An Exploratory Study Of Physiologic Responses To A Passive Exercise Intervention In Mechanically-ventilated Critically Ill Adults

Muscle weakness is the most common and persistent problem after a critical illness. Early mobilization of the critically ill patient, beginning with passive exercise and progressing to ambulation, may mitigate muscle effects of the critical illness. However, mobilization may produce adverse effects, especially early in the illness when risk for physiologic deterioration is common. If safe, introducing a mobility intervention early in the illness may facilitate ventilator weaning, shorten intensive care unit and hospitals stays, and improve functional status and quality of life for mechanically ventilated critically ill patients. The aim of this study was assess the cardiopulmonary and inflammatory responses to an early standardized passive exercise protocol (PEP) in mechanically ventilated critically ill patients. Using a quasi-experimental within-subjects repeated measures design, mechanically ventilated critically ill adults who were physiologically stable received a single standardized PEP within 72 hours of intubation. The PEP consisted of 20 minutes of bilateral passive leg movement delivered by continuous passive motion machines at a rate of 20 repetitions per minute, from 5-75 degrees, to simulate very slow walking. Physiologic parameters evaluated included heart rate (HR), mean blood pressure (MBP), oxygen saturation, and cytokine levels (IL-6 and IL-10), obtained before, during, and after the intervention. The Behavioral Pain Scale (BPS), administered before, during and after the intervention was used as a measure of participant comfort. The study sample was comprised of 18 (60%) males and 12 (40%) females, with a mean age of 56.5 years (SD 16.9 years), who were primarily Caucasian (N=18, 64%). Mean APACHE II scores for the sample were 23.8 (SD 6.2) with a mean predicted death rate of 48.8 (SD 19.8), indicating moderate mortality risk related to illness severity. Number of comorbidities ranged iv from 1-10 (X=4). All participants completed the intervention with no adverse events. Using repeated measures analysis of variance (rmANOVA), no significant differences were found in HR, MBP, or oxygen saturation at any of the four time points in comparison to baseline. BPS scores were significantly reduced (F(2.43, 70.42)=4.08, p=.02) at 5 and 10 minutes after the PEP was started, and were sustained at 20 minutes and for one hour after the PEP was completed. IL-6 was significantly reduced (F(1.60, 43.1)=4.351, p=.03) at the end of the intervention but not at the end of the final rest period. IL-10 values were not significantly different at any of the three time points, but IL-6 to IL-10 ratios did decrease significantly (F(1.61, 43.38)=3.42, p=.05) at the end of the PEP and again after a 60 minute rest period. Passive leg exercise was well tolerated by study participants. HR, MBP, and oxygen saturation were maintained within order set-specified ranges during and for one hour after activity, and patient comfort improved during and after the intervention. A downward trend in HR was noted in participants, which is contrary to usual HR response during exercise, and may represent clinical improvement in this population related to reduction in pain. Reduction of mean IL-6 values at the end of the PEP, but not after the rest period, suggests that the PEP was responsible for the initial IL-6 improvement. Improvement of IL-6 to IL-10 ratios from the end of the PEP to the end of the final rest period suggests that IL-10, although non-significant, may have had some effect, indicating that IL-10 increases may occur later than the time period of study. Passive exercise can be used as an approach to facilitating mobilization in mechanically ventilated critically ill adults until they are ready to participate in more active exercise. It could be that more frequent and aggressive exercise, such as passive cycling at faster rates, four times daily, will be tolerated in this population. While the understanding of clinical significance of cytokine profiles in critically ill patients is still evolving, cytokine levels may be useful in v explaining benefits of mobilization in this population. Further study is required to replicate the impact of passive exercise on pain, and it may represent a novel approach to pain management in critically ill patients

Reconstruction of primary vertices at the ATLAS experiment in Run 1 proton–proton collisions at the LHC

