Evaluation of the start-up of hydraulic conditions of a fluidised bed system.

The development of this research was based on the analysis of an anaerobic fluidised bed reactor from the assembly of its components to the sealing of the system and further fluidisation. A hydrometer and a Venturi were used to identify the best means of measuring the flow rate. Results produced by both devices were similar, however, the latter was less effective due to the low flow rates necessary to operate the system. The hydrometer was the most adequate device for flow rate measurements in the range between 0.1 and 1.0 m³/h, whereas the Venturi proved to be an adequate device for the flow in the range between 0.3 and 0.7 m³/h. Sand with grain sizes varying from 357 to 1000 µm was used as support material. It was not observed statistically significant differences between the minimum fluidisation velocities related to the amount of supported material of 20% and 40% (VSM/Vusable) added to the reactor. Forty percent of the usable volume occupied with sand is adequate to reach fluidisation, instead of only the expansion of the bed. The fluidisation velocities for the sand grain size of 357 µm were 8.4 m/h ± 0.25 for 20%, and 8.6 m/h ± 0.30 for 40%, whereas for the 505 µm they were, respectively for 20% and 40%, 9.2 m/h ±0.70 and 10.1 m/h ± 0.37. The hydraulic tests allow to stress that sand grain sizes varying from 357 to 505 µm are recommended to be used in a system with similar characteristics.

Cerebral venous thrombosis in adolescence: Looking beyond the obvious.

Behçet's disease (BD) is a rare systemic vasculitis with multisystemic involvement. Neurological involvement, called neuro-Behçet's disease (NBD), mostly involves the central nervous system and cerebral venous thrombosis (CVT) is the predominant neurological manifestation in the pediatric age. A 12-year-old female with a past medical history of a CVT, without an identifiable etiology, was admitted with a five-day right fronto-orbital headache. Neuroimage showed a subacute thrombosis of a right superficial sylvian vein, with indirect signs of intracranial hypertension and no imaging signs of vasculitis. Prothrombotic screening and immunologic study were normal. She was started on acetazolamide and hypocoagulation with progressively improving. She had a history of frequent oral aphthae and an episode of a genital ulcer three months before admission. Pathergy test was negative. HLA-B51 was positive. She was diagnosed with NBD and started therapy with colchicine and infliximab. After discharge, the patient remains without symptoms, hypocoagulated, and on infliximab regimen, without complications to report. This case, only diagnosed in the second episode of CVT, is paradigmatic of the difficulty in establishing the diagnosis of BD.

Apolipoprotein E genotype does not influence the risk of symptomatic hemorrhage in acute ischemic stroke.

BACKGROUND: APOE ε4 is independently associated with lobar intracranial hemorrhages (ICH). Although the ε4 allele enhances amyloid deposition in blood vessels, the ε2 allele predisposes to vasculopathic changes leading to rupture of amyloid laden vessels. Thus, ε4 and ε2 carriers might have increased susceptibility to ICH. We aimed to study the impact of the apolipoprotein E alleles in the development of symptomatic ICH (sICH). METHODS: We included 384 consecutive ischemic anterior circulation stroke patients submitted to thrombolysis between January 2014 and March 2016. Admission CT-scans were reviewed to calculate the ASPECTS. Patients were followed for up to at least 6 months post-stroke or until death. Outcome was development of sICH, defined according to the ECASS III. RESULTS: Considering APOE genotyping, three patients had ε2/ε2, four had ε2/ε4, 38 had ε2/ε3, 284 had ε3/ε3, 51 had ε3/ε4 and four had ε4/ε4. sICH was associated with sex and diabetes. In multivariate analysis, sICH was not associated with carrying one or more ε4 alleles (OR: 0.483, 95%CI = [0.059, 3.939], p = 0.497) nor with carrying one or more ε2 alleles (OR: 1.369, 95%CI = [0.278, 6.734], p = 0.699). CONCLUSION: No association was found between APOE genotype and the development of symptomatic intracranial hemorrhage.

Late Cardiac Tamponade in a Patient Victim of Penetrating Trauma - Case Report.

