1,390 research outputs found
History of the Innovation of Damage Control for Management of Trauma Patients: 1902-2016
Objective: To review the history of the innovation of damage control (DC) for management of trauma patients. Background: DC is an important development in trauma care that provides a valuable case study in surgical innovation. Methods: We searched bibliographic databases (1950-2015), conference abstracts (2009-2013), Web sites, textbooks, and bibliographies for articles relating to trauma DC. The innovation of DC was then classified according to the Innovation, Development, Exploration, Assessment, and Long-term study model of surgical innovation. Results: The innovation\u27\u27 of DC originated from the use of therapeutic liver packing, a practice that had previously been abandoned after World War II because of adverse events. It then developed\u27\u27 into abbreviated laparotomy using rapid conservative operative techniques.\u27\u27 Subsequent exploration\u27\u27 resulted in the application of DC to increasingly complex abdominal injuries and thoracic, peripheral vascular, and orthopedic injuries. Increasing use of DC laparotomy was followed by growing reports of postinjury abdominal compartment syndrome and prophylactic use of the open abdomen to prevent intra-abdominal hypertension after DC laparotomy. By the year 2000, DC surgery had been widely adopted and was recommended for use in surgical journals, textbooks, and teaching courses ( assessment\u27\u27 stage of innovation). Long-term study\u27\u27 of DC is raising questions about whether the procedure should be used more selectively in the context of improving resuscitation practices. Conclusions: The history of the innovation of DC illustrates how a previously abandoned surgical technique was adapted and readopted in response to an increased understanding of trauma patient physiology and changing injury patterns and trauma resuscitation practices
Fe XXV and Fe XXVI Diagnostics of the Black Hole and Accretion Disk in Active Galaxies: Chandra Time-Resolved Spectroscopy of NGC 7314
We report the detection of Fe XXV and Fe XXVI emission lines from a
Chandra HETGS observation of the Seyfert~1 galaxy NGC 7314, made simultaneously
with RXTE. The lines are redshifted (cz ~ 1500 km/s) relative to the systemic
velocity and unresolved. We argue that the lines originate in a near face-on
(<7 degrees) disk having a radial line emissivity flatter than r^-2. Line
emission from ionization states of Fe in the range ~Fe I up to Fe XXVI is
observed. The ionization balance of Fe responds to continuum variations on
timescales less than 12.5 ks, supporting an origin of the lines close to the
X-ray source. We present additional, detailed diagnostics from this rich data
set. These results identify NGC 7314 as a key source to study in the future if
we are to pursue reverberation mapping of space-time near black-hole event
horizons. This is because it is first necessary to understand the ionization
structure of accretion disks and the relation between the X-ray continuum and
Fe K line emission. However, we also describe how our results are suggestive of
a means of measuring black-hole spin without a knowledge of the relation
between the continuum and line emission. Finally, these data emphasize that one
{\it can} study strong gravity with narrow (as opposed to very broad) disk
lines. In fact narrow lines offer higher precision, given sufficient energy
resolution.Comment: Accepted for publication in the Astrophysical Journal. 30 pages, six
figures, five of them color. Abstract is abridge
Resolution of Clinical and Laboratory Abnormalities after Diagnosis of Ventilator-Associated Pneumonia in Trauma Patients
Background: Guidelines advise that patients with ventilator-associated pneumonia (VAP) should respond clinically by Day 3 of antibiotics. White blood cell (WBC) count, maximum temperature (Tmax), and PaO2:FIO2 ratio are all said to respond significantly by Day 6. Resolution of abnormalities has not been evaluated in trauma patients.
Methods: Retrospective review of trauma patients with VAP. The WBC count, Tmax, and PaO2:FIO2 were evaluated for 16 days after diagnosis. Patients were grouped into uncomplicated VAP, complicated VAP (those with inadequate empirical therapy [IEAT], VAP relapse/superinfection, or acute respiratory distress syndrome), and concurrent infection +VAP (those also infected at another site).
Results: There were 126 patients (uncomplicated VAP= 29, complicated VAP = 69, and concurrent infection + VAP = 28). The mean Tmax in patients with uncomplicated VAP decreased significantly from diagnosis to Day 4 (Day 1: 39 – 0.5°C vs. Day 4: 38.6 – 0.7°C; p = 0.028) but never normalized. Their WBC counts and PaO2:FIO2 did not change significantly over the 16-day follow-up and never normalized.When comparing the three groups, the probability of resolving all three abnormalities was not different (p = 0.5).
