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Sample records for converting venous values

  1. Valuing Convertible Bonds Based on LSRQM Method

    Directory of Open Access Journals (Sweden)

    Jian Liu

    2014-01-01

    Full Text Available Convertible bonds are one of the essential financial products for corporate finance, while the pricing theory is the key problem to the theoretical research of convertible bonds. This paper demonstrates how to price convertible bonds with call and put provisions using Least-Squares Randomized Quasi-Monte Carlo (LSRQM method. We consider the financial market with stochastic interest rates and credit risk and present a detailed description on calculating steps of convertible bonds value. The empirical results show that the model fits well the market prices of convertible bonds in China’s market and the LSRQM method is effective.

  2. [Automatic regulator of venous pressure and venous outflow in the perfusion system].

    Science.gov (United States)

    Smirnov, L M; Levinskiĭ, M M; Kharnas, S Sh; Cherniak, V A

    1976-01-01

    A scheme for automatic regulation of the venous pressure and venous blood outflow during extracorporeal circulation is proposed. The system consists of a photoelectric sensor placed on a tube led out of the major venous trunkline, a converter and an electromechanical eccentric clamp that compresses the venous trunkline, all of which secures stabilization of the controlled values.

  3. Reference values for venous and capillary S100B in children

    DEFF Research Database (Denmark)

    Astrand, Ramona; Romner, Bertil; Lanke, Jan

    2011-01-01

    The current management guidelines for pediatric mild head injury (MHI) liberally recommend computed tomography (CT) and frequent admission. Serum protein S100B, currently used in management of adult head injury, has recently shown potential for reducing unnecessary CT scans after pediatric mild...... head injury. Capillary sampling in children is commonly used when venous sampling fails or is inappropriate. We present reference values for both venous and capillary samples of protein S100B in children....

  4. Correlation of arterial blood gas measurements with venous blood gas values in mechanically ventilated patients.

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    Razi, Ebrahim; Nasiri, Omid; Akbari, Hossein; Razi, Armin

    2012-01-01

    Arterial blood gas (ABG) analysis is useful in evaluation of the clinical condition of critically ill patients; however, arterial puncture or insertion of an arterial catheter may cause many complications. The aim of this study was to determine whether venous blood gas (VBG) values can be used as an alternative to arterial blood gas measurements in patients under mechanical ventilation. This study was carried out on patients admitted to the Intensive Care Unit of Kashan Beheshti Hospital. Blood for VBG analysis was obtained from the cubital vein, while for ABG analysis blood was taken simultaneously from the radial artery. ABG and VBG samples were obtained simultaneously, and indexes of pH, PCO2, HCO3, base excess (BE), PO2 and O2 saturation level were analyzed. A total of 102 pair of simultaneous venous and arterial blood samples were obtained from 102 patients (mean age 58.4±21.5 years). Seventy (69%) were males. The mean difference between arterial and venous values was 0.04 for pH, 5.6 mm/Hg for PCO2, -0.32 mmol/l for HCO3, -1.03 mmol/l for BE, 53.6 mm/Hg for PO2, and 23.5% for O2 saturation. The Pearson correlation coefficients between arterial and venous values for pH, PCO2, HCO3, BE, PO2 and O2 saturation were 0.874, 0.835, 0.768, 0.810, 0.287, and 0.310, respectively. Linear regression equations for the estimation of pH, PCO2, HCO3, BE, PO2 and O2 saturation were as follows: arterial pH=1.927+0.745×venous pH [r=0.801, parterial HCO3=7.455+0.681×venous HCO3 [r=0.768, parterial BE=-0.952+0.736×venous BE [r=0.810, parterial PO2=70.374+0.620×venous PO2 [r=0.287, p=0.003]; arterial venous saturation= 89.753+0.082×venous O2 saturation [r=0.317, p=0.001]. Venous blood gases, especially pH, Base excess, and PCO2 levels have relatively good correlation with ABG values. Because this correlation is not close, VBG cannot substitute ABG in mechanically ventilated patients.

  5. Prospective study to determine possible correlation between arterial and venous blood gas values.

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    Khan, Zahid Hussain; Samadi, Shahram; Sadeghi, Mostafa; Alemohammad, Mahmood Gholam; Zanjani, Amir Poya; Adine-Hashtjin, Shahin; Makarem, Jalil

    2010-09-01

    Arterial blood gas analysis is an iatric component factor in the clinical evaluation of patients, but arterial puncture has many complications. Our study aimed to determine a correlation between arterial and venous blood gas values. A prospective comparison of 200 samples from 100 patients undergoing lumbar disc surgery was conducted. Arterial and venous samples were obtained simultaneously from each patient. The samples were analyzed and compared using SPSS version 16 software, with Pearson's correlation and 95% confidence intervals (CIs) of the difference. Arterial and venous values for pH, bicarbonate (HCO(3)), base excess (BE), buffer base (BB) and partial pressure of carbon dioxide (PCO(2)) showed close and direct correlation. The comparison showed the following: pH, r = 0.938, p arterial and venous values for pH was 0.025 pH units, for HCO(3) was 2.327 mmol/L, for PCO(2) was 5.32 mmHg, for BE was 1.533 mmol/L, and for BB was 1.983 mmol/L. Venous blood gas values are an acceptable alternative to arterial blood gas values in patients undergoing lumbar disc surgery. Copyright © 2010 Taiwan Society of Anesthesiologists. Published by Elsevier B.V. All rights reserved.

  6. Recognition and measurement of potential share value of conversion for convertible bonds

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To recognize and measure the potential share value of conversion for convertible bonds more accurately, different approaches such as the straight method, the separating method, the expected value approach and the improved approach are comparatively analyzed by taking China Merchants Bank's convertible bonds as an example. There is also a focus on the improved approach that views that convertible bond issue proceeds can be separated into accrual debt value, accrual equity value and accrual option value accor...

  7. The Value of Family History as a Risk Indicator for Venous Thrombosis

    NARCIS (Netherlands)

    Bezemer, Irene D.; Meer, van der Felilx J.M.; Eikenboom, Jeroen C.J.; Rosendaal, Frits R.; Doggen, Carine J.M.

    2009-01-01

    Background A positive family history of venous thrombosis may reflect the presence of genetic risk factors. Once a risk factor has been identified, it is not known whether family history is of additional value in predicting an individual's risk. We studied the contribution of family history to the

  8. The Value of Family History as a Risk Indicator for Venous Thrombosis

    NARCIS (Netherlands)

    Bezemer, Irene D.; van der Meer, Felilx J.M.; Eikenboom, Jeroen C.J.; Rosendaal, Frits R.; Doggen, Catharina Jacoba Maria

    2009-01-01

    Background A positive family history of venous thrombosis may reflect the presence of genetic risk factors. Once a risk factor has been identified, it is not known whether family history is of additional value in predicting an individual's risk. We studied the contribution of family history to the

  9. [The investigation of angiotensin converting enzyme I/D and plasminogen activator inhibitor-1 4G/5G polymorphisms in venous thromboembolism patients].

    Science.gov (United States)

    Kaya, Halide; Karkucak, Mutlu; Salifoğlu, Hatice; Torun, Deniz; Kozan, Salih; Tunca, Yusuf

    2013-01-01

    Deep venous thrombosis and pulmonary embolism, known as venous thromboembolism and seen as a fairly common multifactorial diseases. Differ between populations due to genetic factors, several polymorphisms associated with venous thromboembolism was conducted. As a result of these studies the relationship between disease development and polymorphism is not clear yet. In this study we aimed to investigate the role of angiotensin converting enzyme insersion/deletion (ACE I/D) and plasminogen activator inhibitor-1 4G/5G (PAI-1 4G/5G) polymorphism in the development of disease. In our study, DNA isolated from 80 venous thromboembolism patients and 79 control groups was used. While the classical polymerase chain reaction method used to investigate the ACE I/D polymorphism, the polymerase chain reaction based on allele-specific amplification was used for the detection of PAI-1 4G/5G polymorphism. As a result, there were no significant statistical differences for ACE I/D and PAI-1 4G/5G polymorphism among patient and control groups (p> 0.05). These findings revealed that there is no relationship between these polymorphisms and the development of venous thromboembolism, but large-scale studies are need to be done.

  10. DIAGNOSTIC VALUE OF D-DIMER MEASUREMENT IN PATIENTS SUSPECTED TO HAVE CEREBRAL VENOUS THROMBOSIS

    Directory of Open Access Journals (Sweden)

    M Ghaffarpour

    2008-12-01

    Full Text Available "nAmong the causes of headache, cerebral venous and/or dural sinus thrombosis (CVT is an important challenge because of its variable clinical presentation, having negative brain CT in up to 30% of cases and unavailability of MRI in some situations. On the other hand as D-Dimer (DD test has been reported to be a sensitive test for the exclusion of venous thromboembolism, we sought whether it could be useful in the diagnosis of cerebral venous thrombosis. A prospective study of 104 consecutive patients with headache or unusual ischemic stroke (infarction in brain CT, but not compatible with any brunch of cerebral arteries, suggesting CVT was conducted between 2003 and 2005. D-Dimer test determined for all patients in the emergency ward before MRI or MRV was performed. Titers above 500 ng/ml were regarded as positive test. From a total 104 patients, 21 cases (20.2% were confirmed (by MRI and/or MRV to have CVT, 20/21 (95.7% of whom had positive DD test. In the remainder 83 (without CVT it was only positive in 16.8% (14/83, which was statistically meaningful (P < 0.001. Specificity, sensitivity, negative and positive predictive values of DD test were 83.1, 95.2, 98.6 and 58.8%, respectively, so application of this test would be useful in the diagnosis of CVT and values below 500 ng/ml make acute thrombosis unlikely.

  11. Prediction of arterial blood gas values from venous blood gas values in Asiatic black bears (Ursus thibetanus) anesthetized with intramuscular medetomidine and zolazepam-tiletamine.

    Science.gov (United States)

    Jeong, Dong-Hyuk; Yang, Jeong-Jin; Lee, Lyon; Yeon, Seong-Chan

    2017-09-10

    The objective of this study was to measure differences between arterial and venous blood gas parameters and to evaluate whether arterial blood gas values can be estimated from venous blood in Asiatic black bears (ABBs). Twelve healthy captive ABBs (8 males and 4 females; 8-16 years; 76.8-220 kg) were included in this study. The bears were immobilized with medetomidine and zolazepam-tiletamine using a dart gun. Arterial and venous samples were collected simultaneously at 5 and 35 min after recumbency (5- and 35-min points). Partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), pH, bicarbonate (HCO3(-)), total carbon dioxide (TCO2), oxygen saturation of hemoglobin (SO2) and base excess (BEecf) were analyzed using a portable blood gas analyzer. There was no marked difference in measured and calculated variables over time in both venous and arterial blood except for PO2. However, arterial PO2, SO2 and pH were significantly higher and arterial PCO2, TCO2 and HCO3(-) were lower than those of venous samples at both 5- and 35-min points. In the regression analysis to estimate arterial values from venous values, PCO2, TCO2, HCO3(-), BEecf and pH significantly showed over 0.45 in coefficient of determination value (R(2)), and there were little differences between actual and predicted arterial values. Although there were limits in venous gas values replaced those of arterial blood, if we could not get the arterial samples, the regression formulas for arterial values from venous blood in this study would be useful clinically, except for PO2 and SO2.

  12. [Digital blood flow measurement by venous occlusion plethysmography in Raynaud's phenomenon. Value of the rewarming test].

    Science.gov (United States)

    Cristol, R; Debray, J

    1986-01-01

    The fingertip blood flow measured by mercury strain gauge plethysmography with venous occlusion, at 22 degrees C room temperature, had significantly lower mean values in 190 patients with Raynaud's phenomenon (55 men aged 49 yrs +/- 16, 135 women aged 48 yrs +/- 16) than in 40 age and sex matched controls: 18 ml/100 ml/minute +/- 14.6 versus 35 ml/100 ml/minute +/- 15 at level p less than 0.01. The mean fingertip blood flow was significantly lower (p less than 0.01) in 31 cases of scleroderma and 32 cases of pulpar necrosis (respectively 13 ml +/- 13 and 11 ml +/- 8) than in 55 cases of primary Raynaud's disease (no detectable etiology and normal capillaroscopy 5 years after onset) or in 34 cases of mild Raynaud's phenomenon (respectively 21.6 +/- 16 and 24.4 +/- 18). A warming test (both hands in water at 45 degrees C during 3 minutes) was performed in 50 cases with low basal fingertip blood flow. It induced a "normalized" flow in 22 cases (mostly primary or mild Raynaud), a partly improved flow in 20 cases (mostly secondary Raynaud) and no improvement in 8 cases (scleroderma). The warming test appears to be clinically useful to assess the vasospasm and the vasodilating capabilities.

  13. The value of venous blood gas analysis in the diagnosis of diabetic ketoacidosis.

    Science.gov (United States)

    Rasheed, Jawad Ibrahim; Razak, Manal Khudder Abdul; Hussein, Ahmed Amer Abdul

    2017-06-15

    Newer blood gas analyzers have the ability to report electrolyte values and glucose in addition to pH, so this diagnostic process could be condensed in diagnosing diabetic ketoacidosis (DKA). We aimed to assess the accuracy of the venous blood gas (VBG) analysis with electrolytes for diagnosing DKA. This study prospectively identified a convenience sample of (60 patients) presented with DKA and tested their VBG and serum electrolytes. The diagnosis of DKA was made according to American Diabetes Association criteria. Serum chemistry electrolyte values were considered to be the criterion standard. Sensitivity and specificity of VBG electrolytes results were compared against this standard. In addition, correlation coefficients for individual electrolytes between VBG electrolytes and laboratory chemistry electrolytes were calculated. Paired VBG and serum chemistry panels were available for 60 patients, only 49 patients were included, In this study; 20% of cases were newly diagnosed diabetes mellitus. The total number of diabetic ketoacidosis was 14 patients (28.5%). The sensitivity and specificity of the VBG and electrolytes for diagnosing DKA was 92.9% (95% confidence interval [CI]=89% to 99%) and 97.1% (95% CI=92% to 100%), respectively. Correlation coefficients between VBG and serum chemistry were 0.91, 0.47, 0.61, 0.65, and 0.58 for blood sugar, sodium, potassium, chloride, and creatinine respectively. Findings of this study offer preliminary support for the possibility of using VBG sample rather than VBG sample and serum chemistry electrolytes together to rule out diabetic ketoacidosis. Copyright © 2017. Published by Elsevier Ltd.

  14. Prediction of arterial blood gas values from venous blood gas values in patients with acute exacerbation of chronic obstructive pulmonary disease.

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    Ak, Ahmet; Ogun, Cemile Oztin; Bayir, Aysegul; Kayis, Seyit Ali; Koylu, Ramazan

    2006-12-01

    Arterial blood gas (ABG) analysis has an important role in the clinical assessment of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). However, arterial puncture or insertion of an arterial catheter has many drawbacks. The aim of this study was to evaluate whether venous blood gas (VBG) values of pH, partial pressure of carbon dioxide (PCO(2)) and oxygen (PO(2)), bicarbonate (HCO(3)), and oxygen saturation (SO(2)) can reliably predict ABG levels in patients with AECOPD. One hundred and thirty-two patients with a prior diagnosis of COPD presenting with acute exacerbation according to AECOPD criteria were included in this prospective study. AECOPD is defined as a recent increase in cough, wheezing, the volume and purulence of sputum or shortness of breath necessitating a change in regular medication, including corticosteroids or antibiotics. ABG samples were taken immediately after venous sampling, and both were analyzed. Linear regression analysis was performed and equations were established for the estimation of arterial values. The Pearson correlation coefficients for pH, PCO(2), HCO(3), PO(2), and SO(2) were 0.934, 0.908, 0.927, 0.252, and 0.296, respectively. There was a significant correlation between ABG and VBG values of pH, PCO(2), and HCO(3) (p arterial pH = 1.004 x venous pH; arterial PCO(2) = 0.873 x venous PCO(2); and arterial HCO(3) = 0.951 x venous HCO(3). VBG analysis can reliably predict the ABG values of pH, PCO(2) and HCO(3) in patients with AECOPD.

  15. Agreement between mathematically arterialised venous versus arterial blood gas values in patients undergoing non-invasive ventilation: a cohort study.

    Science.gov (United States)

    Kelly, Anne-Maree; Klim, Sharon; Rees, Stephen E

    2014-10-01

    Blood gas analysis is important for assessment of ventilatory function. Traditionally, arterial analysis has been used. A method for mathematically arterialising venous blood gas values has been developed. Our aim was to validate this method in patients undergoing non-invasive ventilation (NIV) in an emergency department (ED). This post hoc substudy of a prospective cohort study included adult patients undergoing NIV for acute respiratory compromise. When arterial blood gas analysis was required for clinical purposes, a venous sample was also drawn. Mathematically arterialised values were calculated independent of arterial values. Primary outcome of interest was agreement between mathematically arterialised venous and arterial values for pH and pCO2. Bland-Altman agreement plot analysis was used. Eighty sample-pairs (58 patients) were studied. Mean difference for arterial pH (actual-calculated) was 0.01 pH units (95% limits of agreement: -0.04, 0.06). Mean difference for pCO2 (actual-calculated) was -0.06 kPa (95% limits of agreement: -1.34, 1.22). For patients undergoing NIV in an ED, agreement between mathematically arterialised venous values and arterial values was close for pH but only moderate for pCO2. Depending on clinician tolerance for agreement, this method may be a clinically useful alternative to arterial blood gas analysis in the ED. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  16. Clinical value of classification of venous malformations with contrast-enhanced MR Angiography.

    Science.gov (United States)

    Abdel Razek, Ahmed Abdel Khalek; Albair, Germeen Ashmalla; Samir, Sieza

    2016-12-07

    To classify venous malformations based on contrast-enhanced MR angiography that may serve as a basis for treatment plan. A retrospective analysis was performed in 58 patients with venous malformations who underwent contrast-enhanced MR angiography. Venous malformations were classified according to their venous drainage into: type I, isolated malformation without peripheral drainage; type II, malformation that drains into normal veins; type III, malformation that drains into dilated veins; and type IV, malformation that represents dysplastic venous ectasia. Image analysis was done by two reviewers. Intra and inter-observer agreement of both reviewers and intra-class correlation was done. The intra-observer agreement of contrast-enhanced MR angiography classification of venous malformations was excellent for the first reviewer (k = 0.83, 95% CI = 0.724-0.951, P = 0.001) and substantial for the second reviewer (K = 0.79, 95% CI = 0.656-0.931, P = 0.001). The inter-observer agreement of contrast-enhanced MR angiography classification of venous malformations was excellent for both reviewers at the first time (K = 0.96, 95% CI = 0.933-1.000, P = 0.001) and second time (k = 0.81, 95% CI = 0.678-0.942, P = 0.001). There was high intra-class correlation of both reviewers for single measure (ICC = 0.85, 95% CI = 0.776-0.918, P = 0.001) and for average measures (ICC = 0.96, 95% CI = 0.933-0.978, P = 0.001). Contrast-enhanced MR angiography classification of venous malformations may be a useful, simple and reliable tool to accurately classify venous malformation and this topographic classification helps for better management strategy. © The Author(s) 2016.

  17. Improving the validity of peripheral venous blood gas analysis as an estimate of arterial blood gas by correcting the venous values with SvO₂.

    Science.gov (United States)

    Lemoël, Fabien; Govciyan, Sandra; El Omri, Mouna; Marquette, Charles-Hugo; Levraut, Jacques

    2013-03-01

    Peripheral venous blood gas (pVBG) analysis in replacement of arterial blood gas (ABG) is limited by the unpredictable differences between arterial and venous values, especially for PCO2 and pH (ΔPCO2 and ΔpH). We hypothesized that, using the theoretical relationship linking SvO2 and blood flow, we could diminish the effect of local circulatory conditions on ΔPCO2 and ΔpH and thereby increase pVBG validity. This was a prospective cross-sectional study performed in emergency patients requiring a blood gas analysis in which ABG and pVBG were performed simultaneously. The data of 50 randomly selected patients (model group) were used for developing two equations to correct PvCO2 and pHv according to the peripheral SvO2 (SpvO2) level. The formulas derived were PvCO2cor = PvCO2 - 0.30 × (75 - SpvO2), and pHvcor = pHv + 0.001 × (75 - SpvO2). The validity of the corrected values was then tested on the remaining population (validation group). There were 281 patients included in the study, mainly for dyspnea. ΔPCO2 and ΔpH were strongly correlated with SpvO2 (r(2) = 0.62 and r(2) = 0.53, respectively, p 45 mm Hg (AUC ROC = 0.96 ± 0.01 vs. 0.89 ± 0.02, p 7.45 (AUC = 0.91 ± 0.02 vs. 0.81 ± 0.04, p arterial abnormality. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. The real value of thrombophilia markers in identifying patients at high risk of venous thromboembolism.

    Science.gov (United States)

    Mannucci, Pier Mannuccio; Franchini, Massimo

    2014-12-01

    Thrombophilia is defined as a condition predisposing to the development of venous thromboembolic complications. Over the past decades, there have been great advances in the understanding of the pathogenesis of venous thromboembolism (VTE) through the identification of several inherited and acquired risk factors. However, in spite of such progress, a number of questions remain unanswered. In particular, it is well known that some subjects carrying several risk factors for VTE will never experience a thrombotic episode while other individuals developed recurrent thromboembolic events with no known risk factor. In this review, we summarize the current knowledge on the various thrombophilia markers, and also discuss their role in the development of thrombotic complications.

  19. Design of Multi-Valued Quaternary Based Analog-to-Digital Converter

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    A. H.M.Z. Alam

    2009-01-01

    Full Text Available Problem statement: The design of multi-valued quaternary based Analog-to-Digital Converter (ADC circuit was presented. The ADC generates multi-valued logic outputs rather than the conventional binary output system to overall reduction in circuit complexity and size. Approach: Design was implemented using pipeline ADC architecture and was simulated using model parameters based on standard 0.13 µm CMOS process. Results: Performance analysis of the design showed desirable performance parameters in terms of response, low power consumption, and a sampling rate of 10 MHz at a supply voltage of 1.3V was achieved. Conclusion/Recommendations: The ADC design was suitable for the needs of mixed-signal integrated circuit design and can be implemented as a conversion circuit for systems based on multiple-valued logic design.

  20. Value of CT pulmonary arteriography and venography in the evaluation of venous thromboembolism in a multiracial Asian population

    Institute of Scientific and Technical Information of China (English)

    Yeong Ji Lee; Rozman Zakaria; Zaleha Abdul Manaf; Zahiah Mohamed; Yeong Yeh Lee

    2013-01-01

    Background There is increasing evidence that CT pulmonary arteriography and venography allow a better diagnostic yield for deep vein thrombosis (DVT) in suspected acute pulmonary embolism (PE).The aim was to investigate the value for using such an approach in a multiracial Asian population.Methods A total of 135 consecutive subjects with clinically suspected PE in various clinical settings (postoperative in 23 subjects) were referred and evaluated for venous thromboembolism using CT pulmonary arteriography and venography in a tertiary hospital,Malaysia.The distribution of DVT was assessed based on the frequency rate of thrombosis in a particular anatomical region (inferior vena cava,pelvic,femoral and popliteal).Results In 130 subjects,excluding 5 subjects having poor images,both DVT and PE were detected in 11.5% (15/130) subjects and DVT alone was detected in 6.9% (9/130) subjects giving a combined rate of venous thromboembolism of 18.4%.A history of malignancy was significantly associated with positive scans,P=0.02.It was found that left pelvic veins (18.2%) and left femoral veins (19.5%) were more commonly thrombosed in this population.Conclusion CT pulmonary arteriography and venography is a useful technique in the evaluation of venous thromboembolism in a multi-racial Asian population.

  1. Relative value of computed tomography scanning and venous sampling in establishing the cause of primary hyperaldosteronism

    Energy Technology Data Exchange (ETDEWEB)

    Sheaves, R.; Goldin, J.; Reznek, R.H. [and others

    1996-03-01

    The purpose of this study was to evaluate the relative merits of the postural simulation test, adrenal computed tomography (CT) and venous sampling in the differential diagnosis of patients presenting with primary hyperaldosteronism. The records of 20 patients presenting with primary hyperaldosteronism were reviewed retrospectively. There were 15 patients with a unilateral aldosterone-producing adenoma (APA), 4 patients with idiopathic hyperaldosteronism (IHA) and 1 patient with primary adrenal hyperplasia (PAH). Bilateral venous sampling of adrenal veins was attempted in all patients and blood collected for aldosterone and cortisol assay. Plasma aldosterone concentration increased after 4 h of standing in all cases of hyperplasia, but was also demonstrated in 10/15 patients with a surgically-proven APA. CT scanning correctly identified all 15 cases of APA and also classified correctly the remaining 5 cases of hyperplasia. CT scanning may be used alone to confirm the cause of hyperaldosteronism where postural studies suggest an adrenal adenoma, and such patients may be considered for early surgery. 21 refs.

  2. Process for Converting Waste Glass Fiber into Value Added Products, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Hemmings, Raymond T.

    2005-12-31

    Nature of the Event: Technology demonstration. The project successfully met all of its technical objectives. Albacem has signed an exclusive licensing agreement with Vitro Minerals Inc., a specialty minerals company, to commercialize the Albacem technology (website: www.vitrominerals.com). Location: The basic research for the project was conducted in Peoria, Illinois, and Atlanta, Georgia, with third-party laboratory verification carried out in Ontario, Canada. Pilot-scale trials (multi-ton) were conducted at a facility in South Carolina. Full-scale manufacturing facilities have been designed and are scheduled for construction by Vitro Minerals during 2006 at a location in the Georgia, North Carolina, and South Carolina tri-state area. The Technology: This technology consists of a process to eliminate solid wastes generated at glass fiber manufacturing facilities by converting them to value-added materials (VCAS Pozzolans) suitable for use in cement and concrete applications. This technology will help divert up to 250,000 tpy of discarded glass fiber manufacturing wastes into beneficial use applications in the concrete construction industry. This technology can also be used for processing glass fiber waste materials reclaimed from monofills at manufacturing facilities. The addition of take-back materials and reclamation from landfills can help supply over 500,000 tpy of glass fiber waste for processing into value added products. In the Albacem process, waste glass fiber is ground to a fine powder that effectively functions as a reactive pozzolanic admixture for use in portland ce¬ment-based building materials and products, such as concrete, mortars, terrazzo, tile, and grouts. Because the waste fiber from the glass manufacturing industry is vitreous, clean, and low in iron and alkalis, the resulting pozzolan is white in color and highly consistent in chemical composition. This white pozzolan, termed VCAS Pozzolan (for Vitreous Calcium-Alumino-Silicate). is

  3. Clinical value and influencing factors of intraoperative monitoring of jugular venous oxygen saturation

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    Jie SONG

    2016-10-01

    Full Text Available Intraoperative jugular venous oxygen saturation (SjvO2 monitoring has been widely used in clinic, which can monitor cerebral blood flow (CBF and oxygen metabolism. Reverse puncture and catheterization through jugular vein for monitoring SjvO2 is easy to operate and can collect blood samples repeatedly. It is an effective method for real-time dynamic evaluation of cerebral oxygen supply-demand and neurological function. This article reviews the clinical significance and influencing factors of SjvO2 monitoring during operation. It notes in particular that SjvO2 can not be used as the only way to monitor CBF and oxygen metabolism, and a comprehensive evaluation should be done combining with the change of other parameters. DOI: 10.3969/j.issn.1672-6731.2016.10.014

  4. Value of portal venous system radiological indices in predicting esophageal varices

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    Gaduputi V

    2015-02-01

    Full Text Available Vinaya Gaduputi,1 Harish Patel,1 Sailaja Sakam,1 Srivani Neshangi,1 Rafeeq Ahmed,1 Michael Lombino,2 Sridhar Chilimuri11Department of Medicine, 2Department of Radiology, Bronx Lebanon Hospital Center New York, NY, USAIntroduction: Portal hypertension results from increased resistance to portal blood flow and has the potential complications of variceal bleeding and ascites. The splenoportal veins increase in caliber with worsening portal hypertension, and partially decompress by opening a shunt with systemic circulation, ie, a varix. In the event of portosystemic shunting, there is a differential decompression across the portal vein and splenic vein (portal vein > splenic vein, with a resultant decrease in the ratio of portal vein diameter to that of splenic vein. Portal vein to splenic vein diameter ratio and gradient could be valuable tools in predicting the presence of portosystemic shunting.Methods: We retrospectively reviewed patients with cirrhosis who underwent esophagogastroduodenoscopy (EGD for variceal screening and had a computerized tomogram (CT of the abdomen within 6 months of the index endoscopic study, between January 2009 and December 2013. Patients on nonselective beta blockers, patients with presinusoidal portal hypertension (portal vein thrombosis or extrinsic compression, and patients who had undergone portosystemic shunting procedures (transjugular intrahepatic portosystemic shunt [TIPS] or balloon-occluded retrograde transvenous obliteration (BRTO were excluded from the study. Splenic and portal vein diameters were measured (in mm just proximal and distal to the splenomesenteric venous confluence, respectively.Results: A total of 164 patients were included in the study; of these, 60% (n=98 were male and 40% (n=66 were female. The mean age of the study population was 58.7 years. A total of 126 patients (77% had varices, while 38 patients (33% did not. The mean Model for End-Stage Liver Disease (MELD score was 5.9 for those

  5. Low Cardiac Output Secondary to a Malpositioned Umbilical Venous Catheter: Value of Targeted Neonatal Echocardiography

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    Dany E. Weisz

    2014-05-01

    Full Text Available Systemic hypotension is common in very low birthweight preterm infants but the nature of the precipitating cause may be unclear. Targeted neonatal echocardiography (TnEcho is being increasingly used to support hemodynamic decisions in the neonatal intensive care unit (NICU, including identifying impairments in the transitional circulation of preterm infants, providing timely re-evaluation after institution of therapies and evaluating the placement of indwelling catheters. We present a case of a preterm infant with systemic hypotension and low cardiac output secondary to a large transatrial shunt induced by a malpositioned umbilical venous catheter. Repositioning of the line led to resolution of the hemodynamic disturbance and clinical instability, highlighting the utility of TnEcho in the NICU.

