82 resultados para Central venous access device


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Arterio-venous malformations (AVMs) are congenital vascular malformations (CVMs) that result from birth defects involving the vessels of both arterial and venous origins, resulting in direct communications between the different size vessels or a meshwork of primitive reticular networks of dysplastic minute vessels which have failed to mature to become 'capillary' vessels termed "nidus". These lesions are defined by shunting of high velocity, low resistance flow from the arterial vasculature into the venous system in a variety of fistulous conditions. A systematic classification system developed by various groups of experts (Hamburg classification, ISSVA classification, Schobinger classification, angiographic classification of AVMs,) has resulted in a better understanding of the biology and natural history of these lesions and improved management of CVMs and AVMs. The Hamburg classification, based on the embryological differentiation between extratruncular and truncular type of lesions, allows the determination of the potential of progression and recurrence of these lesions. The majority of all AVMs are extra-truncular lesions with persistent proliferative potential, whereas truncular AVM lesions are exceedingly rare. Regardless of the type, AV shunting may ultimately result in significant anatomical, pathophysiological and hemodynamic consequences. Therefore, despite their relative rarity (10-20% of all CVMs), AVMs remain the most challenging and potentially limb or life-threatening form of vascular anomalies. The initial diagnosis and assessment may be facilitated by non- to minimally invasive investigations such as duplex ultrasound, magnetic resonance imaging (MRI), MR angiography (MRA), computerized tomography (CT) and CT angiography (CTA). Arteriography remains the diagnostic gold standard, and is required for planning subsequent treatment. A multidisciplinary team approach should be utilized to integrate surgical and non-surgical interventions for optimum care. Currently available treatments are associated with significant risk of complications and morbidity. However, an early aggressive approach to elimiate the nidus (if present) may be undertaken if the benefits exceed the risks. Trans-arterial coil embolization or ligation of feeding arteries where the nidus is left intact, are incorrect approaches and may result in proliferation of the lesion. Furthermore, such procedures would prevent future endovascular access to the lesions via the arterial route. Surgically inaccessible, infiltrating, extra-truncular AVMs can be treated with endovascular therapy as an independent modality. Among various embolo-sclerotherapy agents, ethanol sclerotherapy produces the best long term outcomes with minimum recurrence. However, this procedure requires extensive training and sufficient experience to minimize complications and associated morbidity. For the surgically accessible lesions, surgical resection may be the treatment of choice with a chance of optimal control. Preoperative sclerotherapy or embolization may supplement the subsequent surgical excision by reducing the morbidity (e.g. operative bleeding) and defining the lesion borders. Such a combined approach may provide an excellent potential for a curative result. Conclusion. AVMs are high flow congenital vascular malformations that may occur in any part of the body. The clinical presentation depends on the extent and size of the lesion and can range from an asymptomatic birthmark to congestive heart failure. Detailed investigations including duplex ultrasound, MRI/MRA and CT/CTA are required to develop an appropriate treatment plan. Appropriate management is best achieved via a multi-disciplinary approach and interventions should be undertaken by appropriately trained physicians.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The safety of percutaneous transapical mitral paravalvular leak (PVL) closure could potentially be enhanced by device closure of the ventricular access site. Percutaneous transapical PVL closure was performed. The 9F delivery sheath was pulled back, and a 6-mm Amplatzer muscular ventricular septal defect occluder was deployed at the apical puncture site. Immediate hemostasis was achieved. Total hospitalization was 9 days. New York Heart Association functional class was improved, hemoglobin and haptoglobin rose, while lactate dehydrogenase fell. Follow-up fluoroscopy and transthoracic echocardiography revealed a good functional result. Closure of the apical access site by means of an Amplatzer muscular ventricular septal defect occluder is feasible.