bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of ultrasound-measured internal jugular vein collapsibility index to determine static intracardiac pressures in patients with presumed pulmonary hypertension
Authors: Parikh Raj , Spring Matthew , Weinberg Janice , Reardon Christine C. , Farber Harrison W. 
Published: October 2019

AbstractBackgroundBedside ultrasound helps to estimate volume status in critically ill patients and has traditionally relied on diameter, respiratory variation, and collapsibility of the inferior vena cava (IVC) to reflect fluid status. We evaluated collapsibility of the internal jugular vein (IJ) with ultrasound and correlated it with concomitant right heart catheterization (RHC) measurements in patients with presumed pulmonary hypertension.Methods and resultsWe studied 71 patients undergoing RHC for evaluation of pulmonary hypertension. Using two-dimensional ultrasound (Sonosite, Washington, USA), we measured the diameter of the IJ at rest, during respiratory variation, and during manual compression. Collapsibility index during respiration (respiratory CI) and during manual compression (compression CI) was calculated. We correlated mean right atrial pressure (mRAP) and pulmonary artery occlusion pressure (PAOP) defined by RHC measurements with respiratory and compression CI. A secondary goal was examining correlations between CI calculations and B-type natriuretic peptide (BNP) levels. Baseline characteristics demonstrated female predominance (n = 51; 71.8%), mean age 59.5 years, and BMI 27.3. There were significant correlations between decrease in compression CI and increase in both mRAP (Spearman: − 0.43;pvalue = 0.0002) and PAOP (Spearman: − 0.35;pvalue = 0.0027). In contrast, there was no significant correlation between respiratory CI and either mRAP (Spearman: − 0.14;pvalue = 0.35) or PAOP (Spearman:− 0.12;pvalue = 0.31). We also observed significant negative correlation between compression CI and BNP (Spearman: − 0.31;pvalue = 0.01) but not between respiratory CI and BNP (Spearman: − 0.12;pvalue = 0.35).ConclusionIncreasing use of ultrasound has led to innovative techniques for estimating volume status. While prior ultrasound studies have used clinical parameters to estimate fluid status, our study used RHC measurements and demonstrated that compression CI potentially reflects directly measured mRAP and PAOP.
Protocol for a systematic review and network meta-analysis of the management of new onset atrial fibrillation in critically unwell adult patients
Authors: Johnston Brian W. , Hill Ruaraidh , Duarte Rui , Chean Chung Shen , McAuley Danny F. , Blackwood Bronagh , Pace Nathan , Welters Ingeborg D. 
Published: October 2019

Abstract

Background
New onset atrial fibrillation is the most commonly encountered arrhythmia in critically unwell patients with a reported incidence of 4% to 29%. The occurrence of new onset atrial fibrillation may precipitate acute heart failure and lead to thromboembolic complications as well as being associated with increased in-hospital and in intensive care unit (ICU) mortality. Despite being common, much of our current knowledge regarding the treatment of new onset atrial fibrillation comes from patients with chronic atrial fibrillation or post cardiac surgery. It is unclear if management strategies in these patient cohorts can be applied to new onset atrial fibrillation in the general ICU. This protocol for a systematic review and network meta-analysis aims to address this uncertainty and define what is the most effective management strategy for the treatment of new onset atrial fibrillation (NOAF) in acutely unwell adult patients.

Methods
In this systematic review and network meta-analysis, we plan to search electronic databases (Cochrane Central Register of Controlled Trials [CENTRAL], MEDLINE, EMBASE, Science Citation Index Expanded on Web of Science and relevant trial registries) for relevant randomised and non-randomised trials. Citations will be reviewed by title, abstract and full text by two independent reviewers and disagreement resolved by discussion and a third independent reviewer, if necessary. The Cochrane Risk of Bias tool will be used to assess risk of bias in randomised trials and the Risk of Bias in Nonrandomised Studies of Interventions (ROBINS-I) tool will be used for non-randomised studies. Statistical analysis will be carried out using R package meta and netmeta. We will first conduct a pairwise meta-analysis. If conditions for indirect comparison are satisfied and suitable data are available, we will conduct network meta-analysis using frequentist methodology. Treatments will be ranked according to efficacy with associated P-scores. We will assess the quality of the evidence in the pairwise using GRADE methodology and network meta-analysis comparisons in the CINeMA module in R package meta.