  6. The value of ultrasonography in the diagnosis of portal vein thrombosis by umbilical venous catheterization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang Keun; Kim, Young Tong; Kim, Il Young [Chonan Hospital, Soonchunhyang University, Chonan (Korea, Republic of)

    2000-12-15

    To evaluate the usefulness of ultrasonography for diagnosis of portal vein thrombosis (PVT) associated with the umbilical venous catheterization (UVC). We reviewed the abnormal ultrasonography of 54 patients with UVC. We observed echogenic thrombus in the portal vein by ultrasonography which has a 5-10 MHz linear transducer. We evaluated the frequency of PVT, the relationship between PVT and duration of UVC, and the location of catheter tip (Group I (n=41): above the diaphragm, Group II (n=9): between the diaphragm and the liver, Group III (n=4): below the liver), the location of thrombus on US, and the change of PVT on the follow-up ultrasonography. PVT was identified in the 7 neonates (13%) among the 54 neonates with UVC. The frequency of PVT was 5% on group I, 45% on group II and 25% on group III. The 6 cases among the 7 cases(86%) of PVT were localized to the umbilical portion of the left portal vein, and there were completely resolved (n=4) or regressed (n=1) on the follow-up ultrasonography(n=5). Remaining one case of PVT was located in the right, left, and main portal veins with collateral formation, and cavernous transformation occurred on the follow-up. Most PVTs by UVC are localized to the umbilical portion of left portal vein. Ultrasonography is a useful modality to diagnose PVT by UVC.

  7. A sustainable biorefinery to convert agricultural residues into value-added chemicals.

    Science.gov (United States)

    Liu, Zhiguo; Liao, Wei; Liu, Yan

    2016-01-01

    Animal wastes are of particular environmental concern due to greenhouse gases emissions, odor problem, and potential water contamination. Anaerobic digestion (AD) is an effective and widely used technology to treat them for bioenergy production. However, the sustainability of AD is compromised by two by-products of the nutrient-rich liquid digestate and the fiber-rich solid digestate. To overcome these limitations, this paper demonstrates a biorefinery concept to fully utilize animal wastes and create a new value-added route for animal waste management. The studied biorefinery includes an AD, electrocoagulation (EC) treatment of the liquid digestate, and fungal conversion of the solid fiber into a fine chemical-chitin. Animal wastes were first treated by an AD to produce methane gas for energy generation to power the entire biorefinery. The resulting liquid digestate was treated by EC to reclaim water. Enzymatic hydrolysis and fungal fermentation were then applied on the cellulose-rich solid digestate to produce chitin. EC water was used as the processing water for the fungal fermentation. The results indicate that the studied biorefinery converts 1 kg dry animal wastes into 17 g fungal biomass containing 12 % of chitin (10 % of glucosamine), and generates 1.7 MJ renewable energy and 8.5 kg irrigation water. This study demonstrates an energy positive and freshwater-free biorefinery to simultaneously treat animal wastes and produce a fine chemical-chitin. The sustainable biorefinery concept provides a win-win solution for agricultural waste management and value-added chemical production.

  8. Venous thromboembolism: Additional diagnostic value and radiation dose of pelvic CT venography in patients with suspected pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Reichert, Miriam, E-mail: Miriam.Reichert@umm.de [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim (Germany); Henzler, Thomas; Krissak, Radko; Apfaltrer, Paul [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim (Germany); Huck, Kurt [1st Department of Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim (Germany); Buesing, Karen [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim (Germany); Sueselbeck, Tim [1st Department of Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim (Germany); Schoenberg, Stefan O.; Fink, Christian [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim (Germany)

    2011-10-15

    Purpose: To assess the additional diagnostic value of indirect CT venography (CTV) of the pelvis and upper thighs performed after pulmonary CT angiography (CTA) for the diagnosis of venous thromboembolism (VTE). Materials and methods: In a retrospective analysis, the radiology information system entries between January 2003 and December 2007 were searched for patients who received pulmonary CTA and additional CTV of the pelvis and upper thighs. Of those patients, the radiology reports were reviewed for the diagnosis of pulmonary embolism (PE) and deep venous thrombosis (DVT) in the pelvic veins and veins of the upper thighs. In cases with an isolated pelvic thrombosis at CTV (i.e. which only had a thrombosis in the pelvic veins but not in the veins of the upper thigh) ultrasound reports were reviewed for the presence of DVT of the legs. The estimated radiation dose was calculated for pulmonary CTA and for CTV of the pelvis. Results: In the defined period 3670 patients were referred to our institution for exclusion of PE. Of those, 642 patients (353 men, 289 women; mean age, 65 {+-} 15 years, age range 18-98 years) underwent combined pulmonary CTA and CTV. Among them, PE was found in 227 patients (35.4%). In patients without PE CTV was negative in all cases. In patients with PE, CTV demonstrated pelvic thrombosis in 24 patients (3.7%) and thrombosis of the upper thighs in 43 patients (6.6%). Of those patients 14 (2.1%) had DVT in the pelvis and upper thighs. In 10 patients (1.5%) CTV showed an isolated pelvic thrombosis. Of those patients ultrasound reports were available in 7 patients, which revealed DVT of the leg veins in 5 cases (1%). Thus, the estimated prevalence of isolated pelvic thrombosis detected only by pelvic CTV ranges between 1-5/642 patients (0.1-0.7%). Radiation dose ranges between 4.8 and 9.7 mSv for additional CTV of the pelvis. Conclusion: CTV of the pelvis performed after pulmonary CTA is of neglectable additional diagnostic value for the

  9. Process for Converting Waste Glass Fiber into Value Added Products, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Hemmings, Raymond T.

    2005-12-31

    Nature of the Event: Technology demonstration. The project successfully met all of its technical objectives. Albacem has signed an exclusive licensing agreement with Vitro Minerals Inc., a specialty minerals company, to commercialize the Albacem technology (website: www.vitrominerals.com). Location: The basic research for the project was conducted in Peoria, Illinois, and Atlanta, Georgia, with third-party laboratory verification carried out in Ontario, Canada. Pilot-scale trials (multi-ton) were conducted at a facility in South Carolina. Full-scale manufacturing facilities have been designed and are scheduled for construction by Vitro Minerals during 2006 at a location in the Georgia, North Carolina, and South Carolina tri-state area. The Technology: This technology consists of a process to eliminate solid wastes generated at glass fiber manufacturing facilities by converting them to value-added materials (VCAS Pozzolans) suitable for use in cement and concrete applications. This technology will help divert up to 250,000 tpy of discarded glass fiber manufacturing wastes into beneficial use applications in the concrete construction industry. This technology can also be used for processing glass fiber waste materials reclaimed from monofills at manufacturing facilities. The addition of take-back materials and reclamation from landfills can help supply over 500,000 tpy of glass fiber waste for processing into value added products. In the Albacem process, waste glass fiber is ground to a fine powder that effectively functions as a reactive pozzolanic admixture for use in portland ce¬ment-based building materials and products, such as concrete, mortars, terrazzo, tile, and grouts. Because the waste fiber from the glass manufacturing industry is vitreous, clean, and low in iron and alkalis, the resulting pozzolan is white in color and highly consistent in chemical composition. This white pozzolan, termed VCAS Pozzolan (for Vitreous Calcium-Alumino-Silicate). is

  10. Diagnostic Value of D-Dimer’s Serum Level in Iranian Patients with Cerebral Venous Thrombosis

    Science.gov (United States)

    Hashami, Leila; Rakhshan, Vahid; Karimian, Hoda; Moghaddasi, Mehdi

    2016-01-01

    Cerebral venous thrombosis (CVT) is a long-term debilitating vascular brain disease with high morbidity and mortality. It may be associated with rise in D-dimer level. The aim of this study was to examine this potential association and identify the critical D-dimer cut-off level corresponding to increase the risk of CVT. This case-control study was conducted on two groups of patients with and without CVT attending the Rasool Akram Hospital (Iran) during 2014 and 2015. D-dimer levels were measured by the rapid sensitive D-dimer assay. Data were analyzed by Spearman’s correlation coefficient test, independent-samples t-test, backward-selection multiple linear regression and multiple binary logistic regression analyses. Sensitivity-specificity tests were used to detect D-dimer cut-off for CVT. Differences between the D-dimer levels of the case and control groups were significant (P<0.001). It showed that each level of increase in the number of symptoms could increase the risk of thrombosis occurrence for about 3.5 times. All symptom types except for headache were associated with D-dimer level, while headache has negative association with D-dimer level. D-dimer cut-off point for CVT diagnosis was estimated at 350 ng/mg. We concluded that D-dimer serum level significantly rises in CVT patients. A rounded cut-off point of 350 ng/mg can be used as a diagnostic criterion for CVT prediction. PMID:27441064

  11. Diagnostic value of D-dimer’s serum level in Iranian patients with cerebral venous thrombosis

    Directory of Open Access Journals (Sweden)

    Leila Hashami

    2016-06-01

    Full Text Available Cerebral venous thrombosis (CVT is a longterm debilitating vascular brain disease with high morbidity and mortality. It may be associated with rise in D-dimer level. The aim of this study was to examine this potential association and identify the critical D-dimer cut-off level corresponding to increase the risk of CVT. This case-control study was conducted on two groups of patients with and without CVT attending the Rasool Akram Hospital (Iran during 2014 and 2015. D-dimer levels were measured by the rapid sensitive D-dimer assay. Data were analyzed by Spearman’s correlation coefficient test, independent-samples t-test, backward-selection multiple linear regression and multiple binary logistic regression analyses. Sensitivity-specificity tests were used to detect D-dimer cut-off for CVT. Differences between the D-dimer levels of the case and control groups were significant (P<0.001. It showed that each level of increase in the number of symptoms could increase the risk of thrombosis occurrence for about 3.5 times. All symptom types except for headache were associated with D-dimer level, while headache has negative association with D-dimer level. D-dimer cut-off point for CVT diagnosis was estimated at 350 ng/mg. We concluded that D-dimer serum level significantly rises in CVT patients. A rounded cut-off point of 350 ng/mg can be used as a diagnostic criterion for CVT prediction.

  12. Comparison of values of traditionally measured venous bicarbonate with calculated arterial bicarbonate in intensive care unit patients of a hospital in a third-world country

    Directory of Open Access Journals (Sweden)

    Waheeda Nargis

    2014-01-01

    Full Text Available Background: Measurement of serum or plasma bicarbonate (HCO3− from a sample of peripheral venous blood is routinely practiced in hospital patient managements. HCO3− status can also be obtained by a simple calculation during blood gas analysis requiring arterial blood as sample which is cumbersome for both patient and doctor. This study compared the measured bicarbonate levels with calculated arterial values in intensive care unit (ICU patients to determine whether traditionally measured venous HCO3− and calculated HCO3− values [from arterial blood gas (ABG analyzers] can be used interchangeably. Materials and Methods: This prospective study was carried out at a tertiary care teaching hospital in Dhaka, the capital of Bangladesh. A total of 56 adult patients with diverse medical conditions, presenting at the ICU of the health centre were enrolled in this study when deemed by the treating physician to have an ABG analysis. Arterial and venous samples were taken as close in time as possible for gas analysis and routine blood tests. Results: The HCO3− levels from ABG and traditionally measured serum showed acceptably narrow 95% limits of agreement using the Bland-Altman method. Conclusions: More widely prescribed venous HCO3− measurements can also be a useful substitute for an expensive ABG analyzer in resource-constrained health care sectors when required. However, accuracy of venous blood in assessment of additional ABG parameters is yet to be discovered.

  13. Angiotensin converting enzyme (ACE DD genotype: relationship with venous thrombosis Genótipo DD da enzima conversora de angiotensina (ECA: relação com trombose venosa

    Directory of Open Access Journals (Sweden)

    Terezinha P. Munhoz

    2005-06-01

    Full Text Available Venous thromboembolism is a common multifactorial disease associated with acquired and inherited predisposing factors. Several polymorphisms, e.g. factor V Leiden, factor II G20210A and deficiency of antithrombin, protein C and protein S, have been associated with venous thromboembolism. Angiotensin converting-enzyme affects hemostasis by decreasing fibrinolysis. Angiotensin converting-enzyme gene polymorphism, a 287 pb insertion/deletion at introns 16, is related to variations in enzyme serum levels. The DD genotype has been associated with increased risk for venous thrombosis. This study examined the frequency of the angiotensin converting-enzyme alleles I and D and their association with venous thrombosis in a group of individuals from the south of Brazil. Seventy-one patients with deep venous thrombosis and/or pulmonary thromboembolism and 71 healthy individuals were analysed in a case-control study. The angiotensin converting-enzyme ID genotyping was performed by polymerase chain reaction. The frequencies of the D allele and DD genotype were, respectively, 51.4% and 22.5% for patients, and 64.7% and 45.0% for controls. The Odds Ratio for the dominant hypothesis (DD+ID versus II genotypes was 0. 75 (CI 95%; 0.29-1.93 and the Odds Ratio for recessive hypothesis (DD versus ID+II was 0.35 (CI 95%; 0.16-0.78. In conclusion, our results indicate a protective effect of the angiotensin converting-enzyme DD genotype on venous thromboembolism.O troemboembolismo venoso (TEV é uma doença multifatorial associada com fatores de risco adquiridos e hereditários. Vários polimorfismos, tais como fator V de Leiden, mutação G20210A da protrombina e as deficiências de proteína C, proteína S e anti-trombina são considerados fatores de risco para TEV. A enzima conversora da angiotensina (ECA afeta a hemostasia diminuindo a fibrinólise. O polimorfismo no gene da ECA, caracterizado pela inserção/deleção de um fragmento de 287 pb no intron16, est

  14. THE MECHANISM AND DIAGNOSTIC-VALUE OF ANGIOTENSIN-I CONVERTING ENZYME-INHIBITION RENOGRAPHY

    NARCIS (Netherlands)

    DEZEEUW, D; JONKER, GJ; HOVINGA, TKK; BEEKHUIS, H; PIERS, DA; HUISMAN, RM; DEJONG, PE

    1991-01-01

    The effect of angiotensin converting enzyme (ACE) inhibition on the sensitivity of radionuclide renography in the diagnosis of a unilateral renal artery stenosis was tested both in a conscious dog model and in the human situation. ACE inhibition (10 mg enalaprilic acid, intravenously) markedly impro

  15. Combined Chemical Activation and Fenton Degradation to Convert Waste Polyethylene into High-Value Fine Chemicals.

    Science.gov (United States)

    Chow, Cheuk-Fai; Wong, Wing-Leung; Ho, Keith Yat-Fung; Chan, Chung-Sum; Gong, Cheng-Bin

    2016-07-04

    Plastic waste is a valuable organic resource. However, proper technologies to recover usable materials from plastic are still very rare. Although the conversion/cracking/degradation of certain plastics into chemicals has drawn much attention, effective and selective cracking of the major waste plastic polyethylene is extremely difficult, with degradation of C-C/C-H bonds identified as the bottleneck. Pyrolysis, for example, is a nonselective degradation method used to crack plastics, but it requires a very high energy input. To solve the current plastic pollution crisis, more effective technologies are needed for converting plastic waste into useful substances that can be fed into the energy cycle or used to produce fine chemicals for industry. In this study, we demonstrate a new and effective chemical approach by using the Fenton reaction to convert polyethylene plastic waste into carboxylic acids under ambient conditions. Understanding the fundamentals of this new chemical process provides a possible protocol to solve global plastic-waste problems.

  16. Value of Duplex Ultrasound Assistance for Thromboaspiration and Dilation of Thrombosed Native Arterio-Venous Fistulae

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Medina, J., E-mail: josegmedina57@gmail.com [Reina Sophia University Hospital, Vascular and Interventional Radiology Unit, Department of Radiology (Spain)

    2013-12-15

    Purpose: To evaluate the value of duplex ultrasound assistance during thromboaspiration of thrombosed arteriovenous fistulae for haemodialysis. Materials and Methods: We prospectively studied 54 thrombosed native fistulae (23 with total thrombosis and 31 with partial thrombosis), in which we performed manual thromboaspiration guided by ultrasonography associated with fluoroscopy. Results: The fistulae were located in the forearm (n = 39) or in the upper arm (n = 15) of 46 patients. Mean patient age was 65 years, and hypertension was the most common risk factor (74 %). Mean access age was 928 days (range 69-2,290), and most fistulae were on the left side (41 cases, 75.92 %). The success rate was 83 % in the total thrombosis group and 100 % in the partial thrombosis group. Including initial failures, the respective primary patency rates in the total thrombosis group and the partial thrombosis group were, respectively, 83 {+-} 8 % (n = 20) and 87 {+-} 6 % (n = 28) at 1 month, 39 {+-} 10 % (n = 10) and 61 {+-} 8 % (n = 20) at 6 months, and 17 {+-} 8 % (n = 5) and 26 {+-} 8 % (n = 9) at 1 year. The mean decrease of fluoroscopy time with ultrasound was 3 min (range 1-5). The mean decrease of radiation dose was 2.6 Gy cm Superscript-Two (range 0.9-4.3]. Conclusion: Ultrasound is a feasible and useful tool in the management of thrombosed native fistulae, thus decreasing radiation exposure, and has no detrimental effect on success rates.

  17. Value of Multidetector Computed Tomography in Evaluation of Thoracic Venous Abnormalities among Pediatrics with Congenital Heart Disease

    Directory of Open Access Journals (Sweden)

    Dalia F Elbeih*, Mervat M El-Gohary *, Naglaa H Shebrya*,Mohammed A Saleh

    2013-04-01

    Full Text Available Introduction: Venous anomalies of the thorax can involve systemic or pulmonary veins and range from isolated incidental findings to components of more complex anomalies, most often congenital heart disease (CHD. Although echocardiography and catheter directed cardiac angiography are generally accepted as the primary imaging techniques for evaluation of CHD, CT and MRI are important complementary diagnostic tools. Multi-detector computed tomography (MDCT with its increasing availability and utility is now becoming a further method of imaging CHD. In light of its widespread availability, MDCT and 3D imaging are increasingly considered as a viable “one-stop shop” for preoperative imaging evaluation of cardiovascular structures in selected pediatric patients.Aim of the work: The aim of this work is to evaluate the role of MDCT in visualization of the thoracic venous system in pediatrics with congenital heart disease, show prevalence and types of venous anomalies and to compare this data with echocardiographic findings.Methods: The studied group included 30 cases referred to us by pediatric cardiologists to be examined by MSCT angiography of the heart and thoracic vessels. All the patients were known cases of congenital heart disease and underwent echocardiography. They were referred to answer specific anatomic question raised by inconclusive echocardiography, to assess suspected systemic and suspected pulmonary venous anomalies. All patients were subjected to full history taking, clinical examination and MDCT examination with CT lightspeed VCT XT 64-detectors row scanner (General Electric, Medical Systems, Milwaukee, Wisconsin, USA.Results: CTA findings had 77.8 % concordance with echocardiographic findings regarding SVC anomalies, 66.7 % concordance with echocardiography regarding IVC anomalies and 90 % concordance regarding pulmonary venous anomalies.Conclusion: Low dose protocol CTA is a promising method that complementary to Echocardioraphy

  18. MRI对脑静脉畸形的诊断价值%Diagnostic value of MRI in cerebral venous malformation

    Institute of Scientific and Technical Information of China (English)

    牛磊; 朱蒙蒙; 王明皓; 崔文; 刘圆圆; 朱斌

    2011-01-01

    目的:探讨MRI对脑静脉畸形(CVM)的诊断价值.方法:收集本院18例脑静脉畸形病例,均行磁共振T1WI、T2WI、FLAIR、SWI、DWI、MRA及T1 Wl增强扫描的资料.结果:CVM位于幕下5例,幕上13例,18例均呈典型的“海蛇头”征.MRI显示髓静脉呈长T1长T2信号,引流静脉呈短T1稍长T2信号或长T1长T2信号.FLAIR上髓静脉为稍高信号,引流静脉为低信号或稍高信号.SWI及DWI上髓静脉和引流静脉均为低信号.增强呈“海蛇头”样改变,即多条髓静脉呈辐射状汇入粗大的引流静脉.结论:MRI能明确诊断脑静脉畸形.T1WI增强扫描及SWI均较敏感.SWI对CVM的诊断价值明显优于常规MRI序列.%Objective:To investigate the diagnostic value of MRI in cerebral venous malformations (CVM). Methods: 18 patients of CVM were collected, and all of them underwent T1 WI, T2WI. FLAIR. SWI. DWI. MRA. And T,W1 enhancement scans. Results:CVMs were located in infra in five cases, and supra tentorium in thirteen eleven patients. Eighteen presented the typical " caput medusae" appearance. As for MRI plain scans.the medullary veins showed hypointensity in T1 WI and hyperintensity in T2WI, while, the drainage veins featured hyperintensity in T1 WI and hyperintensity in T2 WI. FLAIR sequences manifested less medullary veins with hyperintensity and drainage veins with hypointensity or hyperintensity. Both the medullary and the drainage veins appeared hypointensity in DWI and SWI. After enhancement, numerous radiating medullary veins gathered together into one or two larger drainage veins and flowed into superficial or deeper veins. Demonstrating the so-called "Caput Medusae" appearance. Conclusion: MRI is the first choice for suspected CVM patients thus providing more diagnostic information. T1 WI enhancement and SWI are sensitive to manifesting CVMs. SWI diagnosis of CVM is significantly superior to conventional MRI sequences.

  19. Converting citrus wastes into value-added products: Economic and environmently friendly approaches.

    Science.gov (United States)

    Sharma, Kavita; Mahato, Neelima; Cho, Moo Hwan; Lee, Yong Rok

    2017-02-01

    Citrus fruits, including oranges, grapefruits, lemons, limes, tangerines, and mandarins, are among the most widely cultivated fruits around the globe. Its production is increasing every year due to rising consumer demand. Citrus-processing industries generate huge amounts of wastes every year, and citrus peel waste alone accounts for almost 50% of the wet fruit mass. Citrus waste is of immense economic value as it contains an abundance of various flavonoids, carotenoids, dietary fiber, sugars, polyphenols, essential oils, and ascorbic acid, as well as considerable amounts of some trace elements. Citrus waste also contains high levels of sugars suitable for fermentation for bioethanol production. However, compounds such as D-limonene must be removed for efficient bioethanol production. The aim of the present article was to review the latest advances in various popular methods of extraction for obtaining value-added products from citrus waste/byproducts and their potential utility as a source of various functional compounds.

  20. 急诊静脉血气分析的临床价值%Clinical value of venous blood gas analysis in emergency medical care

    Institute of Scientific and Technical Information of China (English)

    徐安忆; 单仁飞; 秦杰; 沈建飞

    2016-01-01

    Objective To analyze the correlation between arterial and peripheral venous blood gas analysis variables. Methods The datas including PubMed,Medline,Embase were systematically searched for the variables in adult emergency peripheral venous and arterial blood gas analysis,including pH,PCO2,HCO3- and BE from January 1966 to March,2015. The quality of studies was critically evaluated and the data were extracted by two reviewers independently. Meta-analysis was conducted by using the RevMan 5.2. Results Totally 17 studies were finally identified. The pH value of arterial blood gas analysis in patients with non shock is similar to venous blood gas analysis (WMD=0.00,95%CI:-0.01~0.02,P>0.05). The PCO2 value of arterial blood gas analysis and venous blood gas analysis is obviously different (WMD=-3.87,95%CI:-4.35~-3.38,P0.05)as well as BE value(MD=0.09,95%CI:-0.97~0.55). Conclusion It had sufficient evidence to support that the pH and HCO3- of the arterial blood gas analysis in patients with non shock patients is similar with peripheral venous blood gas analysis. But there is no enough data to show the correlation between arterial and venous blood gas analysis in patients with shock or disturbance of acid-base balance. The difference between peripheral venous blood gas analysis and arterial blood gas analysis PCO2 value is obvious,it is difficult to predict the PCO2 value of arterial blood gas analysis by using PCO2 value of peripheral venous gas analysis in clinical,but the partial pressure of CO2 could apply in the arterial hypercarbia selection or partial carbon dioxide pressure monitoring.%目的:分析动脉和外周静脉血气分析变量之间的相关性。方法计算机检索PubMed、Medline、Embase数据库,收集1966年1月至2015年3月成人急诊比较外周动脉和静脉血气分析值,包括氢离子浓度指数(pH)值、二氧化碳分压(PCO2)、碳酸氢盐(HCO3-)和剩余碱(BE)的研究。由2名研究者独立对文献进

  1. IC 50-to-K i: a web-based tool for converting IC 50 to K i values for inhibitors of enzyme activity and ligand binding

    OpenAIRE

    Cer, R. Z.; Mudunuri, U.; Stephens, R.; Lebeda, F. J.

    2009-01-01

    A new web-server tool estimates K i values from experimentally determined IC 50 values for inhibitors of enzymes and of binding reactions between macromolecules (e.g. proteins, polynucleic acids) and ligands. This converter was developed to enable end users to help gauge the quality of the underlying assumptions used in these calculations which depend on the type of mechanism of inhibitor action and the concentrations of the interacting molecular species. Additional calculations are performed...

  2. Venous Ultrasound (Extremities)

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Ultrasound - Venous (Extremities) Venous ultrasound uses sound waves to ... limitations of Venous Ultrasound Imaging? What is Venous Ultrasound Imaging? Ultrasound is safe and painless, and produces ...

  3. IC50-to-Ki: a web-based tool for converting IC50 to Ki values for inhibitors of enzyme activity and ligand binding.

    Science.gov (United States)

    Cer, R Z; Mudunuri, U; Stephens, R; Lebeda, F J

    2009-07-01

    A new web-server tool estimates K(i) values from experimentally determined IC(50) values for inhibitors of enzymes and of binding reactions between macromolecules (e.g. proteins, polynucleic acids) and ligands. This converter was developed to enable end users to help gauge the quality of the underlying assumptions used in these calculations which depend on the type of mechanism of inhibitor action and the concentrations of the interacting molecular species. Additional calculations are performed for nonclassical, tightly bound inhibitors of enzyme-substrate or of macromolecule-ligand systems in which free, rather than total concentrations of the reacting species are required. Required user-defined input values include the total enzyme (or another target molecule) and substrate (or ligand) concentrations, the K(m) of the enzyme-substrate (or the K(d) of the target-ligand) reaction, and the IC(50) value. Assumptions and caveats for these calculations are discussed along with examples taken from the literature. The host database for this converter contains kinetic constants and other data for inhibitors of the proteolytic clostridial neurotoxins (http://botdb.abcc.ncifcrf.gov/toxin/kiConverter.jsp).

