Most clinical practice guidelines recommend restrictive red cell transfusion practices, with the goal of minimising exposure to allogeneic blood. The purpose of this review is to compare clinical ...outcomes in patients randomised to restrictive versus liberal transfusion thresholds (triggers).
To examine the evidence for the effect of transfusion thresholds on the use of allogeneic and/or autologous red cell transfusion, and the evidence for any effect on clinical outcomes.
We identified trials by searching; The Cochrane Injuries Group Specialised Register (searched 01 Feb 2011), Cochrane Central Register of Controlled Trials 2011, issue 1 (The Cochrane Library), MEDLINE (Ovid) 1948 to January Week 3 2011, EMBASE (Ovid) 1980 to 2011 (Week 04), ISI Web of Science: Science Citation Index Expanded (1970 to Feb 2011), ISI Web of Science: Conference Proceedings Citation Index- Science (1990 to Feb 2011). We checked reference lists of other published reviews and relevant papers to identify any additional trials.
Controlled trials in which patients were randomised to an intervention group or to a control group. Trials were included where intervention groups were assigned on the basis of a clear transfusion 'trigger', described as a haemoglobin (Hb) or haematocrit (Hct) level below which a red blood cell (RBC) transfusion was to be administered.
Risk ratios of requiring allogeneic blood transfusion, transfused blood volumes and other clinical outcomes were pooled across trials, using a random effects model. Data extraction and assessment of the risk of bias was performed by two people.
Nineteen trials involving a total of 6264 patients were identified, and were similar enough that the results could be combined. Restrictive transfusion strategies reduced the risk of receiving a RBC transfusion by 39% (RR 0.61, 95% CI 0.52 to 0.72). This equates to an average absolute risk reduction (ARR) of 34% (95% CI 24% to 45%). The volume of RBCs transfused was reduced on average by 1.19 units (95% CI 0.53 to 1.85 units). However, heterogeneity between trials was statistically significant (P<0.00001; I(2)≥93%) for these outcomes. Restrictive transfusion strategies did not appear to impact the rate of adverse events compared to liberal transfusion strategies (i.e. mortality, cardiac events, myocardial infarction, stroke, pneumonia and thromboembolism). Restrictive transfusion strategies were associated with a statistically significant reduction in hospital mortality (RR 0.77, 95% CI 0.62-0.95) but not 30 day mortality (RR 0.85, 95% CI 0.70 to 1.03). The use of restrictive transfusion strategies did not reduce functional recovery, hospital or intensive care length of stay. The majority of patients randomised were included in good quality trials, but some items of methodological quality were unclear. There are no trials in patients with acute coronary syndrome.
The existing evidence supports the use of restrictive transfusion triggers in most patients including those with pre-existing cardiovascular disease. As there are no trials, the effects of restrictive transfusion triggers in high risk groups such as acute coronary syndrome need to be tested in further large clinical trials. In countries with inadequate screening of donor blood, the data may constitute a stronger basis for avoiding transfusion with allogeneic red cells.
Background
There is considerable uncertainty regarding the optimal haemoglobin threshold for the use of red blood cell (RBC) transfusions in anaemic patients. Blood is a scarce resource, and in some ...countries, transfusions are less safe than others because of a lack of testing for viral pathogens. Therefore, reducing the number and volume of transfusions would benefit patients.
Objectives
The aim of this review was to compare 30‐day mortality and other clinical outcomes in participants randomized to restrictive versus liberal red blood cell (RBC) transfusion thresholds (triggers) for all conditions. The restrictive transfusion threshold uses a lower haemoglobin level to trigger transfusion (most commonly 7 g/dL or 8 g/dL), and the liberal transfusion threshold uses a higher haemoglobin level to trigger transfusion (most commonly 9 g/dL to 10 g/dL).
Search methods
We identified trials by searching CENTRAL (2016, Issue 4), MEDLINE (1946 to May 2016), Embase (1974 to May 2016), the Transfusion Evidence Library (1950 to May 2016), the Web of Science Conference Proceedings Citation Index (1990 to May 2016), and ongoing trial registries (27 May 2016). We also checked reference lists of other published reviews and relevant papers to identify any additional trials.
Selection criteria
We included randomized trials where intervention groups were assigned on the basis of a clear transfusion 'trigger', described as a haemoglobin (Hb) or haematocrit (Hct) level below which a red blood cell (RBC) transfusion was to be administered.
Data collection and analysis
We pooled risk ratios of clinical outcomes across trials using a random‐effects model. Two people extracted the data and assessed the risk of bias. We conducted predefined analyses by clinical subgroups. We defined participants randomly allocated to the lower transfusion threshold as 'restrictive transfusion' and to the higher transfusion threshold as 'liberal transfusion'.
Main results
A total of 31 trials, involving 12,587 participants, across a range of clinical specialities (e.g. surgery, critical care) met the eligibility criteria. The trial interventions were split fairly equally with regard to the haemoglobin concentration used to define the restrictive transfusion group. About half of them used a 7 g/dL threshold, and the other half used a restrictive transfusion threshold of 8 g/dL to 9 g/dL. The trials were generally at low risk of bias .Some items of methodological quality were unclear, including definitions and blinding for secondary outcomes.
