7,131 research outputs found
A national survey of the diagnosis and management of suspected ventilator-associated pneumonia.
BACKGROUND: Ventilator-associated pneumonia (VAP) affects up to 20% of patients admitted to intensive care units (ICU). It is associated with increased morbidity, mortality and healthcare costs. Despite published guidelines, variability in diagnosis and management exists, the extent of which remains unclear. We sought to characterise consultant opinions surrounding diagnostic and management practice for VAP in the UK. METHODS: An online survey was sent to all consultant members of the UK Intensive Care Society (n=∼1500). Data were collected regarding respondents' individual practice in the investigation and management of suspected VAP including use of diagnostic criteria, microbiological sampling, chest X-ray (CXR), bronchoscopy and antibiotic treatments. RESULTS: 339 (23%) responses were received from a broadly representative spectrum of ICU consultants. All respondents indicated that microbiological confirmation should be sought, the majority (57.8%) stating they would take an endotracheal aspirate prior to starting empirical antibiotics. Microbiology reporting services were described as qualitative only by 29.7%. Only 17% of respondents had access to routine reporting of CXRs by a radiologist. Little consensus exists regarding technique for bronchoalveolar lavage (BAL) with the reported volume of saline used ranging from 5 to 500 mL. 24.5% of consultants felt inadequately trained in bronchoscopy. CONCLUSIONS: There is wide variability in the approach to diagnosis and management of VAP among UK consultants. Such variability challenges the reliability of the diagnosis of VAP and its reported incidence as a performance indicator in healthcare systems. The data presented suggest increased radiological and microbiological support, and standardisation of BAL technique, might improve this situation
Gridmapping the northern plains of Mars: Geomorphological, Radar and Water-Equivalent Hydrogen results from Arcadia Plantia
A project of mapping ice-related landforms was undertaken to understand the role of sub-surface ice in the northern plains. This work is the first continuous regional mapping from CTX (“ConTeXt Camera”, 6 m/pixel; Malin et al., 2007) imagery in Arcadia Planitia along a strip 300 km across stretching from 30°N to 80°N centred on the 170° West line of longitude. The distribution and morphotypes of these landforms were used to understand the permafrost cryolithology. The mantled and textured signatures occur almost ubiquitously between 35° N and 78° N and have a positive spatial correlation with inferred ice stability based on thermal modelling, neutron spectroscopy and radar data. The degradational features into the LDM (Latitude Dependent Mantle) include pits, scallops and 100 m polygons and provide supporting evidence for sub-surface ice and volatile loss between 35-70° N in Arcadia with the mantle between 70-78° N appearing much more intact. Pitted terrain appears to be much more pervasive in Arcadia than in Acidalia and Utopia suggesting that the Arcadia study area had more wide-spread near-surface sub-surface ice, and thus was more susceptible to pitting, or that the ice was less well-buried by sediments. Correlations with ice stability models suggest that lack of pits north of 65-70° N could indicate a relatively young age (~1Ma), however this could also be explained through regional variations in degradation rates. The deposition of the LDM is consistent with an airfall hypothesis however there appears to be substantial evidence for fluvial processes in southern Arcadia with older, underlying processes being equally dominant with the LDM and degradation thereof in shaping the landscape
Dynamics of Light Antiquarks in the Proton
We present a comprehensive analysis of the recent data from the E866
experiment at Fermilab on Drell-Yan production in pD and pp collisions, which
indicates a non-trivial x-dependence for the asymmetry between u-bar and d-bar
quark distributions in the proton. The relatively fast decrease of the
asymmetry at large x suggests the important role played by the chiral structure
of the nucleon, in particular the pi-N and pi-Delta components of the nucleon
wave function. At small x the data require an additional non-chiral component,
which may be attributed to the Pauli exclusion principle as first suggested by
Field and Feynman.Comment: version to appear in Phys. Rev.
Radio source calibration for the VSA and other CMB instruments at around 30 GHz
Accurate calibration of data is essential for the current generation of CMB
experiments. Using data from the Very Small Array (VSA), we describe procedures
which will lead to an accuracy of 1 percent or better for experiments such as
the VSA and CBI. Particular attention is paid to the stability of the receiver
systems, the quality of the site and frequent observations of reference
sources. At 30 GHz the careful correction for atmospheric emission and
absorption is shown to be essential for achieving 1 percent precision. The
sources for which a 1 percent relative flux density calibration was achieved
included Cas A, Cyg A, Tau A and NGC7027 and the planets Venus, Jupiter and
Saturn. A flux density, or brightness temperature in the case of the planets,
was derived at 33 GHz relative to Jupiter which was adopted as the fundamental
calibrator. A spectral index at ~30 GHz is given for each. Cas A,Tau A, NGC7027
and Venus were examined for variability. Cas A was found to be decreasing at
percent per year over the period March 2001 to August 2004.
In the same period Tau A was decreasing at percent per year. A
survey of the published data showed that the planetary nebula NGC7027 decreased
at percent per year over the period 1967 to 2003. Venus showed
an insignificant ( percent) variation with Venusian illumination.