  4. Jugular venous oximetry

    Directory of Open Access Journals (Sweden)

    Avanish Bhardwaj

    2015-01-01

    Full Text Available The measurement of saturation of venous blood as it drains out of brain by sampling it from the jugular bulb provides us with an estimate of cerebral oxygenation, cerebral blood flow and cerebral metabolic requirement. Arterio-jugular venous difference of the oxygen content (AVDO 2 and jugular venous oxygen saturation (SjVO 2 values per se helps clinicians in identifying the impairment of cerebral oxygenation due to various factors thereby prompting implementation of corrective measures and the prevention of secondary injury to the brain due to ischaemia. SjVO 2 values are also used for prognostication of patients after traumatic brain injury and in other clinical situations. Sampling and measuring SjVO 2 intermittently or continuously using fibreoptic oximetry requires the tip of the catheter to be placed in the jugular bulb, which is a relatively simple bedside procedure. In the review below we have discussed the relevant anatomy, physiology, techniques, clinical applications and pitfalls of performing jugular venous oximetry as a tool for measurement of cerebral oxygenation.

  5. [Values of mixed venous oxygen saturation and difference of mixed venous-arterial partial pressure of carbon dioxide in monitoring of oxygen metabolism and treatment after open-heart operation].

    Science.gov (United States)

    Pan, Chuanliang; Zhang, Haiying; Liu, Jianping

    2014-10-01

    To explore the clinic values of early goal directed treatment (EGDT) with the target of mixed venous oxygen saturation (SvO₂) and difference of mixed venous-arterial partial pressure of carbon dioxide (Pv-aCO₂) in monitoring of oxygen metabolism and treatment for patients post open-heart operation. A prospective study was conducted. The adult patients admitted to Third People's Hospital of Chengdu from December 2011 to March 2014 with SvO₂2 mmol/L when admitted in intensive care unit (ICU) were selected on whom elective open-heart operation and pulmonary artery catheter examination were done. All patients received EGDT with the target of SvO₂≥0.65 and Pv-aCO₂<6 mmHg (1 mmHg=0.133 kPa) and were divided into three groups by the values of SvO₂and Pv-aCO₂at 6-hour after ICU admission: A group with SvO₂≥0.65 and Pv-aCO₂<6 mmHg, B group with SvO₂≥0.65 and Pv-aCO₂≥6 mmHg, and C group with SvO₂<0.65. Then the changes and prognosis of the patients in different groups were observed. 103 cases were included, 44 in A group, 31 in B group and 28 in C group. The acute physiology and chronic health evaluation II (APACHEII) score in group A were significantly lower than that in group B or C at 6, 24, 48 and 72 hours (T6, T24, T48, T72) of ICU admission (T6: 11.4 ± 5.8 vs. 13.9 ± 5.4, 13.7 ± 6.4; T24: 8.8 ± 3.7 vs. 10.8 ± 4.8, 11.8 ± 5.4; T48: 8.7 ± 4.1 vs. 9.6 ± 4.2, 10.2 ± 5.1; T72: 7.5 ± 3.4 vs. 8.6 ± 2.9, 9.2 ± 4.2, all P<0.05), and the sequential organ failure assessment (SOFA) showed the same tendency (T6: 6.5 ± 4.3 vs. 8.0 ± 3.8, 9.1 ± 4.5; T24: 6.6 ±3.6 vs. 8.6 ± 3.9, 8.5 ± 3.3; T48: 5.2 ± 3.4 vs. 7.0 ± 3.6, 7.6 ± 5.1; T72: 4.6 ± 2.4 vs. 5.8 ± 2.5, 6.8 ± 3.5, all P<0.05). The values of blood lactic acid (mmol/L) in group A and B were significant lower than that in group C at T6, T24, T48 and T72 (T6: 1.60 ± 0.95, 2.20 ± 1.02 vs. 2.55 ± 1.39; T24: 2.26 ± 1.26, 2.70 ± 1.36 vs. 3.34 ± 2.36; T48: 2.01 ± 1.15, 2.17

  6. Venous oxygen saturation.

    Science.gov (United States)

    Hartog, Christiane; Bloos, Frank

    2014-12-01

    Early detection and rapid treatment of tissue hypoxia are important goals. Venous oxygen saturation is an indirect index of global oxygen supply-to-demand ratio. Central venous oxygen saturation (ScvO2) measurement has become a surrogate for mixed venous oxygen saturation (SvO2). ScvO2 is measured by a catheter placed in the superior vena cava. After results from a single-center study suggested that maintaining ScvO2 values >70% might improve survival rates in septic patients, international practice guidelines included this target in a bundle strategy to treat early sepsis. However, a recent multicenter study with >1500 patients found that the use of central hemodynamic and ScvO2 monitoring did not improve long-term survival when compared to the clinical assessment of the adequacy of circulation. It seems that if sepsis is recognized early, a rapid initiation of antibiotics and adequate fluid resuscitation are more important than measuring venous oxygen saturation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. A Novel Choice Procedure of Magnetic Component Values for Phase Shifted Full Bridge Converters with a Variable Dead-Time Control Method

    Directory of Open Access Journals (Sweden)

    Lei Zhao

    2015-09-01

    Full Text Available Magnetic components are important parts of the phase shifted full bridge (PSFB converter. During the dead-time of switches located in the same leg, the converter can achieve zero-voltage-switching (ZVS by using the energies stored in magnetic components to discharge or charge the output capacitances of switches. Dead-time is usually calculated under a given set of pre-defined load condition which results in that the available energies are insufficient and ZVS capability is lost at light loads. In this paper, the PSFB converter is controlled by variable dead-time method and thus full advantage can be taken of the energies stored in magnetic components. Considering that dead-time has a great effect on ZVS, the relationship between available energies and magnetic component values is formulated by analyzing the equivalent circuits during dead-time intervals. Magnetic component values are chosen based on such relationship. The proposed choice procedure can make the available energies greater than the required energies for ZVS operation over a wide range of load conditions. Moreover, the burst mode control is adopted in order to reduce the standby power loss. Experimental results coincide with the theoretical analysis. The proposed method is a simple and practical solution to extend the ZVS range.

  8. Venous thromboembolism in children

    Directory of Open Access Journals (Sweden)

    Helena Pereira

    2016-02-01

    Full Text Available Introduction: Venous thromboembolism is rare among children and has a multi-factorial aetiology. It’s important to establish the diagnosis and evaluate the functional prognosis. Case report: A previously healthy 11 year old adolescent was observed in the emergency room with clinical signs of superficial venous thrombosis of the upper limb. Laboratorial evaluation showed a sedimentation rate, coagulation study, autoimmune antibodies and homocysteine with normal values. Testing for heritable thrombophilia revealed prothrombin mutation (G20210A, heterozigosity and mutation of PAI-1 (4G e -844A, both of which are associated with hypercoagulable state and indication to do prophylaxis with low molecular weight heparin in higher risk situations. Discussion/Conclusion: The rarity of thromboembolic events at this age and the atypical localization lead to an exhaustive laboratorial evaluation. Thrombophilia mutations may clinically become evident in adolescence, and its detection is important because of children’s lifestyle and the need of prophylactic treatment in some situations.

  9. Cerebral sinus venous thrombosis

    Science.gov (United States)

    Alvis-Miranda, Hernando Raphael; Milena Castellar-Leones, Sandra; Alcala-Cerra, Gabriel; Rafael Moscote-Salazar, Luis

    2013-01-01

    Cerebral sinus venous thrombosis (CSVT) is a rare phenomenon that can be seen with some frequency in young patients. CSVT is a multifactorial condition with gender-related specific causes, with a wide clinical presentation, the leading causes differ between developed and developing countries, converting CSVT in a condition characterized by a highly variable clinical spectra, difficult diagnosis, variable etiologies and prognosis that requires fine medical skills and a high suspicious index. Patients who presents with CSVT should underwent to CT-scan venography (CVT) and to the proper inquiry of the generating cause. This disease can affect the cerebral venous drainage and related anatomical structure. The symptoms may appear in relation to increased intracranial pressure imitating a pseudotumorcerebri. Prognosis depends on the early detection. Correcting the cause, generally the complications can be prevented. Mortality trends have diminished, and with the new technologies, surely it will continue. This work aims to review current knowledge about CSVT including its pathogenesis, etiology, clinical manifestations, diagnosis, and treatment. PMID:24347950

  10. Cerebral sinus venous thrombosis

    Directory of Open Access Journals (Sweden)

    Hernando Raphael Alvis-Miranda

    2013-01-01

    Full Text Available Cerebral sinus venous thrombosis (CSVT is a rare phenomenon that can be seen with some frequency in young patients. CSVT is a multifactorial condition with gender-related specific causes, with a wide clinical presentation, the leading causes differ between developed and developing countries, converting CSVT in a condition characterized by a highly variable clinical spectra, difficult diagnosis, variable etiologies and prognosis that requires fine medical skills and a high suspicious index. Patients who presents with CSVT should underwent to CT-scan venography (CVT and to the proper inquiry of the generating cause. This disease can affect the cerebral venous drainage and related anatomical structure. The symptoms may appear in relation to increased intracranial pressure imitating a pseudotumorcerebri. Prognosis depends on the early detection. Correcting the cause, generally the complications can be prevented. Mortality trends have diminished, and with the new technologies, surely it will continue. This work aims to review current knowledge about CSVT including its pathogenesis, etiology, clinical manifestations, diagnosis, and treatment.

  11. MSCTV直接静脉造影诊断静脉受阻性病变的价值%Value of direct multi-slice computed tomography venography in diagnosing venous obstructive disease

    Institute of Scientific and Technical Information of China (English)

    赖伟; 刘建新; 林晓平

    2015-01-01

    目的:探讨多层螺旋CT直接静脉造影(MSCTV)诊断静脉受阻性病变的临床价值。方法收集35例应用直接MSCTV诊断并经临床证实的静脉受阻性病变患者的临床及影像学资料,研究MSCTV成像方法,分析静脉受阻性病变的影像学表现特征。结果本组共35例患者,其中下肢深静脉血栓19例,上肢深静脉血栓2例,深静脉瘤栓3例,单纯性下肢静脉曲张11例。MSCTV深静脉血栓表现为静脉腔内的充盈缺损,管腔中断,侧支循环形成。深静脉瘤栓表现为静脉腔内和/或腔外软组织肿块影,管腔不规则狭窄并充盈缺损。单纯性下肢静脉曲张表现为静脉血管增多、增粗、纡曲。结论静脉受阻性病变具有一定的MSCT征象,MSCTV对诊断静脉受阻性病变具有较大的临床价值。%Objective To explore the clinical value of direct multi-slice computed tomography venography (MSCTV) in diagnosing venous obstructive disease. Methods The clinical and imaging data of 35 cases of venous obstructive disease diagnosed by MSCTV and confirmed in clinic were reviewed. The imaging features of venous ob-structive disease were analyzed. Results There were a total of 35 cases, with 19 cases located in deep venous throm-bosis of lower extremity, 2 cases located in deep venous thrombosis of upper extremity, 3 cases located in deep venous tumor thrombus, and 11 cases located in simple vein varicosis of lower extremity. MSCTV manifestations of deep ve-nous thrombosis included filling defect in vein intraluminal, luminal interrupt, and formation of collateral circulation. MSCTV manifestations of deep venous tumor thrombus showed soft tissue mass in the vein cavity and/or extralumi-nal, irregular filling defect and stenosis in lumen. Simple varicose veins of lower extremity showed increased number of veins, as well as thickening and tortuosity. Conclusion MSCTV manifestations of venous obstructive disease have some specific features

  12. Gastric large cell neuroendocrine carcinoma with venous tumor thrombus: the value of PET/CT and contrast-enhanced computed tomography.

    Science.gov (United States)

    Song, Le; Jin, Zhu; Zhang, Weifang; Zhang, Yanyan

    2015-01-01

    Venous involvement is commonly detected microscopically on gastric neuroendocrine carcinomas (NECs), but related imaging studies have been rarely documented. We report a rare case of gastric large cell NEC with tumor thrombi in gastric and splenic veins, elevated serum alpha fetoprotein, and multiple hepatic nodules. In this case, (18)F-fluorodeoxyglucose positron emission tomography combined with contrast-enhanced computed tomography provided valuable information on tumor staging. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Assessment of Retrograde Coronary Venous Infusion of Mesenchymal Stem Cells Combined with Basic Fibroblast Growth Factor in Canine Myocardial Infarction Using Strain Values Derived from Speckle-Tracking Echocardiography.

    Science.gov (United States)

    Sun, Qi-Wei; Zhen, Lei; Wang, Qin; Sun, Yan; Yang, Jiao; Li, Yi-Jia; Li, Rong-Juan; Ma, Ning; Li, Zhi-An; Wang, Lu-Ya; Nie, Shao-Ping; Yang, Ya

    2016-01-01

    Speckle-tracking echocardiography was used to assess retrograde coronary venous infusion of mesenchymal stem cells (MSCs) combined with basic fibroblast growth factor (bFGF) in a canine model of acute myocardial infarction (AMI). AMI was induced by ligation of the left anterior descending coronary artery. Coronary venous retroperfusion was performed at 1 wk after AMI. Twenty-eight animals were randomized into four groups: saline, bFGF+saline, saline+MSCs and bFGF+MSCs. Echocardiography was performed before AMI, at 7 d post-AMI and 40 d after retroperfusion. Apoptotic cardiomyocytes in the border zone of the ischemic region were evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling. Vascular endothelial growth factor and factor VIII concentrations were measured by western blotting. The left ventricular end-systolic volume increased significantly, whereas the left ventricular ejection fraction and global and segmental strain values decreased significantly after AMI. After retroperfusion, the strain values of the infarct zone, but not conventional echocardiographic parameters, were significantly different between control and bFGF+MSC groups. Cardiomyocyte apoptosis decreased, whereas vascular endothelial growth factor and factor VIII concentrations were higher in the bFGF+MSC, bFGF and MSC groups. Cardiomyocyte apoptosis was well correlated with the strain values. Although retrograde coronary venous infusion of bFGF and MSCs promoted neo-vascularization of the infarcted myocardium and inhibited apoptosis, there was only a slight strain improvement without a substantial increase in global cardiac functions.

  14. Application and value of MRI in the diagnosis of cerebral venous malformation.%脑静脉性血管畸形MRI应用及价值

    Institute of Scientific and Technical Information of China (English)

    王秀兰; 田为中; 李瑗; 陈锦华; 陈小云

    2011-01-01

    Objective To explore the application and evaluation of a variety of imaging sequences of magnetic resonance (MR) imaging in diagnosing cerebral venous malformation (CVM). Methods The distribution of 22 CVM cases and corresponding MR features were retrospectively analyzed. All the patients underwent conventional routine MRI sean and following examinations including 18 cases with extra enhanced TIWI, 8 cases with contrast enhanced magnetic resonance angiography (CE MRA), 3 eases with 3D time of flight magnetic resonance angiography (3D TOFMRA) and 6 cases with susceptibility-weighted imaging (SWI) were processed. Results he conventional routine MRI scans of draining veins were shown as long T1 and long T2 signal intensities except for few short T2 signal intensifies. Most oft. he conventional routine MRI scans of medullary veins were unclear and shown as long T1 and long T2 or iso T2 signal intensities, and after enhancement, several radial medullary veins were dearly shown afflux into bulky drain veins, demonstrating typical “jellyfish head” appearance or “centipede” and “roots shape” changes.The SWI was rather susceptible to CVM with low intensity on draining veins and medullary veins. Conclusion The characteristic representation of CVM can be achieved by combining a variety of imaging methods, which provided significant value in the diagnosis of CVM and assessment of corresponding eomplieatious.%目的 探讨MRI多种成像序列在脑静脉性畸形诊断中的应用及评价.方法 回顾性分析22例CVM分布及MR征象.常规平扫后,其中18例加做增强后TWI扫描,CE-MRA 8例,3D-TOFMRA 3例,SWI 6例.结果 MRI平扫显示引流静脉(或导静脉)通常为长T长T信号影,少数为短T信号;髓静脉为长T、长T或等T信号,大部分显示不佳,增强后可清晰显示多根髓静脉呈放射状汇入粗大的引流静脉,呈典型"水母头"状或"蜈蚣"、"树根状"改变.SWI显示CVM更为敏感,引流静脉和髓

  15. The value of ratio of hCG, progesterone in local blood of pregnancy location versus venous blood in the diagnosis of ectopic pregnancy.

    Science.gov (United States)

    Lu, Qi; Li, Yuhong; Shi, Hong; Lang, Xiao; Wang, Yudong

    2015-01-01

    The aim of this study is to combine the ratios of venous serum/colporrhagia and hemoperitoneum/venous serum of human chorionic gonadotropin (hCG) and Progesterone (P) to generate and evaluate a new method to improve the prognosis of Ectopic pregnancy (EP). For patients with curettage procedure, curettage material and venous blood were obtained at the same time. For patients receiving culdocentesis and laparoscopic exploration, abdominal fluid and venous blood samples were obtained synchronously during surgery. The sensitivity and specificity of Rp/v-hCG>1.0 and Rp/v-P>1.0 for diagnosis of EP was 88.2% and 80.71%, 93.8% and 87.53%, respectively. The sensitivity of parallel test (Rp/v-hCG>1.0 or Rp/v-P>1.0) was 92.23%. The specificity of serial test (Rp/v-hCG>1.0 and Rp/v-P>1.0) was 100%. For the area under the ROC curve of Rp/v-hCG and Rp/v-P, the parallel test and serial test were 0.91 and 0.82,0.90 and 0.87, respectively. At the determining threshold point of 1.0, the sensitivity of Rv/c-hCG and Rv/c-P for the diagnosis of EP was 56.73% and 60.01%. The specificity was 100% and 100%, respectively. The sensitivity of parallel test (Rv/c-hCG>1.0 or Rv/c-P>1.0) was 73.33%. For the area under the ROC curve of Rv/c-hCG, Rv/c-P and the parallel test was 0.78,0.80 and 0.87, respectively. It is proposed that EP can more rapidly and accurately be diagnosed by multiple biomarkers' test of Rp/v-hCG>1.0 and/or Rp/v-P>1.0, as well as Rv/c-hCG>1.0 and/or Rv/c-P>1.0 via culdocentesis or curettage.

  16. 门样血流在腮腺淋巴瘤超声诊断中的价值%Value of portal venous flow in diagnosis of parotid adenolymphoma by ultrasonic

    Institute of Scientific and Technical Information of China (English)

    陈鹏; 刘亚玲

    2014-01-01

    Objective:To study value of portal venous flow in diagnosis of parotid adenolymphoma by ultrasonic. Methods:The two-dimensional images and Doppler flow's features of 30 cases with parotid adenolymphoma were retrospectively analyzed, who were diagnosed by operations and pathology. Results:The two-dimensional ultrasound could show all the images. Those 30 cases were all confirmed by pathology. Ultrasound showed that the portal venous flow, looking like lymph nodes, had entered the tumor. Conclu-sions:The portal venous flow has an important value to diagnose parotid adenolymphoma by ultrasonic, especially for diagnosing other parotid diseases ( such as parotid mixed tumor and parotid lymphnoditis) .%目的:探讨门样血流在腮腺淋巴瘤超声诊断中的价值。方法:回顾性分析经手术及病理证实的30例腮腺淋巴瘤的二维图像及多普勒血流特点。结果:二维超声对图像显示率为100%,所查30例均经病理证实。超声多普勒显示与淋巴结相似的门样血流进入肿瘤内部。结论:门样血流在腮腺淋巴瘤超声诊断中,尤其诊断其它腮腺疾病(如腮腺混合瘤,腮腺淋巴结炎)超声鉴别诊断中具有重要价值。

  17. The clinical value of color Doppler ultrasound diagnosis of acute lower extremity deep venous thrombosis%彩色多普勒超声诊断下肢深静脉急性血栓的临床价值

    Institute of Scientific and Technical Information of China (English)

    雷声鸣; 童燕燕; 林继平

    2011-01-01

    Objective To evaluate the clinical value of color Doppler ultrasound in acute deep vein thrombosis diagnosis. Methods 38 patients acute deep venous thrombosis were treatment with color Doppler ultrasound then observed the, imaging features and the flow characteristics. Results The data in the diagnosis of acute thrombosis in 38 cases, 1 case of misdiagnosis, diagnosis rate of 97.44%, In which 37 patients with unilateral thrombosis, I case of thrombosis of both lower extremities; left lower extremity venous thrombosis in 27 cases, 10 cases of right lower limb thrombosis. Conclusion Color Doppler ultrasound examination for acute lower extremity deep venous thrombosis diagnosis has important clinical value, the preferred and reliable disease- based inspection methods.%目的 探讨彩色多普勒超声在下肢深静脉急性血栓诊断的价值.方法 应用彩色多普勒超声诊断39例下肢深静脉急性血栓,观察声像图特征及血流特点.结果 本组资料中诊断急性血栓38例,误诊1例,诊断符合率97.44%,其中单侧血栓37例,双下肢血栓1例;左下肢静脉血栓27例,右下肢血栓10例.结论 彩色多普勒超声检查对下肢深静脉急性血栓的诊断有重要的临床价值,为本病的首选和可靠的检查方法.

  18. 彩色多普勒超声对下肢深静脉血栓形成的诊断价值%Application value of color Doppler ultrasound in diagnosing lower extremity deep venous thrombosis

    Institute of Scientific and Technical Information of China (English)

    靳静

    2016-01-01

    目的 探讨彩色多普勒超声对下肢深静脉血栓形成的诊断价值.方法 选取2011年3月至2015年11月河北省廊坊市人民医院行彩色多普勒超声检查的下肢深静脉血栓形成患者63例,结合患者临床表现,分析彩色多普勒超声检查结果.结果 63例下肢深静脉血栓形成患者经彩色多普勒超声检查,左下肢40例(63.5%),右下肢20例(31.7%),双下肢2例(3.2%),漏诊1例(1.6%),诊断率为98.4%(62/63).62例确诊患者中急性栓塞14例(22.2%),亚急性栓塞40例(63.5%),慢性栓塞8例(12.7%).结论 应用彩色多普勒超声对下肢深静脉血栓高危患者进行检查,无创安全、及时准确、可重复操作且经济便捷,为临床提供可靠的诊断依据,是诊断下肢深静脉血栓形成的首选辅助检查方法.%Objective To explore the value of color Doppler ultrasound in diagnosing lower extremity deep venous thrombosis.Methods Sixty-three cases with lower extremity deep venous thrombosis who underwent color Doppler ultrasound from March 2011 to November 2015 were enrolled.The results of color Doppler ultrasound were analyzed based on clinical data.Results Totally 40 cases (63.5%) of left lower limb,20 cases (31.7%) of right lower limb and 2 cases (3.2%) of bilateral lower limb deep venous thrombosis were diagnosed by color Doppler ultrasound,1 case (1.6%) was missed,with diagnostic rate of 98.4% (62/63);among the 62 patients,14 cases (22.2%) were confirmed as acute lower extremity deep venous thrombosis,40 cases (63.5%) were confirmed as subacute lower extremity deep venous thrombosis and 8 cases (12.7%) were confirmed as chronic lower extremity deep venous thrombosis.Conclusion Color doppler ultrasound is non-invasive,safe,timely,accurate,repeatable,inexpensive and convenient,and is a preferred method for diagnosing lower extremity deep venous thrombosis.

  19. Cascaded resonant bridge converters

    Science.gov (United States)

    Stuart, Thomas A. (Inventor)

    1989-01-01

    A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

  20. Application value comparison of peripheral blood and venous blood in blood routine examination%末梢血和静脉血在血常规检验中的应用价值比较

    Institute of Scientific and Technical Information of China (English)

    赖清连

    2015-01-01

    Objective:To explore the application value of peripheral blood and venous blood in blood routine examination.Methods:180 cases of healthy persons and patients with blood routine examination were selected.They were randomly divided into two groups.In the peripheral blood group,peripheral blood was collected to test.In the venous blood groups,venous blood was collected to test.We compared two groups of test results.Results:In peripheral blood group,hemoglobin,white blood cells and red blood cells were higher than those in the venous blood group,and the platelet count was lower than that of the venous blood group(P0.05).At 3 to 6 hours of detection,white blood cells,intermediate cells,red blood cells were significantly increased,and the platelet count was significantly decreased(P<0.05).Conclusion:The detection result of venous blood was more accurate,and it can be repeatedly detected,and it had obvious advantages compared with peripheral blood.Because the human body blood testing was affected by many factors,in order to avoid the error,the blood should be detected in 3 hours.%目的:探讨末梢血与静脉血在血常规检验中的应用价值。方法:收治行健康体检与接受血常规检验患者180例,随机分为两组,末梢血组采集末梢血进行检验,静脉血组采集静脉血进行检验,比较两组的检测结果。结果:末梢血组的血红蛋白、白细胞、红细胞等指标均高于静脉血组,血小板计数值低于静脉血组(P<0.05);两组即刻检测与2 h检测的各项指标均无明显差异(P>0.05),3~6 h检测,白细胞、中间细胞、红细胞等明显升高,血小板计数值明显降低(P<0.05)。结论:静脉血检测结果更为准确,且可重复检测,与末梢血相比,具有明显优势。由于人体血常规检测受多种因素影响,为了避免误差,应在3 h内进行检测。

  1. Wavelength Converters

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Wolfson, David;

    1999-01-01

    at 2.5 Gbit/s, the regeneration causes a reduction of the required input power to an in-line EDFA of ~6 dB for a power penalty of 1 dB at a bit error rate of 10-9. If two converters are concatenated the power requirement is reduced ~8 dB. Obviously, the power reduction allows for longer spans between....... It is predicted that jitter accumulation can be minimised by using a 9-10 dB ratio between the signal and CW power also assuring a high extinction ratio. Using this guideline simulations show that 20 cross-gain modulation converters can be cascaded at 10 Gbit/s with only ~20 ps of accumulated jitter...... and an extinction ratio of ~10 dB.The regenerative capabilities of the cross-phase converters are described and verified experimentally at 20 Gbit/s, where the noise redistribution and improvement of the signal-to-noise ratio clearly is demonstrated by controlling the input power to an EDFA. In a similar experiment...

  2. Mixed total anomalous pulmonary venous connection: Case report with bilateral venous collectors.

    Science.gov (United States)

    Cayre, Raul O; Civetta, Julio D; Roldan, Alberto O; Rousseau, Juan J; Knudson, Ole A; Valdes-Cruz, Lilliam M

    2003-01-01

    We present a case report of a 3-month-old boy with a mixed total anomalous pulmonary venous connection. The patient had situs solitus, small atrial septal defect, and 2 separate venous collectors. The right pulmonary veins drained through a right-sided venous collector into the coronary sinus. The left-sided pulmonary veins drained through the left-sided venous collector directly into the right superior vena cava. The use of the echocardiogram and Doppler color flow mapping to establish a detailed morphologic analysis, the sites of connection, and the presence of pulmonary venous obstructions as well as the value of this information to facilitate a successful surgical repair are discussed.

  3. Converting the reset

    NARCIS (Netherlands)

    Hoogland, J.K.; Neumann, C.D.D.; Bloch, D.

    2001-01-01

    We give a simple algorithm to incorporate the effects of resets in convertible bond prices, without having to add an extra factor to take into account the value of the reset. Furthermore we show that the effect of a notice period, and additional make-whole features, can be treated in a straightforwa

  4. Lifestyle and venous thrombosis

    NARCIS (Netherlands)

    Pomp, Elisabeth Rebekka

    2008-01-01

    In the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis (MEGA study), a large population-based case-control study, we investigated lifestyle factors as risk factors for venous thrombosis. Overweight, smoking and alcohol consumption were addressed and pregnancy and

  5. Radiation effects on DC-DC Converters

    Science.gov (United States)

    Zhang, Dexin; Attia, John O.; Kankam, Mark D. (Technical Monitor)

    2000-01-01

    DC-DC switching converters are circuits that can be used to convert a DC voltage of one value to another by switching action. They are increasing being used in space systems. Most of the popular DC-DC switching converters utilize power MOSFETs. However power MOSFETs, when subjected to radiation, are susceptible to degradation of device characteristics or catastrophic failure. This work focuses on the effects of total ionizing dose on converter performance. Four fundamental switching converters (buck converter, buck-boost converter, cuk converter, and flyback converter) were built using Harris IRF250 power MOSFETs. These converters were designed for converting an input of 60 volts to an output of about 12 volts with a switching frequency of 100 kHz. The four converters were irradiated with a Co-60 gamma source at dose rate of 217 rad/min. The performances of the four converters were examined during the exposure to the radiation. The experimental results show that the output voltage of the converters increases as total dose increases. However, the increases of the output voltage were different for the four different converters, with the buck converter and cuk converter the highest and the flyback converter the lowest. We observed significant increases in output voltage for cuk converter at a total dose of 24 krad (si).

