently present to the emergency department (ED) with headache. Those with sudden severe headache are often evaluated for spontaneous subarachnoid hemorrhage (SAH) with noncontrast cranial computed tomography (CT) followed by lumbar puncture (LP). The authors postulated that in patients without neurologic symptoms or signs, physicians could forgo noncontrast cranial CT and proceed directly to LP. The authors sought to define the safety of this option by having senior neuroradiologists rereview all cranial CTs in a group of such patients for evidence of brain herniation or midline shift.

Methods:  This was a retrospective study that included all patients with a normal neurologic examination and nontraumatic SAH diagnosed by CT presenting to a tertiary care medical center from August 1, 2001, to December 31, 2004. Two neuroradiologists, blinded to clinical information and outcomes, rereviewed the initial ED head CT for evidence of herniation or midline shift.

Results:  Of the 172 patients who presented to the ED with spontaneous SAH diagnoses by cranial CT, 78 had normal neurologic examinations. Of these, 73 had initial ED CTs available for review. Four of the 73 (5%; 95% confidence interval [CI] = 2% to 13%) had evidence of brain herniation or midline shift, including three (4%; 95% CI = 1% to 12%) with herniation. In only one of these patients was herniation or shift noted on the initial radiology report.

Conclusions:  Awake and alert patients with a normal neurologic examination and SAH may have brain herniation and/or midline shift. Therefore, cranial CT should be obtained before LP in all patients with suspected SAH.

ACADEMIC EMERGENCY MEDICINE 2010; 17:423–428 © 2010 by the Society for Academic Emergency Medicine
The Use of Impedance Cardiography in Predicting Mortality in Emergency Department Patients With Severe Sepsis and Septic Shock
Authors: Napoli Anthony M. , Machan Jason T. , Corl Keith , Forcada Ahteri
Published: April 2010

Objectives:  Pulmonary artery catheterization poses significant risks and requires specialized training. Technological advances allow for more readily available, noninvasive clinical measurements of hemodynamics. Few studies exist that assess the efficacy of noninvasive hemodynamic monitoring in sepsis patients. The authors hypothesized that cardiac index, as measured noninvasively by impedance cardiography (ICG) in emergency department (ED) patients undergoing early goal‐directed therapy (EGDT) for sepsis, would be associated with in‐hospital mortality.

Methods:  This was a prospective observational cohort study of patients age over 18 years meeting criteria for EGDT (lactate > 4 or systolic blood pressure < 90 after 2 L of normal saline). Initial measurements of cardiac index were obtained by ICG. Patients were followed throughout their hospital course until discharge or in‐hospital death. Cardiac index measures in survivors and nonsurvivors are presented as means and 95% confidence intervals (CI). Diagnostic performance of ICG in predicting mortality was tested by receiver operating characteristic (ROC) curve and areas under the ROC curves (AUC) were compared using Wilcoxon test.

Results:  Fifty‐six patients were enrolled; one was excluded due to an inability to complete data acquisition. The mean cardiac index in nonsurvivors (2.3 L/min·m2, 95% CI = 1.6 to 3.0) was less than that for survivors (3.2, 95% CI = 2.9 to 3.5) with mean difference of 0.9 (95% CI = 0.12 to 1.71). The AUC for ICG in predicting mortality was 0.71 (95% CI = 0.58 to 0.88; p = 0.004). A cardiac index of < 2 L/min·m2 had a sensitivity of 43% (95% CI = 18% to 71%), specificity of 93% (95% CI = 80% to 95%), positive likelihood ratio of 5.9, and negative likelihood ratio of 0.6 for predicting in‐hospital mortality.

Conclusions:  Early, noninvasive measurement of the cardiac index in critically ill severe sepsis and septic shock patients can be performed in the ED for those who meet criteria for EGDT. There appears to be an association between an initial lower cardiac index as measured noninvasively and in‐hospital mortality.