Conclusions: Clinical and laboratory abnormalities in critically injured patients with VAP do not resolve as quickly as suggested in the guidelines. Future studies should evaluate new methods to determine the response to antibiotic therapy in critically injured patients with VAP
Oxandrolone in trauma patients
Study Objective
To determine the effect of oxandrolone administration on nutritional and clinical outcomes after multiple trauma.
Design
Prospective, randomized, double-blind, placebo-controlled study. Setting. Level 1 trauma center in a university teaching hospital.
Patients
Sixty-two patients requiring enteral nutrition, 60 of whom completed the study.
Intervention
Patients were randomized to receive either oxandrolone 10 mg or placebo twice/day for a maximum of 28 days.
Measurements and Main Results
Total urinary nitrogen, prealbumin, nitrogen balance, total body water, and body cell mass were measured on day 1 of enteral nutrition and then at day 7, day 10, and study exit. Patients were assessed daily for metabolic and infectious complications. The two groups were similar for demographics and dosage of enteral nutrition. Measurement of total urinary nitrogen at study entry showed both groups to be highly catabolic (oxandrolone 17.2 ± 4.9, placebo 19.1 ± 10.8 g/day, NS). On days 7 and 10, total urinary nitrogen increased in both groups; however, there was no significant difference between groups. Nitrogen balance was negative throughout the study in each group. Body cell mass decreased slightly in both groups over the study period. Prealbumin serum concentrations increased significantly in both groups at day 10 and study exit compared with study entry. The groups did not differ significantly for length of hospital stay (oxandrolone 30.8 ± 17.9, placebo 27.0 ± 25.7 days), length of intensive care unit stay (oxandrolone 17.1 ± 7.8, placebo 15.5 ± 9.7 days), and frequency of pneumonia or sepsis (oxandrolone 48, placebo 43 episodes).
Conclusion
Oxandrolone 20 mg/day does not have obvious benefit in nutritional and clinical outcomes during the first month after multiple trauma
Rapamycin-coated expanded polytetrafluoroethylene bypass grafts exhibit decreased anastomotic neointimal hyperplasia in a porcine model
ObjectiveWe tested the hypothesis that rapamycin coated onto, and eluted from, expanded polytetrafluoroethylene (ePTFE) grafts would diminish neointimal hyperplasia in a porcine model.MethodsRapamycin (also called sirolimus) was coated onto the luminal surface of 6-mm-internal-diameter thin-walled ePTFE grafts by using an adhesive polymer that allows timed release of the drug. An adhesive polymer that allows timed release of rapamycin from ePTFE was developed with commercially available chemicals and applied on 6-mm ePTFE grafts. Graft integrity was characterized by scanning electron microscopy, and rapamycin levels were quantified by using high-performance liquid chromatography. Twenty-two mongrel pigs were randomized into three groups: untreated ePTFE (n = 6), adhesive-only coated ePTFE (n = 6), or adhesive- and rapamycin-coated ePTFE (n = 10). End-to-side unilateral aortoiliac bypasses were performed by using 6-mm-internal-diameter ePTFE grafts and standardized anastomotic lengths. Unilateral end-to-side aortoiliac ePTFE grafts (6-mm internal diameter) were inserted by using polypropylene sutures, 6-0 proximally and 7-0 distally; all anastomoses were 12 mm long. All animals received aspirin (325 mg orally) daily. All animals were given oral aspirin (325 mg) daily beginning on the day before surgery. At 28 days, the animals were killed, and the grafts were explanted in continuity with the adjacent aortic cuff and the outflow iliac artery. Variables compared between groups included graft patency, distal anastomotic length and cross-sectional narrowing, and intimal thickness at the arterial-graft junction indexed to the adjacent graft thickness. Microscopic analysis was performed with hematoxylin and eosin and Masson trichrome stains on paraffin sections. A pathologist blinded to experimental groups graded sections for collagen deposition, neointima formation, inflammatory cellular infiltrates, medial necrosis, and aneurysmal degeneration.ResultsAll animals survived until they were killed without clinical evidence of limb ischemia or graft infection. Preplanned t tests in the context of one-way analysis of variance showed no difference in outcome measures between the untreated ePTFE and adhesive-only coated ePTFE groups; therefore, they were combined in further comparisons with the adhesive- and rapamycin-coated ePTFE group. The Rapamycine eluting expanded polytetrafluoroethylene group had longer anastomoses (85.6% vs 60.6% of the initial anastomotic length maintained; P < .0001) and less cross-sectional narrowing