  6. Clinical Value of Thrombelastogram on Patients of Deep Venous Thrombosis and Pulmonary Em-bolism%血栓弹力图在下肢深静脉血栓与肺栓塞的应用价值

    Institute of Scientific and Technical Information of China (English)

    周闯; 向华; 孙林; 张智明; 刘觉仕

    2016-01-01

    [Objective]To investigate the clinical value of thrombelastogram on patients of deep venous throm-bosis (DVT)and DVT combined with pulmonary embolism (PE).[Methods]12 cases of DVT and DVT with PE in the hospital from March 2014 to September 2014 were selected,of which 8 cases were newly diagnosed as DVT patients,and 4 cases as DVT combined with PE.12 healthy subjects with no history of DVT nor PE were selected as control group,who underwent venous ultrasonography,CT pulmonary angiography (CTA)and Thrombelasto-gram examination.Thrombelastogram index related with DVT and DVT with PE such as blood coagulation time (R),coagulation time (K),maximum blood clot strength (MA),angle,blood coagulation indicators were com-pared with.[Results]There was no statistical significant difference between the DVT group,the DVT combined with PE group and the control group in age,gender,R,MA,K,Angel and CL (P >0.05).[Conclusion]Deep venous thrombosis and deep venous thrombosis combined with pulmonary embolism had no obvious difference in the Thrombelastogram index ,the application value of Thrombelastogram in VTE needs to be further studied.%[目的]探讨血栓弹力图对下肢深静脉血栓形成(DVT)患者与DVT合并肺栓塞(PE)患者的应用价值.[方法]选择2014年3~9月本院收治的新发DVT及DVT合并PE患者12例,其中新发DVT患者8例,DVT合并PE患者4例,选择同期无DVT或PE病史的12例健康体检者为对照组,均行下肢静脉彩超、肺动脉CT血管成像(CTA)、血栓弹力图等检查.比较DVT患者及DVT合并PE患者在血栓弹力图相关指标如凝血反应时间(R值)、凝固时间(K值)、最大血凝块强度(MA)、凝固角(Angel)、凝血综合指数(CL)的异同点.[结果]DVT组、DVT合并PE组与对照组在年龄、性别、R、MA、K、Angel、CL方面比较,组间比较差异无统计学意义(P>0.05).[结论]下肢深静脉血栓形成与下肢深静脉血栓形成合并肺栓塞在血栓弹力图指标上无明显差异,血

  7. Idiopathic venous thromboembolism and thrombophilia

    OpenAIRE

    Sinescu, C; Hostiuc, M; Bartos, D.

    2011-01-01

    During the past decade idiopathic venous thromboembolism has become a separate entity, a chronic illness which has required prolonged anticoagulation and other prevention strategies to avoid recurrences. This article reviews recent developments regarding unprovoked venous thromboembolism and its relation with thrombophilia. In the beginning, the latest definition of idiopathic venous thromboembolism is presented. The article continues with statistics about thrombophilia, related venous thromb...

  8. Value of systolic pulmonary venous flow reversal and color Doppler jet measurements assessed with transesophageal echocardiography in recognizing severe pure mitral regurgitation

    NARCIS (Netherlands)

    Pieper, EPG; Hellemans, IM; Hamer, HPM; Ravelli, ACJ; Cheriex, EC; Tijssen, JGP; Lie, KI; Visser, CA

    1996-01-01

    We evaluated the value of color and pulsed Doppler transesophageal echocardiographic parameters and of V waves in estimating the severity of mitral regurgitation (MR) in 62 consecutive patients (38 men and 24 women, aged 39 to 80 years) with angiographically proven chronic pure MR (15 grade I/II, 47

  9. Central venous catheter - flushing

    Science.gov (United States)

    ... during cancer treatment Bone marrow transplant - discharge Central venous catheter - dressing change Peripherally inserted central catheter - flushing Sterile technique Surgical wound care - open Review Date 9/22/2016 Updated by: ...

  10. Cerebral venous sinus thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Renowden, Shelley [Frenchay Hospital, Bristol BS16 1LE (United Kingdom)

    2004-02-01

    A comprehensive synopsis on cerebral venous thrombosis is presented. It emphasizes the various aetiologies, the wide clinical spectrum and the unpredictable outcome. Imaging techniques and pitfalls are reported and the therapeutic options are discussed. (orig.)

  11. Venous thrombosis: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, C.W.

    1986-07-01

    Venous thromboembolic disease contributes to morbidity and mortality in certain groups of hospitalized patients, particularly those who have undergone surgery. Although principles of treatment have changed relatively little during the past 20 years, significant advances have been made in the diagnosis of deep vein thrombosis (DVT). Venography, once the only reliable diagnostic technique, has been largely replaced by noninvasive tests: impedance plethysmography, venous Doppler, /sup 125/I-radiofibrinogen-uptake test, and phleborheography. Virchow's triad of stasis, vessel injury, and hypercoagulability remains a valid explanation of the pathogenesis of thrombus formation, but laboratory and clinical data have refined our knowledge of how these factors interact to result in clinically significant disease. Knowledge of the natural history of venous thrombosis, plus heightened awareness of the long-term morbidity and expense associated with the postphlebitic syndrome, have led to increased interest in preventing DVT. Clinically and economically, venous thrombosis is best managed by prevention. 61 references.

  12. [Homocysteine and venous thromboembolism].

    Science.gov (United States)

    Monnerat, C; Hayoz, D

    1997-09-06

    Congenital homocysteinuria is a rare inherited metabolic disorder with early onset atherosclerosis and arterial and venous trombosis. Moderate hyperhomocysteinemia is more frequently encountered and is recognized as an independent cardiovascular risk factor. Several case-control studies demonstrate an association between venous thromboembolism and moderate hyperhomocysteinemia. A patient with moderate hyperhomocysteinemia has a 2-3 relative risk of developing an episode of venous thromboembolism. The occurrence of mild hyperhomocysteinemia in heterozygotes for the mutation of Leiden factor V involves a 10-fold increase in the risk of venous thromboembolism. The biochemical mechanism by which homocysteine may promote thrombosis is not fully recognized. Homocysteine inhibits the expression of thrombomodulin, the thrombin cofactor responsible for protein C activation, and inhibits antithrombin-III binding. Treatment with folic acid reduces the plasma level of homocysteinemia, but no study has demonstrated its efficacy in reducing the incidence of venous thromboembolism or atherosclerosis. Hyperhomocysteinemia should be included in the screening of abnormalities of hemostasis and thrombosis in patients with idiopathic thromboembolism, and mild hyperhomocysteinemia may justify a trial of folic acid.

  13. Ileofemoral venous thrombectomy.

    Science.gov (United States)

    Lindhagen, J; Haglund, M; Haglund, U; Holm, J; Scherstén, T

    1978-01-01

    Twentyeight patients with ileofemoral venous thrombosis were treated surgically. Five of the patients had moderate degree of venous congestion, 18 patients had phlegmasia alba dolens and five patients had phlegmasia coerulea dolens. The mean age was 54 years, range 15-80 years, and 15 were men and 13 were women. In all cases the thrombosis was verified by phlebography. Thrombectomy was performed with a Fogarty venous thrombectomy catheter. Peroperative phlebography was used in most cases to guarantee complete extraction of thrombotic material. No operative pulmonary embolism or mortality was encountered. Postoperative continuous heparin infusion in the thrombectomized segment was used for the first week followed by dicumarol treatment. The patients were followed from 6 months to 4 years postoperatively. In two patients thrombectomy was not possible to perform. One of these patients developed a pronounced postthrombotic syndrome, the other developed venous congestion of more moderate degree. Excellent long-term time results were obtained in 82% of the patients and satisfactory in 14%. Thrombectomy is an efficient treatment of ileofemoral venous thrombosis.

  14. Hormonal contraception and venous thromboembolism

    DEFF Research Database (Denmark)

    Lidegaard, Øjvind; Milsom, Ian; Geirsson, Reynir Tomas;

    2012-01-01

    New studies about the influence of hormonal contraception on the risk of venous thromboembolism (VTE) have been published.......New studies about the influence of hormonal contraception on the risk of venous thromboembolism (VTE) have been published....

  15. Models of the venous system

    DEFF Research Database (Denmark)

    Mehlsen, J

    2000-01-01

    of the venous system require at least three elements: a resistor, a capacitor and an inductor, with the latter being of more importance in the venous than in the arterial system. Non-linearities must be considered in pressure/flow relations in the small venules, during venous collapse, or low flow conditions...

  16. 彩色多普勒超声对下肢深静脉血栓的诊断价值%Diagnosis Value of Color Doppler Ultrasonography of Deep Venous Thrombosis of the Lower Limbs

    Institute of Scientific and Technical Information of China (English)

    陈淑臻

    2013-01-01

    Objective Discusses color doppler ultrasonography in the diagnosis of deep venous thrombosis of the lower limbs value. Methods Will our deep vein thrombosis of the lower limbs were in patients with the clinical data of 100 patients were retrospectively analyzed. Results 100 cases of lower limb deep vein thrombosis case detection of acute deep vein thrombosis of the lower limbs (45 cases) and detection chronic lower limb deep vein thrombosis in 55 cases. Conclusion Color doppler ultrasound help clinical to make the right diagnosis,deep vein thrombosis of the lower limbs can be used as the first choice for the method, it is worth clinical application.%  目的探讨彩色多普勒超声对下肢深静脉血栓的诊断价值。方法将我院收治的下肢深静脉血栓患者100例的临床资料进行回顾性分析。结果100例下肢深静脉血栓形成病例检出急性下肢深静脉血栓45例,检出慢性下肢深静脉血栓55例。结论彩色多普勒超声有助于临床做出正确诊断,可作为下肢深静脉血栓的首选检查方法,值得临床推广应用。

  17. Simplified design of data converters

    CERN Document Server

    Lenk, John

    1997-01-01

    Simplified Design of Data Converters shows how to design and experiment with data converters, both analog-to-digital and digital to analog. The design approach here is the same one used in all of John Lenk's best-selling books on simplified and practical design. Throughout the book, design problems start with guidelines for selecting all components on a trial-value basis, assuming a specific design goal and set of conditions. Then, using the guideline values in experimental circuits, the desired results are produced by varying the experimental component values, if needed.If you are a w

  18. Venous thromboembolism: The intricacies

    Directory of Open Access Journals (Sweden)

    Dutta T

    2009-01-01

    Full Text Available Venous thromboembolism (VTE has been a subject of great interest of late. Since Rudolph Virchow described the famous Virchow′s triad in 1856, there have been rapid strides in the understanding of the pathogenesis and factors responsible for it. Discovery of various thrombophilic factors, both primary and acquired, in the last 40 years has revolutionized prognostication and management of this potentially life-threatening condition due to its associated complication of pulmonary thromboembolism. Detailed genetic mapping and linkage analyses have been underlining the fact that VTE is a multifactorial disorder and a complex one. There are many gene-gene and gene-environment interactions that alter and magnify the clinical picture in this disorder. Point in case is pregnancy, where the risk of VTE is 100-150 times increased in the presence of Factor V Leiden, prothrombin mutation (Prothrombin 20210A and antithrombin deficiency. Risk of VTE associated with long-haul air flight has now been well recognized. Thrombotic events associated with antiphospholipid syndrome (APS are 70% venous and 30% arterial. Deep venous thrombosis and pulmonary embolism are the most common venous events, though unusual cases of catastrophes due to central vein thrombosis like renal vein thrombosis and Budd-Chiari syndrome (catastrophic APS may occur.

  19. Chronic venous disorders

    African Journals Online (AJOL)

    evaluated by clinical assessment and duplex ultrasound. The rate ... History and physical examination. The most common ... deep venous thrombosis or phlebitis, use of anticoagulation therapy, unexplained ... veins and pulsed Doppler assessment of the direction of ... effective in healing ulcers and preventing recurrences ...

  20. Central venous line - infants

    Science.gov (United States)

    A central venous line (CVL) is a long, soft, plastic tube that is put into a large vein in the chest. WHY IS A CVL USED? A CVL is often put in when a baby cannot get a ... (MCC). A CVL can be used to give nutrients or medicines to a ...

  1. Venous Thromboembolism in China

    Institute of Scientific and Technical Information of China (English)

    赵永强

    2005-01-01

    @@ Deep vein thrombosis (DVT) and pulmonary thromboembolism (PTE) are two manifesttions of venous thromboembolism (VTE) . Although the controversy remained,it has been widely accepted for many years that Chinese people have lower incidence of VTE than Caucasians with the different etiology and clinical features.

  2. Cerebral Venous Thrombosis.

    Science.gov (United States)

    Sassi, Samia Ben; Touati, Nahla; Baccouche, Hela; Drissi, Cyrine; Romdhane, Neila Ben; Hentati, Fayçal

    2016-01-01

    Data regarding cerebral venous thrombosis in North Africa are scarce. This study aims to identify the clinical features, risk factors, outcome, and prognosis of cerebral venous thrombosis in Tunisia. Data of 160 patients with radiologically confirmed cerebral venous thrombosis, hospitalized in Mongi Ben Hmida National Institute of Neurology (Tunis, Tunisia), were retrospectively collected and analyzed. The mean age was 37.3 years with a female predominance (83.1%). The mode of onset was subacute in most cases (56.2%). Headache was the most common symptom (71.3%), and focal neurologic symptoms were the main clinical presentation (41.8%). The most common sites of thrombosis were the superior sagittal sinus (65%) and the lateral sinus (60.6%). More than 1 sinus was involved in 114 (71.2%) patients. Parenchymal lesions observed in 85 (53.1%) patients did not correlate with cerebral venous thrombosis extent. Major risk factors were obstetric causes (pregnancy and puerperium) found in 46 (38.6% of women aged <50 years) patients, followed by anemia (28.1%) and congenital or acquired thrombophilia (16.2%). Mortality rate was of 6.6%. Good outcome at 6 months (modified Rankin Scale ≤2) was observed in 105 (87.5%)of 120 patients available for follow-up. Predictors of poor outcome were altered consciousness and elevated plasma C-reactive protein levels. Clinical and radiologic presentation of cerebral venous thrombosis in Tunisia was quite similar to other parts of the world with, however, a particularly high frequency of obstetric causes. Plasma C-reactive protein level should be considered as a prognostic factor in CVT.

  3. A prospective cohort study on the absolute risks of venous thromboembolism and predictive value of screening asymptomatic relatives of patients with hereditary deficiencies of protein S, protein C or antithrombin

    NARCIS (Netherlands)

    Mahmoodi, B. K.; Brouwer, J-L P.; Ten Kate, M. K.; Lijfering, W. M.; Veeger, N. J. G. M.; Mulder, A. B.; Kluin-Nelemans, H. C.; van der Meer, J.

    2010-01-01

    Background: Absolute risks of venous thromboembolism (VTE) in protein S-, protein C-, or antithrombin-deficient subjects are mainly based on retrospective data. Screening asymptomatic relatives of these patients is disputed, though studies addressing this issue have yet to be conducted. Methods: We

  4. A prospective cohort study on the absolute risks of venous thromboembolism and predictive value of screening asymptomatic relatives of patients with hereditary deficiencies of protein S, protein C or antithrombin.

    NARCIS (Netherlands)

    Mahmoodi, B.K.; Brouwer, J.L.P.; Kate, M.K. Ten; Lijfering, W.M.; Veeger, N.J.; Mulder, A.B.; Kluin-Nelemans, H.C.; Meer, J. van der

    2010-01-01

    BACKGROUND: Absolute risks of venous thromboembolism (VTE) in protein S-, protein C-, or antithrombin-deficient subjects are mainly based on retrospective data. Screening asymptomatic relatives of these patients is disputed, though studies addressing this issue have yet to be conducted. METHODS: We

  5. Venous thromboembolism and pregnancy

    Directory of Open Access Journals (Sweden)

    Maristella D’Uva

    2010-03-01

    Full Text Available Maristella D’Uva1, Pierpaolo Di Micco2, Ida Strina1, Giuseppe De Placido1Department of Obstetrics and Gynecology and Human Reproduction, “Federico II” University of Naples, Naples, Italy; 2Internal Medicine Division, Buonconsiglio Fatebenefratelli Hospital of Naples, Naples, ItalyAbstract: In recent decades, the association between a hypercoagulable state and its causes and adverse pregnancy outcome, in particular recurrent pregnancy loss (RPL has been studied extensively. Although the first studies were focused only on the association between thrombophilia and RPL, subsequent studies underlined also a potential role of antithrombotic treatment to prevent vascular complication such as venous thromboembolism (VTE during pregnancy. Thromboprophylaxis should be considered also for pregnant subjects carriers of molecular thrombophilia or that previously experienced VTE, in order to prevent VTE during pregnancy, while antithrombotic treatment for VTE should be performed during all pregnant periods.Keywords: thrombophilia, venous thromboembolism, recurrent pregnancy loss, factor V Leiden

  6. Venous Leg Ulcers.

    Science.gov (United States)

    Vivas, Alejandra; Lev-Tov, Hadar; Kirsner, Robert S

    2016-08-02

    This issue provides a clinical overview of venous leg ulcers, focusing on prevention, diagnosis, treatment, and practice improvement. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.

  7. Venous leg ulcers.

    Science.gov (United States)

    Nelson, E Andrea

    2011-12-21

    Leg ulcers usually occur secondary to venous reflux or obstruction, but 20% of people with leg ulcers have arterial disease, with or without venous disorders. Between 1.5 and 3.0/1000 people have active leg ulcers. Prevalence increases with age to about 20/1000 in people aged over 80 years. We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of standard treatments, adjuvant treatments, and organisational interventions for venous leg ulcers? What are the effects of advice about self-help interventions in people receiving usual care for venous leg ulcers? What are the effects of interventions to prevent recurrence of venous leg ulcers? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2011 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We found 101 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. In this systematic review we present information relating to the effectiveness and safety of the following interventions: compression bandages and stockings, cultured allogenic (single or bilayer) skin replacement, debriding agents, dressings (cellulose, collagen, film, foam, hyaluronic acid-derived, semi-occlusive alginate), hydrocolloid (occlusive) dressings in the presence of compression, intermittent pneumatic compression, intravenous prostaglandin E1, larval therapy, laser treatment (low-level), leg ulcer clinics, multilayer elastic system, multilayer elastomeric (or non-elastomeric) high-compression regimens or bandages, oral treatments (aspirin, flavonoids, pentoxifylline, rutosides, stanozolol, sulodexide

  8. The aetiology of deep venous thrombosis.

    Science.gov (United States)

    Malone, P C; Agutter, P S

    2006-09-01

    Most ideas about the pathogenesis of deep venous thrombosis (DVT) are dominated by a 'consensus model' first articulated around 1962. This model invokes 'Virchow's triad' and attributes thrombogenesis in veins to some combination of 'hypercoagulability', 'stasis' and 'intimal injury'. This arose as a by-product of studies on the mechanisms of haemostasis and bleeding diatheses that were at best only indirectly relevant to thrombosis, and there are reasons for doubting the causal significance of 'hypercoagulability' and 'stasis' in the aetiology of DVT. Proponents of the consensus model make little reference to a substantial literature, mostly historical, that: (a) emphasizes the significance of the venous valve pockets (VVP) and blood rheology in DVT pathogenesis; and (b) describes morphological features specific to venous thrombi that a valid aetiological model must explain. This literature provides the basis for an alternative hypothesis of DVT aetiology, published some 30 years ago, which has been experimentally corroborated and is compatible with recent cell and molecular biological studies of the venous endothelium. We review this alternative hypothesis, considering its potential value for future research on DVT and embolism, and its significance for clinical practice.

  9. Understanding Guyton's venous return curves

    National Research Council Canada - National Science Library

    Beard, Daniel A; Feigl, Eric O

    2011-01-01

    ...) was experimentally increased the right atrial pressure decreased, Arthur Guyton and coworkers proposed an interpretation that right atrial pressure represents a back pressure restricting venous return...

  10. Medical management of venous ulcers.

    Science.gov (United States)

    Pascarella, Luigi; Shortell, Cynthia K

    2015-03-01

    Venous disease is the most common cause of chronic leg ulceration and represents an advanced clinical manifestation of venous insufficiency. Due to their frequency and chronicity, venous ulcers have a high socioeconomic impact, with treatment costs accounting for 1% of the health care budget in Western countries. The evaluation of patients with venous ulcers should include a thorough medical history for prior deep venous thrombosis, assessment for an hypercoagulable state, and a physical examination. Use of the CEAP (clinical, etiology, anatomy, pathophysiology) Classification System and the revised Venous Clinical Severity Scoring System is strongly recommended to characterize disease severity and assess response to treatment. This venous condition requires lifestyle modification, with affected individuals performing daily intervals of leg elevation to control edema; use of elastic compression garments; and moderate physical activity, such as walking wearing below-knee elastic stockings. Meticulous skin care, treatment of dermatitis, and prompt treatment of cellulitis are important aspects of medical management. The pharmacology of chronic venous insufficiency and venous ulcers include essentially two medications: pentoxifylline and phlebotropic agents. The micronized purified flavonoid fraction is an effective adjunct to compression therapy in patients with large, chronic ulceration.

  11. Models of the venous system

    DEFF Research Database (Denmark)

    Mehlsen, J

    2000-01-01

    Cardiac output is largely controlled by venous return, the driving force of which is the energy remaining at the postcapillary venous site. This force is influenced by forces acting close to the right atrium, and internally or externally upon the veins along their course. Analogue models....... The venous capacitance is also non-linear, but may be considered linear under certain conditions. The models have to include time varying pressure sources created by respiration and skeletal muscles, and if the description includes the upright position, the partly unidirectional flow through the venous...

  12. Chronic Venous Disease under pressure

    OpenAIRE

    Reeder, Suzan

    2013-01-01

    textabstractIn chapter 1 we provide a general introduction of this thesis. Chronic venous disease (CVD) is a common medical condition that affects 2-64% of the worldwide population and leads to leg ulcers in 1% of the Western population. Venous leg ulceration (VLU) has an unfavorable prognosis with regard to non-healing and recurrence rates. Annually 6% of the total healthcare costs are spent on the treatment of venous diseases. CVD results from ambulatory venous hypertension and is the conse...

  13. Clinical Value of Color Doppler Ultrasound in Diagnosis of Lower Extremity Deep Venous Thrombosis%彩色多普勒超声诊断下肢深静脉血栓的临床价值

    Institute of Scientific and Technical Information of China (English)

    段林; 谢军

    2015-01-01

    Objective To study the color Doppler flow imaging (CDFI) Detection of deep venous thrombosis of the application. Methods 46 patients with lower extremity deep venous thrombosis (DVT) in patients using color Doppler ultrasonic diagnostic apparatus of the lower extremity deep venous acute and chronic thrombosis in patients with inspection, observation of its two-dimensional images, color flow characteristics and spectral characteristics. Results 46 patients with vascular lesions in the two-dimensional ultrasound image, color Doppler flow imaging and spectral Doppler area showed a significant specificity and sensitivity. Conclusion Color Doppler ultrasound accurate, sensitive, non-invasive diagnosis of deep venous thrombosis is one ef ective method worthy of clinical application.%目的:探讨彩色多普勒血流显像(CDFI)检测下肢深静脉血栓的应用价值。方法对46例下肢深静脉血栓(DVT)患者,采用彩色多普勒超声诊断仪对下肢深静脉急、慢性血栓患者进行检查,观察其二维图像、彩色血流特点及频谱特征。结果46例患者的病变血管在二维超声图像、彩色多普勒血流显像以及频谱多普勒方面均有显著的特异性和敏感性。结论彩色多普勒超声检查准确、敏感、无创,是诊断下肢深静脉血栓的有效方法之一,值得临床推广应用。

  14. Wavelength converter technology

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov;

    1999-01-01

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on all-optical wavelength converter types based on semiconductor optical amplifiers....

  15. Wavelength converter technology

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov;

    1999-01-01

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on air-optical wavelength converter types based on semiconductor optical amplifiers....

  16. Technologies for converter topologies

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yan; Zhang, Haiyu

    2017-02-28

    In some embodiments of the disclosed inverter topologies, an inverter may include a full bridge LLC resonant converter, a first boost converter, and a second boost converter. In such embodiments, the first and second boost converters operate in an interleaved manner. In other disclosed embodiments, the inverter may include a half-bridge inverter circuit, a resonant circuit, a capacitor divider circuit, and a transformer.

  17. Power Converters for Accelerators

    CERN Document Server

    Visintini, R

    2015-01-01

    Particle accelerators use a great variety of power converters for energizing their sub-systems; while the total number of power converters usually depends on the size of the accelerator or combination of accelerators (including the experimental setup), the characteristics of power converters depend on their loads and on the particle physics requirements: this paper aims to provide an overview of the magnet power converters in use in several facilities worldwide.

  18. Nontraumatic vascular emergencies: imaging and intervention in acute venous occlusion

    Energy Technology Data Exchange (ETDEWEB)

    Haage, Patrick; Schmitz-Rode, Thomas [Department of Diagnostic Radiology, University of Technology Aachen, Pauwelsstrasse 30, 52057 Aachen (Germany); Krings, Timo [Department of Neuroradiology, University of Technology Aachen, Pauwelsstrasse 30, 52057 Aachen (Germany)

    2002-11-01

    Risk factors for acute venous occlusion range from prolonged immobilization to hypercoagulability syndromes, trauma, and malignancy. The aim of this review article is to illustrate the different imaging options for the diagnosis of acute venous occlusion and to assess the value of interventional strategies for venous thrombosis treatment in an emergency setting. First, diagnosis and treatment of the most common form of venous occlusion, at the level of the lower extremities, is presented, followed by pelvic vein and inferior vena cava occlusion, mesenteric venous thrombosis, upper extremity occlusion, acute cerebral vein thrombosis, and finally acute venous occlusion of hemodialysis access. In acute venous occlusion of the lower extremity phlebography is still the reference gold standard. Presently, duplex ultrasound with manual compression is the most sensitive and specific noninvasive test. Limitations of ultrasonography include isolated distal calf vein occlusion, obesity, and patients with lower extremity edema. If sonography is nondiagnostic, venography should be considered. Magnetic resonance venography can differentiate an acute occlusion from chronic thrombus, but because of its high cost and limited availability, it is not yet used for the routine diagnosis of lower extremity venous occlusion only. Regarding interventional treatment, catheter-directed thrombolysis can be applied to dissolve thrombus in charily selected patients with symptomatic occlusion and no contraindications to therapy. Acute occlusion of the pelvic veins and the inferior vena cava, often due to extension from the femoropopliteal system, represents a major risk for pulmonary embolism. Color flow Doppler imaging is often limited owing to obesity and bowel gas. Venography has long been considered the gold standard for identifying proximal venous occlusion. Both CT scanning and MR imaging, however, can even more accurately diagnose acute pelvis vein or inferior vena cava occlusion. MRI is

  19. Chronic Venous Disease under pressure

    NARCIS (Netherlands)

    S.W.I. Reeder (Suzan)

    2013-01-01

    textabstractIn chapter 1 we provide a general introduction of this thesis. Chronic venous disease (CVD) is a common medical condition that affects 2-64% of the worldwide population and leads to leg ulcers in 1% of the Western population. Venous leg ulceration (VLU) has an unfavorable prognosis with

  20. Models of the venous system

    DEFF Research Database (Denmark)

    Mehlsen, J

    2000-01-01

    . The venous capacitance is also non-linear, but may be considered linear under certain conditions. The models have to include time varying pressure sources created by respiration and skeletal muscles, and if the description includes the upright position, the partly unidirectional flow through the venous...