The integrated polarization of Tau A at 33 GHz was found to be
percent at pa .}Comment: 13 pages, 15 figures, submitted to MNRA
Effectiveness of biomarker-based exclusion of ventilator-acquired pneumonia to reduce antibiotic use (VAPrapid-2): study protocol for a randomised controlled trial.
BACKGROUND: Ventilator-acquired pneumonia (VAP) is a common reason for antimicrobial therapy in the intensive care unit (ICU). Biomarker-based diagnostics could improve antimicrobial stewardship through rapid exclusion of VAP. Bronchoalveloar lavage (BAL) fluid biomarkers have previously been shown to allow the exclusion of VAP with high confidence. METHODS/DESIGN: This is a prospective, multi-centre, randomised, controlled trial to determine whether a rapid biomarker-based exclusion of VAP results in fewer antibiotics and improved antimicrobial management. Patients with clinically suspected VAP undergo BAL, and VAP is confirmed by growth of a potential pathogen at [≥] 10(4) colony-forming units per millilitre (CFU/ml). Patients are randomised 1:1, to either a 'biomarker-guided recommendation on antibiotics' in which BAL fluid is tested for IL-1β and IL-8 in addition to routine microbiology testing, or to 'routine use of antibiotics' in which BAL undergoes routine microbiology testing only. Clinical teams are blinded to intervention until 6 hours after randomisation, when biomarker results are reported to the clinician. The primary outcome is a change in the frequency distribution of antibiotic-free days (AFD) in the 7 days following BAL. Secondary outcome measures include antibiotic use at 14 and 28 days; ventilator-free days; 28-day mortality and ICU mortality; sequential organ failure assessment (SOFA) at days 3, 7 and 14; duration of stay in critical care and the hospital; antibiotic-associated infections; and antibiotic-resistant pathogen cultures up to hospital discharge, death or 56 days. A healthcare-resource-utilisation analysis will be calculated from the duration of critical care and hospital stay. In addition, safety data will be collected with respect to performing BAL. A sample size of 210 will be required to detect a clinically significant shift in the distribution of AFD towards more patients having fewer antibiotics and therefore more AFD. DISCUSSION: This trial will test whether a rapid biomarker-based exclusion of VAP results in rapid discontinuation of antibiotics and therefore improves antibiotic management in patients with suspected VAP. TRIAL REGISTRATION: ISRCTN65937227 . Registered on 22 August 2013. ClinicalTrials.gov, NCT01972425 . Registered on 24 October 2013
Randomised controlled trial of GM-CSF in critically ill patients with impaired neutrophil phagocytosis
Background. Critically ill patients with impaired neutrophil phagocytosis have significantly increased risk of nosocomial infection. Granulocyte-macrophage colony-stimulating factor (GM-CSF) improves phagocytosis by neutrophils ex vivo. This study tested the hypothesis that GM-CSF improves neutrophil phagocytosis in critically ill patients in whom phagocytosis is known to be impaired
Methods. This was a multi-centre, phase 2a randomised, placebo-controlled clinical trial Using a personalised medicine approach, only critically ill patients with impaired neutrophil phagocytosis were included. Patients were randomised 1:1 to subcutaneous GM-CSF (3 microgrammws/kg/day) or placebo, once daily for 4 days. The primary outcome measure was neutrophil phagocytosis 2 days after initiation of GM-CSF. Secondary outcomes included neutrophil phagocytosis over time, neutrophil functions other than phagocytosis, monocyte HLA-DR expression, and safety.
Results. Thirty-eight patients were recruited from 5 intensive care units (17 randomised to GM-CSF). Mean neutrophil phagocytosis at day 2 was 57.2% (SD 13.2%) in the GM-CSF group and 49.8% (13.4%) in the placebo group, p=0.73. The proportion of patients with neutrophil phagocytosis >50% at day 2, and monocyte HLA-DR, appeared significantly higher in the GM-CSF group. Neutrophil functions other than phagocytosis did not appear significantly different between the groups. The most common adverse event associated with GM-CSF was pyrexia.
Conclusions. GM-CSF did not improve mean neutrophil phagocytosis at day 2, but was safe and appeared to increase the proportion of patients with adequate phagocytosis. The study suggests proof of principle for a pharmacological effect on neutrophil function in a subset of critically ill patients.This work was funded by a grant from the Medical Research Council (G1100233), with additional support from the National Institute for Health Research (NIHR) Newcastle Biomedical Research Centre. It was sponsored by Newcastle Universit
Diagnostic importance of pulmonary interleukin-1beta and interleukin-8 in ventilator-associated pneumonia.
