Transfusion practices in brazilian Intensive Care Units (pelo FUNDO-AMIB)

BACKGROUND AND OBJECTIVES: Anemia of critical illness is a multifactorial condition caused by blood loss, frequent phlebotomies and inadequate production of red blood cells (RBC). Controversy surrounds the most appropriate hemoglobin concentration trigger for transfusion of RBC. We aimed to evaluate transfusion practices in Brazilian ICUs. METHODS: A prospective study throughout a 2-week period in 19 Brazilian ICUs. Hemoglobin (Hb) level, transfusion rate, organ dysfunction assessment and 28-day mortality were evaluated. Primary indication for transfusion and pretransfusion hemoglobin level were collected for each transfusion. RESULTS: Two hundred thirty-one patients with an ICU length of stay longer than 48h were included. An Hb level lower than 10 g/dL was found in 33% on admission in the ICU. A total of 348 RBC units were transfused in 86 patients (36.5%). The mean pretransfusion hemoglobin level was 7.7 ± 1.1 g/dL. Transfused-patients had significantly higher SOFA score (7.9 ± 4.6 vs 5.6 ± 3.8, p < 0.05, respectively), days on mechanical ventilation (10.7 ± 8.2 vs 7.2 ± 6.4, p < 0.05) and days on vasoactive drugs (6.7 ± 6.4 vs 4.2 ± 4.0, p < 0.05) than non-transfused patients despite similar APACHE II scores (15.2 ± 8.1 vs 14.2 ± 8.1, NS). Transfused patients had higher mortality rate (43.5%) than non-transfused patients (36.3%) (RR 0.60-1.15, NS). Only one patient (0.28%) had febrile non-hemolytic transfusion and urticarial reactions. CONCLUSIONS: Anemia is common in critically ill patients.It seems from the present study that transfusion practices in Brazil have had a more restrictive approach with a lower limit transfusion trigger.JUSTIFICATIVA E OBJETIVOS: A anemia é uma condição comum em pacientes graves. A transfusão de hemoderivados aumenta de forma significativa o risco de transmissão de agentes infecciosos e afeta o perfil imunológico. O objetivo deste estudo foi avaliar a incidência de anemia e a prática de transfusão de hemácias em UTI brasileiras. MÉTODO: Estudo prospectivo, multicêntrico, realizado em 19 UTI em um período de duas semanas. A presença de anemia, as indicações e a utilização de concentrados de hemácias, foram avaliadas diariamente. As complicações que ocorreram durante a internação na UTI e após a transfusão da primeira unidade de concentrado de hemácias foram registradas. RESULTADOS: Um total de 33% apresentava anemia na admissão na UTI e esta proporção aumentou para 55% no final de sete dias de internação. Um total de 348 unidades de concentrado de hemácias foi transfundido em 86 pacientes (36,5%). A média de suas unidades por paciente foi 4,1 ± 3,3 U. O nível de hemoglobina limiar para a transfusão de CH foi 7,7 ± 1,1 g/dL. Pacientes transfundidos tinham mais disfunções orgânicas avaliadas pelo escore SOFA (7,9 ± 4,6 versus 5,6 ± 3,8, transfundidos versus não transfundidos, p < 0,05). As taxas de mortalidade foram 43,5% e 36,3% em pacientes transfundidos e não transfundidos, respectivamente (RR 0,61-11,7, NS). Pacientes transfundidos tiveram número maior de complicações (1,58 ± 0,66 versus 1,33 ± 0,49, p = 0,0001). CONCLUSÕES: A anemia é comum em UTI brasileiras. O limiar transfusional de hemoglobina foi menor do que o observado em outros paises.Faculdade de Medicina de São José do Rio PretoUniversidade de São PauloUFRGS Departamento de Medicina Interna HC de Porto AlegreUniversidade Paris VIUFRJ CTI dos Hospitais Cardiotrauma Ipanema e São LucasAMIBUniversidade Estadual de LondrinaUFRGS FAMED HCPAFaculdade de Medicina de CatanduvaUNIFESP-EPMFundação Padre Albino UTI do Complexo HospitalarUniversidade Federal de São Paulo (UNIFESP) Disciplina de Anestesiologia, Dor e Terapia Intensiva Setor de TerapiaSanta Casa de Misericórdia de São PauloHospital Unimed de LimeiraUTI do Hospital Regional de AssisAMIB Departamento de MedicinaAmerican CollegeFundação Getúlio VargasHospital Pró CardíacoUNIRIOFGVHospital Santa Helena de GoiâniaHospital evangélico de Cachoeiro de Itapemirim Unidade coronarianaSBNHospital Evangélico Cachoeiro de Itapemirim UTI Adulto e CoronarianaUFRJUFRN Hospital Onofre Lopes UTIHospital Novo AtibaiaUNIFESP, EPMUNIFESP, Disciplina de Anestesiologia, Dor e Terapia Intensiva Setor de TerapiaSciEL

