176 research outputs found
A framework for implementation, education, research and clinical use of ultrasound in emergency departments by the Danish Society for Emergency Medicine
The first Danish Society for Emergency Medicine (DASEM) recommendations for the use of clinical ultrasound in emergency departments has been made. The recommendations describes what DASEM believes as being current best practice for training, certification, maintenance of acquired competencies, quality assurance, collaboration and research in the field of clinical US used in an ED
Generating Global Leaf Area Index from Landsat: Algorithm Formulation and Demonstration
This paper summarizes the implementation of a physically based algorithm for the retrieval of vegetation
green Leaf Area Index (LAI) from Landsat surface reflectance data. The algorithm is based on the canopy spectral
invariants theory and provides a computationally efficient way of parameterizing the Bidirectional
Reflectance Factor (BRF) as a function of spatial resolution and wavelength. LAI retrievals from the application
of this algorithm to aggregated Landsat surface reflectances are consistent with those of MODIS for homogeneous
sites represented by different herbaceous and forest cover types. Example results illustrating the
physics and performance of the algorithm suggest three key factors that influence the LAI retrieval process:
1) the atmospheric correction procedures to estimate surface reflectances; 2) the proximity of Landsatobserved
surface reflectance and corresponding reflectances as characterized by the model simulation; and
3) the quality of the input land cover type in accurately delineating pure vegetated components as opposed
to mixed pixels. Accounting for these factors, a pilot implementation of the LAI retrieval algorithm was demonstrated
for the state of California utilizing the Global Land Survey (GLS) 2005 Landsat data archive. In a separate
exercise, the performance of the LAI algorithm over California was evaluated by using the short-wave
infrared band in addition to the red and near-infrared bands. Results show that the algorithm, while ingesting
the short-wave infrared band, has the ability to delineate open canopies with understory effects and may
provide useful information compared to a more traditional two-band retrieval. Future research will involve
implementation of this algorithm at continental scales and a validation exercise will be performed in evaluating
the accuracy of the 30-m LAI products at several field sites
Point-of-care ultrasound induced changes in management of unselected patients in the emergency department - a prospective single-blinded observational trial
Background
Point-of-Care ultrasound (POCUS) changes the management in specific groups of patients in the Emergency Department (ED). It seems intuitive that POCUS holds an unexploited potential on a wide variety of patients. However, little is known about the effect of ultrasound on the broad spectrum of unselected patients in the ED. This study aimed to identify the effect on the clinical management if POCUS was applied on unselected patients. Secondarily the study aimed to identify predictors of ultrasound changing management.
Methods
This study was a blinded observational single center trial. A basic whole body POCUS protocol was performed in extension to the physical examination. The blinded treating physicians were interviewed about the presumptive diagnosis and plan for the patient. Subsequently the physicians were unblinded to the POCUS results and asked to choose between five options regarding the benefit from POCUS results.
Results
A total of 403 patients were enrolled in this study. The treating physicians regarded POCUS examinations influence on the diagnostic workup or treatment as following: 1) No new information: 249 (61.8%), 2) No further action: 45 (11.2%), 3) Further diagnostic workup needed: 52 (12.9%), 4) Presumptive diagnosis confirmed 38 (9.4%), and 5) Immediate treatment needed: 19 (4.7%). Predictors of beneficial ultrasound were: (a) triage > 1, (b) patient comorbidities (cardiac disease, hypertension or lung disease), or (c) patients presenting with abdominal pain, dyspnea, or syncope.
Conclusion
POCUS was found to be potentially beneficial in 27.0% of all patients. High triage score, known cardiac disease, hypertension, pulmonary diseases, a clinical presentation with abdominal pain, dyspnea, or syncope are predictors of this. Future research should focus on patient-important outcomes when applying POCUS on these patients.