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The brain is in many ways an immunologically and pharmacologically privileged site. The blood-brain barrier (BBB) of the cerebrovascular endothelium and its participation in the complex structure of the neurovascular unit (NVU) restrict access of immune cells and immune mediators to the central nervous system (CNS). In pathologic conditions, very well-organized immunologic responses can develop within the CNS, raising important questions about the real nature and the intrinsic and extrinsic regulation of this immune privilege. We assess the interactions of immune cells and immune mediators with the BBB and NVU in neurologic disease, cerebrovascular disease, and intracerebral tumors. The goals of this review are to outline key scientific advances and the status of the science central to both the neuroinflammation and CNS barriers fields, and highlight the opportunities and priorities in advancing brain barriers research in the context of the larger immunology and neuroscience disciplines. This review article was developed from reports presented at the 2011 Annual Blood-Brain Barrier Consortium Meeting.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The central nervous system (CNS) has long been regarded as an immune privileged organ implying that the immune system avoids the CNS to not disturb its homeostasis, which is critical for proper function of neurons. Meanwhile, it is accepted that immune cells do in fact gain access to the CNS and that immune responses can be mounted within this tissue. However, the unique CNS microenvironment strictly controls these immune reactions starting with tightly controlling immune cell entry into the tissue. The endothelial blood-brain barrier (BBB) and the epithelial blood-cerebrospinal fluid (CSF) barrier, which protect the CNS from the constantly changing milieu within the bloodstream, also strictly control immune cell entry into the CNS. Under physiological conditions, immune cell migration into the CNS is kept at a very low level. In contrast, during a variety of pathological conditions of the CNS such as viral or bacterial infections, or during inflammatory diseases such as multiple sclerosis, immunocompetent cells readily traverse the BBB and likely also the choroid plexus and subsequently enter the CNS parenchyma or CSF spaces. This chapter summarizes our current knowledge of immune cell entry across the blood CNS barriers. A large body of the currently available information on immune cell entry into the CNS has been derived from studying experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis. Therefore, most of this chapter discussing immune cell entry during CNS pathogenesis refers to observations in the EAE model, allowing for the possibility that other mechanisms of immune cell entry into the CNS might apply under different pathological conditions such as bacterial meningitis or stroke.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

BACKGROUND/AIMS: Rebound tonometry (RT) is performed without anaesthesia with a hand held device. The primary aim was to compare RT with Goldmann applanation tonometry (GAT) and to correlate with central corneal thickness (CCT). The secondary aim was to prove tolerability and practicability of RT under "study conditions" and "routine practice conditions." METHODS: In group 1 (52 eyes/28 patients), all measurements were taken by the same physician, in the same room and order: non-contact optical pachymetry, RT, slit lamp inspection, GAT. Patients were questioned about discomfort or pain. In group 2 (49 eyes/27 patients), tonometry was performed by three other physicians during routine examinations. RESULTS: RT was well tolerated and safe. Intraocular pressure (IOP) ranged between 6 mm Hg and 48 mm Hg. No different trends were found between the groups. RT tended to give slightly higher readings: n = 101, mean difference 1.0 (SD 2.17) mm Hg; 84.1% of RT readings within plus or minus 3 mm Hg of GAT; 95% confidence interval in the Bland-Altman analysis -3.2 mm Hg to +5.2 mm Hg. Both RT and GAT showed a weak positive correlation with CCT (r2 0.028 and 0.025, respectively). CONCLUSIONS: RT can be considered a reliable alternative for clinical screening and in cases where positioning of the head at the slit lamp is impossible or topical preparations are to be avoided.