ACADEMIC EMERGENCY MEDICINE 2010; 17:452–455 © 2010 by the Society for Academic Emergency Medicine
The Usefulness of Design of Experimentation in Defining the Effect Difficult Airway Factors and Training Have on Simulator Oral–Tracheal Intubation Success Rates in Novice Intubators
Authors: Thomas Frank , Carpenter Judi , Rhoades Carol , Holleran Renee , Snow Gregory
Published: April 2010

Objectives:  This exploratory study examined novice intubators and the effect difficult airway factors have on pre‐ and posttraining oral–tracheal simulation intubation success rates.

Methods:  Using a two‐level, full‐factorial design of experimentation (DOE) involving a combination of six airway factors (curved vs. straight laryngoscope blade, trismus, tongue edema, laryngeal spasm, pharyngeal obstruction, or cervical immobilization), 64 airway scenarios were prospectively randomized to 12 critical care nurses to evaluate pre‐ and posttraining first‐pass intubation success rates on a simulator. Scenario variables and intubation outcomes were analyzed using a generalized linear mixed‐effects model to determine two‐way main and interactive effects.

Results:  Interactive effects between the six study factors were nonsignificant (p = 0.69). For both pre‐ and posttraining, main effects showed the straight blade (p = 0.006), tongue edema (p = 0.0001), and laryngeal spasm (p = 0.004) significantly reduced success rates, while trismus (p = 0.358), pharyngeal obstruction (p = 0.078), and cervical immobilization did not significantly change the success rate. First‐pass intubation success rate on the simulator significantly improved (p = 0.005) from pre‐ (19%) to posttraining (36%).

Conclusions:  Design of experimentation is useful in analyzing the effect difficult airway factors and training have on simulator intubation success rates. Future quality improvement DOE simulator research studies should be performed to help clarify the relationship between simulator factors and patient intubation rates.

ACADEMIC EMERGENCY MEDICINE 2010; 17:460–463 © 2010 by the Society for Academic Emergency Medicine
Out‐of‐hospital Cardiac Arrest in Denver, Colorado: Epidemiology and Outcomes
Authors: Haukoos Jason S. , Witt Gary , Gravitz Craig , Dean Julianne , Jackson David M. , Candlin Thomas , Vellman Peter , Riccio John , Heard Kennon , Kazutomi Tom , Luyten Dylan , Pineda Gilbert , Gunter Jeff , Biltoft Jennifer , Colwell Christopher ,   for the Colorado Cardiac Arrest & Resuscitation Collaborative Study Group* and the Denver Metro EMS Medical Directors†
Published: April 2010

Objectives:  The annual incidence of out‐of‐hospital cardiac arrest (OOHCA) in the United States is approximately 6 per 10,000 population and survival remains low. Relatively little is known about the performance characteristics of a two‐tiered emergency medical services (EMS) system split between fire‐based basic life support (BLS) dispersed from fixed locations and hospital‐based advanced life support (ALS) dispersed from nonfixed locations. The objectives of this study were to describe the incidence of OOHCA in Denver, Colorado, and to define the prevalence of survival with good neurologic function in the context of this particular EMS system.

Methods:  This was a retrospective cohort study using standardized abstraction methodology. A two‐tiered hospital‐based EMS system for the County of Denver and 10 receiving hospitals were studied. Consecutive adult patients who experienced nontraumatic OOHCA from January 1, 2003, through December 31, 2004, were enrolled. Demographic, prehospital arrest characteristics, treatment data, and survival data using the Utstein template were collected. Good neurologic survival was defined by a Cerebral Performance Categories (CPC) score of 1 or 2.