Restrictive transfusion strategies reduced the risk of receiving a RBC transfusion by 43% across a broad range of clinical specialties (risk ratio (RR) 0.57, 95% confidence interval (CI) 0.49 to 0.65; 12,587 participants, 31 trials; high‐quality evidence), with a large amount of heterogeneity between trials (I² = 97%). Overall, restrictive transfusion strategies did not increase or decrease the risk of 30‐day mortality compared with liberal transfusion strategies (RR 0.97, 95% CI 0.81 to 1.16, I² = 37%; N = 10,537; 23 trials; moderate‐quality evidence) or any of the other outcomes assessed (i.e. cardiac events (low‐quality evidence), myocardial infarction, stroke, thromboembolism (high‐quality evidence)). Liberal transfusion did not affect the risk of infection (pneumonia, wound, or bacteraemia).
Authors' conclusions
Transfusing at a restrictive haemoglobin concentration of between 7 g/dL to 8 g/dL decreased the proportion of participants exposed to RBC transfusion by 43% across a broad range of clinical specialities. There was no evidence that a restrictive transfusion strategy impacts 30‐day mortality or morbidity (i.e. mortality at other points, cardiac events, myocardial infarction, stroke, pneumonia, thromboembolism, infection) compared with a liberal transfusion strategy. There were insufficient data to inform the safety of transfusion policies in certain clinical subgroups, including acute coronary syndrome, myocardial infarction, neurological injury/traumatic brain injury, acute neurological disorders, stroke, thrombocytopenia, cancer, haematological malignancies, and bone marrow failure. The findings provide good evidence that transfusions with allogeneic RBCs can be avoided in most patients with haemoglobin thresholds above 7 g/dL to 8 g/dL.
Prolonged immobility during a critical illness may predispose patients to the development of joint contracture. We sought to document the incidence of, the risk factors for and the reversibility of ...joint contractures among patients who stayed in a tertiary intensive care unit (ICU) for 2 weeks or longer.
We conducted a chart review to collect data on the presence of and risk factors for joint contractures in the shoulders, elbows, hips, knees and ankles among patients admitted to the ICU between January 2003 and March 2005.
At the time of transfer out of the ICU, at least 1 joint contracture was recorded in 61 (39%) of 155 patients; 52 (34%) of the patients had joint contractures of an extent documented to impair function. Time spent in the ICU was a significant risk factor for contracture: a stay of 8 weeks or longer was associated with a significantly greater risk of any joint contracture than a stay of 2 to 3 weeks (adjusted odds ratio OR 7.09, 95% confidence interval (CI) 1.29-38.9; p = 0.02). Among the variables tested, only the use of steroids conferred a protective effect against joint contractures (adjusted OR 0.35, 95% CI 0.14-0.83; p = 0.02). At the time of discharge to home, which occurred a median of 6.6 weeks after transfer out of intensive care, 50 (34%) of the 147 patients not lost to follow-up still had 1 or more joint contractures, and 34 (23%) of the patients had at least 1 functionally significant joint contracture.
Following a prolonged stay in the ICU, a functionally significant contracture of a major joint occurred in more than one-third of patients, and most of these contractures persisted until the time of discharge to home.
Through laboratory and field studies, the utility of amino acid compound-specific nitrogen isotope analysis (AA-CSIA) in avian studies is investigated. Captive American kestrels (Falco sparverius) ...were fed an isotopically characterized diet and patterns in δ15N values of amino acids (AAs) were compared to those in their tissues (muscle and red blood cells) and food. Based upon nitrogen isotope discrimination between diet and kestrel tissues, AAs could mostly be categorized as source AAs (retaining baseline δ15N values) and trophic AAs (showing 15N enrichment). Trophic discrimination factors based upon the source (phenylalanine, Phe) and trophic (glutamic acid, Glu) AAs were 4.1 (muscle) and 5.4 (red blood cells), lower than those reported for metazoan invertebrates. In a field study involving omnivorous herring gulls (Larus argentatus smithsonianus), egg AA isotopic patterns largely retained those observed in the laying female’s tissues (muscle, red blood cells, and liver). Realistic estimates of gull trophic position were obtained using bird Glu and Phe δ15N values combined with β values (difference in Glu and Phe δ15N in primary producers) for aquatic and terrestrial food webs. Egg fatty acids were used to weight β values for proportions of aquatic and terrestrial food in gull diets. This novel approach can be applied to generalist species that feed across ecosystem boundaries.