  1. Chronic Venous Disease under pressure

    NARCIS (Netherlands)

    S.W.I. Reeder (Suzan)

    2013-01-01

    textabstractIn chapter 1 we provide a general introduction of this thesis. Chronic venous disease (CVD) is a common medical condition that affects 2-64% of the worldwide population and leads to leg ulcers in 1% of the Western population. Venous leg ulceration (VLU) has an unfavorable prognosis with

  2. Management of venous malformations.

    Science.gov (United States)

    Richter, Gresham T; Braswell, Leah

    2012-12-01

    Venous malformations (VMs) frequently occur in the head and neck with a predilection for the parotid gland, submandibular triangle, buccal space, muscles of mastication, lips, and upper aerodigestive tract. They are composed of congenitally disrupted ectatic veins with inappropriate connections and tubular channels. Because VMs have poorly defined boundaries and a tendency to infiltrate normal tissue, they require calculated treatment decisions in the effort to preserve surrounding architecture. Sclerotherapy, surgical excision, neodymium:yttrium aluminum garnet laser therapy, or a combination of these modalities is employed in the management of VMs. Although many small VMs can be cured, the objective is often to control the disease with periodic therapy. Location, size, and proximity to vital structures dictate the type of therapy chosen. Vigilance with long-term follow up is important. This review outlines current diagnostic and therapeutic approaches to simple and extensive cervicofacial VMs. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  3. Venous thromboembolism in women

    DEFF Research Database (Denmark)

    Group, ESHRE Capri Workshop; Skouby, Sven Olaf

    2013-01-01

    BACKGROUND Venous thromboembolism (VTE) is a specific reproductive health risk for women. METHODS Searches were performed in Medline and other databases. The selection criteria were high-quality studies and studies relevant to clinical reproductive medicine. Summaries were presented and discussed...... is associated with an inherited thrombophilia in men and women. Changes in the coagulation system and in the risk of clinical VTE in women also occur during pregnancy, with the use of reproductive hormones and as a consequence of ovarian stimulation when hyperstimulation syndrome and conception occur together...... therapy (HRT) increases the VTE risk 2- to 4-fold. There is a synergistic effect between thrombophilia and the various reproductive risks. Prevention of VTE during pregnancy should be offered to women with specific risk factors. In women who are at high risk, CHC and HRT should be avoided. CONCLUSIONS...

  4. Overview of venous thromboembolism.

    Science.gov (United States)

    Abad Rico, José Ignacio; Llau Pitarch, Juan Vicente; Rocha, Eduardo

    2010-12-14

    Thrombosis occurs at sites of injury to the vessel wall, by inflammatory processes leading to activation of platelets, platelet adherence to the vessel wall and the formation of a fibrin network. A thrombus that goes on to occlude a blood vessel is known as a thromboembolism. Venous thromboembolism begins with deep vein thrombosis (DVT), which forms in the deep veins of the leg (calf) or pelvis. In some cases, the DVT becomes detached from the vein and is transported to the right-hand side of the heart, and from there to the pulmonary arteries, giving rise to a pulmonary embolism (PE). Certain factors predispose patients toward the development of venous thromboembolism (VTE), including surgery, trauma, hospitalization, immobilization, cancer, long-haul travel, increased age, obesity, major medical illness and previous VTE; in addition, there may also be a genetic component to VTE. VTE is responsible for a substantial number of deaths per annum in Europe. Anticoagulants are the mainstay of both VTE treatment and VTE prevention, and many professional organizations have published guidelines on the appropriate use of anticoagulant therapies for VTE. Treatment of VTE aims to prevent morbidity and mortality associated with the disease, and any long-term complications such as VTE recurrence or post-thrombotic syndrome. Generally, guidelines recommend the use of low molecular weight heparins (LMWH), unfractionated heparin (UFH) or fondaparinux for the pharmacological prevention and treatment of VTE, with the duration of therapy varying according to the baseline characteristics and risk profile of the individual. Despite evidence showing that the use of anticoagulation prevents VTE, the availability of several convenient, effective anticoagulant therapies and the existence of clear guideline recommendations, thromboprophylaxis is underused, particularly in patients not undergoing surgery. Greater adherence to guideline-recommended therapies, such as LMWH, which can be

  5. The photoelectric displacement converter

    Science.gov (United States)

    Dragoner, Valeriu V.

    2005-02-01

    In the article are examined questions of constructing photoelectric displacement converter satisfying demands that are stated above. Converter has channels of approximate and precise readings. The approximate reading may be accomplished either by the method of reading from a code mask or by the method of the consecutive calculation of optical scale gaps number. Phase interpolator of mouar strips" gaps is determined as a precise measuring. It is shown mathematical model of converter that allow evaluating errors and operating speed of conversion.

  6. Epidemiology of recurrent venous thrombosis

    Directory of Open Access Journals (Sweden)

    D.D. Ribeiro

    2012-01-01

    Full Text Available Venous thrombosis, including deep vein thrombosis and pulmonary embolism, is a common disease that frequently recurs. Recurrence can be prevented by anticoagulants, but this comes at the risk of bleeding. Therefore, assessment of the risk of recurrence is important to balance the risks and benefits of anticoagulant treatment. This review briefly outlines what is currently known about the epidemiology of recurrent venous thrombosis, and focuses in more detail on potential new risk factors for venous recurrence. The general implications of these findings in patient management are discussed.

  7. Chronic cerebrospinal venous insufficiency and venous stenoses in multiple sclerosis

    DEFF Research Database (Denmark)

    Blinkenberg, M; Akeson, P; Sillesen, H;

    2012-01-01

    The traditional view that multiple sclerosis (MS) is an autoimmune disease has recently been challenged by the claim that MS is caused by chronic cerebrospinal venous insufficiency (CCSVI). Although several studies have questioned this vascular theory, the CCSVI controversy is still ongoing. Our...... aim was to assess the prevalence of CCSVI in Danish MS patients using sonography and compare these findings with MRI measures of venous flow and morphology....

  8. Transpulmonary passage of venous air emboli

    Science.gov (United States)

    Butler, B. D.; Hills, B. A.

    1985-01-01

    Twenty-seven paralyzed anesthetized dogs were embolized with venous air to determine the effectiveness of the pulmonary vasculature for bubble filtration or trapping. Air doses ranged from 0.05 to 0.40 ml/kg min in 0.05-ml increments with ultrasonic Doppler monitors placed over arterial vessels to detect any microbubbles that crossed the lungs. Pulmonary vascular filtration of the venous air infusions was complete for the lower air doses ranging from 0.05 to 0.30 ml/kg min. When the air doses were increased to 0.35 ml/kg min, the filtration threshold was exceeded with arterial spillover of bubbles occurring in 50 percent of the animals and reaching 71 percent for 0.40 ml/kg min. Significant elevations were observed in pulmonary arterial pressure and pulmonary vascular resistance. Systemic blood pressure and cardiac output decreased, whereas left ventricular end-diastolic pressure remained unchanged. The results indicate that the filtration of venous bubbles by the pulmonary vasculature was complete when the air infusion rates were kept below a threshold value of 0.30 ml/kg min.

  9. Doppler ultrasound study and venous mapping in chronic venous insufficiency.

    Science.gov (United States)

    García Carriazo, M; Gómez de las Heras, C; Mármol Vázquez, P; Ramos Solís, M F

    2016-01-01

    Chronic venous insufficiency of the lower limbs is very prevalent. In recent decades, Doppler ultrasound has become the method of choice to study this condition, and it is considered essential when surgery is indicated. This article aims to establish a method for the examination, including venous mapping and preoperative marking. To this end, we review the venous anatomy of the lower limbs and the pathophysiology of chronic venous insufficiency and explain the basic hemodynamic concepts and the terminology required to elaborate a radiological report that will enable appropriate treatment planning and communication with other specialists. We briefly explain the CHIVA (the acronym for the French term "cure conservatrice et hémodynamique de l'insuffisance veineuse en ambulatoire"=conservative hemodynamic treatment for chronic venous insufficiency) strategy, a minimally invasive surgical strategy that aims to restore correct venous hemodynamics without resecting the saphenous vein. Copyright © 2015 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  10. Urinary hemosiderin: role in evaluation of chronic venous insufficiency

    Directory of Open Access Journals (Sweden)

    Ashish Lal Shrestha

    2012-08-01

    Full Text Available Chronic venous insufficiency (CVI leads to skin changes with dermal hemosiderin deposition. We studied the presence of hemosiderin in the urine to assess if this could be used as a biochemical marker for CVI. Hereby we present a case control study conducted in a tertiary care centre in South India. There were 100 cases with evidence of advanced CVI (the Clinical-Etiology-Anatomy-Pathophysiology classification: C5, C6 confirmed by duplex scanning. Controls were 50 patients with leg ulcers due to other etiologies. All patients were subjected to urinary hemosiderin testing. In all 100 patients with CVI (C5 and C6 disease axial venous reflux was confirmed by duplex ultrasound. Superficial venous reflux was noted in 71% of patients and deep venous reflux in 54.%. Primary venous insufficiency was the etiology in 81% of patients. Only 4/100 patients had detectable amounts of hemosiderin in the urine. Urine hemosiderin testing to determine presence or absence of CVI yielded the following values: positive predictive value-80%; negative predictive value-33%; sensitivity-4% and specificity-98%. The test could not be recommended as a marker of CVI. In Indian patients urinary hemosiderin is not a useful screening test in CVI.

  11. 肾上腺静脉采血在原发性醛固酮增多症分型诊断中的价值%Value of adrenal venous sampling in the subtypic diagnosis of primary aldosteronism

    Institute of Scientific and Technical Information of China (English)

    赵家胜; 李颖; 贺铭; 刘琦; 尚鸣异; 王宏保

    2013-01-01

    Objective To assess the diagnostic value of adrenal venous sampling (AVS) in the subtype diagnosis of primary aldosteronism (PA).Methods The diagnosis of PA was made in 36 patients based on an elevated ratio of plasma aldosterone (ALD) to plasma rennin activity (PRA) (ARR) and confirmed tests (saline infusion or captopril challenge) in recent 3 years.All PA patients underwent adrenal computed tomographic scan (CT) and AVS.The diagnostic accuracy of CT and AVS in the subtype differentiation of PA were evaluated by comparing the differences of CT findings,AVS results and clinical outcomes.Results Fifteen of 36 patients (42%) had a final diagnosis of aldosterone-producing adenoma (APA) and aother 21 patients (58%) with bilateral adrenal hyperplasia (BAH).The level of ALD was significantly higher in APA group than that in BAH group (298.9 ± 91.0 vs 226.3-± 59 ng/L,P < 0.05).PRA (ng · ml-1 · h-1) in APA patients were markedly lower than that in BAH counterparts (0.18 ±0.14 vs 0.28-±0.29 ng · ml-1 · h-1,P <0.01).Consequently,ARR in APA group was evidently higher than that in BAH group (2444.7 ± 1405.2 vs 1550.0 ± 1059.8,P < 0.05).Plasma potassium in APA patients was lower than that in those with BAH (2.71 ±0.57 vs 3.17 ±0.40 mmol/L).But there was no statistic significance (P > 0.05).The CT findings were discordant with the AVS results in 27.8% of patients (10/36).The accuracy of adrenal CT scan was only 72.2% in the subtypic diagnosis of PA,provided AVS was the gold standard for distinguishing between APA and BAH.Reliance on CT findings could lead to inappropriate management in 25% of PA patients.Conversely,the AVS results were concordant with the clinical outcomes in 94.4% of all patients.Conclusion CT scan is not a reliable method of differentiating primary aldosteronism.Compared with CT,AVS is more accurate in establishing a correct diagnosis of primary aldosteronism.AVS should be performed routinely before operation in PA patients

  12. Central venous catheter - dressing change

    Science.gov (United States)

    ... during cancer treatment Bone marrow transplant - discharge Central venous catheter - flushing Peripherally inserted central catheter - flushing Sterile technique Surgical wound care - open Review Date 9/17/2016 Updated by: ...

  13. Venous Thromboembolism and Atherosclerosis link

    Institute of Scientific and Technical Information of China (English)

    刘泽霖

    2011-01-01

    @@ Past always venous thrombosis and arterial thrombo-sis as a separate system to be discussed, the main reason is because there is between the anatomical and pathologi-cal physiological differences, the clinical manifestations are very different.

  14. Venous complications of pancreatitis: a review.

    Science.gov (United States)

    Aswani, Yashant; Hira, Priya

    2015-01-31

    Pancreatitis is notorious to cause vascular complications. While arterial complications include pseudoaneurysm formation with a propensity to bleed, venous complications can be quite myriad. Venous involvement in pancreatitis often presents with thrombosis. From time to time case reports and series of unusual venous complications associated with pancreatitis have, however, been described. In this article, we review multitudinous venous complications in the setting of pancreatitis and propose a system to classify pancreatitis associated venous complications.

  15. A comparison of central venous-arterial and mixed venous-arterial carbon dioxide tension gradient in circulatory failure.

    Science.gov (United States)

    Ho, K M; Harding, R; Chamberlain, J

    2007-10-01

    The arterial and mixed venous carbon dioxide tension gradient has been shown to increase when there is a decrease in cardiac output. Monitoring central venous gases is an attractive alternative to monitoring mixed venous gases in circulatory failure because central venous catheterisation is a less invasive procedure than pulmonary artery catheterisation. This study aims to evaluate the agreement between central venous-arterial carbon dioxide (CVA-CO2) and mixed venous-arterial carbon dioxide (SVA-CO2) tension gradients and assess whether CVA-CO2 tension gradient can be used to predict cardiac output in circulatory failure. Samples of arterial, central venous and mixed venous blood were obtained from 16 patients with circulatory failure at different inspired oxygen concentrations and cardiac indexes within 24 hours of study enrolment. CVA-CO2 and SVA-CO2 tension gradient were not interchangeable numerically (bias = 0.14 mmHg, 95% limits of agreement: -3.0 to 3.2 mmHg). CVA-CO2 (Spearman correlation coefficient r = -0.385) and SVA-CO, (r = -0.578) tension gradient were significantly correlated with the cardiac index but the cardiac index only accounted for 21% and 32% of the variability of CVA-CO, and SVA-CO2 tension gradient, respectively. The ability of CVA-CO2 tension gradient (area under the ROC curve = 0.77, 95% confidence interval [CI]: 0.49-0.99; P = 0.08) to predict a low cardiac output state (cardiac index tension gradient appeared to be limited to their negative predictive value to exclude a low cardiac output state when CVA-CO, or SVA-CO, tension gradient was normal (< or =5 mmHg).

  16. Neonatal Venous Thromboembolism

    Directory of Open Access Journals (Sweden)

    Kristina M. Haley

    2017-06-01

    Full Text Available Neonates are the pediatric population at highest risk for development of venous thromboembolism (VTE, and the incidence of VTE in the neonatal population is increasing. This is especially true in the critically ill population. Several large studies indicate that the incidence of neonatal VTE is up almost threefold in the last two decades. Central lines, fluid fluctuations, sepsis, liver dysfunction, and inflammation contribute to the risk profile for VTE development in ill neonates. In addition, the neonatal hemostatic system is different from that of older children and adults. Platelet function, pro- and anticoagulant proteins concentrations, and fibrinolytic pathway protein concentrations are developmentally regulated and generate a hemostatic homeostasis that is unique to the neonatal time period. The clinical picture of a critically ill neonate combined with the physiologically distinct neonatal hemostatic system easily fulfills the criteria for Virchow’s triad with venous stasis, hypercoagulability, and endothelial injury and puts the neonatal patient at risk for VTE development. The presentation of a VTE in a neonate is similar to that of older children or adults and is dependent upon location of the VTE. Ultrasound is the most common diagnostic tool employed in identifying neonatal VTE, but relatively small vessels of the neonate as well as frequent low pulse pressure can make ultrasound less reliable. The diagnosis of a thrombophilic disorder in the neonatal population is unlikely to change management or outcome, and the role of thrombophilia testing in this population requires further study. Treatment of neonatal VTE is aimed at reducing VTE-associated morbidity and mortality. Recommendations for treating, though, cannot be extrapolated from guidelines for older children or adults. Neonates are at risk for bleeding complications, particularly younger neonates with more fragile intracranial vessels. Developmental alterations in the

  17. High speed data converters

    CERN Document Server

    Ali, Ahmed MA

    2016-01-01

    This book covers high speed data converters from the perspective of a leading high speed ADC designer and architect, with a strong emphasis on high speed Nyquist A/D converters. For our purposes, the term 'high speed' is defined as sampling rates that are greater than 10 MS/s.

  18. Electrical Power Converter

    NARCIS (Netherlands)

    Ferreira, J.A.

    2014-01-01

    Electrical power converter for converting electrical power of a power source connected or connectable at an input to electrical DC-power at an output, wherein between the input and the output a first circuit of submodules is provided, wherein said first circuit of submodules and the power source for

  19. Correlation of mixed venous and central venous oxygen saturation and its relation to cardiac index

    Directory of Open Access Journals (Sweden)

    Ramakrishna M

    2006-01-01

    Full Text Available Background and Aim: The clinical applicability of substitution of central venous oxygen saturation for mixed venous oxygen saturations in monitoring global tissue hypoxia is still a matter of controversy. Hence aim of the study is comparison of paired samples of mixed venous and central venous oxygen saturation and comparison in relation to cardiac index in varying hemodynamic conditions. Materials and Methods: Prospective clinical observation: Postoperative cardiac surgical ITU: 60 adult patients,> 18 years of age of either sex: A PAC was inserted through ® IJV, triple lumen catheter was inserted through ® IJV. Blood samples were taken from distal tip of PAC and central venous catheters. An arterial blood sample was drawn from either radial or femoral arterial line. Measurements: Continuous cardiac output monitoring. Analysis of blood samples for hemoglobin concentration and oxygen saturation. Mixed venous oxygen saturations and central venous oxygen saturations were compared. The study was carried over a period of 30h in the postoperative period and samples were taken at 6h intervals. Patients were classified into three groups as follows depending on the CI: Low (< 2.5 L/m 2, medium (2.5-4 L/m 2, high (> 4 L/m2 and correlated with Svo 2 and Scvo 2 . Results: 298 Comparative sets of samples were obtained. Svo2 was consistently lower than Scvo2 throughout the study period. The difference was statistically significant. By using Bland - Altman plot, the mean difference between Svo 2 and Scvo 2 (Svo 2 -Scvo 2 was - 2.9% ± 5.14 and confidence limits are + 7.17% and - 12.97%. The co-efficient r is > 0.7 throughout the study period for all paired samples. The correlation Svo 2 and Scvo 2 with cardiac index in all the three groups were> 0.7. Conclusion: Scvo 2 and Svo 2 are closely related and are interchangeable. Even though individual values differ trends in Scvo 2 may be substituted for trend in Svo 2

  20. Inverse relation between aldosterone and venous capacitance in chronically treated congestive heart failure.

    Science.gov (United States)

    Rietzschel, E; Duprez, D A; De Buyzere, M L; Clement, D L

    2000-04-15

    The purpose of this study was to examine if there is a relation between the aldosterone escape phenomenon and venous capacitance of the upper and lower limbs in patients with long-term congestive heart failure (CHF) receiving chronic treatment with angiotensin-converting enzyme (ACE) inhibitors. The study group consisted of 16 subjects with ischemic CHF in New York Heart Association functional class II (age 59 +/-2 years, ejection fraction 24+/-4%), stabilized under a constant drug regimen comprising furosemide, captopril 50 mg 3 times daily, and digoxin for at least 3 months. Thirteen apparently healthy volunteers, aged 50+/-4 years acted as controls. Forearm and calf venous capacitances were measured simultaneously by venous occlusion plethysmography using mercury-in-silastic strain gauges. The equilibration technique was used to derive venous capacitance from the recorded pressure-volume curves. Active renin, angiotensin II, and aldosterone levels were determined on venous blood samples obtained in the supine position. Angiotensin II (paldosterone (paldosterone escape phenomenon). In CHF, forearm venous capacitance was 2.19+/-0.18 ml/100 ml; calf venous capacitance was 2.83+/-0.27 ml/100 ml. Aldosterone significantly and inversely correlated with venous capacitance in both upper (r = -0.586; p = 0.017) and lower (r = -0.625; p = 0.01) limbs. No correlations were found between forearm or calf venous capacitance and renin or angiotensin II. In patients with heart failure chronically treated with diuretics and full ACE inhibition, venous capacitance is inversely correlated with aldosterone through the mechanism of aldosterone escape, creating the potential for further deterioration of the CHF process.

  1. Reductions in Central Venous Pressure by Lower Body Negative Pressure or Blood Loss Elicit Similar Hemodynamic Responses

    Science.gov (United States)

    2014-05-29

    individual r2 values and individual regression line slope values of hemodynamic variables vs. central venous pressure r2 r2 Range Slope Slope Range...JUL 2014 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Reductions in Central Venous Pressure by Lower Body Negative Pressure...ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Reductions in central venous pressure by

  2. Contemporary diagnosis of venous malformation

    Directory of Open Access Journals (Sweden)

    Lee BB

    2013-11-01

    Full Text Available BB Lee,1 I Baumgartner21Department of Surgery, George Washington University, Washington, DC, USA; 2Swiss Cardiovascular Center, University Hospital Bern, Bern, SwitzerlandAbstract: Venous malformation is a congenital vascular malformation resulting from defective development during various stages of embryogenesis and selectively affecting the venous system. Depending on the embryologic stage when the developmental arrest occurred, the clinical presentation of venous malformation is extremely variable in location, extent, severity, natural progression, and hemodynamic impact. Extratruncular lesions occur in the earlier stages of embryonic life, and retain characteristics unique to mesenchymal cells (angioblasts, growing and proliferating when stimulated internally (eg, by menarche, pregnancy, and hormones or externally (eg, by trauma or surgery. These lesions also have a significant hemodynamic impact on the venous system involved, in addition to the risk of localized intravascular coagulopathy. However, truncal lesions, as defective developments along the late stage, no longer carry the risk of proliferation and recurrence due to lack of mesenchymal characteristics. Although, they often have serious hemodynamic consequences due to direct involvement of the main vein trunk. Therefore, a thorough clinical history and careful physical examination should be followed by an appropriate combination of noninvasive and less invasive tests (eg, Doppler ultrasonography, magnetic resonance imaging, computed tomography to confirm the clinical impression as well as to define the extent and severity of the venous malformation. Invasive tests, eg, phlebography or angiography, are seldom needed for the diagnosis per se. Additional evaluation for coagulation abnormalities, eg, D-dimer and fibrinogen levels, is generally recommended, especially for the treatment of surgery and endovascular candidates with extensive lesions to assess the localized intravascular

  3. Venous chest anatomy: clinical implications

    Energy Technology Data Exchange (ETDEWEB)

    Chasen, M.H.; Charnsangavej, C. [Department of Diagnostic Imaging, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States)

    1998-03-01

    This article provides a practical approach to the clinical implications and importance of understanding the collateral venous anatomy of the thorax. Routine radiography, conventional venography, computed tomography (CT), and magnetic resonance (MR) imaging studies provide correlative anatomic models for the demonstration of how interconnecting collateral vascular networks within the thorax maintain venous stability at all times. Five major systems comprise the collateral venous network of the thorax ( Fig. 1 ). These include the paravertebral, azygos-hemiazygos, internal mammary, lateral thoracic, and anterior jugular venous systems (AJVS). The five systems are presented in the following sequence: (a) a brief introduction to the importance of catheter position and malposition in understanding access to the thoracic venous system, (b) the anatomy of the azygos-hemiazygos systems and their relationship with the paravertebral plexus, (c) the importance of the AJVS, (d) 'loop' concepts interconnecting the internal mammary and azygos-hemiazygos systems by means of the lateral thoracic and intercostal veins, and (e) the interconnecting venous networks on the thoracic side of the thoracoabdominal junction. Certain aspects of the venous anatomy of the thorax will not be discussed in this chapter and include (a) the intra-abdominal anastomoses between the superior and inferior vena cavae (IVC) via the internal mammary, lateral thoracic, and azygos-hemiazygos systems (beyond the scope of this article), (b) potential collateral vessels involving vertebral, parascapular, thyroidal, thymic, and other smaller veins that might anastomose with the major systems, and (c) anatomic variants and pitfalls that may mimic pathologic conditions (space limitations). (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  4. Microcirculatory efficacy of topical treatment with aescin + essential phospholipids gel in venous insufficiency and hypertension: new clinical observations.

    Science.gov (United States)

    Belcaro, G; Cesarone, M R; Dugall, M

    2004-01-01

    Aescin + essential phospholipids (AEPL) topical gels are used for local treatment of venous and microcirculatory alterations (varicose veins, chronic venous insufficiency). Bruises, swelling, thrombophlebitis, and contusions are effectively treated with AEPL. Active ingredients are escinate and essential phospholipids (EPL). The aim of this new study was the evaluation of the efficacy of the effects of AEPL gel on the microcirculation in subjects with chronic venous insufficiency, venous hypertension (CVH), and venous microangiopathy. Patients were assessed measuring skin flux with laser-Doppler flowmetry (LDF). After 2 weeks of local treatment, all individual values (100%) were significantly decreased (p < 0.05), indicating an improvement in the microcirculation. In all treated patients, flux decreased at least 30% (indicating a decrease in the level of venous microangiopathy) (p < 0.05). Considering these observations, topical treatment with AEPL in areas of venous microangiopathy is beneficial, can prevent ulceration, and improves the skin healing processes.

  5. Microcirculatory efficacy of topical treatment with aescin + essential phospholipids gel on transcutaneous PO2 in venous insufficiency.

    Science.gov (United States)

    Cesarone, M R; Belcaro, G; Ippolito, E; Ricci, A; Ruffini, M; Dugall, M

    2004-01-01

    A gel including aescin, essential phospholipids (EPL), and heparin (EG) has been used for many years for local treatment of venous, microcirculatory alterations (varicose veins, chronic venous insufficiency). Bruises, swelling, thrombophlebitis, and contusions are effectively treated with this compound. The aim of this study was the evaluation of the efficacy of the effects of an AEPL (aescin+EPL) gel on the microcirculation in subjects with chronic venous insufficiency, venous hypertension (CVH), and venous microangiopathy. Transcutaneous PO(2) was measured at the perimalleolar region. After 2 weeks of treatment, all individual values (100%) were significantly increased (p < 0.05). In all patients, PO(2) increased, indicating a decrease in level of venous microangiopathy. Considering transcutaneous skin PO(2), treatment with AEPL in areas of venous microangiopathy is beneficial in the prevention of ulceration and improves skin healing.

  6. Venous hemodynamic changes in lower limb venous disease

    DEFF Research Database (Denmark)

    Lee, Byung Boong; Nicolaides, Andrew N; Myers, Kenneth

    2016-01-01

    ). Their aim was to confirm or dispel long-held hemodynamic principles and to provide a comprehensive review of venous hemodynamic concepts underlying the pathophysiology of lower limb venous disorders, their usefulness for investigating patients and the relevant hemodynamic changes associated with various......There are excellent guidelines for clinicians to manage venous diseases but few reviews to assess their hemodynamic background. Hemodynamic concepts that evolved in the past have largely remained unchallenged in recent decades, perhaps due to their often complicated nature and in part due...... not provide the physiological basis for understanding the hemodynamics of flow, pressure, compliance and resistance. Hemodynamic investigations appear to provide a better correlation with post-treatment clinical outcome and quality of life than ultrasound findings. There is a far better prospect...

  7. 脑静脉窦血栓形成患者磁共振成像与磁共振静脉血管成像联合诊断的价值%The value of magnetic resonance imaging combined with magnetic resonance venography in diagnosis of cere-bral venous sinus thrombosis

    Institute of Scientific and Technical Information of China (English)

    徐炳福

    2015-01-01

    Objective To investigate the value of the magnetic resonance imaging (MRI) combined with magnetic reso‐nance venography (MRV) in the diagnosis of cerebral venous sinus thrombosis. Methods Patients who were collected from A‐pril 2009 to May 2013 in our hospital were analyzed retrospectively. All of the patients were scanned by MR ,12 of which went on DSA (digital subtraction angiography) ,6 of which were scanned by MRV and 22 of which were received enhanced scan. Re‐sults 6 patients with the thrombosis of single transverse sinus ,and 8 patients with superior sagittal sinus ,transverse sinus and sigmoid sinus involvement was observed;while single sigmoid sinus involvement in 16 and both superior sagittal sinus and transverse sinus in 10 patients.Abnormal venous enhancement was found on contrast enhanced MRI in 22 patients ,but venous sinus thrombosis did not be enhanced. The results of MRV in 6 patients and DSA in 12 patients showed that the cerebral ve‐nous sinus was not obvious ,narrow and irregular. Conclusion The value of the magnetic resonance imaging (MRI) combined with magnetic resonance venography (MRV) in the diagnosis of cerebral venous sinus thrombosis is effective ,should be widely applied to clinical practice.%目的:探讨脑静脉窦血栓(cerebral venous sinus thrombosis ,CVST )形成患者磁共振成像与磁共振静脉血管成像联合诊断的价值。方法选取脑静脉窦血栓患者40例进行分析。诊断过程中,全体患者均接受磁共振(magnetic resonance venography ,MR)平扫,数字减影血管造影(digital subtraction angiography ,DSA)检查12例,MRV检测6例,增强扫描22例。结果单一横窦受累6例,上矢状窦、乙状窦及横窦受累8例,单一乙状窦受累16例,横窦和上矢状窦联合受累10例。所有患者磁共振成像(magnetic resonance venography ,MRI)及磁共振静脉成像(magnetic resonance venography ,MRV)均表现出信号改变。22例

  8. Converting Nonclassicality into Entanglement

    Science.gov (United States)

    Killoran, N.; Steinhoff, F. E. S.; Plenio, M. B.