Search for the standard model Higgs boson produced in association with top quarks and decaying into a bbˉb\bar{b} pair in pppp collisions at s\sqrt{s} = 13 TeV with the ATLAS detector

A search for the standard model Higgs boson produced in association with a top-quark pair, tt¯H, is presented. The analysis uses 36.1  fb-1 of pp collision data at s=13  TeV collected with the ATLAS detector at the Large Hadron Collider in 2015 and 2016. The search targets the H→bb¯ decay mode. The selected events contain either one or two electrons or muons from the top-quark decays, and are then categorized according to the number of jets and how likely these are to contain b-hadrons. Multivariate techniques are used to discriminate between signal and background events, the latter being dominated by tt¯+jets production. For a Higgs boson mass of 125 GeV, the ratio of the measured tt¯H signal cross-section to the standard model expectation is found to be μ=0.84-0.61+0.64. A value of μ greater than 2.0 is excluded at 95% confidence level (C.L.) while the expected upper limit is μ<1.2 in the absence of a tt¯H signal.Peer Reviewe

Performance of the ATLAS Track Reconstruction Algorithms in Dense Environments in LHC Run 2

With the increase in energy of the Large Hadron Collider to a centre-of-mass energy of 13  $\text {TeV}$ for Run 2, events with dense environments, such as in the cores of high-energy jets, became a focus for new physics searches as well as measurements of the Standard Model. These environments are characterized by charged-particle separations of the order of the tracking detectors sensor granularity. Basic track quantities are compared between 3.2 fb$^{-1}$ of data collected by the ATLAS experiment and simulation of proton–proton collisions producing high-transverse-momentum jets at a centre-of-mass energy of 13  $\text {TeV}$ . The impact of charged-particle separations and multiplicities on the track reconstruction performance is discussed. The track reconstruction efficiency in the cores of jets with transverse momenta between 200 and 1600 $\text {GeV}$ is quantified using a novel, data-driven, method. The method uses the energy loss, ${\text { d}}{} \textit{E}/d\textit{x}$ , to identify pixel clusters originating from two charged particles. Of the charged particles creating these clusters, the measured fraction that fail to be reconstructed is $0.061 \pm 0.006\ {\text {(stat.)}} \pm 0.014\ {\text {(syst.)}}$ and $0.093 \pm 0.017\ {\text {(stat.)}}\pm 0.021\ {\text {(syst.)}}$ for jet transverse momenta of 200–400  $\text {GeV}$ and 1400–1600  $\text {GeV}$ , respectively.Peer Reviewe

A search for top squarks with R-parity-violating decays to all-hadronic final states with the ATLAS detector in s\sqrt{s} = 8 TeV proton-proton collisions

A search for the pair production of top squarks, each with R-parity-violating decays into two Standard Model quarks, is performed using 17.4 fb$^{−1}$ of $\sqrt{s}=8$ TeV proton-proton collision data recorded by the ATLAS experiment at the LHC. Each top squark is assumed to decay to a b- and an s-quark, leading to four quarks in the final state. Background discrimination is achieved with the use of b-tagging and selections on the mass and substructure of large-radius jets, providing sensitivity to top squark masses as low as 100 GeV. No evidence of an excess beyond the Standard Model background prediction is observed and top squarks decaying to $\overline{b}\overline{s}$ are excluded for top squark masses in the range $100\ \le {m}_{\overline{t}}\le\ 315$ GeV at 95% confidence level.Peer Reviewe

Measurements of ttˉt\bar{t} differential cross-sections of highly boosted top quarks decaying to all-hadronic final states in pppp collisions at s=13 \sqrt{s}=13\, TeV using the ATLAS detector