in the outflow graft (16.2% vs 28.5%; P = .0007) when compared with the other two groups by using two-tailed Student t tests. There was no evidence of medial necrosis or aneurysmal degeneration. All patent grafts had complete endothelialization on hematoxylin and eosin sections. Rapamycin was detectable and quantifiable in the arterial wall at 28 days after implantation.ConclusionsRapamycin can be coated onto and eluted from ePTFE by using a nonionic polymer and a simple coating technique. At 4 weeks after implantation, the rapamycin-eluting ePTFE grafts demonstrate gross, pathologic, and morphometric features of diminished neointimal hyperplasia when compared with non–drug-eluting ePTFE. Four weeks after implantation in a porcine model, rapamycin-eluting ePTFE grafts demonstrated gross, pathologic, and morphometric features of diminished neointimal hyperplasia when compared with untreated and adhesive-only coated ePTFE grafts.Clinical RelevanceRapamycin-eluting ePTFE grafts decrease neointimal hyperplasia in a porcine model. Further studies are needed to evaluate whether patency will be improved. Rapamycin-eluting ePTFE grafts may allow the use of prosthetic grafts in situations in which autologous vein is unavailable and in which neointimal hyperplasia is pronounced, such as in small-diameter (<6-mm) vessels typical of infrapopliteal interventions
Probing the extragalactic fast transient sky at minute timescales with DECam
Searches for optical transients are usually performed with a cadence of days
to weeks, optimised for supernova discovery. The optical fast transient sky is
still largely unexplored, with only a few surveys to date having placed
meaningful constraints on the detection of extragalactic transients evolving at
sub-hour timescales. Here, we present the results of deep searches for dim,
minute-timescale extragalactic fast transients using the Dark Energy Camera, a
core facility of our all-wavelength and all-messenger Deeper, Wider, Faster
programme. We used continuous 20s exposures to systematically probe timescales
down to 1.17 minutes at magnitude limits (AB), detecting hundreds of
transient and variable sources. Nine candidates passed our strict criteria on
duration and non-stellarity, all of which could be classified as flare stars
based on deep multi-band imaging. Searches for fast radio burst and gamma-ray
counterparts during simultaneous multi-facility observations yielded no
counterparts to the optical transients. Also, no long-term variability was
detected with pre-imaging and follow-up observations using the SkyMapper
optical telescope. We place upper limits for minute-timescale fast optical
transient rates for a range of depths and timescales. Finally, we demonstrate
that optical -band light curve behaviour alone cannot discriminate between
confirmed extragalactic fast transients such as prompt GRB flashes and Galactic
stellar flares.Comment: Published in MNRA
Pooling as a Strategy for the Timely Diagnosis of Soil-Transmitted Helminths in Stool: Value and Reproducibility
Background: The strategy of pooling stool specimens has been extensively used in the field of parasitology in order to facilitate the screening of large numbers of samples whilst minimizing the prohibitive cost of single sample analysis. The aim of this study was to develop a standardized reproducible pooling protocol for stool samples, validated between two different laboratories, without jeopardizing the sensitivity of the quantitative polymerase chain reaction (qPCR) assays employed for the detection of soil-transmitted helminths (STHs). Two distinct experimental phases were recruited. First, the sensitivity and specificity of the established protocol was assessed by real-time PCR for each one of the STHs. Secondly, agreement and reproducibility of the protocol between the two different laboratories were tested. The need for multiple stool sampling to avoid false negative results was also assessed. Finally, a cost exercise was conducted which included labour cost in low- and high-wage settings, consumable cost, prevalence of a single STH species, and a simple distribution pattern of the positive samples in pools to estimate time and money savings suggested by the strategy. Results: The sensitivity of the pooling method was variable among the STH species but consistent between the two laboratories. Estimates of specificity indicate a \u27pooling approach\u27 can yield a low frequency of \u27missed\u27 infections. There were no significant differences regarding the execution of the protocol and the subsequent STH detection between the two laboratories, which suggests in most cases the protocol is reproducible by adequately trained staff. Finally, given the high degree of agreement, there appears to be little or no need for multiple sampling of either individuals or pools. Conclusions: Our results suggest that the pooling protocol developed herein is a robust and efficient strategy for the detection of STHs in \u27pools-of-five\u27. There is notable complexity of the pool preparation to ensure even distribution of helminth DNA throughout. Therefore, at a given setting, cost of labour among other logistical and epidemiological factors, is the more concerning and determining factor when choosing pooling strategies, rather than losing sensitivity and/or specificity of the molecular assay or the method