    2016-02-01

    Quantum mechanics exhibits a wide range of nonclassical features, of which entanglement in multipartite systems takes a central place. In several specific settings, it is well known that nonclassicality (e.g., squeezing, spin squeezing, coherence) can be converted into entanglement. In this work, we present a general framework, based on superposition, for structurally connecting and converting nonclassicality to entanglement. In addition to capturing the previously known results, this framework also allows us to uncover new entanglement convertibility theorems in two broad scenarios, one which is discrete and one which is continuous. In the discrete setting, the classical states can be any finite linearly independent set. For the continuous setting, the pertinent classical states are "symmetric coherent states," connected with symmetric representations of the group S U (K ). These results generalize and link convertibility properties from the resource theory of coherence, spin coherent states, and optical coherent states, while also revealing important connections between local and nonlocal pictures of nonclassicality.

  9. Improving Power Converter Reliability

    DEFF Research Database (Denmark)

    Ghimire, Pramod; de Vega, Angel Ruiz; Beczkowski, Szymon

    2014-01-01

    The real-time junction temperature monitoring of a high-power insulated-gate bipolar transistor (IGBT) module is important to increase the overall reliability of power converters for industrial applications. This article proposes a new method to measure the on-state collector?emitter voltage...... of a high-power IGBT module during converter operation, which may play a vital role in improving the reliability of the power converters. The measured voltage is used to estimate the module average junction temperature of the high and low-voltage side of a half-bridge IGBT separately in every fundamental...... is measured in a wind power converter at a low fundamental frequency. To illustrate more, the test method as well as the performance of the measurement circuit are also presented. This measurement is also useful to indicate failure mechanisms such as bond wire lift-off and solder layer degradation...

  10. Converting Nonclassicality into Entanglement.

    Science.gov (United States)

    Killoran, N; Steinhoff, F E S; Plenio, M B

    2016-02-26

    Quantum mechanics exhibits a wide range of nonclassical features, of which entanglement in multipartite systems takes a central place. In several specific settings, it is well known that nonclassicality (e.g., squeezing, spin squeezing, coherence) can be converted into entanglement. In this work, we present a general framework, based on superposition, for structurally connecting and converting nonclassicality to entanglement. In addition to capturing the previously known results, this framework also allows us to uncover new entanglement convertibility theorems in two broad scenarios, one which is discrete and one which is continuous. In the discrete setting, the classical states can be any finite linearly independent set. For the continuous setting, the pertinent classical states are "symmetric coherent states," connected with symmetric representations of the group SU(K). These results generalize and link convertibility properties from the resource theory of coherence, spin coherent states, and optical coherent states, while also revealing important connections between local and nonlocal pictures of nonclassicality.

  11. Thermionic photovoltaic energy converter

    Science.gov (United States)

    Chubb, D. L. (Inventor)

    1985-01-01

    A thermionic photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or gallium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

  12. Cerebral venous thrombosis in childhood

    Energy Technology Data Exchange (ETDEWEB)

    Huisman, T.A.G.M.; Martin, E.; Willi, U.V. [Dept. of Diagnostic Imaging and Radiology, University Children' s Hospital Zurich (Switzerland); Holzmann, D. [Dept. of Otorhinolaryngology, University Children' s Hospital Zurich, Zurich (Switzerland)

    2001-09-01

    This was a retrospective study to determine different etiologies of cerebral venous thrombosis (CVT) in childhood and to correlate extent and location of thrombosis with the etiology and the age of the child as well as the final outcome. In addition, the radiologic approach is discussed. This was a retrospective analysis of 19 children with CVT. The children were examined by contrast-enhanced dynamic CT. Radiologic findings were correlated with the etiology of CVT. Cerebral venous thrombosis is not as infrequent in children as has been thought. Cerebral venous thrombosis in children can occur due to trauma (n=9), infections (n=7), or coagulation disorders (n=3). Extent and location of thrombosis, as well as complications, final outcome, and therapy, depend on the etiology. Computed tomography remains a valuable primary imaging modality in the diagnosis of CVT in the acutely injured or diseased child. (orig.)

  13. Dutch Venous Ulcer guideline update.

    Science.gov (United States)

    Maessen-Visch, M Birgitte; de Roos, Kees-Peter

    2014-05-01

    The revised guideline of 2013 is an update of the 2005 guideline "venous leg ulcer". In this special project four separate guidelines (venous leg ulcer, varicose veins, compression therapy and deep venous disorders) were revised and developed simultaneously. A meeting was held including representatives of any organisation involved in venous disease management including patient organizations and health insurance companies. Eighteen clinical questions where defined, and a new strategy was used to accelerate the process. This resulted in two new and two revised guidelines within one year. The guideline committee advises use of the C of the CEAP classification as well as the Venous Clinical Severity Score (VCSS) and a Quality of life (QoL) score in the assessment of clinical signs. These can provide insight into the burden of disease and the effects of treatment as experienced by the patient. A duplex ultrasound should be performed in every patient to establish the underlying aetiology and to evaluate the need for treatment (which is discussed in a separate guideline). The use of the TIME model for describing venous ulcers is recommended. There is no evidence for antiseptic or antibiotic wound care products except for a Cochrane review in which some evidence is presented for cadexomer iodine. Signs of infection are the main reason for the use of oral antibiotics. When the ulcer fails to heal the use of oral aspirin and pentoxifylline can be considered as an adjunct. For the individual patient, the following aspects should be considered: the appearance of the ulcer (amount of exudate) according to the TIME model, the influence of wound care products on moisturising the wound, frequency of changing compression bandages, pain and allergies. The cost of the dressings should also be considered. Education and training of patients t improves compliance with compression therapy but does not influence wound healing rates.

  14. A young man with nonhealing venous ulcers

    NARCIS (Netherlands)

    Vloedbeld, M. G.; Venema, A. W.; Smit, A. J.

    2006-01-01

    A 35-year-old man presented with nonhealing ulcers at an atypical location on his left foot, caused by a combination of venous insufficiency (after deep venous thrombosis) and arterial insufficiency. The underlying cause was Buerger's disease.

  15. The impact of the 'Better Care Better Value' prescribing policy on the utilisation of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers for treating hypertension in the UK primary care setting: longitudinal quasi-experimental design.

    Science.gov (United States)

    Baker, Amanj; Chen, Li-Chia; Elliott, Rachel A; Godman, Brian

    2015-09-10

    In April/2009, the UK National Health Service initiated four Better Care Better Value (BCBV) prescribing indicators, one of which encouraged the prescribing of cheaper angiotensin-converting enzyme inhibitors (ACEIs) instead of expensive angiotensin receptor blockers (ARBs), with 80 % ACEIs/20 % ARBs as a proposed, and achievable target. The policy was intended to save costs without affecting patient outcomes. However, little is known about the actual impact of the BCBV indicator on ACEIs/ARBs utilisation and cost-savings. Therefore, this study aimed to evaluate the impact of BCBV policy on ACEIs/ARBs utilisation and cost-savings, including exploration of regional variations of the policy's impact. This cross-sectional study used data from the UK Clinical Practice Research Datalink. Segmented time-series analysis was applied to monthly ACEIs prescription proportion, adjusted number of ACEIs/ARBs prescriptions and costs. Overall, the proportion of ACEIs prescription decreased during the study period from 71.2% in April/2006 to 70.7% in March/2012, with a small but a statistically significant pre-policy reduction in its monthly trend of 0.02% (p ACEIs prescription; however, it resulted in a statistically significant increase in the post-policy monthly trend of ACEIs prescription proportion of 0.013% (p ACEIs/ARBs prescriptions was increasing; however, their trends declined after the policy implementation. The policy affected neither total ACEIs/ARBs cost nor individual ACEIs or ARBs costs. ACEIs/ARBs utilisation was not affected by the BCBV policy. The small increase in post-policy ACEIs prescription proportion was not associated with any savings. This study represents a case study of a failed or ineffective policy and thus provides key learning lessons for other healthcare authorities. Given the existing opportunity of potential cost-savings from achieving the 80 % target, specific measures would be needed to enhance the policy implementation and uptake; however

  16. Voltage-sharing Characteristics and Protection Value Setting of Modular Multilevel Converter at Static DC Charging State%MMC静态直流充电时电容均压特性研究和保护定值整定

    Institute of Scientific and Technical Information of China (English)

    李超; 唐志军; 林国栋; 邹焕雄; 翟博龙; 陈锦山

    2016-01-01

    A common problem in the static DC charging process of modular multilevel converter is voltage polarization.Some sub-modules”voltage sags even cause startup and shutdown repeatedly.In order to analyze the voltage-sharing characteristics of MMC,firstly,equivalent impedance of energy-absorbing source is introduced into the simulation model of sub-module;secondly,the mechanism of voltage polarization is studied based on the improved model;finally,a setting process of static DC charging tolerance time protection is proposed which can reduce the degree of voltage polarization.The static DC charging experiment and single tower test are conducted at Xiamen HVDC flexible transmission project and the results show consistence between simulation and experiment,which prove the feasibility of the improved simulation model of the sub-module,the mechanism analysis result of voltage polarization,the correction of static DC charging tolerance time protection value setting method.%模块化多电平换流器在静态直流充电时存在电容电压两极分化的问题,部分子模块甚至因电压跌落导致反复启动。先通过引入取能电源等效阻抗动态参数改进子模块等效模型,然后根据改进后模型仿真分析了电容电压两极分化的机理,最后在仿真基础上提出了静态直流充电耐受时间定值整定方法,通过优化保护定值降低电容电压两极分化程度。依托厦门柔性直流输电工程进行了静态直流充电和单个阀塔加压试验,试验结果与仿真结果基本一致,验证了所提子模块等效模型、电容电压两极分化机理分析和保护定值整定方法的正确性。

  17. 股骨头坏死介入治疗前后孤立性小腿肌间静脉丛血栓超声检测的临床价值%The clinical value of ultrasonography in diagnosis of isolated calf muscular venous thrombosis in femo-ral head osteonecrosis patients during pre and post interventional therapy

    Institute of Scientific and Technical Information of China (English)

    郭辉; 陈静; 郝建华; 王洋

    2015-01-01

    目的:探讨彩色多普勒超声在股骨头坏死介入治疗前后孤立性小腿肌间静脉丛血栓中的临床应用价值。方法以股骨头坏死介入治疗前后下肢静脉超声检出深静脉血栓137例患者为研究对象,着重分析其中孤立性小腿肌间静脉丛血栓的特点。结果孤立性小腿肌间静脉丛血栓69例(50.4%),单肢病变56例(81.2%),其中左侧29例(51.8%),右侧27例(48.2%),双肢病变13例(18.8%);共156处肌间静脉丛血栓,其中比目鱼肌间静脉丛血栓111处(71.2%),血栓直径为(8.5±2.8) mm,累及长度为(4.2±1.1)cm;腓肠肌间静脉丛血栓45处(28.8%),血栓直径为(7.1±1.9)mm,累及长度为(2.1±0.7)cm,比目鱼肌血栓直径及累及长度均大于腓肠肌(P<0.05);急性期和慢性期血栓声像图特点不同,69例患者中47例符合急性期血栓声像图特点,治疗后超声复查21例完全再通,26例部分再通;22例符合慢性期血栓声像图特点,复查后无明显变化。结论彩色多普勒超声可准确判断血栓发生的部位、数量、时期、累及范围,超声复查亦简便易行,为临床治疗及疗效评估提供可靠依据,是诊断股骨头坏死介入治疗前后并发孤立性小腿肌间静脉血栓的首选方法。%ObjectiveTo explore the clinical value of color Doppler ultrasonography in diagnosis of isolated calf muscular venous thrombosis in femoral head osteonecrosis patients during pre- and post- interventional therapy.Method137 femoral head osteonecrosis patients with deep venous thrombosis diagnosed by color Doppler ultrasonography during pre- and post- interventional therapy were chose as research objects. Features of isolated calf muscular venous thrombosis were mainly analyzed.ResultAmong 137 cases, 69 cases (50.4%) were diagnosed as isolated calf muscular venous thrombosis, 56 cases (81.2%) were unilateral limb lesions, including 29

  18. Central venous line complications and tip detection

    OpenAIRE

    Ameneh Rezaee Gheshlaghi; Hamid Zamani Moghadam Dolu; Elham Pishbin; Maryam Salehi

    2015-01-01

    Central venous line is one of a creative instrument that saves human’s life in critical medical situation. Central venous line access is frequently involved in the disease management. It is used for rapid fluid therapy, transvenous pacemakers, infusion of some medications, hemodialysis or plasmapheresis and etc. Most of the emergency departments have some staffs that are trained for central venous line insertion but related complications occur during central venous line placement.Central veno...

  19. The clinical value of color doppler flow imaging in diagonosis of perforating venous insufficiency of the lower extremity%彩色多普勒超声诊断下肢交通支静脉功能不全的临床价值

    Institute of Scientific and Technical Information of China (English)

    周晗; 吴庆华; 陈忠; 唐小斌; 杨培; 张煜亚

    2011-01-01

    Objective;To investigate the clinical value of color Doppler flow imaging (CDFI) in di-agonosis of perforating venous insufficiency of the lower extremity. Methods; The clinical data of 64 cases(82 limbs) undergoing high ligation and striping of great saphenous vein and perforator surgery were reviewed retrospectively. The dilated and insufficient perforating venous were diagnosed and located by CDFI. The results were compared with surgery. Results;Total consistent rate, sensitivity,specificity, omission diagonostic rate, mistake diagnostic rate, Youden index,Odd product, positive predictive value, negative predictive value, and Kappa of CDFI in diagnosis of perforating venous insufficiency of the lower extremity was respectively 93. 8% , 96. 5% ,88. 2% ,3.5% , 11. 8% ,0. 837,206.5,98.8% ,71.4% and 0.766 ( P < 0.0001). The CDFI foundings were consistent with operation results very well. Conclusion; CDFI is a useful technique for the diagnosis and locating the dilated and insufficient perforating venous correctly and provide important basis for the operation.%目的:研究彩色多普勒超声诊断下肢交通支静脉功能不全的临床价值.方法:回顾性分析行大隐静脉高位结扎加剥脱术、交通支静脉离断术的64例患者(82条肢体)的临床资料.术前应用彩色多普勒超声检出功能不全的交通支静脉并将其定位,与手术结果相对比.结果:与手术结果相比,彩色多普勒超声诊断准确率、敏感性、特异性、漏诊率、误诊率、约登指数、比数积、阳性预测值、阴性预测值及Kappa值为分别是95.8%、96.5%、88.2%、3.5%、11.8%、0.837、206.5、98.8%、71.4%及1.766.由于彩色多普勒超声的Kappa值为0.766 >0.75,且(P<0.0001),说明其与手术结果非常吻合.结论:彩色多普勒超声能够准确诊断并定位功能不全的交通支静脉,为诊断和治疗提供重要的依据,具有很高的临床价值.

  20. Venous manifestations of spinal arteriovenous fistulas

    NARCIS (Netherlands)

    Andersson, T; van Dijk, JMC; Willinsky, RA

    2003-01-01

    Impairment of the spinal cord venous outflow may create symptoms caused by venous hypertension and congestion. This has been referred to as venous congestive myelopathy. Spinal dural arteriovenous fistulas, as well as some of the epidural arteriovenous fistulas and perimedullary spinal cord arteriov

  1. Anomalous pulmonary venous return: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gyeong Min; Kang, MinJin; Lee, Han Bee; Bae, Kyung Eun; Lee, Jaehe; Kim, Jae Hyung; Jeong, Myeong Ja; Kang, Tae Kyung [Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of)

    2013-10-15

    Partial anomalous pulmonary venous return is a type of congenital pulmonary venous anomaly. We present a rare type of partial pulmonary venous return, subaortic vertical vein drains left lung to superior vena cava, accompanying hypoplasia of the ipsilateral lung and pulmonary artery. We also review the previous report and relationship of these structures.

  2. Angiotensin-converting enzyme

    DEFF Research Database (Denmark)

    Sørensen, P G; Rømer, F K; Cortes, D

    1984-01-01

    In order to evaluate bleomycin-associated lung damage in humans, lung function parameters and serum levels of the endothelial-bound angiotensin-converting enzyme (ACE) were determined by serial measurements in 11 patients who were treated for testicular cancer. None developed clinical or radiolog......In order to evaluate bleomycin-associated lung damage in humans, lung function parameters and serum levels of the endothelial-bound angiotensin-converting enzyme (ACE) were determined by serial measurements in 11 patients who were treated for testicular cancer. None developed clinical...

  3. Hormonal contraceptives and venous thrombosis

    NARCIS (Netherlands)

    Stegeman, Berendina Hendrika (Bernardine)

    2013-01-01

    Oral contraceptive use is associated with venous thrombosis. However, the mechanism behind this remains unclear. The aim of this thesis was to evaluate genetic variation in the first-pass metabolism of contraceptives, to identify the clinical implications of hormonal contraceptive use after a

  4. Venous thrombosis : a patient's view

    NARCIS (Netherlands)

    Korlaar, Inez van

    2006-01-01

    The studies described in this thesis had two main aims: 1) To study the quality of life of patients with venous thrombosis and to examine the role of illness perceptions in explaining the quality of life of these patients. 2) To assess the psychological consequences of genetic testing for thrombop

  5. Familial clustering of venous thromboembolism

    DEFF Research Database (Denmark)

    Sindet-Pedersen, Caroline; Østergaard, Louise Bruun; Gundlund, Anna

    2016-01-01

    BACKGROUND: Identification of risk factors for venous thromboembolism (VTE) is of utmost importance to improve current prophylactic regimes and treatment guidelines. The extent to which a family history contributes to the risk of VTE needs further exploration. OBJECTIVES: To examine the relative ...

  6. Hormonal contraceptives and venous thrombosis

    NARCIS (Netherlands)

    Stegeman, Berendina Hendrika (Bernardine)

    2013-01-01

    Oral contraceptive use is associated with venous thrombosis. However, the mechanism behind this remains unclear. The aim of this thesis was to evaluate genetic variation in the first-pass metabolism of contraceptives, to identify the clinical implications of hormonal contraceptive use after a thromb

  7. Venous thrombosis : a patient's view

    NARCIS (Netherlands)

    Korlaar, Inez van

    2006-01-01

    The studies described in this thesis had two main aims: 1) To study the quality of life of patients with venous thrombosis and to examine the role of illness perceptions in explaining the quality of life of these patients. 2) To assess the psychological consequences of genetic testing for

  8. Venous thromboembolic disease. CT evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, L. R. [Medical College of Wisconsin, Pulmonary Medicine and Intensive Care, Dept. of Diagnostic Radiology, Milwaukee, WI (United States)

    2001-12-01

    Helical and multidetector CT has proven to be a valuable imaging modality for both pulmonary embolism and deep venous thrombosis. This paper will review the sensitivity and specificity of CT and discuss diagnostic algorithms utilizing CT and more established imaging technologies.

  9. MR磁敏感加权成像在脑发育性静脉异常诊断中的应用%Value of susceptibility-weighted MR imaging for diagnosing developmental venous anomaly

    Institute of Scientific and Technical Information of China (English)

    梁长松; 陈忠; 叶文钦; 陈泽文; 李伟峰

    2013-01-01

      目的评价MR磁敏感加权成像(SWI)在脑发育性静脉异常(DVA)的应用价值。方法回顾性分析30例经磁共振诊断为脑静脉异常的患者MR表现,行常规MR扫描、增强扫描及SWI,10例加做MRA扫描。结果平扫5例DVA引流静脉呈条状稍长T1、稍长T2信号,3例呈长T1、短T2流空信号,22例显示不清,10例MRA显示引流静脉呈条状血管影,30例DVA增强扫描显示引流静脉及髓静脉强化,呈高信号“海蛇头”征,SWI也同时显示引流静脉及髓静脉,呈特征性“海蛇头”状低信号。结论常规MR序列显示DVA引流静脉不佳,增强扫描及SWI可同时显示引流静脉与髓静脉,SWI显示更佳,可作为诊断DVA的常规序列。%  Objective To evaluate susceptibility-weighted imaging for diagnosing developmental venous anomaly(DVA). Methods The conventional MRI(30),SWI(30)and MRV(10)of 30 patients with diagnosis of DVA on MRI were retrospectively analyzed.Results On unenhanced MRI draining veins were clearly demonstrated as hypointensity on T1WI and T2WI in 3 cases, hypointensity on T1WI and hyperintensity on T2WI in 5 cases. In 22 patients the draining veins were not seen.MRV showed the draining veins in all 10 patients. On contrast-enhanced MRI,medullary and draining veins were enhanced with the characteristic hyperintense caput medusa appearance. Hypointense caput medusa pattern was visible on SWI.Conclusions The draining veins of DVA were not well shown on conventional MRI but clearly demonstrated on contrast-enhanced MRI and SWI. More medullary veins are visible on SWI,which is valuable for diagnosing DVA.

  10. Venous muscle pump function during pregnancy. Assessment by ambulatory strain-gauge plethysmography

    DEFF Research Database (Denmark)

    Struckmann, J R; Meiland, H; Bagi, P

    1990-01-01

    virtually disappeared post partum, corresponding to the muscle pump normalization. No statistical correlation was found between venous muscle pump values and changes in hormone concentrations of estradiol, estriol and progesterone. It is suggested that venous insufficiency development in pregnancy is caused...... primarily by mechanical obstruction, or hormonal influence other than that of estradiol, estriol or progesterone. 17% (4.7-37%) of the women with a normal pregnancy developed a pathological venous muscle pump function.......The venous muscle pump function was quantitatively assessed through pregnancy weeks 16, 30, 38 and 3 months (week 53) following delivery, in 24 pregnant women who completed a normal pregnancy. A statistically significant increase was found in the mean venous reflux (P less than 0.01), which...

  11. [Pain in venous thrombosis of the leg].

    Science.gov (United States)

    Henriet, J P

    1992-01-01

    According to D. Reinharez, pain and edema are the commonest presenting symptoms in phlebology. Pain is one of the most classical symptoms of an ordinary deep venous thrombosis, a valuable feature when present, in the form of deep tension, heaviness, swelling and a feeling of dead weight. It is often absent or slight. It may consist merely of a dull cramp, or of an "undefinable" (C. Bourde) odd, heavy leg. It generally affects the calf but may involve the sole of the foot, the heel, the thigh, the groin or even the true pelvis. This feeling, although "imprecise and variable" (P. Wallois, P. Griton) is highly suggestive. It increases on standing and walking in the form of unilateral uncomfortable tension, heaviness or painful swelling, which maybe a source of worry or even anxiety to the patient. Tenderness on palpation of venous tracts and their stretching is more suggestive. In the opinion of M. Duruble, Neuhof's sign (feeling of tender fullness of the calf) is more reliable than Homans' sign (pain in the calf caused by passive dorsiflexion of the foot, with the lower limb in extension) which essentially stretches only the posterior tibial venous system. The value of Sigg's sign (pain in the popliteal fossa on passive extension of the knee) is controversial. Far more rare is phlegmasia coerulea dolens or Grégoire's blue leg, complicating phlegmasia alba dolens or of sudden onset, with initial very severe or even "intolerable" pain (J.J. Pinot) in Scarpa's triangle, rapidly spreading to the limb. In varicose phlebitis (M. Perrin) or superficial thrombophlebitis or varico-phlebitis (A.A. Ramelet) or superficial venitis (J.P. Henriet), pain most often consists of moderate burning tension overlying the thrombosed vein(s), increased by palpation and mobilisation. Sometimes severe initially, it is exacerbated by the slightest touch. In total, pain, regardless of its characteristics, its site and/or its severity, is one of the most constant clinical features of venous

  12. An Electromagnetic Beam Converter

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to an electromagnetic beam converter and a method for conversion of an input beam of electromagnetic radiation having a bell shaped intensity profile a(x,y) into an output beam having a prescribed target intensity profile l(x',y') based on a further development...

  13. Definition of Power Converters

    CERN Document Server

    Bordry, F

    2015-01-01

    The paper is intended to introduce power conversion principles and to define common terms in the domain. The concept s of sources and switches are defined and classified. From the basic laws of source interconnections, a generic method of power converter synthesis is presented. Some examples illustrate this systematic method. Finally, the commutation cell and soft commuta tion are introduced and discussedd.

  14. Convertible Proxy Signcryption Scheme

    Institute of Scientific and Technical Information of China (English)

    李继国; 李建中; 曹珍富; 张亦辰

    2004-01-01

    In 1996, Mambo et al introduced the concept of proxy signature. However, proxy signature can only provide the delegated authenticity and cannot provide confidentiality. Recently, Gamage et al and Chan and Wei proposed different proxy signcryption schemes respectively, which extended the concept of proxy signature.However, only the specified receiver can decrypt and verify the validity of proxy signcryption in their schemes.To protect the receiver' s benefit in case of a later dispute, Wu and Hsu proposed a convertible authenticated encryption scheme, which carn enable the receiver to convert signature into an ordinary one that can be verified by anyone. Based on Wu and Hsu' s scheme and improved Kim' s scheme, we propose a convertible proxy signcryption scheme. The security of the proposed scheme is based on the intractability of reversing the one-way hash function and solving the discrete logarithm problem. The proposed scheme can satisfy all properties of strong proxy signature and withstand the public key substitution attack and does not use secure channel. In addition, the proposed scheme can be extended to convertible threshold proxy signcryption scheme.

  15. The Convertible Arbitrage Strategy Analyzed

    NARCIS (Netherlands)

    Loncarski, I.; Ter Horst, J.R.; Veld, C.H.

    2006-01-01

    This paper analyzes convertible bond arbitrage on the Canadian market for the period 1998 to 2004.Convertible bond arbitrage is the combination of a long position in convertible bonds and a short position in the underlying stocks. Convertible arbitrage has been one of the most successful strategies

  16. Mixed venous-arterial CO2 tension gradient after cardiopulmonary bypass.

    Science.gov (United States)

    Takami, Yoshiyuki; Masumoto, Hiroshi

    2005-09-01

    Significant venous hypercarbia has been reported in septic shock and circulatory failure. Cardiopulmonary bypass also impairs systemic and pulmonary blood perfusion. The objective of this study was to determine the clinical significance of the increased venous-arterial CO2 tension gradient resulting from venous hypercarbia after cardiopulmonary bypass. On arrival in the intensive care unit, venous and arterial CO2 tensions were measured in the radial and pulmonary arteries in 140 consecutive patients who had undergone coronary (n = 79), valve (n = 34), aortic (n = 20), and other (n = 7) surgery under cardiopulmonary bypass. The mean venous-arterial CO2 tension gradient was 5.0 +/- 3.3 mm Hg (range, 7.7 to 15.7 mm Hg). By linear regression analysis, the factors that significantly correlated with venous-arterial CO2 tension gradient were bypass duration, aortic crossclamp time, initial arterial lactate level, transpulmonary arteriovenous lactate difference, arterial bicarbonate level, base excess, cardiac index, mixed venous O2 saturation, O2 delivery, O2 consumption, and the peak value of creatine kinase. The venous-arterial CO2 tension gradient may reflect impaired perfusion and anaerobic metabolism induced by cardiopulmonary bypass and could be a simple and useful indicator for patient management after surgery under cardiopulmonary bypass.

  17. Analysis of Arterial and Venous Blood Gases in Healthy Gyr Falcons ( Falco rusticolus ) Under Anesthesia.

    Science.gov (United States)

    Raghav, Raj; Middleton, Rachael; BSc, Rinshiya Ahamed; Arjunan, Raji; Caliendo, Valentina

    2015-12-01

    Arterial and venous blood gas analysis is useful in the assessment of tissue oxygenation and ventilation and in diagnosis of metabolic and respiratory derangements. It can be performed with a relatively small volume of blood in avian patients under emergency situations. Arterial and venous blood gas analysis was performed in 30 healthy gyr falcons ( Falco rusticolus ) under anaesthesia to establish temperature-corrected reference intervals for arterial blood gas values and to compare them to temperature-corrected venous blood gas values with a portable point-of-care blood gas analyzer (i-STAT 1, Abbott Laboratories, Abbott Park, IL, USA). Statistically significant differences were observed between the temperature-corrected values of pH, partial pressure of carbon dioxide (Pco2), and partial pressure of oxygen (Po2) and the corresponding nontemperature-corrected values of these parameters in both arterial and venous blood. Values of temperature-corrected pH, temperature-corrected Pco2, bicarbonate concentrations, and base excess of extra cellular fluid did not differ significantly between arterial and venous blood, suggesting that, in anesthetized gyr falcons, venous blood gas analysis can be used in place of arterial blood gas analysis in clinical situations. Values for hematocrit, measured by the point-of-care analyzer, were significantly lower compared with those obtained by the microhematocrit method.