Results:  During the study period, 1,985 arrests occurred. Of these, 715 (36%) had attempted resuscitation by paramedics and constitute our study sample. The median age was 65 years (interquartile range = 52–78 years), 69% were male, 41% had witnessed arrest, 25% had bystander cardiopulmonary resuscitation (CPR) performed, and 30% had ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) as their initial rhythm. Of the 715 patients, 545 (76%) were transported to a hospital, 223 (31%) had return of spontaneous circulation (ROSC), 175 (25%) survived to hospital admission, 58 (8%) survived to hospital discharge, and 42 (6%, 95% confidence interval [CI] = 4% to 8%) had a good neurologic outcome.

Conclusions:  Out‐of‐hospital cardiac arrest survival in Denver, Colorado, is similar to that of other United States communities. This finding provides the basis for future epidemiologic and health services research in the out‐of‐hospital and ED settings in our community.

ACADEMIC EMERGENCY MEDICINE 2010; 17:391–398 © 2010 by the Society for Academic Emergency Medicine
Effect of an Electronic Control Device Exposure on a Methamphetamine‐intoxicated Animal Model
Authors: Dawes Donald M. , Ho Jeffrey D. , Cole Jon B. , Reardon Robert F. , Lundin Erik J. , Terwey Karen S. , Falvey Dan G. , Miner James R.
Published: April 2010

Objectives: Because of the prevalence of methamphetamine abuse worldwide, it is not uncommon for subjects in law enforcement encounters to be methamphetamine‐intoxicated. Methamphetamine has been present in arrest‐related death cases in which an electronic control device (ECD) was used. The primary purpose of this study was to determine the cardiac effects of an ECD in a methamphetamine intoxication model.

Methods: Sixteen anesthetized Dorset sheep (26–78 kg) received 0.0 mg/kg (control animals,n = 4), 0.5 mg/kg (n = 4), 1.0 mg/kg (n = 4), or 1.5 mg/kg (n = 4) of methamphetamine hydrochloride as a slow intravenous (IV) bolus during continuous cardiac monitoring. The animals received the following exposures in sequence from a TASER X26 ECD beginning at 30 minutes after the administration of the drug: 1) 5‐second continuous exposure, 2) 15‐second intermittent exposure, 3) 30‐second intermittent exposure, and 4) 40‐second intermittent exposure. Darts were inserted at the sternal notch and the cardiac apex, to a depth of 9 mm. Cardiac motion was determined by thoracotomy (smaller animals, ≤ 32 kg) or echocardiography (larger animals, > 68 kg). Data were analyzed using descriptive statistics and chi‐square tests.

Results: Animals given methamphetamine demonstrated signs of methamphetamine toxicity with tachycardia, hypertension, and atrial and ventricular ectopy in the 30‐minute period immediately after administration of the drug. Smaller animals (n = 8, ≤ 32 kg, mean = 29.4 kg) had supraventricular dysrhythmias immediately after the ECD exposures. Larger animals (n = 8, > 68 kg, mean = 72.4) had only sinus tachycardia after the exposures. One of the smaller animals had frequent episodes of ventricular ectopy after two exposures, including runs of delayed onset, nonsustained six‐ to eight‐beat unifocal and multifocal ventricular tachycardia that spontaneously resolved. This animal had significant ectopy prior to the exposures as well. Thoracotomy performed on three smaller animals demonstrated cardiac capture during ECD exposure consistent with previous animal studies. In the larger animals, none of the methamphetamine‐intoxicated animals demonstrated cardiac capture. Two control sheep showed evidence of capture similar to the smaller animals. No ventricular fibrillation occurred after the exposure in any animal.

Conclusions: In smaller animals (32 kg or less), ECD exposure exacerbated atrial and ventricular irritability induced by methamphetamine intoxication, but this effect was not seen in larger, adult‐sized animals. There were no episodes of ventricular fibrillation after exposure associated with ECD exposure in methamphetamine‐intoxicated sheep.