L'information tirée du questionnaire détaillé du recensement guide souvent la planification et l'évaluation des programmes dans les ministères fédéraux et à d'autres paliers de gouvernement. En soins ...de santé, c'est un outil essentiel pour la planification et la prestation des services. Le questionnaire produit des données exactes et fiables sur les tendances et les enjeux sociaux, y compris les déterminants de la santé, comme les liens entre le revenu, le sexe, l'éducation, la région, le travail et d'autres facteurs qui influencent l'accès aux soins et les résultats pour la santé. En fait, le questionnaire détaillé du recensement est la seule source qui réunit toutes ces variables et permet aux chercheurs d'étudier de nouvelles façons de comprendre les déterminants de la santé. Le gouvernement Stephen Harper a indiqué que Statistique Canada portera de 20 % à 30 % l'échantillonnage aléatoire, ce qui devrait coûter 30 millions de dollars de plus. Or, un taux inégal de réponses minera fatalement la qualité des données recueillies. Dans le contexte d'une enquête à participation volontaire, les communautés autochtones, les quartiers pauvres, les nouveaux immigrants et les ménages très bien nantis produiront des taux de réponse inférieurs à ceux des Canadiens de la classe moyenne. Cela signifie que certaines communautés seront sous-représentées ou le seront à peine. L'ajout de répondants ne fera que produire un volume plus important de données partiales, en grande partie inutilisables. Si l'on ne casse pas cette décision, le Canada sera le seul pays industrialisé à ne pas avoir d'information détaillée sur sa population. Le gouvernement Harper semblera avoir pris une décision basée sur l'idéologie plutôt que sur la preuve. Il y encore pire : il a imposé une approche non éclairée des politiques publiques à tous les autres ordres de gouvernement, aux autorités sanitaires et aux établissements. Le gouvernement Harper aura indiqué qu'il n'est plus voué à l'imputabilité.
In this paper, we report on the angular distribution of thickness, composition, microstructure and sheet resistance of a zinc oxide film obtained by pulsed laser deposition (PLD) at room temperature ...under 10
–6
mbar on a 40 mm large SiO
2
/Si substrate. Rutherford backscattering spectroscopy (RBS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and electrical resistivity measurements were carried out to fully characterize the zinc oxide film for different zones of the substrate. The results show the anisotropy of its structural and physical properties along the substrate. In the external part of the film, which corresponds to an angular deviation of around 25°–30° from the normal to the laser impact, a pure (002) textured and stoichiometric ZnO is evidenced. In contrast, the formation of a nanocomposite is observed in its central part and exhibits nearly stoichiometric ZnO, oxygen-deficient ZnO
1−
x
and metallic Zn nanocrystallites. Due to their small sizes (a few nm), such Zn nanocrystallites are not detected by classical
θ
/2
θ
XRD and can only be evidenced by TEM experiments. The non-uniformities in composition, microstructure and physical properties of the films are due to the PLD process for which the angular distribution of the Zn and O species in the ablation plume is not homogeneous. The observed anisotropy is not detrimental for PLD experiments performed with low size substrate (1–2 cm
2
) which is located in the main propagation axis of the PLD plume.
In this paper, the syntheses of a set of cerium-bismuth mixed oxides with the formula Ce
Bi
O
, where the range of x is 0.0 to 1.0 in 10 mol% steps, via co-precipitation methods is described. Two ...synthesis routes are tested: The "normal" and the so called "reverse strike" (RS) co-precipitation route. The syntheses are performed with an automated synthesis robot. The activity for Diesel soot oxidation is measured by temperature programmed oxidation with an automated, serial thermogravimetric and differential scanning calorimetry system (TGA/DSC). P90 is used as a model soot. An automated and reproducible tight contact between soot and catalyst is used. The synthesized catalysts are characterized in terms of the specific surface area according to Brunauer, Emmett and Teller (
), as well as the dynamic oxygen storage capacity (
). The crystalline phases of the catalysts are analysed by powder X-ray diffraction (PXRD) and Raman spectroscopy. The elemental mass fraction of the synthesized catalysts is verified by X-ray fluorescence (XRF) analysis. A correlation between the
values,
and
has been discovered. The best catalytic performance is exhibited by the catalyst with the formula RS-Ce
Bi
O
which is synthesized by the reverse strike co-precipitation route. Here, a correlation between activity,
, and
can be confirmed based on structural properties.
We report on four radio-detected cosmic-ray (CR) or CR-like events observed with the Antarctic Impulsive Transient Antenna (ANITA), a NASA-sponsored long-duration balloon payload. Two of the four ...were previously identified as stratospheric CR air showers during the ANITA-I flight. A third stratospheric CR was detected during the ANITA-II flight. Here, we report on characteristics of these three unusual CR events, which develop nearly horizontally, 20-30 km above the surface of Earth. In addition, we report on a fourth steeply upward-pointing ANITA-I CR-like radio event which has characteristics consistent with a primary that emerged from the surface of the ice. This suggests a possible τ-lepton decay as the origin of this event, but such an interpretation would require significant suppression of the standard model τ-neutrino cross section.
We report results from 120 h of live time with the Goldstone lunar ultrahigh energy neutrino experiment (GLUE). The experiment searches for < or = 10 ns microwave pulses from the lunar regolith, ...appearing in coincidence at two large radio telescopes separated by 22 km and linked by optical fiber. Such pulses would arise from subsurface electromagnetic cascades induced by interactions of > or = 100 EeV (1 EeV = 10(18) eV neutrinos in the lunar regolith. No candidates are yet seen, and the implied limits constrain several current models for ultrahigh energy neutrino fluxes.
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