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Before entering the central nervous system (CNS) immune cells have to penetrate any one of its barriers, namely either the endothelial blood-brain barrier, the epithelial blood-cerebrospinal fluid barrier or the tanycytic barrier around the circumventricular organs, all of which maintain homeostasis within the CNS. The presence of these barriers in combination with the lack of lymphatic vessels and the absence of classical MHC-positive antigen presenting cells characterizes the CNS as an immunologically privileged site. In multiple sclerosis a large number of inflammatory cells gains access to the CNS parenchyma. Studies performed in experimental autoimmune encephalomyelitis (EAE), a rodent model for multiple sclerosis, have enabled us to understand some of the molecular mechanisms involved in immune cell entry into the CNS. In particular, the realization that /alpha4-integrins play a predominant role in leukocyte trafficking to the CNS has led to the development of a novel drug for the treatment of relapsing-remitting multiple sclerosis, which targets /alpha4-integrin mediated immune cell migration to the CNS. At the same time, the involvement of other adhesion and signalling molecules in this process remains to be investigated and novel molecules contributing to immune cell entry into the CNS are still being identified. The entire process of immune cell trafficking into the CNS is strictly controlled by the brain barriers not only under physiological conditions but also during neuroinflammation, when some barrier properties are lost. Thus, immune cell entry into the CNS critically depends on the unique characteristics of the brain barriers maintaining CNS homeostasis.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In multiple sclerosis and in its animal model experimental autoimmune encephalomyelitis (EAE), inflammatory cells migrate across the highly specialized endothelial blood-brain barrier (BBB) and gain access to the central nervous system (CNS). It is well established that leukocyte recruitment across this vascular bed is unique due to the predominant involvement of alpha4-integrins in mediating the initial contact to as well as firm adhesion with the endothelium. In contrast, the involvement of the selectins, L-selectin, E- and P-selectin and their respective carbohydrate ligands such as P-selectin glycoprotein (PSGL)-1 in this process has been controversially discussed. Intravital microscopic analysis of immune cell interaction with superficial brain vessels demonstrates a role for E- and P-selectin and their common ligand PSGL-1 in lymphocyte rolling. However, E- and P-selectin-deficient SJL- or C57Bl/6 mice or PSGL-1-deficient C57Bl/6 mice develop EAE indistinguishable from wild-type mice. Considering these apparently discrepant observations, it needs to be discussed whether the molecular mechanisms involved in leukocyte trafficking across superficial brain vessels are irrelevant for EAE pathogenesis or whether the therapeutic efficacy of targeting alpha4-integrins in EAE is truly dependent on the inhibition of leukocyte trafficking across the BBB.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Application of the specular reflection intensity was previously reported for the quantification of early dental erosion. Further development of the technique and assembly of the miniaturized pen-size instrument are described. The optical system was adjusted to fit into a handy device which could potentially access different positions in the oral cavity. The assembled instrument could successfully detect early erosion progression in both polished (n=70) and native (n=20) human enamels. Different severities of enamel erosion were induced by varying incubation time of polished enamel in 1% citric acid (pH=3.60, 0.5 to 10 min), while the native incisors were treated in the commercial orange juice (Tropicana Pure Premium®, pH=3.85, 10 to 60 min). The instrument provided a good differentiation between various severities of the erosion in vitro. The size of the measurement spot affected the erosion monitoring in native enamel (human incisors). The erosion measurement in the 0.7-mm (diameter) cervical spots showed systematically lower reflection intensities compared with the analysis of central and incisal small spots. The application of larger spot areas (2.3 mm) for the erosion monitoring revealed no effect (p>0.05) of the spot position on the reflection signal. High variation of the teeth susceptibility toward in vitro erosion was detected in native enamel.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

BACKGROUND Acute cardiogenic shock after myocardial infarction is associated with high in-hospital mortality attributable to persisting low-cardiac output. The Impella-EUROSHOCK-registry evaluates the safety and efficacy of the Impella-2.5-percutaneous left-ventricular assist device in patients with cardiogenic shock after acute myocardial infarction. METHODS AND RESULTS This multicenter registry retrospectively included 120 patients (63.6±12.2 years; 81.7% male) with cardiogenic shock from acute myocardial infarction receiving temporary circulatory support with the Impella-2.5-percutaneous left-ventricular assist device. The primary end point evaluated mortality at 30 days. The secondary end point analyzed the change of plasma lactate after the institution of hemodynamic support, and the rate of early major adverse cardiac and cerebrovascular events as