BACKGROUND: Ventilator-associated pneumonia (VAP) is the most commonly fatal nosocomial infection. Clinical diagnosis of VAP remains notoriously inaccurate. The hypothesis was tested that significantly augmented inflammatory markers distinguish VAP from conditions closely mimicking VAP. METHODS: A prospective, observational cohort study was carried out in two university hospital intensive care units recruiting 73 patients with clinically suspected VAP, and a semi-urban primary care practice recruiting a reference group of 21 age- and sex-matched volunteers. Growth of pathogens at >10(4) colony-forming units (cfu)/ml of bronchoalveolar lavage fluid (BALF) distinguished VAP from "non-VAP". Inflammatory mediators were quantified in BALF and serum. Mediators showing significant differences between patients with and without VAP were analysed for diagnostic utility by receiver operator characteristic (ROC) curves. RESULTS: Seventy-two patients had recoverable lavage-24% had VAP. BALF interleukin-1beta (IL-1beta), IL-8, granulocyte colony-stimulating factor and macrophage inflammatory protein-1alpha were significantly higher in the VAP group (all p<0.005). Using a cut-off of 10 pg/ml, BALF IL-1beta generated negative likelihood ratios for VAP of 0.09. In patients with BALF IL-1beta <10 pg/ml the post-test probability of VAP was 2.8%. Using a cut-off value for IL-8 of 2 ng/ml, the positive likelihood ratio was 5.03. There was no difference in cytokine levels between patients with sterile BALF and those with growth of <10(4) cfu/ml. CONCLUSIONS: BALF IL-1beta and IL-8 are amongst the strongest markers yet identified for accurately demarcating VAP within the larger population of patients with suspected VAP. These findings have potential implications for reduction in unnecessary antibiotic use but require further validation in larger populations
Supersymmetry Without Prejudice
We begin an exploration of the physics associated with the general
CP-conserving MSSM with Minimal Flavor Violation, the pMSSM. The 19 soft SUSY
breaking parameters in this scenario are chosen so as to satisfy all existing
experimental and theoretical constraints assuming that the WIMP is a
conventional thermal relic, ie, the lightest neutralino. We scan this parameter
space twice using both flat and log priors for the soft SUSY breaking mass
parameters and compare the results which yield similar conclusions. Detailed
constraints from both LEP and the Tevatron searches play a particularly
important role in obtaining our final model samples. We find that the pMSSM
leads to a much broader set of predictions for the properties of the SUSY
partners as well as for a number of experimental observables than those found
in any of the conventional SUSY breaking scenarios such as mSUGRA. This set of
models can easily lead to atypical expectations for SUSY signals at the LHC.Comment: 61 pages, 24 figs. Refs., figs, and text added, typos fixed; This
version has reduced/bitmapped figs. For a version with better figs please go
to http://www.slac.stanford.edu/~rizz
Associations of built environment and proximity of food outlets with weight status:Analysis from 14 cities in 10 countries
The study aimed to examine associations of neighborhood built environments and proximity of food outlets (BE measures) with body weight status using pooled data from an international study (IPEN Adult). Objective BE measures were calculated using geographic information systems for 10,008 participants (4463 male, 45%) aged 16-66 years in 14 cities. Participants self-reported proximity to three types of food outlets. Outcomes were body mass index (BMI) and overweight/obesity status. Male and female weight status associations with BE measures were estimated by generalized additive mixed models. Proportion (95% CI) of overweight (BMI 25 to = 30) from 2.9% (1.3, 4.4) to 31.3% (27.7, 34.7), with Hong Kong being the lowest and Cuernavaca, Mexico highest for both proportions. Results differed by sex. Greater street intersection density, public transport density and perceived proximity to restaurants (males) were associated with lower odds of overweight/obesity (BMI >= 25). Proximity to public transport stops (females) was associated with higher odds of overweight/obesity. Composite BE measures were more strongly related to BMI and overweight/obesity status than single variables among men but not women. One standard deviation improvement in the composite measures of BE was associated with small reductions of 0.1-0.5% in BMI but meaningful reductions of 2.5-5.3% in the odds of overweight/obesity. Effects were linear and generalizable across cities. Neighborhoods designed to support public transport, with food outlets within walking distance, may contribute to global obesity control
Aerodynamic investigations of ventilated brake discs.
The heat dissipation and performance of a ventilated brake disc strongly depends
on the aerodynamic characteristics of the flow through the rotor passages. The
aim of this investigation was to provide an improved understanding of ventilated
brake rotor flow phenomena, with a view to improving heat dissipation, as well
as providing a measurement data set for validation of computational fluid
dynamics methods. The flow fields at the exit of four different brake rotor
geometries, rotated in free air, were measured using a five-hole pressure probe
and a hot-wire anemometry system. The principal measurements were taken using
two-component hot-wire techniques and were used to determine mean and unsteady
flow characteristics at the exit of the brake rotors. Using phase-locked data
processing, it was possible to reveal the spatial and temporal flow variation
within individual rotor passages. The effects of disc geometry and rotational
speed on the mean flow, passage turbulence intensity, and mass flow were
determined. The rotor exit jet and wake flow were clearly observed as
characterized by the passage geometry as well as definite regions of high and
low turbulence. The aerodynamic flow characteristics were found to be reasonably
independent of rotational speed but highly dependent upon rotor geometry
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