Detection of a glitch in the pulsar J1709-4429
We report the detection of a glitch event in the pulsar J17094429 (also
known as B170644) during regular monitoring observations with the Molonglo
Observatory Synthesis Telescope (UTMOST). The glitch was found during timing
operations, in which we regularly observe over 400 pulsars with up to daily
cadence, while commensally searching for Rotating Radio Transients, pulsars,
and FRBs. With a fractional size of ,
the glitch reported here is by far the smallest known for this pulsar,
attesting to the efficacy of glitch searches with high cadence using UTMOST.Comment: 3 pages, 1 figur
HST Imaging of the Host Galaxies of High Redshift Radio-Loud Quasars
We present rest-frame UV and Ly-alpha images of spatially-resolved structures
around five high-redshift radio-loud quasars obtained with the WFPC2 camera on
the Hubble Space Telescope. We find that all five quasars are extended and this
"fuzz" contains ~5-40% of the total continuum flux and 15-65% of the Ly-alpha
flux within a radius of about 1.5 arcsec. The rest-frame UV luminosities of the
hosts are log lambda P_lambda = 11.9 to 12.5 solar luminosities (assuming no
internal dust extinction), comparable to the luminous radio galaxies at similar
redshifts and a factor 10 higher than both radio-quiet field galaxies at z~2-3
and the most UV-luminous low redshift starburst galaxies. The Ly-alpha
luminosities of the hosts are (in the log) approximately 44.3-44.9 erg/s which
are also similar to the those of luminous high redshift radio galaxies and
considerably larger than the Ly-alpha luminosities of high redshift field
galaxies. To generate the Ly-alpha luminosities of the hosts would require
roughly a few percent of the total observed ionizing luminosity of the quasar.
We find good alignment between the extended Ly-alpha and the radio sources,
strong evidence for jet-cloud interactions in two cases, again resembling radio
galaxies, and what is possibly the most luminous radio-UV synchrotron jet in
one of the hosts at z=2.110.Comment: 36 pages (latex, aas macros), 3 figures (3 gif and 10 postscript
files), accepted for publication in the the Astrophysical Journal Supplement
Serie
Effects of Mergers and Core Structure on the Bulk Properties of Nearby Galaxy Clusters
We use morphological measurements and the scatter of clusters about observed
and simulated scaling relations to examine the impact of merging and
core-related phenomena on the structure of galaxy clusters. All relations
constructed from emission-weighted mean temperature and intracluster medium
mass, X-ray luminosity, isophotal size, or near-IR luminosity show a separation
between cool core (CC) and non-cool core (NCC) clusters. We attribute this
partially to a temperature bias in CC clusters, and partially to other cool
core-related structural changes. We attempt to minimize CC/NCC separation in
scaling relations by applying a uniform scale factor to CC cluster temperatures
and determining the scale factor for each relation that minimizes the
separation between CC and NCC populations, and by introducing central surface
brightness as a third parameter in relations. The latter approach reduces
scatter in relations more than temperature scaling. We compare the scatter
within subsamples split by CC/NCC and morphological merger indicators. CC
clusters and clusters with less substructure generally exhibit higher scatter
about relations. The larger structural variations in CC clusters exit well
outside the core, suggesting that a process more global than core radiative
instability is at work. Simulations without cooling mechanisms also show no
correlation between substructure and larger scatter about relations, indicating
that any merger-related scatter increases are subtle. The results indicate that
cool core related phenomena, not merging processes, are the primary contributor
to scatter in scaling relations. Our analysis does not appear to support the
scenario in which clusters evolve cool cores over time unless they experience
major mergers. (Abridged)Comment: 18 pages, 17 figures; minor changes to text to match accepted
version. To appear in Ap
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