CASE PRESENTATION: A case of a 49-year-old patient, male, victim of stab wound, developing belatedly cardiac tamponade and hemodynamic stability was reported. The patient underwent a pericardial window with drainage of pericardial effusion of blackened aspect; however, without visualization of the cardiac lesion, enlargement of the incision by median sternotomy was opted for. A hematoma was spotted at the left ventricle with epicardial lesion and a patch of pericardium was made with 3-0 polypropylene. The patient developed acute pulmonary edema and atrial fibrillation, which improved after the intensive care unit clinical management, with hospital discharge in the 7th postoperative day.

Late cardiac tamponade in a patient victim of penetrating trauma - case report

Abstract Case Presentation: A case of a 49-year-old patient, male, victim of stab wound, developing belatedly cardiac tamponade and hemodynamic stability was reported. The patient underwent a pericardial window with drainage of pericardial effusion of blackened aspect; however, without visualization of the cardiac lesion, enlargement of the incision by median sternotomy was opted for. A hematoma was spotted at the left ventricle with epicardial lesion and a patch of pericardium was made with 3-0 polypropylene. The patient developed acute pulmonary edema and atrial fibrillation, which improved after the intensive care unit clinical management, with hospital discharge in the 7th postoperative day.

Disconnection as a mechanism for social cognition impairment in multiple sclerosis.

OBJECTIVE: To assess the contribution of microstructural normal-appearing white matter (NAWM) damage to social cognition impairment, specifically in the theory of mind (ToM), in multiple sclerosis (MS). METHODS: We enrolled consecutively 60 patients with MS and 60 healthy controls (HC) matched on age, sex, and education level. All participants underwent ToM testing (Eyes Test, Videos Test) and 3T brain MRI including conventional and diffusion tensor imaging sequences. Tract-based spatial statistics (TBSS) were applied for whole-brain voxel-wise analysis of fractional anisotropy (FA) and mean diffusivity (MD) on NAWM. RESULTS: Patients with MS performed worse on both tasks of ToM compared to HC (Eyes Test 58.7 ± 13.8 vs 81.9 ± 10.4, p < 0.001, Hedges g -1.886; Videos Test 75.3 ± 9.3 vs 88.1 ± 7.1, p < 0.001, Hedges g -1.537). Performance on ToM tests was correlated with higher values of FA and lower values of MD across widespread white matter tracts. The largest effects (≥90% of voxels with statistical significance) for the Eyes Test were body and genu of corpus callosum, fornix, tapetum, uncinate fasciculus, and left inferior cerebellar peduncle, and for the Videos Test genu and splenium of corpus callosum, fornix, uncinate fasciculus, left tapetum, and right superior fronto-occipital fasciculus. CONCLUSIONS: These results indicate that a diffuse pattern of NAWM damage in MS contributes to social cognition impairment in the ToM domain, probably due to a mechanism of disconnection within the social brain network. Gray matter pathology is also expected to have an important role; thus further research is required to clarify the neural basis of social cognition impairment in MS.

Stent-assisted coiling of wide-neck bifurcation aneurysms with a branch incorporated in the aneurysm base: long-term follow-up in 49 patients with 53 aneurysms.

