Variation in Structure and Process of Care in Traumatic Brain Injury: Provider Profiles of European Neurotrauma Centers Participating in the CENTER-TBI Study.

INTRODUCTION: The strength of evidence underpinning care and treatment recommendations in traumatic brain injury (TBI) is low. Comparative effectiveness research (CER) has been proposed as a framework to provide evidence for optimal care for TBI patients. The first step in CER is to map the existing variation. The aim of current study is to quantify variation in general structural and process characteristics among centers participating in the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study. METHODS: We designed a set of 11 provider profiling questionnaires with 321 questions about various aspects of TBI care, chosen based on literature and expert opinion. After pilot testing, questionnaires were disseminated to 71 centers from 20 countries participating in the CENTER-TBI study. Reliability of questionnaires was estimated by calculating a concordance rate among 5% duplicate questions. RESULTS: All 71 centers completed the questionnaires. Median concordance rate among duplicate questions was 0.85. The majority of centers were academic hospitals (n = 65, 92%), designated as a level I trauma center (n = 48, 68%) and situated in an urban location (n = 70, 99%). The availability of facilities for neuro-trauma care varied across centers; e.g. 40 (57%) had a dedicated neuro-intensive care unit (ICU), 36 (51%) had an in-hospital rehabilitation unit and the organization of the ICU was closed in 64% (n = 45) of the centers. In addition, we found wide variation in processes of care, such as the ICU admission policy and intracranial pressure monitoring policy among centers. CONCLUSION: Even among high-volume, specialized neurotrauma centers there is substantial variation in structures and processes of TBI care. This variation provides an opportunity to study effectiveness of specific aspects of TBI care and to identify best practices with CER approaches

Variation in general supportive and preventive intensive care management of traumatic brain injury: a survey in 66 neurotrauma centers participating in the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study

Abstract Background General supportive and preventive measures in the intensive care management of traumatic brain injury (TBI) aim to prevent or limit secondary brain injury and optimize recovery. The aim of this survey was to assess and quantify variation in perceptions on intensive care unit (ICU) management of patients with TBI in European neurotrauma centers. Methods We performed a survey as part of the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study. We analyzed 23 questions focused on: 1) circulatory and respiratory management; 2) fever control; 3) use of corticosteroids; 4) nutrition and glucose management; and 5) seizure prophylaxis and treatment. Results The survey was completed predominantly by intensivists (n = 33, 50%) and neurosurgeons (n = 23, 35%) from 66 centers (97% response rate). The most common cerebral perfusion pressure (CPP) target was > 60 mmHg (n = 39, 60%) and/or an individualized target (n = 25, 38%). To support CPP, crystalloid fluid loading (n = 60, 91%) was generally preferred over albumin (n = 15, 23%), and vasopressors (n = 63, 96%) over inotropes (n = 29, 44%). The most commonly reported target of partial pressure of carbon dioxide in arterial blood (PaCO2) was 36–40 mmHg (4.8–5.3 kPa) in case of controlled intracranial pressure (ICP) < 20 mmHg (n = 45, 69%) and PaCO2 target of 30–35 mmHg (4–4.7 kPa) in case of raised ICP (n = 40, 62%). Almost all respondents indicated to generally treat fever (n = 65, 98%) with paracetamol (n = 61, 92%) and/or external cooling (n = 49, 74%). Conventional glucose management (n = 43, 66%) was preferred over tight glycemic control (n = 18, 28%). More than half of the respondents indicated to aim for full caloric replacement within 7 days (n = 43, 66%) using enteral nutrition (n = 60, 92%). Indications for and duration of seizure prophylaxis varied, and levetiracetam was mostly reported as the agent of choice for both seizure prophylaxis (n = 32, 49%) and treatment (n = 40, 61%). Conclusions Practice preferences vary substantially regarding general supportive and preventive measures in TBI patients at ICUs of European neurotrauma centers. These results provide an opportunity for future comparative effectiveness research, since a more evidence-based uniformity in good practices in general ICU management could have a major impact on TBI outcome