  18. Advanced DC/DC converters

    CERN Document Server

    Luo, Fang Lin

    2003-01-01

    INTRODUCTIONHistorical ReviewMultiple Quadrant ChoppersPump CircuitsDevelopment of DC/DC Conversion TechniqueCategorize Prototypes and DC/DC Converters Family TreeVOLTAGE-LIFT CONVERTERSIntroductionSeven Self-Lift ConvertersPositive Output Luo-ConvertersNegative Output Luo-ConvertersModified Positive Output Luo-Converters Double Output Luo-ConvertersPOSITIVE OUTPUT SUPER-LIFT LUO-CONVERTERS IntroductionMain SeriesAdditional SeriesEnhanced Series Re-Enhanced Series Multiple-Enhanced Series Summary of Positive Output

  19. Venous Thromboembolism After Knee Arthroscopy in Undiagnosed Familial Thrombophilia.

    Science.gov (United States)

    Jetty, Vybhav; Glueck, Charles J; Freiberg, Richard A; Wang, Ping

    2016-11-01

    Venous thromboembolism is uncommon after knee arthroscopy, and there are no guidelines for thromboprophylaxis in elective routine knee arthroscopy. Preoperative evaluation of common thrombophilias should provide guidance for postarthroscopy thromboprophylaxis in otherwise healthy patients who are at high risk for venous thromboembolism. This study assessed 10 patients with venous thromboembolism after total hip or knee arthroplasty. Patients were assessed if venous thromboembolism occurred within 6 months after knee arthroscopy (n=10) or total hip or knee arthroplasty (n=21). This study assessed gene mutations (factor V Leiden, prothrombin G20210A, plasminogen activator inhibitor, methylenetetrahydrofolate reductase) and serologic thrombophilias (high levels of factors VIII and XI, homocysteine, anticardiolipin immunoglobulin G and immunoglobulin M antibodies, and lupus anticoagulant; low antigenic protein C, S, and free S; and antithrombin III deficiency). The same coagulation data were obtained for normal subjects (n=110). The major thrombophilias in the arthroscopy group were factor V Leiden heterozygosity (40%), high factor VIII level (50%), and high homocysteine (30%). The respective values in control subjects were 2% (P=.0004), 7% (P=.0011), and 5% (P=.02). When the arthroscopy group was compared with the 21 patients who had venous thromboembolism after total hip or knee arthroplasty, the sole difference was factor V Leiden heterozygosity, which was 40% vs 0%, respectively (P=.007). Although venous thromboembolism after knee arthroscopy is uncommon, to identify high-risk patients and guide postoperative thromboprophylaxis, the authors suggest routine preoperative measurement of 3 common familial thrombophilias: factor V Leiden, factor VIII, and homocysteine. [Orthopedics. 2016; 39(6):e1052-e1057.].

  20. Effectiveness of mesoglycan in patients with previous deep venous thrombosis and chronic venous insufficiency.

    Science.gov (United States)

    Andreozzi, G M

    2007-12-01

    mg twice per day. Group 1 (1(st) episode DVT): the recurrence prevalence was 3.5% at 6 months, 9% at 12 months, 12.5% at 18 months, 14.28% at 24, 30 and 36 months. At the end of the 3 follow-up years the PTS diagnosis could be performed in 10 patients (17.85%). Group 2 (recurrent DVT): the recurrence prevalence was 3.7% at 6 months, 11.11% at 12 months, 14.81% at 24 months, 18.51% at 36 months during mesoglycan treatment. In the preceding period the prevalence was 11.11% at 6 months from the preceding episode, 16.66% at 12 months, 33.33% at 24 months and 37.03% at 36 months. In the remaining 62.96% the recurrence occurred at 36 and 48 months. The comparison between the two series showed a significant difference with P mesoglycan is effective in preventing thrombotic recurrence in patients with previous DVT. The recurrence prevalence in patients with DVT at 1(st) episode was lower than the prevalence reported by the literature data (17.5% within 2 years and 24.6% within 5 years). The positive trend was also confirmed in the recurrent DVT group, although with a major prevalence (18.51%) due to a higher thrombotic risk. However, the prevalence in the treatment period is significantly lower than the previous thrombotic episode. Mesoglycan was also effective in CVI patients, with a progressive and significant improvement of disability, pain and edema, which are the pathophysiologic elements responsible for the impairment of quality of life. At the various follow-up points the mean score value significantly reduced compared to T0 and to the values of the preceding control. In conclusion mesoglycan is a useful and effective medication in the treatment of venous disorders, both in the subacute phase of DVT and in the long-term therapy for CVI, and is worth more extensive documentation, in accordance with the criteria of evidence-based medicine.

  1. Clinical aspects of venous thrombophilia.

    Science.gov (United States)

    Girolami, Antonio; Fabris, Fabrizio; Girolami, Bruno

    2002-01-01

    Venous thrombophilia is the result of clotting changes namely of a hypercoagulable state together with blood flow and vessel wall changes. There is no need for all these components to be present in order for thrombosis to occur. As the matter of fact, thrombosis may occur even if only one of these conditions is present. In clinical practice a combination of factors is usualy seen. In comparison with arterial thrombophilia, clotting changes and blood flow seen to play a major role in venous thrombosis. Venous thrombophilia may remain asynptomatic or may result in a series of clinical syndromes. The commonest of these are: 1. Superficial vein thrombosis, 2. Deep vein thrombosis of legs, 3. Deep vein thrombosis of arms, 4. Caval veins thrombosis, 5. Portal vein thrombosis, 6. Hepatic veins thrombosis, 7. Renal vein thrombosis, 8. Cerebral sinuses thrombosis, 9. Right heart thrombosis, 10. Miscellaneous (ovarian, adrenal veins thrombosis, etc.). Since the first two are widely and easily recognized, these is no need for an extensive discussion. Deep vein thromboses of upper limbs are not as frequent as those of lower limbs or of superficial phlebitis but they can still be recognized on clinical grounds and non invasive techniques. The remaining 7 syndromes are less common and therefore less frequently suspected and recognized. Of particular interest, among these less common manifestations of venous thrombophilia are hepatic vein and renal vein thrombosis. Hepatic veins thrombosis, sometimes part of inferior vena cava thrombosis is most frequently due to an isolated occlusion of hepatic veins thereby causing a form of venocclusive disease. Occasionally diagnosis may be difficult because of slow onset of symptoms (hepatomegaly, right flank pain, fever, ascites etc.). The same is true for renal vein thrombosis which may also be of difficult diagnosis since it causes proteinuria and flank pain. The proteinuria is often interpreted as due to a nephrotic syndrome which

  2. Radiologically-placed venous ports in children under venous anesthesia

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Joo Yeon; Jeon, Ung Bae; Choo, Ki Seok; Hwang, Jae Yeon; Kim, Yong Woo; Lee, Yun Jin; Nam, Sang Ool; Lim, Young Tak [Pusan National University School of Medicine, Yangsan (Korea, Republic of)

    2015-02-15

    To evaluate the efficacy and safety of radiologic venous port placement in children under venous anesthesia. Between April 2009 and July 2011, 44 ports were implanted in 41 children (24 boys, 17 girls). The age of patients ranged from 9 months to 19 years (mean, 6.5 years) and their body weights ranged from 6.8 kg to 56.3 kg (mean, 23.2 kg). Right internal jugular vein access was used in 42 ports, right subclavian vein in 1, and left subclavian in 1. Durability and complications of port implantation were reviewed. The technical success rate was 100%. The catheter life was 10-661 days (mean 246 days). Two patients died during the follow-up period, 21 and 6 ports were removed at the end of treatment or as a result of complications, respectively. One port was removed and replaced by a Hickmann catheter. Three ports were explanted due to port-related sepsis, one due to a catheter kink, and two for unexplained fever or insertion site pain. The overall port-related infection was 3 cases (6.8%, 0.28/1000 catheter days). Venous port placement by interventional radiologists in children under intravenous sedation is relatively safe, with a high rate of technical success and low rate of complications.

  3. Review article: Can venous blood gas analysis replace arterial in emergency medical care.

    Science.gov (United States)

    Kelly, Anne-Maree

    2010-12-01

    The objectives of the present review are to describe the agreement between variables on arterial and venous blood gas analysis (in particular pH, pCO(2) , bicarbonate and base excess) and to identify unanswered questions. MEDLINE search of papers published from 1966 to January 2010 for studies comparing arterial and peripheral venous blood gas values for any of pH, pCO(2) , bicarbonate and base excess in adult patients with any condition in an emergency department setting. The outcome of interest was mean difference weighted for study sample size with 95% limits of agreement. The weighted mean arterio-venous difference in pH was 0.035 pH units (n= 1252), with narrow limits of agreement. The weighted mean arterio-venous difference for pCO(2) was 5.7 mmHg (n= 760), but with 95% limits of agreement up to the order of ±20 mmHg. For bicarbonate, the weighted mean difference between arterial and venous values was -1.41 mmol/L (n= 905), with 95% limits of agreement of the order of ±5 mmol/L. Regarding base excess, the mean arterio-venous difference is 0.089 mmol/L (n= 103). There is insufficient data to determine if these relationships persist in shocked patients or those with mixed acid-base disorders. For patients who are not in shock, venous pH, bicarbonate and base excess have sufficient agreement to be clinically interchangeable for arterial values. Agreement between arterial and venous pCO(2) is too poor and unpredictable to be clinically useful as a one-off test but venous pCO(2) might be useful to screen for arterial hypercarbia or to monitor trends in pCO(2) for selected patients. © 2010 The Author. EMA © 2010 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  4. Mixed Capillary Venous Retroperitoneal Hemangioma

    Directory of Open Access Journals (Sweden)

    Mohit Godar

    2013-01-01

    Full Text Available We report a case of mixed capillary venous hemangioma of the retroperitoneum in a 61-year-old man. Abdominal ultrasonography showed a mass to be hypoechoic with increased flow in color Doppler imaging. Dynamic contrast-enhanced computed tomography revealed a centripetal filling-in of the mass, located anterior to the left psoas muscle at the level of sacroiliac joint. On the basis of imaging features, preoperative diagnosis of hemangioma was considered and the mass was excised by laparoscopic method. Immunohistochemical studies were strongly positive for CD31 and CD34, and negative for calretinin, EMA, WT1, HMB45, Ki67, synaptophysin, and lymphatic endothelial cell marker D2–40. Histologically, the neoplasm was diagnosed as mixed capillary venous hemangioma.

  5. Microprocessor controlled static converter

    Directory of Open Access Journals (Sweden)

    Stefan Szabo

    2005-10-01

    Full Text Available This paper wants to demonstrate a way of implementing a microcontroller into an DC motor speed control loop. The static power converter is a fully controlled rectifier bridge, using standard SCR's. The bridge's control signals are supplied by the microcontroller and are phase-angle or burst types. The automation loop contains a software PI-style regulator. All the experimental results shows that this aproach is flexibile enough to be used on a large scale.

  6. DSP controlled power converter

    OpenAIRE

    Chan, CH; Pong, MH

    1995-01-01

    A digital controller is designed and implemented by a Digital Signal Processor (DSP) to replace the Pulse Width Modulator (PWM) and error amplifier compensation network in a two wheeler forward converter. The DSP controller is designed in three approaches: a) Discretization of analog controller - the design is based on the transfer function of the error amplifier compensation network. b) Digital PID controller design - the design is based on the general form of the pulse transfer function of ...

  7. Hydrocephalus in cerebral venous thrombosis.

    Science.gov (United States)

    Zuurbier, Susanna M; van den Berg, René; Troost, Dirk; Majoie, Charles B; Stam, Jan; Coutinho, Jonathan M

    2015-01-01

    Increased intracranial pressure is common in cerebral venous thrombosis (CVT), but hydrocephalus is rarely reported in these patients. We examined the frequency, pathophysiology and associated clinical manifestations of hydrocephalus in patients with CVT admitted to our hospital between 2000 and 2010 (prospectively since July 2006). Hydrocephalus was defined as a bicaudate index larger than the 95th percentile for age, and/or a radial width of the temporal horn of ≥ 5 mm. We excluded patients in whom hydrocephalus was caused by a disease other than CVT or if it was iatrogenic. 20 out of 99 patients with CVT had hydrocephalus. 6 patients with hydrocephalus were excluded from the analysis. Patients with hydrocephalus more often had focal neurological deficits (86 vs. 49%, p = 0.02) and were more frequently comatose (43 vs. 16%, p = 0.06), as compared to patients without hydrocephalus. Deep cerebral venous thrombosis (64 vs. 9%, p hydrocephalus. Intraventricular hemorrhage was present in 1 patient with hydrocephalus, compared to none among patients without hydrocephalus (7 vs. 0%, p = 0.15). Outcome at follow-up was worse in patients with hydrocephalus (mRS 0-1, 36 vs. 68%, p = 0.02; mortality 29 vs. 9%, p = 0.07). Hydrocephalus occurs more frequently in cerebral venous thrombosis than previously believed, especially in patients with deep cerebral venous thrombosis and edema of the basal ganglia. The presence of hydrocephalus is associated with a worse clinical outcome, but a direct causal relation is unlikely. Routine shunting procedures are not advisable.

  8. SSG Wave Energy Converter

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Vicinanza, Diego; Frigaard, Peter

    2008-01-01

    head hydroturbines are converting the potential energy of the stored water into power. A key to success for the SSG will be the low cost of the structure and its robustness. The construction of the pilot plant is scheduled and this paper aims to describe the concept of the SSG wave energy converter...... and the studies behind the process that leads to its construction. The pilot plant is an on-shore full scale module in 3 levels with an expected power production of 320 MWh/y in the North Sea. Location, wave climate and laboratory tests results will be used here to describe the pilot plant and its characteristics.......The SSG (Sea Slot-cone Generator) is a wave energy converter of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level, in which the water of incoming waves is stored temporary. In each reservoir, expressively designed low...

  9. Parametric study of minimum converter loss in an energy-storage dc-to-dc converter

    Science.gov (United States)

    Wong, R. C.; Owen, H. A., Jr.; Wilson, T. G.

    1982-01-01

    Through a combination of analytical and numerical minimization procedures, a converter design that results in the minimum total converter loss (including core loss, winding loss, capacitor and energy-storage-reactor loss, and various losses in the semiconductor switches) is obtained. Because the initial phase involves analytical minimization, the computation time required by the subsequent phase of numerical minimization is considerably reduced in this combination approach. The effects of various loss parameters on the optimum values of the design variables are also examined.

  10. Pricing Chinese Convertible Bonds with Dynamic Credit Risk

    Directory of Open Access Journals (Sweden)

    Ping Li

    2014-01-01

    Full Text Available To price convertible bonds more precisely, least squares Monte Carlo (LSM method is used in this paper for its advantage in handling the dependence of derivatives on the path, and dynamic credit risk is used to replace the fixed one to make the value of convertible bonds reflect the real credit risk. In the empirical study, we price convertible bonds based on static credit risk and dynamic credit risk, respectively. Empirical results indicate that the ICBC convertible bond has been overpriced, resulting from the underestimation of credit risk. In addition, when there is an issue of dividend, the conversion price will change in China's convertible bonds, while it does not change in the international convertible bonds. So we also empirically study the difference between the convertible bond's prices by assuming whether the conversion price changes or not.

  11. Ruptured venous aneurysm of cervicomedullary junction

    Directory of Open Access Journals (Sweden)

    Ashish Aggarwal

    2014-01-01

    Full Text Available Background: Ruptured venous aneurysm is often seen with arterio-venous malformation (AVM or developmental venous anomaly (DVA. However, isolated venous aneurysm is unusual. Case Description: We present a case of ruptured venous aneurysm that presented with subarachnoid hemorrhage (SAH and intraventricular hemorrhage (IVH. Digital substraction angiography (DSA revealed a saccular contrast filling pouch in the left lateral aspect of cervicomedullary junction (CMJ. Endovascular intervention was not a viable option. During surgery, a saccular pliable structure approx. 1.5 Χ 1 cm was found in the subarachnoid space that was clipped and excised. There were no arterial feeders, no evidence of surrounding AVM, and no dilated perimedullary vein. Conclusion: This is perhaps the first reported case of ruptured venous aneurysm (without associated AVM of CMJ, which was successfully managed surgically. The possible etiologies remain an unnoticed head trauma or a congenital vessel wall abnormality. Surgically clipping and excision remains the treatment of choice for such lesion.

  12. Fast Constant Weight Codeword to Index Converter

    Science.gov (United States)

    2011-08-01

    is achievable; a 64-out- of-128 bit converter uses only 9% of the available ALMs. The large values of n required special Verilog programming. For...n r ) in a MATLAB program and wrote it to a header file that was included in the Verilog code. III. COMPLEX DISJOINT DECOMPOSITION SOLUTION It can

  13. Using venous blood gas analysis in the assessment of COPD exacerbations: a prospective cohort study.

    Science.gov (United States)

    McKeever, Tricia M; Hearson, Glenn; Housley, Gemma; Reynolds, Catherine; Kinnear, William; Harrison, Tim W; Kelly, Anne-Maree; Shaw, Dominick E

    2016-03-01

    Identifying acute hypercapnic respiratory failure is crucial in the initial management of acute exacerbations of COPD. Guidelines recommend obtaining arterial blood samples but these are more difficult to obtain than venous. We assessed whether blood gas values derived from venous blood could replace arterial at initial assessment. Patients requiring hospital treatment for an exacerbation of COPD had paired arterial and venous samples taken. Bland-Altman analyses were performed to assess agreement between arterial and venous pH, CO2 and HCO3-. The relationship between SpO2 and SaO2 was assessed. The number of attempts and pain scores for each sample were measured. 234 patients were studied. There was good agreement between arterial and venous measures of pH and HC)3- (mean difference 0.03 and -0.04, limits of agreement -0.05 to 0.11 and -2.90 to 2.82, respectively), and between SaO2 and SpO2 (in patients with an SpO2 of >80%). Arterial sampling required more attempts and was more painful than venous (mean pain score 4 (IQR 2-5) and 1 (IQR 0-2), respectively, pArterial sampling is more difficult and more painful than venous sampling. There is good agreement between pH and HCO3- values derived from venous and arterial blood, and between pulse oximetry and arterial blood gas oxygen saturations. These agreements could allow the initial assessment of COPD exacerbations to be based on venous blood gas analysis and pulse oximetry, simplifying the care pathway and improving the patient experience. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  14. Calf venous compliance measured by venous occlusion plethysmography: methodological aspects.

    Science.gov (United States)

    Skoog, Johan; Zachrisson, Helene; Lindenberger, Marcus; Ekman, Mikael; Ewerman, Lea; Länne, Toste

    2015-02-01

    Calf venous compliance (C calf) is commonly evaluated with venous occlusion plethysmography (VOP) during a standard cuff deflation protocol. However, the technique relies on two not previously validated assumptions concerning thigh cuff pressure (P cuff) transmission and the impact of net fluid filtration (F filt) on C calf. The aim was to validate VOP in the lower limb and to develop a model to correct for F filt during VOP. Strain-gauge technique was used to study calf volume changes in 15 women and 10 age-matched men. A thigh cuff was inflated to 60 mmHg for 4 and 8 min with a subsequent decrease of 1 mmHg s(-1). Intravenous pressure (P iv) was measured simultaneously. C calf was determined with the commonly used equation [Compliance = β 1 + 2β 2 × P cuff] describing the pressure-compliance relationship. A model was developed to identify and correct for F filt. Transmission of P cuff to P iv was 100 %. The decrease in P cuff correlated well with P iv reduction (r = 0.99, P < 0.001). Overall, our model showed that C calf was underestimated when F filt was not accounted for (all P < 0.01). F filt was higher in women (P < 0.01) and showed a more pronounced effect on C calf compared to men (P < 0.05). The impact of F filt was similar during 4- and 8-min VOP. P cuff is an adequate substitute for P iv in the lower limb. F filt is associated with an underestimation of C calf and differences in the effect of F filt during VOP can be accounted for with the correction model. Thus, our model seems to be a valuable tool in future studies of venous wall function.

  15. X-Y Converter Family

    DEFF Research Database (Denmark)

    Bhaskar, Mahajan Sagar; Sanjeevikumar, Padmanaban; Wheeler, Patrick

    2016-01-01

    A New breed of a buck boost converter, named as the XY converter family is proposed in this article. In the XY family, 16 topologies are presented which are highly suitable for renewable energy applications which require a high ratio of DC-DC converter; such as a photovoltaic multilevel inverter...... system, high voltage automotive applications and industrial drives. Compared to the traditional boost converter and existing recent converters, the proposed XY converter family has the ability to provide a higher output voltage by using less number of power devices and reactive components. Other distinct...... features of the XY converter family are i) Single control switch ii) Provide negative output voltage iii) Non-isolated topologies iv) High conversion ratio without making the use of high duty cycle and v) modular structure. XY family is compared with the recent high step-up converters and the detailed...

  16. Transpleural central venous catheter discovered during thoracotomy

    Directory of Open Access Journals (Sweden)

    Ashima Malhotra

    2014-01-01

    Full Text Available We report an uncommon complication of subclavian central venous catheterization, discovered at thoracotomy. The central venous catheter (CVC was placed by left infraclavicular route after induction of general anesthesia. CVC was secured after aspiration of blood and satisfactory central venous tracing. On thoracotomy, CVC was noticed to traverse the pleural cavity while the tracing was normal. CVC was thus removed consequent to which bleeding from each puncture site was noticed, that were secured surgically.

  17. Mathematical arterialization of venous blood in emergency medicine patients

    DEFF Research Database (Denmark)

    Tygesen, Gitte Boier; Matzen, Helle; Grønkjær, Karen;

    2012-01-01

    .83; and Bland-Altman limits of agreement well within the limits of acceptable laboratory and clinical performance. The calculated values of arterial PO2 followed a set of predefined rules relating calculated and measured PO2 levels in all cases. The method represents an improvement on the use of venous blood......OBJECTIVES: Arterial punctures represent a painful and unpleasant experience. Acid-base and oxygenation status can be assessed from peripheral venous blood, but agreement with arterial values is not always clinically acceptable. This study evaluates a method for mathematically transforming...... alone where the correlation coefficients were as follows: group A, pH 0.85, PCO2 0.88; group B, pH 0.79, PCO2 0.59; and limits of agreement for PCO2 at the border of (group A) or beyond (group B) acceptable clinical limits. CONCLUSION: Application of the mathematical arterialization method may reduce...

  18. Resonant power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2012-01-01

    This book is devoted to resonant energy conversion in power electronics. It is a practical, systematic guide to the analysis and design of various dc-dc resonant inverters, high-frequency rectifiers, and dc-dc resonant converters that are building blocks of many of today's high-frequency energy processors. Designed to function as both a superior senior-to-graduate level textbook for electrical engineering courses and a valuable professional reference for practicing engineers, it provides students and engineers with a solid grasp of existing high-frequency technology, while acquainting them wit

  19. Cycloidal Wave Energy Converter

    Energy Technology Data Exchange (ETDEWEB)

    Stefan G. Siegel, Ph.D.

    2012-11-30

    This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will

  20. The impact of obesity on venous insufficiency.

    Science.gov (United States)

    Seidel, A C; Belczak, C E Q; Campos, M B; Campos, R B; Harada, D S

    2015-08-01

    Association between chronic venous disease and obesity has recently been studied, with indications that it may worsen in obese patients. The aim of study was to correlate clinical classes of chronic venous disease according to Clinical Etiology Anatomy Pathophysiology (CEAP) classification and body mass index, as well as to compare the severity of chronic venous disease in obese and nonobese patients. This retrospective cross-sectional prevalence study was conducted at the Maringá State University and Belczak Vascular Center along a period of 2 years, consisting of a random sample of 482 patients with complaints compatible with chronic venous disease. Data obtained from patient's files included gender, age, weight and height (for calculating body mass index), and clinical class (C) of chronic venous disease according to CEAP classification. Statistical analysis included Spearman's correlation coefficient, Chi-square test (for comparing frequencies), and Student's t-test (for comparing means). Significant positive correlation between body mass index and clinical classes was established for women (0.43), but not for men (0.07). Obesity (body mass index  : ≥  : 30.0) was significantly more frequent in patients with chronic venous disease in clinical classes 3 (p venous disease in clinical class 1 (p venous disease in women, but not in men. It also corroborated the negative impact of obesity on the clinical severity of chronic venous disease.

  1. Central vein stenosis masquerading as venous thrombosis

    National Research Council Canada - National Science Library

    Nagapriya Vellalacheruvu; Naresh Monigari; Tom Devasia; Hashir Kareem

    2014-01-01

    .... 3 Learning points Central venous stenosis (CVS), although rare, is a known complication in patients requiring maintenance haemodialysis but symptomatic CVS requiring intervention is not common...

  2. Central venous line complications and tip detection

    Directory of Open Access Journals (Sweden)

    Ameneh Rezaee Gheshlaghi

    2015-06-01

    Full Text Available Central venous line is one of a creative instrument that saves human’s life in critical medical situation. Central venous line access is frequently involved in the disease management. It is used for rapid fluid therapy, transvenous pacemakers, infusion of some medications, hemodialysis or plasmapheresis and etc. Most of the emergency departments have some staffs that are trained for central venous line insertion but related complications occur during central venous line placement.Central venous line might have some complications and complication follow-up should be considered. Thromboembolism and infection are two important medical complications. Arterial puncture, hematoma, pneumothorax and hemothorax are mechanical Central venous line complications. Chest X-ray and some other techniques should be used for detecting these complications.Central venous line tip misplace is a considerable problem for emergency department staffs, previously chest X-ray has been used for central venous line misplace detection. In some recent studies, contrast-enhanced ultrasonography and intravascular electrocardiography have been used for central venous line misplace.

  3. Characterizing the Risk Factors Associated With Venous Thromboembolism in Pediatric Patients After Central Venous Line Placement

    OpenAIRE

    Wisecup, Sarah; Eades, Shannan; Turiy, Yuliya

    2015-01-01

    OBJECTIVES: With the apparent increase in venous thromboembolism noted in the pediatric population, it is important to define which children are at risk for clots and to determine optimal preventative therapy. The purpose of this study was to determine the risk factors for venous thromboembolism in pediatric patients with central venous line placement.

  4. Bidirectional buck boost converter

    Science.gov (United States)

    Esser, Albert Andreas Maria

    1998-03-31

    A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero.

  5. Gallium phosphide energy converters

    Energy Technology Data Exchange (ETDEWEB)

    Sims, P.E.; Dinetta, L.C.; Goetz, M.A.

    1995-10-01

    Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp {minus}17) A/sq cm have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.