PURPOSE: Wide-neck bifurcation intracranial aneurysms (WNBA) with a branch incorporated in the aneurysm base remain difficult to treat by embolization. We aim to report our long-term follow-up of stent-assisted coiling (SAC) in this subgroup of patients. METHODS: This study was approved by our local ethical committee. A retrospective review of our prospectively maintained database identified all patients treated in our institution by SAC for a WNBA with a branch incorporated in the aneurysm base. Technical issues, immediate, long-term outcomes were evaluated. RESULTS: Between 2007 and 2015, 49 patients with 53 intracranial aneurysms (IAs) (52 unruptured, 1 ruptured) were identified and successfully treated. No morbidity/mortality occurred. The incorporated branch was preserved in all patients but one who was treated during a vasospasm phase. At the first 6-month imaging control, the branch was patent. Immediate occlusion was near-complete in 11/53 aneurysms (20.8%), neck remnant in 20/53 aneurysms (37.7%), and incomplete in 22/53 aneurysms (41.5%). Available imaging follow-up of 47 IAs, ranging from 3 to 84 months (mean 26 months ± 19.6 months), showed 27 progressive thrombosis (57.4%), 17 stable occlusions (36.2%), 1 minor recanalization (2.1%), and 2 significant recanalizations that were retreated (4.3%). The latest imaging control showed 30 near-complete occlusions (63.8%), 13 neck remnants (27.7%), and 4 incomplete occlusions (8.5%). CONCLUSION: Stent-assisted coiling is safe and effective for the treatment of WNBA with a branch incorporated in the aneurysm base. Despite poor immediate anatomical results, long-term follow-up shows a high rate of progressive thrombosis achieving adequate and stable occlusion in most patients.

The impact of automated hippocampal volumetry on diagnostic confidence in patients with suspected Alzheimer's disease: A European Alzheimer's Disease Consortium study.

INTRODUCTION: Hippocampal volume is a core biomarker of Alzheimer's disease (AD). However, its contribution over the standard diagnostic workup is unclear. METHODS: Three hundred fifty-six patients, under clinical evaluation for cognitive impairment, with suspected AD and Mini-Mental State Examination ≥20, were recruited across 17 European memory clinics. After the traditional diagnostic workup, diagnostic confidence of AD pathology (DCAD) was estimated by the physicians in charge. The latter were provided with the results of automated hippocampal volumetry in standardized format and DCAD was reassessed. RESULTS: An increment of one interquartile range in hippocampal volume was associated with a mean change of DCAD of -8.0% (95% credible interval: [-11.5, -5.0]). Automated hippocampal volumetry showed a statistically significant impact on DCAD beyond the contributions of neuropsychology, 18F-fluorodeoxyglucose positron emission tomography/single-photon emission computed tomography, and cerebrospinal fluid markers (-8.5, CrI: [-11.5, -5.6]; -14.1, CrI: [-19.3, -8.8]; -10.6, CrI: [-14.6, -6.1], respectively). DISCUSSION: There is a measurable effect of hippocampal volume on DCAD even when used on top of the traditional diagnostic workup.

Leo stent for endovascular treatment of intracranial aneurysms: very long-term results in 50 patients with 52 aneurysms and literature review.

INTRODUCTION: The Leo stent was the first retrievable stent for endovascular treatment of intracranial aneurysms (IAs). We report our experience with this device with emphasis on very long-term follow-up. METHODS: This study was approved by authors' ethical committee. A retrospective review of our prospectively maintained database identified all patients treated for a saccular IA with this stent in our institution. Technical issues and immediate and long-term outcomes (at least 12 months) were evaluated. RESULTS: Between 2004 and 2015, 50 patients with 52 IAs were identified. In two patients, the stent could not safely be placed (failure rate = 3.8%). Among 48 treated patients with 50 IAs, there were 44 women and 4 men (mean age, 53 years). Mean aneurysm diameter was 7.2 mm. All IAs but six were wide-necked. There was no immediate morbidity or mortality. Anatomical results included 76% complete occlusions, 22% neck remnants, and 2% incomplete occlusions. Mean follow-up was 50.2 months (range, 12-139 months). Two patients had delayed TIAs but long-term morbidity rate remained = 0%. At follow-up, occlusion was stable in 68% IAs, showed thrombosis in 12%, and recanalization in 20% IAs. Complementary treatment was required in 8% IAs. Final results showed 70% complete occlusions, 24% neck remnants, and 6% incomplete occlusions. Asymptomatic stent occlusion and significant stenosis occurred in one and two cases, respectively. CONCLUSION: The Leo stent is safe and effective for treatment of wide-necked saccular IAs. Very long-term results show high rates of adequate and stable occlusion. Moreover, the stent is well tolerated.

Endovascular treatment of intracranial aneurysms with the p64 flow diverter stent: mid-term results in 35 patients with 41 intracranial aneurysms.