Variation in neurosurgical management of traumatic brain injury

Background: Neurosurgical management of traumatic brain injury (TBI) is challenging, with only low-quality evidence. We aimed to explore differences in neurosurgical strategies for TBI across Europe. Methods: A survey was sent to 68 centers participating in the Collaborative European Neurotrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study. The questionnaire contained 21 questions, including the decision when to operate (or not) on traumatic acute subdural hematoma (ASDH) and intracerebral hematoma (ICH), and when to perform a decompressive craniectomy (DC) in raised intracranial pressure (ICP). Results: The survey was completed by 68 centers (100%). On average, 10 neurosurgeons work in each trauma center. In all centers, a neurosurgeon was available within 30 min. Forty percent of responders reported a thickness or volume threshold for evacuation of an ASDH. Most responders (78%) decide on a primary DC in evacuating an ASDH during the operation, when swelling is present. For ICH, 3% would perform an evacuation directly to prevent secondary deterioration and 66% only in case of clinical deterioration. Most respondents (91%) reported to consider a DC for refractory high ICP. The reported cut-off ICP for DC in refractory high ICP, however, differed: 60% uses 25 mmHg, 18% 30 mmHg, and 17% 20 mmHg. Treatment strategies varied substantially between regions, specifically for the threshold for ASDH surgery and DC for refractory raised ICP. Also within center variation was present: 31% reported variation within the hospital for inserting an ICP monitor and 43% for evacuating mass lesions. Conclusion: Despite a homogeneous organization, considerable practice variation exists of neurosurgical strategies for TBI in Europe. These results provide an incentive for comparative effectiveness research to determine elements of effective neurosurgical care

Global and Polynomial-Time Convergence of an Infeasible-Interior-Point Algorithm Using Inexact Computation(Continuous and Discrete Mathematical Optimization)

Social learning can be fundamental to cohesive group living, and schooling fishes have proven ideal test subjects for recent work in this field. For many species, both demographic factors, and inter- (and intra-) generational information exchange are considered vital ingredients in how movement decisions are reached. Yet key information is often missing on the spatial outcomes of such decisions, and questions concerning how migratory traditions are influenced by collective memory, density-dependent and density-independent processes remain open. To explore these issues, we focused on Atlantic herring (Clupea harengus), a long-lived, dense-schooling species of high commercial importance, noted for its unpredictable shifts in winter distribution, and developed a series of Bayesian space-time occurrence models to investigate wintering dynamics over 23 years, using point-referenced fishery and survey records from Icelandic waters. We included covariates reflecting local-scale environmental factors, temporally-lagged prey biomass and recent fishing activity, and through an index capturing distributional persistence over time, derived two proxies for spatial memory of past wintering sites. The previous winter's occurrence pattern was a strong predictor of the present pattern, its influence increasing with adult population size. Although the mechanistic underpinnings of this result remain uncertain, we suggest that a ‘wisdom of the crowd’ dynamic may be at play, by which navigational accuracy towards traditional wintering sites improves in larger and/or denser, better synchronized schools. Wintering herring also preferred warmer, fresher, moderately stratified waters of lower velocity, close to hotspots of summer zooplankton biomass, our results indicative of heightened environmental sensitivity in younger cohorts. Incorporating spatiotemporal correlation structure and time-varying regression coefficients improved model performance, and validation tests on independent observations one-year ahead illustrate the potential of uniting demographic information and non-stationary models to quantify both the strength of collective memory in animal groups and its relevance for the spatial management of populations

Data from: Low inter-basin connectivity in a facultatively diadromous fish: evidence from genetics and otolith chemistry

Southern smelts (Retropinna spp.) in coastal rivers of Australia are facultatively diadromous, with populations potentially containing individuals with diadromous or wholly freshwater life-histories. The presence of diadromous individuals is expected to reduce genetic structuring between river basins due to larval dispersal via the sea. We use otolith chemistry to distinguish between diadromous and non-diadromous life-histories and population genetics to examine inter-basin connectivity resulting from diadromy. Otolith strontium isotope (87Sr:86Sr) transects identified three main life history patterns: amphidromy, freshwater residency and estuarine/marine residency. Despite the potential for inter-basin connectivity via larval mixing in the marine environment, we found unprecedented levels of genetic structure for an amphidromous species. Strong hierarchical structure along putative taxonomic boundaries was detected, along with highly structured populations within groups using microsatellites (FST = 0.046 – 0.181), and mtDNA (ΦST = 0.498 – 0.816). The presence of strong genetic subdivision, despite the fact that many individuals reside in saline water during their early life-history, appears incongruous. However, analysis of multi-elemental signatures in the otolith cores of diadromous fish revealed strong discrimination between river basins, suggesting that diadromous fish spend their early lives within chemically distinct estuaries rather than the more homogenous marine environment, thus avoiding dispersal and maintaining genetic structure