Discussion
Our review will be the first to assess direct and indirect evidence to assess the efficacy and rank the treatments available for new onset atrial fibrillation in critically unwell patients. Our review findings will be applicable to the care of people in a range of acute settings including, ICU, the emergency department and acute medical units.

Systematic review registration
PROSPERO registry number: CRD42019121739.
Axial–Flexural Interaction in FRP-Wrapped RC Columns
Authors: Al-Nimry Hanan Suliman , Al-Rabadi Rabi Amer 
Published: October 2019

Abstract
The study reported herein aims at investigating the behavior of medium-scale circular reinforced concrete columns wrapped with fiber reinforced polymer (FRP) sheets under concentric and eccentric axial loads. The experimental program was devised to assess the effects of loading conditions, absence/presence of an FRP jacket as well as the FRP wrapping system. To achieve the study objectives, four column groups were tested under axial compression at 0, 25, 50 and 65 mm loading eccentricities corresponding to eccentricity-to-diameter ratios of 0, 0.13, 0.26 and 0.34, respectively. Specimens in a fifth group were tested in pure bending simulating axial compression at infinite loading eccentricities. Three column subcategories were tested under each of the 5 loading eccentricities: unwrapped; wrapped with one ply of hoop FRP sheets; and wrapped with two FRP plies with fibers oriented at 0 and 90° to the longitudinal column axis thereby providing externally-bonded longitudinal reinforcement and hoop confinement, respectively. Tests confirmed that FRP confinement enhances the axial–flexural column resistance even at large eccentricities that exceed the balanced state of unconfined columns. Although axial column resistance decreased with increasing bending moments, relative enhancements (25–35%) in axial resistance provided by FRP confinement were found to be more significant under eccentric loading than in pure compression. Compared to hoop FRP-confined columns, using additional longitudinal sheets resulted in minor (7–9%) but stable enhancements in axial resistance that were unaffected by the increase in loading eccentricity. The FRP hoop wraps had a minor effect on the flexural resistance of specimens tested in pure bending but managed to double their resistance when combined with the externally-bonded longitudinal FRP sheets. Finally, three stress–strain models of FRP-confined concrete were used in conventional section analysis to assess the axial–flexural interaction in the FRP-jacketed columns. Strength predictions made using the stress–strain model proposed in ACI 440.2R-17 design guidelines did not agree with the test results of the eccentrically-loaded columns and underestimated the moment resistance at a given axial force even when considering higher confinement ratios than those permitted by the guidelines. Strength predictions made using eccentricity-dependent stress–strain models showed better results especially when accounting for the increase in ultimate axial strains under eccentric loading.
[18F]-AV-1451 binding profile in chronic traumatic encephalopathy: a postmortem case series
Authors: Marquié Marta , Agüero Cinthya , Amaral Ana C. , Villarejo-Galende Alberto , Ramanan Prianca , Chong Michael Siao Tick , Sáez-Calveras Nil , Bennett Rachel E. , Verwer Eline E. , Kim Sally Ji Who , Dhaynaut Maeva , Alvarez Victor E. , Johnson Keith A. , McKee Ann C. , Frosch Matthew P. , Gómez-Isla Teresa 
Published: October 2019

Abstract

Introduction
Chronic traumatic encephalopathy (CTE) is a tauopathy associated to repetitive head trauma. There are no validated in vivo biomarkers of CTE and a definite diagnosis can only be made at autopsy. Recent studies have shown that positron emission tomography (PET) tracer AV-1451 (Flortaucipir) exhibits high binding affinity for paired helical filament (PHF)-tau aggregates in Alzheimer (AD) brains but relatively low affinity for tau lesions in other tauopathies like temporal lobal degeneration (FTLD)-tau, progressive supranuclear palsy (PSP) or corticobasal degeneration (CBD). Little is known, however, about the binding profile of this ligand to the tau-containing lesions of CTE.

Objective
To study the binding properties of [18F]-AV-1451 on pathologically confirmed CTE postmortem brain tissue samples.

Methods
We performed [18F]-AV-1451 phosphor screen and high resolution autoradiography, quantitative tau measurements by immunohistochemistry and Western blot and tau seeding activity assays in brain blocks containing hippocampus, superior temporal cortex, superior frontal cortex, inferior parietal cortex and occipital cortex from 5 cases of CTE, across the stages of disease: stage II-III (n = 1), stage III (n = 3), and stage IV (n = 1). Importantly, low or no concomitant classic AD pathology was present in these brains.