INTRODUCTION: The p64 flow diverter (FD) device is a fully resheathable and detachable stent dedicated for endovascular treatment (EVT) of intracranial aneurysms (IAs). We report our mid-term experience with this device. METHODS: Between January 2015 and February 2016, we retrospectively identified, in our prospectively maintained database, all patients treated with p64 FDs in two institutions. Independent clinical follow-up was performed by a vascular neurologist. Imaging follow-up included a digitalized subtraction angiography (DSA) at 3, 6, and 12 months and a magnetic resonance angiography (MRA) at 12 months. RESULTS: Thirty-nine patients (22 women/17 men; median age 54 years) with 48 IAs (median aneurysm size 6.2 mm; mean neck size 3.4 mm) were identified. All IAs were saccular and unruptured. Failure of safe stent delivery occurred in 15% of cases (7/48 IAs) which were excluded. Transient neurological morbidity occurred in 2/35 patients (5.7%) including one delayed thromboembolic complication. No permanent morbidity or mortality was encountered. Complete aneurysmal occlusion at 3, 6, and 12 months was 20/30 (66.6%), 18/27 (66.6%), and 24/28 (85.7%), respectively. Intra-stent stenosis was observed in 9/29 patients (31%) and classified as moderate in 4/29 (13.7%) and mild in 5/29 patients (17.2%). These stenoses gradually improved over time, with only mild stenoses being identified at 6 months and at 12 months. CONCLUSION: In our small case series, the p64 FD stent appears safe and effective for EVT of IAs. A high occlusion rate and a low morbidity rate were observed.

Three-Dimensional Face Recognition in Mild Cognitive Impairment: A Psychophysical and Structural MR Study.

OBJECTIVES: Mild cognitive impairment (MCI) has been associated with a high risk of conversion to Alzheimer's dementia. In addition to memory complaints, impairments in the visuospatial domain have been reported in this condition. We have previously shown that deficits in perceiving structure-from-motion (SFM) objects are reflected in functional reorganization of brain activity within the visual ventral stream. Here we aimed to identify structural correlates of psychophysical complex face and object recognition performance in amnestic MCI patients (n=30 vs. n=25 controls). This study was, therefore, motivated by evidence from recent studies showing that a combination of visual information across dorsal and ventral visual streams may be needed for the perception of three-dimensional (3D) SFM objects. METHODS: In our experimental paradigm, participants had to discriminate 3D SFM shapes (faces and objects) from 3D SFM meaningless (scrambled) shapes. RESULTS: Morphometric analysis established neuroanatomical evidence for impairment in MCI as demonstrated by smaller hippocampal volumes. We found association between cortical thickness and face recognition performance, comprising the occipital lobe and visual ventral stream fusiform regions (overlapping the known location of face fusiform area) in the right hemisphere, in MCI. CONCLUSIONS: We conclude that impairment of 3D visual integration exists at the MCI stage involving also the visual ventral stream and contributing to face recognition deficits. The specificity of such observed structure-function correlation for faces suggests a special role of this processing pathway in health and disease. (JINS, 2016, 22, 744-754).

Stent-assisted coiling of intracranial aneurysms located on small vessels: midterm results with the LVIS Junior stent in 40 patients with 43 aneurysms.