ACADEMIC EMERGENCY MEDICINE 2010; 17:436–443 © 2010 by the Society for Academic Emergency Medicine
Complement Activation in Emergency Department Patients With Severe Sepsis
Authors: Younger John G. , Bracho David O. , Chung‐Esaki Hangyul M. , Lee Moonseok , Rana Gurpreet K. , Sen Ananda , Jones Alan E.
Published: April 2010

Objectives:  This study assessed the extent and mechanism of complement activation in community‐acquired sepsis at presentation to the emergency department (ED) and following 24 hours of quantitative resuscitation.

Methods:  A prospective pilot study of patients with severe sepsis and healthy controls was conducted among individuals presenting to a tertiary care ED. Resuscitation, including antibiotics and therapies to normalize central venous and mean arterial pressure (MAP) and central venous oxygenation, was performed on all patients. Serum levels of Factor Bb (alternative pathway), C4d (classical and mannose‐binding lectin [MBL] pathway), C3, C3a, and C5a were determined at presentation and 24 hours later among patients.

Results:  Twenty patients and 10 healthy volunteer controls were enrolled. Compared to volunteers, all proteins measured were abnormally higher among septic patients (C4d 3.5‐fold; Factor Bb 6.1‐fold; C3 0.8‐fold; C3a 11.6‐fold; C5a 1.8‐fold). Elevations in C5a were most strongly correlated with alternative pathway activation. Surprisingly, a slight but significant inverse relationship between illness severity (by sequential organ failure assessment [SOFA] score) and C5a levels at presentation was noted. Twenty‐four hours of structured resuscitation did not, on average, affect any of the mediators studied.

Conclusions:  Patients with community‐acquired sepsis have extensive complement activation, particularly of the alternative pathway, at the time of presentation that was not significantly reversed by 24 hours of aggressive resuscitation.

ACADEMIC EMERGENCY MEDICINE 2010; 17:353–359 © 2010 by the Society for Academic Emergency Medicine
Irradiance Uniformity and Distribution from Dental Light Curing Units
Authors: PRICE RICHARD B. T. , RUEGGEBERG FREDERICK A. , LABRIE DANIEL , FELIX CHRISTOPHER M.
Published: April 2010

Problem:  The irradiance from dental light‐curing units (LCUs) is commonly reported as a single number, but this number does not properly describe the light output.

Purpose:  This study examined the irradiance uniformity and distribution from a variety of LCUs as well as the effect of different light guides.

Materials and Methods:  Five LCUs representing quartz‐tungsten‐halogen, plasma arc, and light emitting diode units were evaluated. One LCU was evaluated using two different light guides (Standard or Turbo style). The total power emitted from each LCU was measured and the irradiance calculated using conventional methods (ICM). In addition, a beam profiler was used to determine the optically active emitting area, the mean irradiance (IBP), the irradiance distribution, and the Top Hat Factor (THF). Five replications were performed for each test and compared using analysis of variance with Fisher's PLSD tests at a pre‐set alpha of 0.05.

Results:  The spatial distribution of the irradiance from LCUs was neither universally symmetrical nor was it uniformly distributed across the tip end. Significant differences in both the emitted power and THF were found among the LCUs. The THF values ranged from a high of 0.74 ± 0.01 to a low of 0.32 ± 0.01. Changing from a standard to a turbo light guide increased the irradiance, but significantly reduced beam homogeneity, reduced the total emitted power, and reduced the optical tip area by 60%.

Conclusions:  Using different light guides on the same LCU significantly affected the power output, irradiance values, and beam homogeneity. For all LCUs, irradiance values calculated using conventional methods (ICM) did not represent the irradiance distribution across the tip end of the LCU.

CLINICAL SIGNIFICANCE

Irradiance values calculated using conventional methods assume power uniformity within the beam and do not validly characterize the distribution of the irradiance delivered from dental light curing units.