Results
Despite the presence of abundant tau aggregates in multiple regions in all CTE brains, only faint or no [18F]-AV-1451 binding signal could be detected by autoradiography. The only exception was the presence of a strong signal confined to the region of the choroid plexus and the meninges in two of the five cases. Tau immunostaining and Thioflavin-S staining ruled out the presence of tau aggregates in those regions. High resolution nuclear emulsion autoradiography revealed the presence of leptomeningeal melanocytes as the histologic source of this off-target binding. Levels of abnormally hyperphosphorylated tau species, as detected by Western Blotting, and tau seeding activity were both found to be lower in extracts from cases CTE when compared to AD.

Conclusion
AV-1451 may have limited utility for in vivo selective and reliable detection of tau aggregates in CTE. The existence of disease-specific tau conformations may likely explain the differential binding affinity of this tracer for tau lesions in different tauopathies.
Occurrence of F region echoes for the polar cap SuperDARN radars
Authors: Koustov Alexander V. , Ullrich Sydney , Ponomarenko Pavlo V. , Nishitani Nozomu , Marcucci Federica M. , Bristow William A. 
Published: October 2019

Abstract
Observations by six Super Dual Auroral Radar Network (SuperDARN) polar cap radars, three in the northern hemisphere and three in the southern hemispheres, are considered to assess F region echo occurrence rates over solar, season, and day cycles and to establish relationship between the echo occurrence rate and the background electron density and plasma flow velocity magnitude. The echo occurrence rate is shown to increase toward the solar cycle maximum, more distinctly on the nightside, consistent with a general trend of the background electron density. Over the last 5 years, the echo occurrence rates decline at a rate of 5–10% per year. The pattern of seasonal and diurnal variations in echo occurrence is found to be consistent with previous SuperDARN publications. Minor dips in echo occurrence rate are observed in winter solstices, and these are related to an overall decrease in the electron density. In most of the time sectors, the echo occurrence rate increases with the electron density but only up to a certain threshold value after which the dependence saturates. The level of the saturation depends on season, local time, and average plasma flow velocity magnitude. For the summer daytime observations, the echo occurrence rate correlates with variations of both electron density and plasma flow velocity magnitude.
Prescribed burning in a mediterranean-climate region mitigates the disturbance by bushfire to a critical food resource for an endangered bird, the Carnaby’s cockatoo
Authors: Densmore Valerie S. , Clingan Emma S. 
Published: October 2019

Abstract

Background
Prescribed burning is used to reduce fire hazard in highly flammable vegetation types, including Banksia L.f. woodland that occurs on the Swan Coastal Plain (SCP), Western Australia, Australia. The 2016 census recorded well over 1.9 million people living on the SCP, which also encompasses Perth, the fourth largest city in Australia. Banksia woodland is prone to frequent ignitions that can cause extensive bushfires that consume canopy-stored banksia seeds, a critical food resource for an endangered bird, the Carnaby’s cockatoo (Calyptorynchus latirostris, Carnaby 1948). The time needed for banksias to reach maturity and maximum seed production is several years longer than the typical interval between prescribed burns. We compared prescribed burns to bushfires and unburned sites at three locations in banksia woodland to determine whether low-intensity prescribed burns affect the number of adult banksias and their seed production. Study sites were matched to the same vegetation complex, fire regime, and time-since-fire to isolate fire intensity as a variable.

Results
Headfire rates of spread and differenced normalized burn ratios indicated that prescribed burning was generally of a much lower intensity than bushfire. The percentage survival of adult banksias and their production of cones and follicles (seeds) did not decrease during the first three years following a prescribed burn. However, survival and seed production were significantly diminished followed high-intensity bushfire. Thus, carrying capacity for Carnaby’s cockatoo was unchanged by prescribed burning but decreased markedly following bushfire in banksia woodland.

Conclusions
These results suggest that prescribed burning is markedly different from bushfire when considering appropriate fire intervals to conserve canopy habitats in fire-resilient vegetation communities. Therefore, low-intensity prescribed burning represents a viable management tool to reduce the frequency and extent of bushfire impacts on banksia woodland and Carnaby’s cockatoo.
Bevölkerungsdichte, Stadtstruktur und Umweltverschmutzung
Authors: Borck Rainald 
Published: October 2019