well as long-term survival. Thirty-day mortality was 64.2% in the study population. After Impella-2.5-percutaneous left-ventricular assist device implantation, lactate levels decreased from 5.8±5.0 mmol/L to 4.7±5.4 mmol/L (P=0.28) and 2.5±2.6 mmol/L (P=0.023) at 24 and 48 hours, respectively. Early major adverse cardiac and cerebrovascular events were reported in 18 (15%) patients. Major bleeding at the vascular access site, hemolysis, and pericardial tamponade occurred in 34 (28.6%), 9 (7.5%), and 2 (1.7%) patients, respectively. The parameters of age >65 and lactate level >3.8 mmol/L at admission were identified as predictors of 30-day mortality. After 317±526 days of follow-up, survival was 28.3%. CONCLUSIONS In patients with acute cardiogenic shock from acute myocardial infarction, Impella 2.5-treatment is feasible and results in a reduction of lactate levels, suggesting improved organ perfusion. However, 30-day mortality remains high in these patients. This likely reflects the last-resort character of Impella-2.5-application in selected patients with a poor hemodynamic profile and a greater imminent risk of death. Carefully conducted randomized controlled trials are necessary to evaluate the efficacy of Impella-2.5-support in this high-risk patient group.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In the field of thrombosis and haemostasis, many preanalytical variables influence the results of coagulation assays and measures to limit potential results variations should be taken. To our knowledge, no paper describing the development and maintenance of a haemostasis biobank has been previously published. Our description of the biobank of the Swiss cohort of elderly patients with venous thromboembolism (SWITCO65+) is intended to facilitate the set-up of other biobanks in the field of thrombosis and haemostasis. SWITCO65+ is a multicentre cohort that prospectively enrolled consecutive patients aged ≥65 years with venous thromboembolism at nine Swiss hospitals from 09/2009 to 03/2012. Patients will be followed up until December 2013. The cohort includes a biobank with biological material from each participant taken at baseline and after 12 months of follow-up. Whole blood from all participants is assayed with a standard haematology panel, for which fresh samples are required. Two buffy coat vials, one PAXgene Blood RNA System tube and one EDTA-whole blood sample are also collected at baseline for RNA/DNA extraction. Blood samples are processed and vialed within 1 h of collection and transported in batches to a central laboratory where they are stored in ultra-low temperature archives. All analyses of the same type are performed in the same laboratory in batches. Using multiple core laboratories increased the speed of sample analyses and reduced storage time. After recruiting, processing and analyzing the blood of more than 1,000 patients, we determined that the adopted methods and technologies were fit-for-purpose and robust.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

HYPOTHESIS Facial nerve monitoring can be used synchronous with a high-precision robotic tool as a functional warning to prevent of a collision of the drill bit with the facial nerve during direct cochlear access (DCA). BACKGROUND Minimally invasive direct cochlear access (DCA) aims to eliminate the need for a mastoidectomy by drilling a small tunnel through the facial recess to the cochlea with the aid of stereotactic tool guidance. Because the procedure is performed in a blind manner, structures such as the facial nerve are at risk. Neuromonitoring is a commonly used tool to help surgeons identify the facial nerve (FN) during routine surgical procedures in the mastoid. Recently, neuromonitoring technology was integrated into a commercially available drill system enabling real-time monitoring of the FN. The objective of this study was to determine if this drilling system could be used to warn of an impending collision with the FN during robot-assisted DCA. MATERIALS AND METHODS The sheep was chosen as a suitable model for this study because of its similarity to the human ear anatomy. The same surgical workflow applicable to human patients was performed in the animal model. Bone screws, serving as reference fiducials, were placed in the skull near the ear canal. The sheep head was imaged using a computed tomographic scanner and segmentation of FN, mastoid, and other relevant structures as well as planning of drilling trajectories was carried out using a dedicated software tool. During the actual procedure, a surgical drill system was connected to a nerve monitor and guided by a custom built robot system. As the planned trajectories were drilled, stimulation and EMG response signals were recorded. A postoperative analysis was achieved after each surgery to determine the actual drilled positions. RESULTS Using the calibrated pose synchronized with the EMG signals, the precise relationship between distance to FN and EMG with 3 different stimulation intensities could be determined for 11 different tunnels drilled in 3 different subjects. CONCLUSION From the results, it was determined that the current implementation of the neuromonitoring system lacks sensitivity and repeatability necessary to be used as a warning device in robotic DCA. We hypothesize that this is primarily because of the stimulation pattern achieved using a noninsulated drill as a stimulating probe. Further work is necessary to determine whether specific changes to the design can improve the sensitivity and specificity.