This paper presents the method and performance of primary vertex reconstruction in proton–proton collision data recorded by the ATLAS experiment during Run 1 of the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of √s=8 TeV. The performance has been measured as a function of the number of interactions per bunch crossing over a wide range, from one to seventy. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed. A longitudinal vertex position resolution of about 30μm is achieved for events with high multiplicity of reconstructed tracks. The transverse position resolution is better than 20μm and is dominated by the precision on the size of the luminous region. An analytical model is proposed to describe the primary vertex reconstruction efficiency as a function of the number of interactions per bunch crossing and of the longitudinal size of the luminous region. Agreement between the data and the predictions of this model is better than 3% up to seventy interactions per bunch crossing

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Observation of electroweak production of two jets in association with an isolated photon and missing transverse momentum, and search for a Higgs boson decaying into invisible particles at 13 TeV with the ATLAS detector

This paper presents the measurement of the electroweak production of two jets in association with a $Z\gamma$ pair with the $Z$ boson decaying into two neutrinos. It also presents the search for invisible or partially invisible decays of a Higgs boson with a mass of 125 GeV produced through vector-boson fusion with a photon in the final state. These results use data from LHC proton-proton collisions at $\sqrt{s}$ = 13 TeV collected with the ATLAS detector corresponding to an integrated luminosity of 139 fb$^{-1}$. The event signature, shared by all benchmark processes considered for measurements and searches, is characterized by a significant amount of unbalanced transverse momentum and a photon in the final state, in addition to a pair of forward jets. For electroweak production of $Z\gamma$ in association with two jets, the background-only hypothesis is rejected with an observed (expected) significance of 5.2 (5.1) standard deviations. The measured fiducial cross-section for this process is 1.31$\pm$0.29 fb. Observed (expected) upper limit of 0.37 (0.34) at 95% confidence level is set on the branching ratio of a 125 GeV Higgs boson to invisible particles, assuming the Standard Model production cross-section. The signature is also interpreted in the context of decays of a Higgs boson to a photon and a dark photon. An observed (expected) 95% CL upper limit on the branching ratio for this decay is set at 0.018 (0.017), assuming the 125 GeV Standard Model Higgs boson production cross-section

The ATLAS inner detector trigger performance in pp collisions at 13 TeV during LHC Run 2

The design and performance of the inner detector trigger for the high level trigger of the ATLAS experiment at the Large Hadron Collider during the 2016-18 data taking period is discussed. In 2016, 2017, and 2018 the ATLAS detector recorded 35.6 fb$^{-1}$, 46.9 fb$^{-1}$, and 60.6 fb$^{-1}$ respectively of proton-proton collision data at a centre-of-mass energy of 13 TeV. In order to deal with the very high interaction multiplicities per bunch crossing expected with the 13 TeV collisions the inner detector trigger was redesigned during the long shutdown of the Large Hadron Collider from 2013 until 2015. An overview of these developments is provided and the performance of the tracking in the trigger for the muon, electron, tau and $b$-jet signatures is discussed. The high performance of the inner detector trigger with these extreme interaction multiplicities demonstrates how the inner detector tracking continues to lie at the heart of the trigger performance and is essential in enabling the ATLAS physics programme

The ATLAS inner detector trigger performance in pp collisions at 13 TeV during LHC Run 2

The design and performance of the inner detector trigger for the high level trigger of the ATLAS experiment at the Large Hadron Collider during the 2016-18 data taking period is discussed. In 2016, 2017, and 2018 the ATLAS detector recorded 35.6 fb$^{-1}$, 46.9 fb$^{-1}$, and 60.6 fb$^{-1}$ respectively of proton-proton collision data at a centre-of-mass energy of 13 TeV. In order to deal with the very high interaction multiplicities per bunch crossing expected with the 13 TeV collisions the inner detector trigger was redesigned during the long shutdown of the Large Hadron Collider from 2013 until 2015. An overview of these developments is provided and the performance of the tracking in the trigger for the muon, electron, tau and $b$-jet signatures is discussed. The high performance of the inner detector trigger with these extreme interaction multiplicities demonstrates how the inner detector tracking continues to lie at the heart of the trigger performance and is essential in enabling the ATLAS physics programme