INTRODUCTION: The Low-profile Visualized Intraluminal Support (LVIS) Junior stent is dedicated for endovascular treatment of wide-neck intracranial aneurysms located on small-diameter vessels (2-3.5 mm). This study reports midterm clinical and anatomical results of this device. METHODS: This study was approved by authors' ethical committees. A retrospective review of our prospectively maintained database identified all patients treated by this stent in three institutions. Technical issues and immediate and mid-term anatomical and clinical outcomes were evaluated. RESULTS: Forty patients (30 women/10 men, mean age of 55 years) with 43 aneurysms were identified. Mean aneurysm diameter was 5.6 mm (range, 2-13 mm). In all patients, treatment was successful and the stent could be precisely placed. There were three procedure-related complications, one stent thrombosis and two aneurysm ruptures, leading to immediate morbidity in one patient. Delayed ischemic events occurred in three patients including two transient attacks and one permanent deficit. The overall permanent morbidity rate was thus 5 %. No mortality occurred. Immediate aneurysm occlusion consisted of 36 complete occlusions (83.7 %), five neck remnants (11.6 %), and two incomplete occlusions (4.7 %). Twenty-seven patients (29 aneurysms) and 11 patients (11 aneurysms) had a 12- and 6-month angiographic follow-up, respectively. Final anatomical results included 36 complete occlusions (90 %) and four neck remnants (10 %). Two minor recanalizations were seen but did not require retreatment. Non-significant intrastent stenosis occurred in 7/40 followed-up cases (17.5 %). CONCLUSION: The LVIS Junior stent appears safe and effective for endovascular treatment of wide-neck intracranial aneurysms located on small vessels. Midterm results show high rates of adequate and stable occlusion.

The pCONus device for the endovascular treatment of wide neck bifurcation aneurysms.

BACKGROUND AND PURPOSE: The pCONus is a new stent featuring a distal end that opens like a blossoming flower with four petals. The device is implanted in the aneurysm sac at the level of the neck. We report our initial experience in a series of patients treated with this device. METHODS: This retrospective study was approved by the authors' ethics committees. 18 patients with 19 unruptured wide neck bifurcation intracranial aneurysms (IA) were treated by pCONus placement and coiling. Technical issues, immediate post treatment angiographic findings, and clinical and imaging follow-up were assessed. RESULTS: Embolization was successful in all patients. There were 11 women and 7 men with a mean age of 60 years. Median aneurysm size was 9 mm (range 5.5-25 mm). The device was precisely placed and detached in all cases, allowing for subsequent coiling. Two patients experienced a symptomatic complication, one of which, a thromboembolism, was related to the use of the pCONus. This patient had a slight hand paresis. 16 patients had a normal neurological examination at discharge. Immediate anatomical results were 13 complete occlusions, 2 neck remnants, and 4 incomplete occlusions. Imaging follow-up was obtained in 12 patients (mean 9.5 months, range 2-24 months) and showed 9 stable occlusions and 3 recanalizations, of which 2 were retreated. CONCLUSIONS: In this initial series of patients, endovascular treatment of wide neck bifurcation IAs with the pCONus was feasible, with acceptable clinical and anatomical outcomes. Further studies are needed to evaluate the indications, safety, and efficacy of this new device.

The Silk flow-diverter stent for endovascular treatment of intracranial aneurysms.

Flow diverter (FD) stents represent a new endovascular technique developed for the treatment of complex intracranial aneurysms (wide neck, fusiform, large, and giant aneurysms) that are challenging for classic endovascular techniques such as coiling, balloon-assisted coiling and stent-assisted coiling. Low porosity, high metal coverage, and high pore density are the main properties of FD stents. These properties induce hemodynamic changes redirecting the blood flow away from the aneurysm and into the parent artery leading to gradual thrombosis of the aneurysm. FD stents also provide scaffolding for subsequent neoendothelial proliferation, and vessel wall remodeling. This is considered as a paradigm shift compared to prior endovascular methods, which predominantly aimed at providing treatment inside the aneurysmal sac. This paper describes in detail the first released FD stent, the Silk flow-diverter stent (Balt Extrusion, Montmorency, France), its mechanism of action and deployment technique. It reviews the pertinent literature regarding safety, efficacy and potential risks and complications associated with the use of this stent.

[Carotid atherosclerosis and white matter hypodensities: a controversial relationship]. / Aterosclerose Carotídea e Hipodensidades da Substância Branca: uma Relação Controversa.

