31 research outputs found
Trends in survival among extremely-low-birth-weight infants (less than 1000 g)without significant bronchopulmonary dysplasia
Objective The aim of this study was to analyze the evolution from 1997 to 2009 of survival without significant (moderate and severe) bronchopulmonary dysplasia (SWsBPD) in extremely-low-birth-weight (ELBW) infants and to determine the influence of changes in resuscitation, nutrition and mechanical ventilation on the survival rate. Study design In this study, 415 premature infants with birth weights below 1000 g (ELBW) were divided into three chronological subgroups: 1997 to 2000 (nâ=â65), 2001 to 2005 (nâ=â178) and 2006 to 2009 (nâ=â172). Between 1997 and 2000, respiratory resuscitation in the delivery room was performed via a bag and mask (AmbuÂź, Ballerup, Sweden) with 40-50% oxygen. If this procedure was not effective, oral endotracheal intubation was always performed. Pulse oximetry was never used. Starting on January 1, 2001, a change in the delivery room respiratory policy was established for ELBW infants. Oxygenation and heart rate were monitored using a pulse oximeter (NellcorÂź) attached to the newborn"s right hand. If resuscitation was required, ventilation was performed using a face mask, and intermittent positive pressure was controlled via a ventilator (Babylog2, DrĂ€gger). In 2001, a policy of aggressive nutrition was also initiated with the early provision of parenteral amino acids. We used standardized parenteral nutrition to feed ELBW infants during the first 1224 hours of life. Lipids were given on the first day. The glucose concentration administered was increased by 1 mg/kg/minute each day until levels reached 8 mg/kg/minute. Enteral nutrition was started with trophic feeding of milk. In 2006, volume guarantee treatment was instituted and administered together with synchronized intermittent mandatory ventilation (SIMVâ+âVG). The complications of prematurity were treated similarly throughout the study period. Patent ductus arteriosus was only treated when hemodynamically significant. Surgical closure of the patent ductus arteriosus was performed when two courses of indomethacin or ibuprofen were not sufficient to close it. Mild BPD were defined by a supplemental oxygen requirement at 28 days of life and moderate BPD if breathing room air or a need for <30% oxygen at 36 weeks postmenstrual age or discharge from the NICU, whichever came first. Severe BPD was defined by a supplemental oxygen requirement at 28 days of life and a need for greater than or equal to 30% oxygen use and/or positive pressure support (IPPV or nCPAP) at 36 weeks postmenstrual age or discharge, whichever came first. Moderate and severe BPD have been considered together as"significant BPD". The goal of pulse oximetry was to maintain a hemoglobin saturation of between 88% and 93%. Patients were considered to not need oxygen supplementation when it could be permanently withdrawn....
Impact of chorioamnionitis on exhaled nitric oxide and endotracheal aspirate levels of nitrites-nitrates and interleukin-8 in mechanically ventilated preterm neonates.
OBJECTIVES: To assess the influence of maternal chorioamnionitis on early exhaled nitric oxide (NO) and levels of nitrites-nitrates and interleukin (IL)-8 in endotracheal aspirate fluid in mechanically ventilated preterm neonates. STUDY DESIGN: Cross-sectional study. PATIENT-SUBJECT SELECTION: Between September 2007 and August 2009, 54 mechanically ventilated preterm neonates were included. Patients were divided into two groups according to the presence or absence of maternal chorioamnionitis, and those without chorioamnionitis (controls) were further stratified into two subgroups by birth weight < or â„ 2,000 g. METHODOLOGY: The ventilator used was a Babylog 8000. The NO level assessed was the plateau value given by the software of the Sievers NOA apparatus. Collection of endotracheal aspirate fluid samples was performed coinciding with routine aspirations and using the dry technique. RESULTS: The two groups of control neonates showed statistically significant differences in exhaled NO expressed as nl/min and normalized exhaled NO expressed as either nl/min or nl/min/kg, so they are not homogeneous and cannot be used in clinical practice. Serum C-reactive protein and endotracheal aspirate levels of nitrites-nitrates were significantly higher in the chorioamnionitis group than in controls (3.6 vs. 1.07 ”mol/L; P = 0.035). Nitrites-nitrates levels were positively correlated with exhaled NO in ppb (Ï = 0.367; P = 0.006). Minute exhaled endogenous NO was significantly higher in the chorioamnionitis group (0.48 vs. 0.27 nl/min/kg; P = 0.021). CONCLUSIONS: In mechanically ventilated preterm infants weighing <2,000 g, maternal chorioamnionitis was associated with an increase of early exhaled NO (nl/min/kg) and serum levels of C-reactive protein and levels of nitrites-nitrates in endotracheal aspirate fluid