ZusammenfassungIn diesem Aufsatz wird der Zusammenhang zwischen Bevölkerungsdichte, Stadtstruktur und Umweltverschmutzung untersucht. Der Beitrag präsentiert stadtökonomische Modelle, in denen die Haupttreiber der städtischen Verschmutzung analysiert werden. Zudem wird empirische Evidenz zu den betrachteten Zusammenhängen präsentiert sowie wirtschaftspolitische Implikationen diskutiert. Kurz gesagt: größere und dichter besiedelte Städte produzieren mehr Luftverschmutzung und$$\text{CO}_{2}$$CO2, aber vermutlich weniger$$\text{CO}_{2}$$CO2pro Kopf. Ohne Regulierung werden Städte zu wenig dicht bebaut, und große Städte könnten im Vergleich zum Wohlfahrtsoptimum zu klein sein.
Yield and Practice Patterns of Surveillance Colonoscopy Among Older Adults: An Analysis of the GI Quality Improvement Consortium
Authors: Calderwood Audrey H. , Holub Jennifer L. , Greenwald David A. , Robertson Douglas J. 
Published: October 2019

OBJECTIVES:
There is little guidance regarding when to stop surveillance colonoscopy in individuals with a history of adenomas or colorectal cancer (CRC). We evaluated both yield and recommendations for follow-up colonoscopy in a large cohort of older individuals undergoing colonoscopy, using the GI Quality Improvement Consortium registry.

METHODS:
We analyzed the yield of colonoscopy in adults aged ≥75 years, comparing those who had an indication of surveillance as opposed to an indication of diagnostic or screening, stratified by 5-year age groups. Our primary outcome was CRC and advanced lesions. We also evaluated recommended follow-up intervals by age and findings.

RESULTS:
Between 2010 and 2017, 376,686 colonoscopies were performed by 3,976 endoscopists at 628 sites, of which 43.2% were for surveillance. Detection of CRC among surveillance patients increased with age from 0.51% (age 75–79 years) to 1.8% (age ≥ 90 years); however, these risks were lower when compared with both the diagnostic and screening for the same age band (P < 0.0001). Yield of advanced lesions also increased by every 5-year interval of age across all groups by indication. Even at the most advanced ages and in those with nonadvanced findings, only a minority of patients were recommended for no further colonoscopy. For example, in patients aged 90 years and older with only low risk findings, 62.9% were recommended to repeat colonoscopy.

DISCUSSION:
Surveillance colonoscopy is frequently recommended at advanced ages even when recent findings may be clinically insignificant. Further work is needed to develop guidelines to inform best practice around when to stop surveillance in older adults.
Low-dose Vitamin K can Improve Warfarin Control in Patients on LVAD Support
Authors: Tanaka Daizo , Kotch Venessa L. , Abbas Cheryl , Reeves Gordon R. , Entwistle III John WC 
Published: October 2019

Background
Anticoagulation with oral vitamin K antagonists (VKA) is very important in patients supported on a left ventricular assist device (LVAD) to prevent thromboembolic complications. Some patients tolerate VKAs poorly and have an unstable INR as a result. It is reported that low-dose vitamin K can improve INR control in patients with an unstable INR in other clinical settings. We evaluated its safety and effectiveness in patients on LVAD support.
Methods
The records of all patients supported on an implantable LVAD between January, 2013 and March, 2014 were reviewed retrospectively to identify those who had received low-dose vitamin K while on warfarin. INR values and warfarin doses before and after initiation of vitamin K supplementation were compared to evaluate its effectiveness.
Results
There were six LVAD patients who were on low-dose vitamin K due to an unstable INR out of a total of 59 VAD patients followed as an outpatient. The standard deviation (SD) of INR decreased significantly after starting vitamin K (p=0.04) while the SD of warfarin dose did not (p=0.22). Comparing divergence from target INR, INR became significantly closer to target INR after starting vitamin K. The number of bleeding complications tended to be fewer on vitamin K, but this did not reach statistical significance (p=0.09).
Conclusions
Daily low-dose vitamin K supplementation can improve INR control in LVAD patients with unstable INR without increasing thromboembolic complications.
Decrease in Driveline Infections with Change in Driveline Management Protocol
Authors: Aslam Saima , Dan Jennifer , Topik Amanda , Belyk Michael , Torriani Francesca , Taplitz Randy , Silva-Enciso Jorge , Barnard Denise , Greenberg Barry , Copeland Jack , Pretorius Victor , Adler Eric 
Published: October 2019

Background

Driveline infections (DLI) are a significant cause of morbidity and mortality in ventricular assist device (VAD) recipients. We compared driveline infection (DLI) rate after an institutional change in driveline management protocol.