INTRODUCTION: White matter hypodensities of presumed vascular origin, are recognized as an important cause of morbidity with established clinical and cognitive consequences. Nonetheless, many doubts remain on its physiopathology. Our goal is to clarify the potential role of carotid atherosclerosis and other vascular risk factors in the development of white matter hypodensities of presumed vascular origin. MATERIAL AND METHODS: We included patients that underwent CT brain scan and neurosonologic evaluation within a one-month period. Full assessment of vascular risks factors was performed. We seek to find independent associations between white matter hypodensities of presumed vascular origin, carotid intima-media thickness and vascular risk factors. RESULTS: 472 patients were included, mean age was 67.32 (SD: 14.75), 274 (58.1%) were male. The independent predictors of white matter hypodensities of presumed vascular origin were age (OR: 1.067, 95% IC: 1.049 - 1.086, p < 0.001) and hypertension (OR: 1.726, 95% IC: 1.097 - 2.715, p = 0.018). No association was found between IMT (OR: 2.613, 95% IC: 0.886 - 7.708, p = 0.082) or carotid artery stenosis (OR: 1.021, 95% IC: 0.785 - 1.328, p = 0.877) and white matter hypodensities of presumed vascular origin. DISCUSSION: Only age and hypertension proved to have an independent association with white matter hypodensities of presumed vascular origin. Carotid atherosclerosis, evaluated by IMT and the degree of carotid artery stenosis, showed no association with white matter hypodensities of presumed vascular origin. Since atherosclerosis is a systemic pathology, these results suggest that alternative mechanisms are responsible for the development of white matter hypodensities of presumed vascular origin. CONCLUSION: Age and hypertension seem to be the main factors in the development of white matter hypodensities of presumed vascular origin. No association was found between carotid atherosclerosis and white matter hypodensities of presumed vascular origin.

Introdução: As hipodensidades da substância branca de provável etiologia vascular, são uma causa importante de morbilidade, condicionando deterioração cognitiva. No entanto, numerosas dúvidas persistem quanto à sua fisiopatologia. O objectivo deste estudo é clarificar o papel da aterosclerose carotídea e outros factores de risco vascular no desenvolvimento das hipodensidades da substância branca de provável etiologia vascular.Material e Métodos: Realizou-se uma avaliação imagiológica, por tomografia computadorizada crânio-encefálica e ecografia carotídea, com menos de um mês de intervalo. Procedeu-se à recolha de informação sobre os factores de risco vascular. Determinámos associações independentes entre hipodensidades da substância branca de provável etiologia vascular, espessura da íntima média carotídea, estenose carotídea ateromatosa e factores de risco vascular.Resultados: Foram incluídos 472 doentes, idade média de 67,32 (DP: 14.75), 274 (58,1%) sexo masculino. Os preditores independentes da hipodensidades da substância branca de provável etiologia vascular foram: idade (OR: 1,067, 95% IC: 1,049 – 1,086, p < 0,001) e a hipertensão (OR: 1,726, 95% IC: 1,097 – 2,715, p = 0,018). Não foi encontrada uma associação entre a espessura da intima média carotídea (OR: 2,613, 95% IC: 0,886 – 7,708, p = 0,082) ou grau de estenose carotídea (OR: 1,021, 95% IC: 0,785 – 1,328, p = 0,877) e hipodensidades da substância branca de provável etiologia vascular.Discussão: Dos diversos factores de risco analisados, apenas a idade e hipertensão se associaram de forma independente às hipodensidades da substância branca de provável etiologia vascular. Não foi encontrada uma relação entre a aterosclerose extracraniana, expressa pela espessura do complexo intima-média ou grau de estenose, com o desenvolvimento de hipodensidades da substância branca de provável etiologia vascular. Sendo a aterosclerose um fenómeno sistémico, estes achados sugerem que as hipodensidades da substância branca de provável etiologia vascular, tenham um mecanismo alternativo ou concorrente à aterosclerose no seu desenvolvimento.Conclusão: Os dados deste estudo, sugerem que a idade e hipertensão sejam os principais factores de risco no desenvolvimento de hipodensidades da substância branca de provável etiologia vascular. Não foi encontrada uma associação independente entre a aterosclerose carotídea e as hipodensidades da substância branca de provável etiologia vascular.

Frontotemporal dementia: neuroanatomical correlates of an atypical presentation.