Measurements are made of differential cross-sections of highly boosted pair-produced top quarks as a function of top-quark and tt¯ system kinematic observables using proton-proton collisions at a center-of-mass energy of s=13  TeV. The data set corresponds to an integrated luminosity of 36.1  fb-1, recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. Events with two large-radius jets in the final state, one with transverse momentum pT>500  GeV and a second with pT>350  GeV, are used for the measurement. The top-quark candidates are separated from the multijet background using jet substructure information and association with a b-tagged jet. The measured spectra are corrected for detector effects to a particle-level fiducial phase space and a parton-level limited phase space, and are compared to several Monte Carlo simulations by means of calculated χ2 values. The cross-section for tt¯ production in the fiducial phase-space region is 292±7(stat)±71(syst)  fb, to be compared to the theoretical prediction of 384±36  fb.Peer Reviewe

Measurement of charged-particle distributions sensitive to the underlying event in s=13 \sqrt{s}=13 TeV proton-proton collisions with the ATLAS detector at the LHC

We present charged-particle distributions sensitive to the underlying event, measured by the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV, in low-luminosity Large Hadron Collider fills corresponding to an integrated luminosity of 1.6 nb$^{−1}$. The distributions were constructed using charged particles with absolute pseudorapidity less than 2.5 and with transverse momentum greater than 500 MeV, in events with at least one such charged particle with transverse momentum above 1 GeV. These distributions characterise the angular distribution of energy and particle flows with respect to the charged particle with highest transverse momentum, as a function of both that momentum and of charged-particle multiplicity. The results have been corrected for detector effects and are compared to the predictions of various Monte Carlo event generators, experimentally establishing the level of underlying-event activity at LHC Run 2 energies and providing inputs for the development of event generator modelling. The current models in use for UE modelling typically describe this data to 5% accuracy, compared with data uncertainties of less than 1%.Peer Reviewe

Measurement of the cross section for isolated-photon plus jet production in pppp collisions at s=13\sqrt s=13 TeV using the ATLAS detector

The dynamics of isolated-photon production in association with a jet in proton–proton collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset with an integrated luminosity of 3.2 fb −1 . Photons are required to have transverse energies above 125 GeV. Jets are identified using the anti- kt algorithm with radius parameter R=0.4 and required to have transverse momenta above 100 GeV. Measurements of isolated-photon plus jet cross sections are presented as functions of the leading-photon transverse energy, the leading-jet transverse momentum, the azimuthal angular separation between the photon and the jet, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass system. Tree-level plus parton-shower predictions from Sherpa and Pythia as well as next-to-leading-order QCD predictions from Jetphox and Sherpa are compared to the measurements.Peer Reviewe

The performance of the jet trigger for the ATLAS detector during 2011 data taking

The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton–proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon–nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction.Peer Reviewe

Beam-induced and cosmic-ray backgrounds observed in the ATLAS detector during the LHC 2012 proton-proton running period

This paper discusses various observations on beam-induced and cosmic-ray backgrounds in the ATLAS detector during the LHC 2012 proton-proton run. Building on published results based on 2011 data, the correlations between background and residual pressure of the beam vacuum are revisited. Ghost charge evolution over 2012 and its role for backgrounds are evaluated. New methods to monitor ghost charge with beam-gas rates are presented and observations of LHC abort gap population by ghost charge are discussed in detail. Fake jets from colliding bunches and from ghost charge are analysed with improved methods, showing that ghost charge in individual radio-frequency buckets of the LHC can be resolved. Some results of two short periods of dedicated cosmic-ray background data-taking are shown, in particular cosmic-ray muon induced fake jet rates are compared to Monte Carlo simulations and to the fake jet rates from beam background. A thorough analysis of a particular LHC fill, where abnormally high background was observed, is presented. Correlations between backgrounds and beam intensity losses in special fills with very high β(*) are studied.Peer Reviewe

Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

This article presents measurements of $t\bar{t}$ differential cross-sections in a fiducial phase-space region, using an integrated luminosity of 3.2 fb$^{-1}$ of proton–proton data at a centre-of-mass energy of $\sqrt{s} = 13$  TeV recorded by the ATLAS experiment at the LHC in 2015. Differential cross-sections are measured as a function of the transverse momentum and absolute rapidity of the top quark, and of the transverse momentum, absolute rapidity and invariant mass of the $t\bar{t}$ system. The $t\bar{t}$ events are selected by requiring one electron and one muon of opposite electric charge, and at least two jets, one of which must be tagged as containing a b-hadron. The measured differential cross-sections are compared to predictions of next-to-leading order generators matched to parton showers and the measurements are found to be consistent with all models within the experimental uncertainties with the exception of the Powheg-Box $+$ Herwig++ predictions, which differ significantly from the data in both the transverse momentum of the top quark and the mass of the $t\bar{t}$ system.Peer Reviewe