(J Esthet Restor Dent 22:86–103, 2010)
Effect of Finishing Instrumentation on the Marginal Integrity of Resin‐based Composite Restorations
Authors: MARESCA CRISTINA , PIMENTA LUIZ A. F. , HEYMANN HARALD O. , ZIEMIECKI THOMAS L. , RITTER ANDRÉ V.
Published: April 2010

Purpose:  This study evaluated the effect of the use of different finishing instruments on the marginal integrity of resin composite restorations.

Materials and Methods:  Bovine incisors (N = 75) embedded in epoxy resin had the facial enamel ground and polished to 1200‐grit. A standardized cavity (3 × 3 mm, 2 mm deep) was prepared on each specimen and restored with a 2‐step total‐etch adhesive (Single Bond, 3M ESPE, St. Paul, MN, USA) and a hybrid resin composite (Filtek Z250, 3M ESPE) in a single increment. The restorations were mechanically polished to 1200‐grit. Specimens were randomized into different groups (N = 5) according to finishing technique: positive control (1200‐grit paper), negative control (regular‐grit diamond), fine cross‐cut laminated burs, straight‐cut laminated burs, spiral‐cut laminated burs, and finishing diamonds. The straight‐cut burs, spiral‐cut burs, and finishing diamonds were tested individually as fine, extra‐fine, and ultra‐fine, as well as sequentially as a series. A high‐speed, water‐cooled handpiece under standardized pressure (0.5 N) and time (40 seconds) was used for all finishing procedures. Specimens were processed for scanning electron microscope, and margin gaps were systematically measured. Data were analyzed with one‐way analysis of variance and Duncan test.

Results:  The negative control specimens (course diamond) presented the largest gaps, whereas the positive control specimens (mechanically polished) generated the smallest gaps. No statistically significant difference was noted between the finishing diamonds and the positive control. The negative control exhibited significantly larger gaps when compared with the other finishing instruments. Intermediate results were observed for cross‐cut, straight‐cut, and spiral‐cut laminated burs. Fine, extra‐fine and ultra‐fine finishing diamonds generated smaller gaps compared with laminated burs, but the differences were not always statistically significant.

Conclusion:  Fine, extra‐fine and ultra‐fine finishing diamonds used to finish composite restorations generated better marginal integrity when compared with carbides and regular‐grit diamonds.

CLINICAL SIGNIFICANCE

When finishing composite restorations, finishing diamond burs result in better composite margins than carbide laminated burs.

(J Esthet Restor Dent 22:104–113, 2010)
Comparison of Various Resin Composite Shades and Layering Technique with a Shade Guide
Authors: DA COSTA JULIANA , FOX PAUL , FERRACANE JACK
Published: April 2010

Purpose: The purpose of this study was to compare the final shade of different shades of composites (enamel shades) over a white backing (WB) and black backing (BB), and a layering technique (enamel over dentin composite) with the corresponding Vita Classical Shade tabs (VST).

Materials and Methods: Composite disk specimens enamel (N = 5) shades B1, B2, A1, and A2, and dentin (N = 1) shades A1, A2, and A3 were made. The color of the VST B1, B2, A1, and A2, enamel shade disks, and layering composites of the same brand and different brands were assessed using a colorimeter over a WB and BB. The total color difference (ΔE*ab = [(ΔL*)2 + (Δa*ab)2 + (Δb*ab)2]1/2) between the VST and the corresponding resin composite was calculated. The results were analyzed by one‐way analysis of variance/Tukey's test (p < 0.05).

Results: Overall, theL*,a*, andb* values of the enamel composite shades were significantly different from the corresponding VST. Only a few layered composites matched theL*,a*, andb* of the keyed VST. Out of the 72 combinations, 20 (28%) resulted in ΔE*abbelow the 3.3 clinically perceptible limit.

CLINICAL SIGNIFICANCE

Composite shades do not match well to the Vita shade guide tabs, even when the layering technique is used. As demonstrated in this study, only a few composites matched the corresponding Vita shade guide tabs.

(J Esthet Restor Dent22:114–126, 2010)