Search for the decay D0âÏ+ÏâÎŒ+ÎŒâ
A search for the D0âÏ+ÏâÎŒ+ÎŒâ decay, where the muon pair does not originate from a resonance, is
performed using protonâproton collision data corresponding to an integrated luminosity of 1.0 fbâ1
recorded by the LHCb experiment at a centre-of-mass energy of 7 TeV. No signal is observed
and an upper limit on the relative branching fraction with respect to the resonant decay mode
D0âÏ+Ïâ
Ï(âÎŒ+ÎŒâ
), under the assumption of a phase-space model, is found to be
B D0âÏ
+
Ï
â
Ό
+
Ό
â /B D0âÏ
+
Ï
â
Ï âÎŒ
+
Ό
â < 0.96
at 90% confidence level. The upper limit on the absolute branching fraction is evaluated to be
B(D0âÏ+ÏâÎŒ+ÎŒâ
) < 5.5Ă10â7 at 90% confidence level. This is the most stringent to date.S
Evidence for the decay X(3872) âÏ(2S)Îł
Evidence for the decay mode X(3872) âÏ(2S)Îłin B+âX(3872)K+decays is found with a sig-nificance of 4.4 standard deviations. The analysis is based on adata sample of protonâproton collisions, corresponding to an integrated luminosity of3fbâ1, collected with the LHCb detector, at centre-of-mass energies of 7and8TeV. The ratio of the branching fraction of the X(3872) âÏ(2S)Îłdecay to that of the X(3872) âJ/ÏÎłdecay is measured to be
B(X(3872)âÏ(2S)Îł)
B(X(3872)âJ/ÏÎł)
= 2.46± 0.64±0.29,
where the first uncertainty is statistical and the second is systematic. The measured value does not support apureDÂŻ
Dâmolecular interpretation of the X(3872)state.S
A study of CP violation in B± âDK± and B±âDϱ decays with DâK0SK±Ïâ final states
A first study of CP violation in the decay modes B±â[KS 0 K±Ïâ] D h±and B±â[KS 0 Kâ ϱ]
D h±, where h labels a K or Ï meson and D labels a D 0 or D⟠0 meson, is performed. The
analysis uses the LHCb data set collected in pp collisions, corresponding to an integrated
luminosity of 3 fbâ 1. The analysis is sensitive to the CP-violating CKM phase Îł through
seven observables: one charge asymmetry in each of the four modes and three ratios of the
charge-integrated yields. The results are consistent with measurements of Îł using other decay modesS
Measurement of the B+c meson lifetime using B+câJ/ÏÎŒ+ΜΌX decays
The lifetime of the B+c meson is measured using semileptonic decays having a J/Ï meson and a muon in the final state. The data, corresponding to an integrated luminosity of 2 fb â1, are collected by the LHCb detector in pp collisions at a centre-of-mass energy of 8 TeV. The measured lifetime is
Ï=509±8±12 fs,
where the first uncertainty is statistical and the second is systematic.S
Search for CP violation in the decay D+âÏâÏ+Ï+
A search for CP violation in the phase space of the decay D+âÏâÏ+Ï+ is reported using pp collision
data, corresponding to an integrated luminosity of 1.0 fbâ1, collected by the LHCb experiment at a centreof-
mass energy of 7 TeV. The Dalitz plot distributions for 3.1Ă106 D+ and Dâ candidates are compared
with binned and unbinned model-independent techniques. No evidence for CP violation is foundS
Study of J/Ï production and cold nuclear matter effects in pPb collisions at âsNN = 5 TeV
The production of J/Ï mesons with rapidity 1.5 < y < 4.0 or â5.0 < y < â2.5 and transverse momentum p T < 14 GeV/c is studied with the LHCb detector in proton-lead collisions at a nucleon-nucleon centre-of-mass energy âsNN = 5TeV. The J/Ï mesons are reconstructed using the dimuon decay mode. The analysis is based on a data sample corresponding to an integrated luminosity of about 1.6 nbâ1. For the first time the nuclear modification factor and forward-backward production ratio are determined separately for prompt J/Ï mesons and J/Ï from b-hadron decays. Clear suppression of prompt J/Ï production with respect to proton-proton collisions at large rapidity is observed, while the production of J/Ï from b-hadron decays is less suppressed. These results show good agreement with available theoretical predictions. The measurement shows that cold nuclear matter effects are important for interpretations of the related quark-gluon plasma signatures in heavy-ion collisions.S
Measurement of the flavour-specific CP-violating asymmetry assl in B0s decays
The CP-violating asymmetry as
sl is studied using semileptonic decays of B0s
and B0s
mesons produced in
pp collisions at a centre-of-mass energy of 7 TeV at the LHC, exploiting a data sample corresponding
to an integrated luminosity of 1.0 fbâ1. The reconstructed final states are D±
s ÎŒâ, with the D±
s particle
decaying in the Ïϱ mode. The D±
s ÎŒâ yields are summed over B0s
and B0s
initial states, and integrated
with respect to decay time. Data-driven methods are used to measure efficiency ratios. We obtain as
sl
=
(â0.06±0.50±0.36)%, where the first uncertainty is statistical and the second systematic.S