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Leafing phenology of two dry-forest sites on soils of different depth (S = shallow, D = deep) at Shipstern Reserve, Belize, were compared at the start of the rainy season (April-June 2000). Trees greater than or equal to 2.5 cm dbh were recorded weekly for 8 wk in three 0.04-ha plots per site. Ten species were analysed individually for their phenological patterns, of which the three most common were Bursera simaruba, Metopium brownei and Jatropha gaumeri. Trees were divided into those in the canopy (> 10 cm dbh) and the subcanopy (less than or equal to 10 cm dbh). Site S had larger trees on average than site D. The proportion of trees flushing leaves at any one time was generally higher in site S than in site D, for both canopy and subcanopy trees. Leaf flush started 2 wk earlier in site S than site D for subcanopy trees, but only 0.5 wk earlier for the canopy trees. Leaf flush duration was 1.5 wk longer in site S than site D. Large trees in the subcanopy flushed leaves earlier than small ones at both sites but in the canopy just at site D. Large trees flushed leaves earlier than small ones in three species and small trees flushed leaves more rapidly in two species. Bursera and Jatropha followed the general trends but Metopium, with larger trees in site D than site S, showed the converse with onset of flushing I wk earlier in site D than site S. Differences in response of the canopy and subcanopy trees on each site can be accounted for by the predominance of spring-flushing or stem-succulent species in site S and a tendency for evergreen species to occur in site D. Early flushing of relatively larger trees in site D most likely requires access to deeper soil water reserves but small and large trees utilize stored tree water in site S.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

BackgroundAnatomical differences between humans and domestic mammals preclude the use of reported stereotactic approaches to the brainstem in animals. In animals, brainstem biopsies are required both for histopathological diagnosis of neurological disorders and for research purposes. Sheep are used as a translational model for various types of brain disease and therefore a species-specific approach needs to be developed. The aim of the present study was to establish a minimally invasive, accurate and reproducible stereotactic approach to the brainstem of sheep, using the magnetic resonance imaging guided BrainsightTM frameless stereotactic system.ResultsA transoccipital transcerebellar approach with an entry point in the occipital bone above the vermis between the transverse sinus and the external occipital protuberance was chosen. This approach provided access to the target site in all heads. The overall mean needle placement error was 1.85¿±¿1.22 mm.ConclusionsThe developed transoccipital transcerebellar route is short, provides accurate access to the ovine caudal cranial fossa and is a promising approach to be assessed further in live animals.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

BACKGROUND Venous thromboembolism (VTE) often complicates the clinical course of cancer. The risk is further increased by chemotherapy, but the safety and efficacy of primary thromboprophylaxis in cancer patients treated with chemotherapy is uncertain. This is an update of a review first published in February 2012. OBJECTIVES To assess the efficacy and safety of primary thromboprophylaxis for VTE in ambulatory cancer patients receiving chemotherapy compared with placebo or no thromboprophylaxis. SEARCH METHODS For this update, the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched May 2013), CENTRAL (2013, Issue 5), and clinical trials registries (up to June 2013). SELECTION CRITERIA Randomised controlled trials (RCTs) comparing any oral or parenteral anticoagulant or mechanical intervention to no intervention or placebo, or comparing two different anticoagulants. DATA COLLECTION AND ANALYSIS Data were extracted on methodological quality, patients, interventions, and outcomes including symptomatic VTE and major bleeding as the primary effectiveness and safety