Trial registration
The trail was registered prior to patient inclusion with the Danish Data Protection Agency (https://www.datatilsynet.dk/ Case no: 1–16–02-603-14) and Clinical Trials (www.clinicaltrials.gov/ Protocol ID: DNVK1305018)
Exploring Simple Algorithms for Estimating Gross Primary Production in Forested Areas from Satellite Data
Algorithms that use remotely-sensed vegetation indices to estimate gross primary production (GPP), a key component of the global carbon cycle, have gained a lot of popularity in the past decade. Yet despite the amount of research on the topic, the most appropriate approach is still under debate. As an attempt to address this question, we compared the performance of different vegetation indices from the Moderate Resolution Imaging Spectroradiometer (MODIS) in capturing the seasonal and the annual variability of GPP estimates from an optimal network of 21 FLUXNET forest towers sites. The tested indices include the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Leaf Area Index (LAI), and Fraction of Photosynthetically Active Radiation absorbed by plant canopies (FPAR). Our results indicated that single vegetation indices captured 50–80% of the variability of tower-estimated GPP, but no one index performed universally well in all situations. In particular, EVI outperformed the other MODIS products in tracking seasonal variations in tower-estimated GPP, but annual mean MODIS LAI was the best estimator of the spatial distribution of annual flux-tower GPP (GPP = 615 × LAI − 376, where GPP is in g C/m2/year). This simple algorithm rehabilitated earlier approaches linking ground measurements of LAI to flux-tower estimates of GPP and produced annual GPP estimates comparable to the MODIS 17 GPP product. As such, remote sensing-based estimates of GPP continue to offer a useful alternative to estimates from biophysical models, and the choice of the most appropriate approach depends on whether the estimates are required at annual or sub-annual temporal resolution
New generation geostationary satellite observations support seasonality in greenness of the Amazon evergreen forests
Assessing the seasonal patterns of the Amazon rainforests has been difficult because of the paucity of ground observations and persistent cloud cover over these forests obscuring optical remote sensing observations. Here, we use data from a new generation of geostationary satellites that carry the Advanced Baseline Imager (ABI) to study the Amazon canopy. ABI is similar to the widely used polar orbiting sensor, the Moderate Resolution Imaging Spectroradiometer (MODIS), but provides observations every 10–15 min. Our analysis of NDVI data collected over the Amazon during 2018–19 shows that ABI provides 21–35 times more cloud-free observations in a month than MODIS. The analyses show statistically significant changes in seasonality over 85% of Amazon forest pixels, an area about three times greater than previously reported using MODIS data. Though additional work is needed in converting the observed changes in seasonality into meaningful changes in canopy dynamics, our results highlight the potential of the new generation geostationary satellites to help us better understand tropical ecosystems, which has been a challenge with only polar orbiting satellites
Effect of a Point-of-Care Ultrasound-Driven vs Standard Diagnostic Pathway on 24-Hour Hospital Stay in Emergency Department Patients with Dyspnea-Protocol for A Randomized Controlled Trial
PURPOSE: Point-of-care ultrasound (POCUS) helps emergency department (ED) physicians make prompt and appropriate decisions, but the optimal diagnostic integration and potential clinical benefits remain unclear. We describe the protocol and statistical analysis plan for a randomized controlled trial. The objective is to determine the effect of a POCUS-driven diagnostic pathway in adult dyspneic ED patients on the proportion of patients having a hospital stay of less than 24 hours when compared to the standard diagnostic pathway.PATIENTS AND METHODS: This is a multicenter, randomized, investigator-initiated, open-labeled, pragmatic, controlled trial. Adult ED patients with chief complaint dyspnea are eligible. Patients are randomized (1:1) to the POCUS-driven diagnostic pathway or standard diagnostic pathway, with 337 patients in each group. The primary outcome is the proportion of patients having a hospital stay (from ED arrival to hospital discharge) of less than 24 hours. Key secondary outcomes include hospital length-of-stay, 72-hour revisits, and 30-day hospital-free days.CONCLUSION: Sparse evidence exists for any clinical benefit from a POCUS-integrated diagnostic pathway. The results from this trial will help clarify the promising signals for POCUS to influence patient care among ED patients with dyspnea.</p
Effect of a Point-of-Care Ultrasound-Driven vs Standard Diagnostic Pathway on 24-Hour Hospital Stay in Emergency Department Patients with Dyspnea—Protocol for A Randomized Controlled Trial