Insights into mixing and movement of South Pacific albacore Thunnus alalunga derived from trace elements in otoliths

Information on the movement and stock structure of commercially important tunas underpins the effective management of exploited populations. In the case of the South Pacific albacore (Thunnus alalunga) stock, longstanding questions remain regarding the degree of connectivity among larval pools, the migration routes of juveniles and adults and the biophysical factors influencing these processes. We measured trace elements (Li, Mg, Mn, Cu, Sr, Ba, Pb, Ca) in albacore otoliths collected across a broad geographical range in the South Pacific Ocean to address these knowledge gaps. Capture locations in French Polynesia, New Caledonia and New Zealand were discriminated with high accuracy (overall 85% of individuals correctly classified) based on analyses at the otolith edge (reflecting the final <1 month of life) using LA-ICPMS. Spatial comparisons of otolith core chemistry (reflecting the first ∼2 weeks of life post-hatch) from the 2005/06 cohort suggest some mixing of larval pools for fish sampled from New Caledonia and New Zealand, whereas French Polynesian fish may have originated from a chemically and/or geographically distinct larval source. Annual and/or sub-annual cycles in Sr:Ca and Ba:Ca were evident along ablation transects encompassing the full life history of individuals. These patterns may reflect seasonal north-south movements across ocean fronts; however, the vertical behaviours of albacore and the lack of opportunities for controlled experiments on temperature effects and time-lags in elemental incorporation complicates environmental reconstructions based on trace element data alone. Expanding the present analysis across multiple years and regions, and integrating data from several sources (e.g. commercial catch data, tag returns, otolith δ13C and δ18O, ocean circulation models) could help clarify the linkages between environmental factors and mixing and movement patterns in albacore

DataSheet_1_Sample contamination explains evidence of close kin proximity in yellowfin tuna (Thunnus albacares) in the Western and Central Pacific Ocean.csv

Anderson et al.’s 2019 paper ‘Close Kin Proximity in Yellowfin Tuna (Thunnus albacares) as a Driver of Population Genetic Structure in the Tropical Western and Central Pacific’ provided observations of genetically related individuals among sampled yellowfin tuna. Resampling of some individuals from the original study produced very different sequencing results when compared with the original dataset, one possible explanation of which is cross-contamination among the original samples. Re-analyses produced no indication of strong population structure, including a very slightly and consistent heterozygosity deficit with only one statistically significant pairwise FST value of 0.002. We identified only one pair of genetically similar individuals that could still be an artefact of lingering contamination. These new results therefore support a highly connected population of yellowfin tuna in the study area, although we do not rule out the potential for local adaptation driven by non-observed loci or genetic sub-structure operating at more contemporary scales.</p

DataSheet_2_Sample contamination explains evidence of close kin proximity in yellowfin tuna (Thunnus albacares) in the Western and Central Pacific Ocean.docx

Anderson et al.’s 2019 paper ‘Close Kin Proximity in Yellowfin Tuna (Thunnus albacares) as a Driver of Population Genetic Structure in the Tropical Western and Central Pacific’ provided observations of genetically related individuals among sampled yellowfin tuna. Resampling of some individuals from the original study produced very different sequencing results when compared with the original dataset, one possible explanation of which is cross-contamination among the original samples. Re-analyses produced no indication of strong population structure, including a very slightly and consistent heterozygosity deficit with only one statistically significant pairwise FST value of 0.002. We identified only one pair of genetically similar individuals that could still be an artefact of lingering contamination. These new results therefore support a highly connected population of yellowfin tuna in the study area, although we do not rule out the potential for local adaptation driven by non-observed loci or genetic sub-structure operating at more contemporary scales.</p

MEC-13-1244_msat_data_GENEPOP

MEC-13-1244_msat_data_GENEPO