Frontotemporal dementia (FTD) is a heterogeneous group of disorders characterised by frontal and temporal lobes atrophy. Three different clinical subtypes are recognised: behavioural variant, progressive non-fluent aphasia and semantic dementia. Neuroanatomical associations in a diffuse neurodegenerative disease such as FTD should be interpreted carefully; however, each FTD subtype has provided a clinical model that has contributed immensely to our understanding of clinical/neuroanatomical relationships. This case report and recent studies suggest that neuroanatomical findings concerning face-processing mechanisms in FTD can identify the brain regions that are critical for face processing. As seen in this case, right fusiform gyrus atrophy seems to be implied in the aetiology of prosopagnosia.

[How xenon works: neuro and cardioprotection mechanisms]. / Como Funciona o Xénon: Mecanismos de Neuro e Cardioprotecção.

INTRODUCTION: The Xenon, a noble gas, has anesthetics properties, associated with remarkable hemodynamic stability as well as cardioprotective, neuroprotective proprieties. Its physicochemical characteristics give him a quick induction and emergence of anesthesia, being free of deleterious effects in all organs and showing no teratogenicity. Such properties have led to a growing interest in improving the knowledge about this noble gas, in order to assess the mechanisms of neuro and cardioprotection induced and to assess the clinical indications for its use. MATERIAL AND METHODS: Qualitative review of clinical trials on anesthesia with xenon. Studies were identified from MEDLINE and by hand-searching, using the following keywords: xenon, xenon anestesia, xenon neuroprotection, xenon cradioprotection. RESULTS: After several studies, including two randomized multicenter controlled trials, the use of xenon as an anesthetic in patients ASA I-II was approved in March 2007. However his use in clinical practice has been strongly limited by it's high price. It seems unlikely that the advantages it offers in relation to other anesthetics justify it's use in patients ASA I-II. Although, xenon may be a valuable asset in the reduction of co-morbilities and mortality in anesthesia of patients ASA III-IV, unfortunately, there are no large randomized control studies to prove it. DISCUSSION: Unfortunately, there are still no randomized or multicentric studies showing a favourable cost-benefit profile of xenon in ASA III-IV patients vs. other anaesthetics. CONCLUSION: The usefulness of xenon in Anesthesiology requires more studies to be defined.

Introdução: O xénon, um gás nobre, possui qualidades anestésicas, associadas a uma notável estabilidade hemodinâmica assim como propriedades cardioprotectoras e neuroprotectoras. As suas características físico-químicas conferem-lhe uma rápida indução e emergência anestésica, estando livre de efeitos deletérios importantes nos diversos orgãos e não apresentando teratogenicidade; o que suscitou um recente recrudescimento no interesse de aprofundar o conhecimento sobre este gás nobre, afim de compreender osseus mecanismos de acção e determinar as várias indicações que possui para a prática clínica.Material e Métodos: Revisão da literatura dos artigos considerados relevantes sobre o tema, com recurso à pesquisa de artigos indexados na Medline, com as palavras-chaves: xénon, xénon anestesia, xénon neuroproteção, xénon cardioproteção.Resultados: A aprovação do uso do xénon em doentes ASA I-II, ocorreu em Março 2007, após a realização de dois ensaios clínicos aleatorizados multicêntricos. No entanto, o seu uso na prática clínica, tem sido limitado pelo seu preço elevado. Parece pouco provável que as vantagens que oferece em relação aos restantes anestésicos justifique o seu uso em doentes ASA I-II. No entanto, poderá ser uma preciosa ajuda para a redução das co-morbilidades e mortalidade na anestesia de doentes ASA III-IV. As suas propriedades neuro e cardio-protectoras, são também alvo de intensa investigação, com resultados promissores.Discussão: Infelizmente, ainda não existem estudos de aleatorizados e multicêntricos que comprovem um perfil favorável do custobenefício do xénon em doentes ASA III-IV, em relação aos demais anestésicos.Conclusão: O lugar do xénon na Anestesiologia ainda se encontra por definir.