outcomes, respectively. MAIN RESULTS We identified 12 additional RCTs (6323 patients) in the updated search so that this update considered 21 trials with a total of 9861 patients, all evaluating pharmacological interventions and performed mainly in patients with advanced cancer. Overall, the risk of bias varied from low to high. One large trial of 3212 patients found a 64% (risk ratio (RR) 0.36, 95% confidence interval (CI) 0.22 to 0.60) reduction of symptomatic VTE with the ultra-low molecular weight heparin (uLMWH) semuloparin relative to placebo, with no apparent difference in major bleeding (RR 1.05, 95% CI 0.55 to 2.00). LMWH, when compared with inactive control, significantly reduced the incidence of symptomatic VTE (RR 0.53, 95% CI 0.38 to 0.75; no heterogeneity, Tau(2) = 0%) with similar rates of major bleeding events (RR 1.30, 95% CI 0.75 to 2.23). In patients with multiple myeloma, LMWH was associated with a significant reduction in symptomatic VTE when compared with the vitamin K antagonist warfarin (RR 0.33, 95% CI 0.14 to 0.83), while the difference between LMWH and aspirin was not statistically significant (RR 0.51, 95% CI 0.22 to 1.17). No major bleeding was observed in the patients treated with LMWH or warfarin and in less than 1% of those treated with aspirin. Only one study evaluated unfractionated heparin against inactive control and found an incidence of major bleeding of 1% in both study groups while not reporting on VTE. When compared with placebo, warfarin was associated with a statistically insignificant reduction of symptomatic VTE (RR 0.15, 95% CI 0.02 to 1.20). Antithrombin, evaluated in one study involving paediatric patients, had no significant effect on VTE nor major bleeding when compared with inactive control. The new oral factor Xa inhibitor apixaban was evaluated in a phase-II dose finding study that suggested a promising low rate of major bleeding (2.1% versus 3.3%) and symptomatic VTE (1.1% versus 10%) in comparison with placebo. AUTHORS' CONCLUSIONS In this update, we confirmed that primary thromboprophylaxis with LMWH significantly reduced the incidence of symptomatic VTE in ambulatory cancer patients treated with chemotherapy. In addition, the uLMWH semuloparin significantly reduced the incidence of symptomatic VTE. However, the broad confidence intervals around the estimates for major bleeding suggest caution in the use of anticoagulation and mandate additional studies to determine the risk to benefit ratio of anticoagulants in this setting. Despite the encouraging results of this review, routine prophylaxis in ambulatory cancer patients cannot be recommended before safety issues are adequately addressed.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

BACKGROUND Cold atmospheric plasma (CAP, i.e. ionized air) is an innovating promising tool in reducing bacteria. OBJECTIVE We conducted the first clinical trial with the novel PlasmaDerm(®) VU-2010 device to assess safety and, as secondary endpoints, efficacy and applicability of 45 s/cm(2) cold atmospheric plasma as add-on therapy against chronic venous leg ulcers. METHODS From April 2011 to April 2012, 14 patients were randomized to receive standardized modern wound care (n = 7) or plasma in addition to standard care (n = 7) 3× per week for 8 weeks. The ulcer size was determined weekly (Visitrak(®) , photodocumentation). Bacterial load (bacterial swabs, contact agar plates) and pain during and between treatments (visual analogue scales) were assessed. Patients and doctors rated the applicability of plasma (questionnaires). RESULTS The plasma treatment was safe with 2 SAEs and 77 AEs approximately equally distributed among both groups (P = 0.77 and P = 1.0, Fisher's exact test). Two AEs probably related to plasma. Plasma treatment resulted in a significant reduction in lesional bacterial load (P = 0.04, Wilcoxon signed-rank test). A more than 50% ulcer size reduction was noted in 5/7 and 4/7 patients in the standard and plasma groups, respectively, and a greater size reduction occurred in the plasma group (plasma -5.3 cm(2) , standard: -3.4 cm(2) ) (non-significant, P = 0.42, log-rank test). The only ulcer that closed after 7 weeks received plasma. Patients in the plasma group quoted less pain compared to the control group. The plasma applicability was not rated inferior to standard wound care (P = 0.94, Wilcoxon-Mann-Whitney test). Physicians would recommend (P = 0.06, Wilcoxon-Mann-Whitney test) or repeat (P = 0.08, Wilcoxon-Mann-Whitney test) plasma treatment by trend. CONCLUSION Cold atmospheric plasma displays favourable antibacterial effects. We demonstrated that plasma treatment with the PlasmaDerm(®) VU-2010 device is safe and effective in patients with chronic venous leg ulcers. Thus, larger controlled trials and the development of devices with larger application surfaces are warranted.