1,720,957 research outputs found
Is dexmedetomidine a favorable agent for cerebral hemodynamics?
No full textHemodynamic stability, with special attention to arterial
pressure in order to warrant an adequate cerebral perfusion,
is a cornerstone of neuroanesthesia (NA) and neurocritical
care (NCC) management. An abrupt elevation of arterial
blood pressure can aggravate cerebral edema or induce
cerebral hematoma, resulting in a prolonged NCC unit
stay. On the other hand, hypotension is associated with an
increased risk for cerebral ischemia that is more pronounced
when autoregulation of cerebral blood flow (CBF) is
impaired, and there is a compromised cerebral compliance.
[1,2] However, NCC encompasses subgroups of patients such
as traumatic brain injury (TBI), subarachnoid hemorrhage
(SAH), and intracerebral hemorrhage ones in whom there
is the unique need to maintain supranormal blood pressure
values with a view to ensure adequate cerebral perfusion
and to optimize outcome.[1-3] Moreover, any derangement
of cerebrovascular hemodynamics may contribute to
intracranial pressure (ICP) elevation with concomitant
cerebral perfusion pressure (CPP) deterioration, which can
further exacerbate ischemic damage.[3
Role of Dexmedetomidine for Sedation in Neurocritical Care Patients: A Qualitative Systematic Review and Meta-analysis of Current Evidence
No full textIntroduction: This systematic review appraises the clinical evidence on
efficacy and safety of dexmedetomidine (DEX), as a sole sedative or as
sedative adjunct in adult neurocritical care (NCC) patients.
Materials and Methods: A database search was conducted to identify
randomized clinical trials and observational studies reporting the use of
DEX alone or as adjunct for sedation in NCC setting. The primary outcome
was the occurrence of hemodynamic changes, whereas the secondary out comes were sedative and analgesic efficacy, quality and time to awakening,
and development of adverse events.
Results: Eight trials including 3 randomized controlled trials and 5 obser vational studies, enrolling 650 patients, were selected. All the retrieved
studies had a high risk of bias and a low to moderate quality. Dexmedetomi dine provided a better sedation score and reduced analgesic requirements
when compared to propofol or midazolam sedation. No statistically signif icant difference in the combined hemodynamic effect (hypotension or bra dycardia) between DEX and controls (risk ratio, 1.50; 95% confidence
interval, 0.65–3.48; P = 0.34; I
2 = 56%) was identified. Adverse events
were not consistently reported.
Conclusions: Available clinical literature supporting the efficacy and
safety of DEX use in adult NCC setting is of limited quantity and quality.
However, from the current evidence on the use of DEX in NCC, as sole
sedative agent or as an adjunct, seems to be both efficient and safe
Dexmedetomidine as a sedative and analgesic adjuvant in spine surgery: a systematic review and meta-analysis of randomized controlled trials
No full textDexmedetomidine as a sedative and analgesic adjuvant in spine surgery: a systematic review and
meta-analysis of randomized controlled trials
Georgia G. Tsaousi1 & Chryssa Pourzitaki1 & Simone Aloisio2 & Federico Bilotta2
Received: 21 April 2018 / Accepted: 6 July 2018
# Springer-Verlag GmbH Germany, part of Springer Nature 2018
Abstract
Purpose This systematic review and meta-analysis appraise the clinical evidence on efficacy and
safety of dexmedetomidine (DEX), as a sedative and analgesic adjunct in adult patients undergoing
spine surgery.
Methods A database search was conducted to identify randomized clinical trials (RCTs) pertinent to
the perioperative use of DEX in spine surgery. Sedative and analgesic efficacy of DEX constituted
the primary outcomes, whilst the incidence of hemodynamic changes, quality of recovery and
occurrence of adverse events served as secondary ones.
Results Fifteen studies enrolling a total of 913 patients were selected for qualitative analysis,
among which eight RCTs incor- porating a placebo comparison group were included in the
meta-analysis. Most of the retrieved studies were of moderate to good quality and demonstrated an
acceptable risk of bias. DEX-treated patients showed a significant reduction of both propofol [mean
difference (MD), −214.47 mg; 95%CI, −253.16 to −175.78; P < 0.001] and morphine equivalents
consumption both intraoper- atively and postoperatively (MD, −2.69; 95% CI, −3.05 to −2.33; P <
0.001 and MD, −4.36 mg; 95%CI, −6.93 to −1.79; P < 0.001, respectively) compared to those assigned
to placebo. Postoperative nausea and vomiting incidence were comparable between DEX and placebo
groups, whilst other adverse events were not consistently reported.