Methods

We retrospectively reviewed records of left VAD recipients at our institution, based on driveline management. Group 1: daily driveline dressing change consisting of chlorhexidine cleansing, sterile 4x4 gauze, and use of an abdominal binder. Group 2: Dressing change every 3 days consisting of chlorhexidine cleansing, non-sterile silver-impregnated foam with overlying clear dressing, and use of a driveline anchor. Follow-up was censored at first DLI, device removal, transplant or death. Additionally, Group 1 patients’ follow-up was censored when the change in protocol occurred. Statistical analysis: Student’s t-test, Fisher’s exact test, Kaplan-Meier curve and log-rank test.

Results
DLI occurred in 16% of 88 VAD recipients (Group 1 n=24, Group 2 n=64). The new driveline management protocol resulted in significantly fewer DLI in Group 2 (6.3% vs. 41.7%, p<0.0001).

Conclusions
An updated driveline management protocol demonstrated significant reduction in DLI at our institution. Studies evaluating the optimal approach for driveline management are needed in order to develop a standardized regimen aimed at lowering the risk of DLI.
Venoarterial extracorporeal membrane oxygenation for cardiogenic shock: a retrospective analysis based on the etiology of shock
Authors: Burchett Andrew , Tribble Thomas , Charnigo Richard , Smyth Susan , Guglin Maya 
Published: October 2019

Background
We performed a retrospective analysis to evaluate the efficacy of VA-ECMO support in cardiogenic shock based on various etiologies.
Methods
We retrospectively analyzed 99 patients supported with VA-ECMO from January 1, 2012 to January 1, 2015. Outcomes included survival to discontinuation of VA-ECMO support and survival to hospital discharge. The etiologies of cardiogenic shock included cardiac arrest (CPR), acute myocardial infarction (AMI), decompensated congestive heart failure (CHF), pulmonary embolism (PE), right ventricular failure (RVF) not secondary to an acute pulmonary embolism, and post-cardiotomy syndrome (PCS). The PCS group was used as a reference group; odds ratios were estimated and Fisher’s exact tests were performed to compare each other group to the reference.
Results
Patients supported with VA-ECMO due to PE and CHF had better survival to hospital discharge (83.3% and 54.2%, with p = 0.003 and p = 0.011, respectively) versus the PCS group (7.7%). The PE, CHF, and AMI groups had statistically improved survival to VA-ECMO discontinuation. There was no statistically significant difference in survival to VA-ECMO discontinuation or hospital discharge in four subgroup analyses.
Conclusions
Patients supported with VA-ECMO in cardiogenic shock due to PE or CHF demonstrated increased rates of survival to hospital discharge when compared to the PCS group. This study also highlights the need for a more uniform system of categorizing etiologies of cardiogenic shock.
Fatal Flaw – Driveline Fracture as a Rare But Serious Complication Of Mechanical Circulatory Support With Left Ventricular Assist Devices
Authors: Boyechko Yuri , Tribble Thomas , Guglin Maya 
Published: October 2019

Background
Patients with advanced heart failure have seen decreased mortality and improved quality of life due to mechanical circulatory support with left ventricular assist devices (LVAD). Regardless of such outcomes, many complications still exist and remain a significant cause of morbidity and mortality. Our purpose is to study the prevalence, clinical course, and outcomes specifically of patients with LVAD driveline (DL) fractures.
Methods
This single-center, retrospective review included all patients at our institution who had continuous flow LVADs and experienced DL fracture/injury from January 2012 - December 2015.
Results
Thirteen of 110 LVAD patients (11.8%) had DL fractures (Table 1). Time from implant to time of fracture was 23+/-16.5 months. The majority of fractures were external (62%), due to trauma (i.e. cut during dressing change). Internal injury, proximal to the cutaneous exit site, occurred in 38% of patients, usually due to unknown causes. Only one patient (7.6%) survived on LVAD support. One survived LVAD explant, two underwent pump exchange, and four others underwent heart transplantation. The remaining 5 expired. All patients with untreated internal fractures died (60%).
Conclusions
Driveline fracture is a rare complication of LVAD and is often lethal when it occurs. Only one patient in our cohort survived without the need for heart transplant, LVAD exchange, or explant. Internal driveline fractures portend a very high mortality. Driveline fracture, especially one that cannot be promptly repaired or if internal fracture is suspected, requires immediate pump exchange or listing for heart transplant.