Stig Holm Ovesen,1,2 Søren Helbo Skaarup,3 Rasmus Aagaard,4 Hans Kirkegaard,1 Bo Løfgren,1,5 Michael Dan Arvig,6– 8 Bo Martin Bibby,9 Stefan Posth,10 Christian B Laursen,11,12 Jesper Weile1,2 1Research Center for Emergency Medicine, Department of Clinical Medicine, Aarhus University Hospital and Aarhus University, Aarhus, Denmark; 2Emergency Department, Horsens Regional Hospital, Horsens, Denmark; 3Department of Respiratory Diseases and Allergy, Aarhus University Hospital, Aarhus, Denmark; 4Department of Anesthesiology, Aarhus University Hospital, Aarhus, Denmark; 5Department of Internal Medicine, Randers Regional Hospital, Randers, Denmark; 6Emergency Department, Slagelse Hospital, Slagelse, Denmark; 7Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; 8Department of Regional Health Research, University of Southern Denmark, Odense, Denmark; 9Department of Biostatistics, Aarhus University, Aarhus, Denmark; 10Emergency Department, Odense University Hospital, Odense, Denmark; 11Department of Respiratory Medicine, Odense University Hospital, Odense, Denmark; 12Odense Respiratory Research Unit (ODIN), Department of Clinical Research, University of Southern Denmark, Odense, DenmarkCorrespondence: Stig Holm Ovesen, Research Center for Emergency Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, J103, Aarhus, 8200, Denmark, Email [email protected]: Point-of-care ultrasound (POCUS) helps emergency department (ED) physicians make prompt and appropriate decisions, but the optimal diagnostic integration and potential clinical benefits remain unclear. We describe the protocol and statistical analysis plan for a randomized controlled trial. The objective is to determine the effect of a POCUS-driven diagnostic pathway in adult dyspneic ED patients on the proportion of patients having a hospital stay of less than 24 hours when compared to the standard diagnostic pathway.Patients and Methods: This is a multicenter, randomized, investigator-initiated, open-labeled, pragmatic, controlled trial. Adult ED patients with chief complaint dyspnea are eligible. Patients are randomized (1:1) to the POCUS-driven diagnostic pathway or standard diagnostic pathway, with 337 patients in each group. The primary outcome is the proportion of patients having a hospital stay (from ED arrival to hospital discharge) of less than 24 hours. Key secondary outcomes include hospital length-of-stay, 72-hour revisits, and 30-day hospital-free days.Conclusion: Sparse evidence exists for any clinical benefit from a POCUS-integrated diagnostic pathway. The results from this trial will help clarify the promising signals for POCUS to influence patient care among ED patients with dyspnea.Keywords: focused lung ultrasound, focused cardiac ultrasound, shortness-of-breath, diagnostic effectivenes
Trauma facilities in Denmark - a nationwide cross-sectional benchmark study of facilities and trauma care organisation
Background
Trauma is a leading cause of death among adults aged < 44 years, and optimal care is a challenge. Evidence supports the centralization of trauma facilities and the use multidisciplinary trauma teams. Because knowledge is sparse on the existing distribution of trauma facilities and the organisation of trauma care in Denmark, the aim of this study was to identify all Danish facilities that care for traumatized patients and to investigate the diversity in organization of trauma management.
Methods
We conducted a systematic observational cross-sectional study. First, all hospitals in Denmark were identified via online services and clarifying phone calls to each facility. Second, all trauma care manuals on all facilities that receive traumatized patients were gathered. Third, anesthesiologists and orthopedic surgeons on call at all trauma facilities were contacted via telephone for structured interviews.
Results
A total of 22 facilities in Denmark were found to receive traumatized patients. All facilities used a trauma care manual and all had a multidisciplinary trauma team. The study found three different trauma team activation criteria and nine different compositions of teams who participate in trauma care. Training was heterogeneous and, beyond the major trauma centers, databases were only maintained in a few facilities.
Conclusion
The study established an inventory of the existing Danish facilities that receive traumatized patients. The trauma team activation criteria and the trauma teams were heterogeneous in both size and composition. A national database for traumatized patients, research on nationwide trauma team activation criteria, and team composition guidelines are all called for
Vegetation Functional Properties Determine Uncertainty of Simulated Ecosystem Productivity: A Traceability Analysis in the East Asian Monsoon Region
Global and regional projections of climate change by Earth system models are limited by their uncertain estimates of terrestrial ecosystem productivity. At the middle to low latitudes, the East Asian monsoon region has higher productivity than forests in Europe-Africa and North America, but its estimate by current generation of terrestrial biosphere models (TBMs) has seldom been systematically evaluated. Here, we developed a traceability framework to evaluate the simulated gross primary productivity (GPP) by 15 TBMs in the East Asian monsoon region. The framework links GPP to net primary productivity, biomass, leaf area and back to GPP via incorporating multiple vegetation functional properties of carbon-use efficiency (CUE), vegetation C turnover time (tau(veg)), leaf C fraction (F-leaf), specific leaf area (SLA), and leaf area index (LAI)-level photosynthesis (P-LAI), respectively. We then applied a relative importance algorithm to attribute intermodel variation at each node. The results showed that large intermodel variation in GPP over 1901-2010 were mainly propagated from their different representation of vegetation functional properties. For example, SLA explained 77% of the intermodel difference in leaf area, which contributed 90% to the simulated GPP differences. In addition, the models simulated higher CUE (18.1 21.3%), tau(veg) (18.2 26.9%), and SLA (27.436.5%) than observations, leading to the overestimation of simulated GPP across the East Asian monsoon region. These results suggest the large uncertainty of current TBMs in simulating GPP is largely propagated from their poor representation of the vegetation functional properties and call for a better understanding of the covariations between plant functional properties in terrestrial ecosystems.PublishedYe
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