Conclusions DEX emerges as an attractive alternative to standard sedative and analgesic modalities
applied in spine surgery, by attaining a notable sedative and opioid-sparing effect, which goes
with an enhanced safety profile. Yet, no definite conclusion can be drawn due to the considerable
heterogeneity of available data.
Trial registration PROSPERO CRD42015029537
Control of Hemodynamic Responses and Perioperative Outcomes in Transsphenoidal Pituitary Surgery: A Qualitative Systematic Review of the Available Evidence
No full textAbstract: Transnasal transsphenoidal (TNTS) pituitary surgery is
associated with short-lived but intense nociceptive stimuli which
cause substantial hemodynamic perturbations that may increase
blood loss and impair visualization of the surgical field. This
systematic review aimed to critically appraise the clinical evi dence for the efficacy and safety of various anesthetic techniques,
other pharmacological modalities, and supplementary inter ventions by assessing intraoperative systemic hemodynamics, use
of adjunct medications, quality of the surgical field, intra operative blood loss, and recovery profiles in patients undergoing
TNTS pituitary surgery. Relevant randomized clinical trials and
observational studies were identified in a systematic literature
search; 16 studies (13 randomized clinical trials, 3 observational
studies) enrolling a total of 907 patients were identified for in clusion in this review. Propofol provided more potent hemody namic control compared with volatile anesthetics with a sparing
effect on the need for additional drugs to blunt hemodynamic
responses. Recovery profiles between propofol and sevoflurane
were either equivalent or favored sevoflurane, but both agents
were superior to isoflurane. Regarding intraoperative analgesia,
remifentanil was associated with superior hemodynamic control
and recovery profiles than fentanyl. Dexmedetomidine had
beneficial effects on hemodynamics, surgical field quality, re covery characteristics, and nociceptive properties compared with
placebo. Although there was no clear-cut superiority of other
adjunct pharmacological modalities on hemodynamic responses
during surgery, regional blocks were associated with beneficial
impacts on both primary and secondary outcomes. In summary,
short-acting anesthetics, analgesics and dexmedetomidine seem
to improve intraoperative hemodynamics, blood loss, and re covery qualities during TNTS pituitary surgery. However, de finitive conclusions cannot be drawn because of methodological
heterogeneity in the identified studie
Early and late clinical outcomes after decompressive craniectomy for traumatic refractory intracranial hypertension: a systematic review and meta-analysis of current evidence
No full textIntroduction: Decompressive craniectomy (DC) to control refractory intracranial hypertension in patients with traumatic brain injury (TBI), has been listed as possible but controversial therapeutic approach in the latest version of TBI management guidelines. This study aimed to perform a systematic review and meta-analysis on efficacy and safety of DC compared to standard care in TBI patients.
Evidence acquisition: A database search from 2011 to 2017 was conducted to identify studies pertinent to DC compared to standard care after TBI. The primary outcomes were mortality and functional outcome upon hospital discharge and at 6 and 12 months after intervention, whereas secondary outcomes were intracranial pressure (ICP) control, hospitalization data and occurrence of adverse events.
Evidence synthesis: Three randomized controlled trials and two observational studies enrolling 3451 patients were selected for qualitative analysis, among which four were included in the meta-analysis. DC-treated patients showed a significant reduction of overall mortality (RR, 0.57; 95% CI: 0.5-0.66; P<0.001; I2=17%) with no profound beneficial effect on functional outcome (RR, 0.89; 95% CI: 0.78-1.02; P=0.09; I2=58%) compared to those receiving standard care. A more efficient ICP reduction and a tendency towards shorter duration of hospitalization were recorded in DC versus standard care group. Adverse events are more common in DC-treated patients.
Conclusions: It seems that, in TBI patients with intracranial hypertension, the use of DC is associated with survival benefit when compared to medical therapy alone, but with no clear improvement of functional outcome. Yet no definite conclusion can be drawn due to limited quantity and considerable heterogeneity of available data
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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