  6. The Same Angiographic Factors Predict Venous and Arterial Graft Patency

    Science.gov (United States)

    Gaudino, Mario; Niccoli, Giampaolo; Roberto, Marco; Cammertoni, Federico; Cosentino, Nicola; Falcioni, Elena; Panebianco, Mario; D’Amario, Domenico; Crea, Filippo; Massetti, Massimo

    2016-01-01

    Abstract To evaluate the value of angiographic factors in predicting failure of both venous and arterial coronary artery bypass graft. We retrieved from our angiographic database 148 patients who underwent venous and/or arterial CABG and for whom a control coronary angiography at more than 1 month after surgery was available. Pre-CABG and follow-up angiographies were analyzed in order to evaluate diameter stenosis (DS,%), stenosis length (mm), Bogaty score (extent index), Sullivan score, and Gensini score for the extent of coronary artery disease, and Jeopardy Duke score for the extent of myocardial area supplied by an artery. Thirty-nine patients (26%) experienced graft failure at follow-up (mean follow-up 11.3 ± 4.6 months). Patients with venous graft failure [26 (20%)] had significantly smaller DS (P = 0.013), shorter stenosis length (P = 0.01), and lower extent index (P = 0.015), Sullivan score (P = 0.013), Gensini score (P = 0.04) as compared with those without venous graft failure. Patients with arterial graft failure [13 (11%)] had significantly lower DS (P = 0.008), shorter stenosis length (P = 0.001), and lower extent index (P = 0.03) and Sullivan score (P = 0.023) as compared with those without arterial graft failure. Venous and arterial graft failure are associated with less severe stenosis and less extensive atherosclerosis of the grafted vessel. PMID:26735525

  7. The Impact of Central Venous Catheters on Pediatric Venous Thromboembolism

    Science.gov (United States)

    Jaffray, Julie; Bauman, Mary; Massicotte, Patti

    2017-01-01

    The use of central venous catheters (CVCs) in children is escalating, which is likely linked to the increased incidence of pediatric venous thromboembolism (VTE). In order to better understand the specific risk factors associated with CVC-VTE in children, as well as available prevention methods, a literature review was performed. The overall incidence of CVC-VTE was found to range from 0 to 74%, depending on the patient population, CVC type, imaging modality, and study design. Throughout the available literature, there was not a consistent determination regarding whether a particular type of central line (tunneled vs. non-tunneled vs. peripherally inserted vs. implanted), catheter material, insertion technique, or insertion location lead to an increased VTE risk. The patient populations who were found to be most at risk for CVC-VTE were those with cancer, congenital heart disease, gastrointestinal failure, systemic infection, intensive care unit admission, or involved in a trauma. Both mechanical and pharmacological prophylactic techniques have been shown to be successful in preventing VTE in adult patients, but studies in children have yet to be performed or are underpowered. In order to better determine true CVC-VTE risk factors and best preventative techniques, an increase in large, prospective pediatric trials needs to be performed. PMID:28168186

  8. The Impact of Central Venous Catheters on Pediatric Venous Thromboembolism.

    Science.gov (United States)

    Jaffray, Julie; Bauman, Mary; Massicotte, Patti

    2017-01-01

    The use of central venous catheters (CVCs) in children is escalating, which is likely linked to the increased incidence of pediatric venous thromboembolism (VTE). In order to better understand the specific risk factors associated with CVC-VTE in children, as well as available prevention methods, a literature review was performed. The overall incidence of CVC-VTE was found to range from 0 to 74%, depending on the patient population, CVC type, imaging modality, and study design. Throughout the available literature, there was not a consistent determination regarding whether a particular type of central line (tunneled vs. non-tunneled vs. peripherally inserted vs. implanted), catheter material, insertion technique, or insertion location lead to an increased VTE risk. The patient populations who were found to be most at risk for CVC-VTE were those with cancer, congenital heart disease, gastrointestinal failure, systemic infection, intensive care unit admission, or involved in a trauma. Both mechanical and pharmacological prophylactic techniques have been shown to be successful in preventing VTE in adult patients, but studies in children have yet to be performed or are underpowered. In order to better determine true CVC-VTE risk factors and best preventative techniques, an increase in large, prospective pediatric trials needs to be performed.

  9. A linear temperature-to-frequency converter

    DEFF Research Database (Denmark)

    Løvborg, Leif

    1965-01-01

    The possibility of converting temperature into a frequency signal by means of a thermistor which is part of the frequency-determining network of an RC oscillator is investigated. It is shown that a temperature - frequency characteristic which has a point of inflection may be realized, and that th......The possibility of converting temperature into a frequency signal by means of a thermistor which is part of the frequency-determining network of an RC oscillator is investigated. It is shown that a temperature - frequency characteristic which has a point of inflection may be realized......, and that the maximum value of the temperature-frequency coefficient beta in this point is-1/3 alpha, where a is the temperature coefficient of the thermistor at the corresponding temperature. Curves showing the range in which the converter is expected to be linear to within plusmn0.1 degC are given. A laboratory...

  10. Manufacturing method of photoelectric converter

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Shunpei; Suzuki, Kunio; Fukada, Takeshi; Kanehana, Mikio

    1987-06-25

    This is a photoelectric converter wherein a photoelectromotive force is generated by utilizing the shorter wavelength side by the 1st converter and by utilizing the longer wavelength side by the 2nd converter; as a whole, wider wavelength range of light can be converted into electricity. In the 1st. converter, an electrode on the side of semi-incident surface is made transparent as well as an electrode equipped on the back of a non-mono-crystalline semiconductor. Light which passed this is introduced into the 2nd converter to generate an electromotive force. This invention especially relates with a method of forming this 2nd converter. In preparing I-type non-mono-crystalline semiconductor among the semiconductors having PIN junction, PCVD method is used by means of ECR (Electron Cyclotron Resonance) by using a hydrogen- or halogen- added Si-semiconductor instead of using expensive Ge, etc, which are common in the conventional method. (3 figs)

  11. Elastic compression treatment of chronic superficial venous insufficiency of the lower limbs based on Doppler venous pressure index measurements

    Directory of Open Access Journals (Sweden)

    Leonardo Corcos

    2015-03-01

    Full Text Available Ineffectiveness or discomfort from graduated elastic compression stockings (GES in patients with chronic venous insufficiency (CVI and/or varicose veins of the lower limbs (VVLL can depend of inappropriate counter pressure applied. Counter pressure was calculated by Doppler venous pressure index (VPI. The aim of this study was to verify the value VPI in the choice of GES. A total of 1212 LL of 606 patients subjected to VPI measurements VPI correlated with the various sites of reflux (R and C of Clinical-Etiology-Anatomy-Pathophysiology (CEAP classification. The difference between standing VPI the and normal values=counter pressure to be applied by GES. Questionnaire to 96 patients with CVI/VVLL wearing GES. Mean VPI values: greater saphenous (GSV>smaller saphenous; GSV with isolated venous reflux (R at the leg>GSV at the thigh; additional R in perforators increases VPI in all the districts; superficial R increases VPI in PT. Relation between VPI/C of CEAP: P<0.05-0.0001; 81/83/96 (97.5% patients improved; 0 complained. R in GSV at the leg and in perforators increases VPI in deep veins. Few discrepancies VPI/CEAP can be expected. Standing VPI is highly predictive. The best choice of GES can be based on the VPI measurement.

  12. Biological characteristics of the cerebral venous system and its hemodynamic response to intracranial hypertension

    Institute of Scientific and Technical Information of China (English)

    CHEN Jie; WANG Xi-ming; LUAN Li-ming; CHAO Bao-ting; PANG Bo; SONG Hui; PANG Qi

    2012-01-01

    Background The role of the cerebral venous system (CVS) in intracranial pressure (ICP) regulation remains largely unclear.In the present study,the interaction between ICP and the cerebral venous system and its possible mechanism were investigated with respect to the biological characteristics of the cerebral venous system and its hemodynamic response under increased ICP.@@Methods We created intracranial hypertension animal model,measured and calculated the venous flow velocity and diameter of the outflow terminal of the CVS with color ultrasonic system and recorded the vascular morphology by 3-dimensional anatomical microscopy.Patients who suffered from raised ICP underwent MRI and digital subtraction angiography (DSA) examination to show the length in the vertical direction of the wall of the bridging vein representing the diameter value.Pathological autopsy was performed from bodies of patients who had died from non-cerebral causes to observe the juncture part between the venous sinuses and tributary vertical brain veins.@@Results Under increased ICP conditions,venous drainage through the outlet cuff segment,a unique structure between the bridge vein and sinus,was obstructed and in turn venous blood became congested.Therefore,the increased blood volume worsened the pre-existing ICP according to the well-accepted theory regarding volume-pressure relationship.This phenomenon was described as concurrent “Venogenic intracranial hypertension”,which is characterized by intracranial venous blood stasis responsive to and together with the original increased ICP.@@Conclusions The existence of this special pathophysiological process is prevalent,rather than rare,in various intracranial disorders.This finding would definitely provide new insight into the area of cerebral venous system research.

  13. Unity power factor converter

    Science.gov (United States)

    Wester, Gene W. (Inventor)

    1980-01-01

    A unity power factor converter capable of effecting either inversion (dc-to-dc) or rectification (ac-to-dc), and capable of providing bilateral power control from a DC source (or load) through an AC transmission line to a DC load (or source) for power flow in either direction, is comprised of comparators for comparing the AC current i with an AC signal i.sub.ref (or its phase inversion) derived from the AC ports to generate control signals to operate a switch control circuit for high speed switching to shape the AC current waveform to a sine waveform, and synchronize it in phase and frequency with the AC voltage at the AC ports, by selectively switching the connections to a series inductor as required to increase or decrease the current i.

  14. Electromagnetic wave energy converter

    Science.gov (United States)

    Bailey, R. L. (Inventor)

    1973-01-01

    Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

  15. [Central venous blood gas analysis].

    Science.gov (United States)

    Marano, Marco; D'Amato, Anna; Guiotto, Giovanna; Schiraldi, Fernando

    2015-01-01

    The hemodialysis might interfere with patients hemodynamic, as the technique allows a sophisticated game with extra and intravascular fluids. As the cardiocirculatory response could sometimes be unpredictable, it is interesting to collect valuable information by reaching a deep understanding of the tissue metabolism which is mirrored by the blood gas analysis of variations in arterial and central venous blood samples. Particularly interesting are the time course variations of the central venous hemoglobin saturation (ScvO2), which are directly related to the patient with O2-demand as well as to the O2-Delivery (DO2). The ScvO2 is determined by four parameters (cardiac output, Hb concentration, arterial Hb saturation and O2 consumption): If the fluids subtraction during dialysis was about to determine an occult hypoperfusion, the ScvO2 reduction would be a timely warning sign to be considered. Moreover, while the normal veno-arterial PCO2 difference is 2-4 mmHg, whenever a mismatch between O2-demand and DO2arise, a larger v-aPCO2 difference should be observed.

  16. Venous thromboembolism in cancer patients

    Directory of Open Access Journals (Sweden)

    Mehmet Fuat Eren

    2013-09-01

    Full Text Available Venous thromboembolism (VTE is a major complication of cancer and represents an important cause of morbidity and mortality. The incidence of VTE is 0.6-7.8% in patients with cancer more than double the incidence of VTE in patients without cancer. The risk of VTE which includes deep venous thrombosis (DVT and pulmonary embolism (PE is increased two to seven fold in patients with cancer. VTE risk is especially high among certain groups such as hospitalized patients with cancer and those receiving active antineoplastic therapy. Also cancer patients, who undergoing major surgery, are increased risk of VTE. Trauma, long-haul travel, increased age, obesity, previous VTE and genetic component are also predisposing factors for VTE. Patients with cancer who develop VTE should be managed multidisciplinary treatment guidelines. The primary goal of thromboprophylaxis in patients with cancer is to prevent VTE. The large majority of cancer patients should be treated with therapeutic doses of unfractioned heparin (UFH or low molecular weight heparin (LMWH. Prophylaxis should include cancer patients who underwent major surgery for cancer and patients with a history of VTE.

  17. Wartime major venous vessel injuries.

    Science.gov (United States)

    Hudorovic, Narcis

    2008-02-01

    The aim of this study is to declare our experience and to identify the important factors that influence the mortality and morbidity in patients with combat-related penetrating wounds of the abdomen (CR-PWA) with major venous vessel injuries. Twenty-six wounded with combat-related injuries of major abdominal venous vessels, admitted in the University Clinic cardiovascular surgery department during the period from 1 August 1991 through 30 October 1995, were analyzed. Patients with concomitant injured arteries and extra-abdominal injuries (n=150; 85.2%) were excluded from this study. The Penetrating Abdominal Trauma Index (PATI) score for each patient was calculated. Fifteen patients (57.69%) sustained with PATI score greater than 25 died. The mean duration of hospitalization was 16 days (range 0-86). The average hospitalization time for those surviving their complications was 17 days with a PATI of 25 or less, and 43 days with a score more than 25. Three clinical assessments of the long-term outcome were performed after a median of about 3, 5 and 10 years, respectively. Surviving patients (42.31%) were symptom free and had normal Duplex scans as well as no other surgical related complications. Higher PATI scores, postoperative complications and reoperations exert an unfavorable effect on patient outcome.

  18. Developmental Venous Anomaly: Benign or Not Benign

    Science.gov (United States)

    AOKI, Rie; SRIVATANAKUL, Kittipong

    2016-01-01

    Developmental venous anomalies (DVAs), previously called venous angiomas, are the most frequently encountered cerebral vascular malformations. However, DVA is considered to be rather an extreme developmental anatomical variation of medullary veins than true malformation. DVAs are composed of dilated medullary veins converging centripetally into a large collecting venous system that drains into the superficial or deep venous system. Their etiology and mechanism are generally accepted that DVAs result from the focal arrest of the normal parenchymal vein development or occlusion of the medullary veins as a compensatory venous system. DVAs per se are benign and asymptomatic except for under certain unusual conditions. The pathomechanisms of symptomatic DVAs are divided into mechanical, flow-related causes, and idiopathic. However, in cases of DVAs associated with hemorrhage, cavernous malformations (CMs) are most often the cause rather than DVAs themselves. The coexistence of CM and DVA is common. There are some possibilities that DVA affects the formation and clinical course of CM because CM related to DVA is generally located within the drainage territory of DVA and is more aggressive than isolated CM in the literature. Brain parenchymal abnormalities surrounding DVA and cerebral varix have also been reported. These phenomena are considered to be the result of venous hypertension associated with DVAs. With the advance of diagnostic imagings, perfusion study supports this hypothesis demonstrating that some DVAs have venous congestion pattern. Although DVAs should be considered benign and clinically silent, they can have potential venous hypertension and can be vulnerable to hemodynamic changes. PMID:27250700

  19. Risk factors for venous thromboembolism during pregnancy

    DEFF Research Database (Denmark)

    Jensen, Thomas Bo; Gerds, Thomas Alexander; Grøn, Randi;

    2013-01-01

    Pregnant women are at an increased risk of venous thromboembolism (VTE). Risk factors for VTE among pregnant women are not sufficiently investigated.......Pregnant women are at an increased risk of venous thromboembolism (VTE). Risk factors for VTE among pregnant women are not sufficiently investigated....

  20. Diagnosis and treatment of venous ulcers.

    Science.gov (United States)

    Collins, Lauren; Seraj, Samina

    2010-04-15

    Venous ulcer, also known as stasis ulcer, is the most common etiology of lower extremity ulceration, affecting approximately 1 percent of the U.S. population. Possible causes of venous ulcers include inflammatory processes resulting in leukocyte activation, endothelial damage, platelet aggregation, and intracellular edema. The primary risk factors for venous ulcer development are older age, obesity, previous leg injuries, deep venous thrombosis, and phlebitis. On physical examination, venous ulcers are generally irregular, shallow, and located over bony prominences. Granulation tissue and fibrin are typically present in the ulcer base. Associated findings include lower extremity varicosities, edema, venous dermatitis, and lipodermatosclerosis. Venous ulcers are usually recurrent, and an open ulcer can persist for weeks to many years. Severe complications include cellulitis, osteomyelitis, and malignant change. Poor prognostic factors include large ulcer size and prolonged duration. Evidence-based treatment options for venous ulcers include leg elevation, compression therapy, dressings, pentoxifylline, and aspirin therapy. Surgical management may be considered for ulcers that are large in size, of prolonged duration, or refractory to conservative measures.

  1. An unusual Complication of Central Venous Cannulation

    Directory of Open Access Journals (Sweden)

    Ashvini Kumar

    2013-04-01

    Full Text Available Central venous catheter (CVC hub fracture is a rare complication of central venous cannulation. We report a case where catheter hub fracture was detected immediately after CVC insertion. Causes of catheter hub fracture and its complications are discussed.

  2. Sex-specific aspects of venous thrombosis

    NARCIS (Netherlands)

    Roach, Rachel Elizabeth Jo

    2014-01-01

    Venous thrombosis is a disease that occurs in 1-2 per 1000 people per year. At the time of their first venous thrombosis, approximately 50% of women are exposed to reproductive risk factors (oral contraception, postmenopausal hormone therapy, pregnancy and the puerperium). In this thesis, we showed

  3. U turn to venous air embolism

    Directory of Open Access Journals (Sweden)

    Singh Harsimran

    2009-01-01

    Full Text Available There is a definitive risk of venous air embolism when the fluid infusion is complete and the drip set is still open in a glass bottle.We have devised a novel way of preventing the chances of air embolism when the fluid in the glass bottle finishes. It really gives a "U" turn to the chances of venous air embolism.

  4. Integrated power electronic converters and digital control

    CERN Document Server

    Emadi, Ali; Nie, Zhong

    2009-01-01

    Non-isolated DC-DC ConvertersBuck ConverterBoost ConverterBuck-Boost ConverterIsolated DC-DC ConvertersFlyback ConverterForward ConverterPush-Pull ConverterFull-Bridge ConverterHalf-Bridge ConverterPower Factor CorrectionConcept of PFCGeneral Classification of PFC CircuitsHigh Switching Frequency Topologies for PFCApplication of PFC in Advanced Motor DrivesIntegrated Switched-Mode Power ConvertersSwitched-Mode Power SuppliesThe Concept of Integrated ConverterDefinition of Integrated Switched-Mode Power Supplies (ISMPS)Boost-Type Integrated TopologiesGeneral Structure of Boost-Type Integrated T

  5. Another look at Statics and Dynamics of Switching Power Converters

    Science.gov (United States)

    Sasaki, Seigo; Watanabe, Haruo

    Three types of switching power supply, which are buck, boost, buck/boost converter, are statically and dynamically analysed. A framework of large signal analysis presents characteristics of converters which vary with operating points, and discusses a relationship between statics and dynamics. It is shown that boost and buck/boost converters substantially change their characteristics. There exists the operating points where for low frequencies the phases become -90° or -180° and the gains fall off to low values. The phenomenon is characterized by a zero of transfer function of the converter and also by the statics.

  6. Advanced power electronics converters PWM converters processing AC voltages

    CERN Document Server

    dos Santos, Euzeli

    2014-01-01

    This book covers power electronics, in depth, by presenting the basic principles and application details, which can be used both as a textbook and reference book.  Introduces a new method to present power electronics converters called Power Blocks Geometry. Applicable for courses focusing on power electronics, power electronics converters, and advanced power converters. Offers a comprehensive set of simulation results to help understand the circuits presented throughout the book

  7. Clinical quality indicators of venous leg ulcers

    DEFF Research Database (Denmark)

    Kjaer, Monica L; Mainz, Jan; Soernsen, Lars T

    2005-01-01

    In the clinical setting, diagnosis and treatment of venous leg ulcers can vary considerably from patient to patient. The first step to reducing this variation is to document venous leg ulcer care through use of quantitative scientific documentation principles. This requires the development of valid...... and reliable evidence-based quality indicators of venous leg ulcer care. A Scandinavian multidisciplinary, cross-sectional panel of wound healing experts developed clinical quality indicators on the basis of scientific evidence from the literature and subsequent group nominal consensus of the panel......; an independent medical doctor tested the feasibility and reliability of these clinical indicators, assessing the quality of medical technical care on 100 consecutive venous leg ulcer patients. Main outcome measures were healing, recurrence, pain, venous disease diagnosis, differential diagnosis and treatment...

  8. Segmentation and separation of venous vasculatures in liver CT images

    Science.gov (United States)

    Wang, Lei; Hansen, Christian; Zidowitz, Stephan; Hahn, Horst K.

    2014-03-01

    Computer-aided analysis of venous vasculatures including hepatic veins and portal veins is important in liver surgery planning. The analysis normally consists of two important pre-processing tasks: segmenting both vasculatures and separating them from each other by assigning different labels. During the acquisition of multi-phase CT images, both of the venous vessels are enhanced by injected contrast agent and acquired either in a common phase or in two individual phases. The enhanced signals established by contrast agent are often not stably acquired due to non-optimal acquisition time. Inadequate contrast and the presence of large lesions in oncological patients, make the segmentation task quite challenging. To overcome these diffculties, we propose a framework with minimal user interactions to analyze venous vasculatures in multi-phase CT images. Firstly, presented vasculatures are automatically segmented adopting an efficient multi-scale Hessian-based vesselness filter. The initially segmented vessel trees are then converted to a graph representation, on which a series of graph filters are applied in post-processing steps to rule out irrelevant structures. Eventually, we develop a semi-automatic workow to refine the segmentation in the areas of inferior vena cava and entrance of portal veins, and to simultaneously separate hepatic veins from portal veins. Segmentation quality was evaluated with intensive tests enclosing 60 CT images from both healthy liver donors and oncological patients. To quantitatively measure the similarities between segmented and reference vessel trees, we propose three additional metrics: skeleton distance, branch coverage, and boundary surface distance, which are dedicated to quantifying the misalignment induced by both branching patterns and radii of two vessel trees.

  9. Arterio-venous malformations of uterus - diagnostic and management dilemmas.

    Science.gov (United States)

    Narang, H K; Puri, M; Patra, S; Trivedi, S S

    2015-01-01

    Keeping in mind the life-threatening consequences of curettage in cases of undiagnosed uterine arterio-venous malformation (AVM), its possibility should be considered in patients presenting with abnormal heavy uterine bleeding and negative Human Chorionic Gonadotropin (β-hCG) values. We collected a series of cases in which the patients presented with abnormal heavy uterine bleeding, some not responding to conservative treatment. In the presence of declining or low serum β-hCG levels and ultrasound Doppler showing increased vascularity, patients were investigated to detect the possible presence of uterine AVM. In those patients in whom angiographic confirmation of uterine AVM was made, embolisation was done and the outcome was followed. In those patients in whom hysterectomy was done the histopathogy specimen was studied for the possible cause of increased vascularity. Arterio-venous shunting seen on ultrasound does not always imply a uterine AVM and some cases can present diagnostic and management dilemmas.

  10. Converter Turbine and Stator

    Directory of Open Access Journals (Sweden)

    B. V. Marathe

    1995-01-01

    the shell suction surface inside the stator blade passage. The unsteadiness in the flow properties upstream of the stator is high. The rms value of the unsteady total velocity is approx. 20% of the steady state value. Periodic and aperiodic unsteadiness were also found significant.

  11. Design & Implementation of Zero Voltage Switching Buck Converter

    Directory of Open Access Journals (Sweden)

    A.Suresh Kumar

    2014-09-01

    Full Text Available Zero voltage switching (ZVS buck converter is more preferable over hard switched buck converter for low power, high frequency DC-DC conversion applications. In Zero voltage switching converter, turn on & turn off of a switch occurs at zero voltage that results in lower switching losses. In this converter soft switching is achieved by using resonant components. The optimal values of resonant components are determined by using electric functions derived from circuit configuration. This type of soft switched resonant converter offers very low electromagnetic interference (EMI.This study presents the circuit configuration with least components to realize highly efficient zero voltage switching resonant converter. It’s feasibility is confirmed with the developed proto type model and experimental results are verified.

  12. Nanostructure Neutron Converter Layer Development

    Science.gov (United States)

    Park, Cheol (Inventor); Sauti, Godfrey (Inventor); Kang, Jin Ho (Inventor); Lowther, Sharon E. (Inventor); Thibeault, Sheila A. (Inventor); Bryant, Robert G. (Inventor)

    2016-01-01

    Methods for making a neutron converter layer are provided. The various embodiment methods enable the formation of a single layer neutron converter material. The single layer neutron converter material formed according to the various embodiments may have a high neutron absorption cross section, tailored resistivity providing a good electric field penetration with submicron particles, and a high secondary electron emission coefficient. In an embodiment method a neutron converter layer may be formed by sequential supercritical fluid metallization of a porous nanostructure aerogel or polyimide film. In another embodiment method a neutron converter layer may be formed by simultaneous supercritical fluid metallization of a porous nanostructure aerogel or polyimide film. In a further embodiment method a neutron converter layer may be formed by in-situ metalized aerogel nanostructure development.

  13. Impedance source power electronic converters

    CERN Document Server

    Liu, Yushan; Ge, Baoming; Blaabjerg, Frede; Ellabban, Omar; Loh, Poh Chiang

    2016-01-01

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding control methods. Presents the latest power conversion solutions that aim to advance the role of pow...

  14. [Partial anomalous pulmonary venous connection as incidental finding: Explanation for apparently paradoxical central venous blood gas analysis results].

    Science.gov (United States)

    Brandt, L; Artmeier-Brandt, U

    2015-10-01

    A partial anomalous pulmonary venous connection (PAPVC) is a congenital abnormality of the great thoracic vessels the incidence of which is underestimated and is associated with a left-right shunt. It rarely develops into a right-sided cardiac insufficiency. Because of the mostly low left-right shunt volume, a PAPVC is often asymptomatic and mostly incidentally detected in advanced age. Incorrect positioning of a central venous catheter or paradoxical blood gas parameters can serve to indicate the presence of a PAPVC. This article presents the case a 50-year-old patient with a PAPVC of the left upper lobe pulmonary vein draining into the left innominate vein without prior clinical symptoms. Blood gas analyses from the superior vena cava, where the catheter placement was confirmed by computed tomography angiography, showed unexplainable arterial values. The anatomical abnormality was confirmed by computed tomography.

  15. A thermochemical energy converter

    Energy Technology Data Exchange (ETDEWEB)

    Toyeguti, K.; Indzima, T.

    1982-08-09

    Mercury is used as the active mass of the anode in the converter and 0/sub 2/ is used as the active cathode material. The reaction of Mercury + 1/2 0/sub 2/-Hg0 occurs with a discharge. With heating to 500/sup 0/C the regeneration of the Mercury, Hg0 yields Mercury + 1/2 0/sub 2/, occurs. The device for performing the thermochenical conversion of energy contains an element body, an oxygen chamber, an oxygen electrode, a chamber with an alkaline liquid electrolyte, a separator, an auxiliary separator, an electrode and a chamber with the Mercury. The thermochemical reaction occurs in the reactor to which the Hg0 is transported along a pipe which has a refrigerator and a valve. The Mercury is fed into the element from a reservoir. The Mercury reduced in the reactor and in a reaction tower is fed into it through a closed cycle. The bellows is connected with the reactor by a pipe with a refrigerator. Through it the 0/sub 2/ goes in a closed cycle to the chamber. The current forming reactions are Hg + 20H-anion yields Hg0 + H/sub 2/0 + 2e and 1/2 0/sub 2/ + H/sub 2/0 + 2e yields 20H-anion. The voltage on the outleads of the element is approximately 0.3 volts.

  16. DC to DC converters: operation; Hacheurs: fonctionnement

    Energy Technology Data Exchange (ETDEWEB)

    Bernot, F. [Ecole d' Ingenieurs de Tours, 37 (France)

    2002-05-01

    This article deals with pulse width modulation (PWM) and pulse position modulation (PPM) DC to DC converters. A tri-phase PWM converter is made of 6 simple DC/DC converters grouped together into 3 reversible converters of the same type: 1 - single-quadrant voltage lowering converters (hydraulic analogy, study with ideal elements, full scheme with input and output filters); 2 - single-quadrant voltage raising converters (hydraulic analogy, operation); 3 - two quadrants reversible converters (structure construction, quadrants of operation, reversible converter connected to a DC motor); 4 - four-quadrants reversible converters; 5 - other converters structure (current converters and converters with intermediate storage, asymmetrical converters, converters with capacitive storage, insulated converters, resonating converters, status); 6 - conclusion. (J.S.)

  17. Measurement of Episcleral Venous Pressure in Normal Chinese People

    Institute of Scientific and Technical Information of China (English)

    Yimin Zhong; Dawei Peng

    2000-01-01

    Purpose: To measure episcleral venous pressure (EVP) in normal Chinese people.Methods: EVP was measured in 110 eyes of 74 subjects distributed in seven age groups from 10 to 80 years using episcleral venomanometer (EV-310). The differences in EVP values were analyzed with age and either eye.Results: EVP values of the 110 eyes appeared as normal distribution. The value x ± SD was (9. 11 ± 1.22) mmHg, and the 95% normal value range was 6. 73 mmHg~11.50mmHg. No statistically significant difference of EVP was found in the seven age groups.And there was no statistically significant difference of EVP between the right and left eyes.Conclusions: The value x ± SD of EVP in Chinese normal eyes is 9. 11 mmHg ± 1.22mmHg. The normal value of EVP does not vary with age and either eye.

  18. Haemoptysis due to pulmonary venous stenosis

    Directory of Open Access Journals (Sweden)

    Silke Braun

    2014-06-01

    Full Text Available Haemoptysis is a potentially life-threatening condition with the need for prompt diagnosis. In about 10–20% of all cases the bleeding source remains unexplained with the standard diagnostic approach. The aim of this article is to show the necessity of widening the diagnostic approach to haemoptysis with consideration of pulmonary venous stenosis as a possible cause of even severe haemoptysis and haemoptoe. A review of the literature was performed using the Medline/PubMed database with the terms: “pulmonary venous stenosis”, “pulmonary venous infarction” and “haemoptysis”. Further references from the case reports were considered. 58 case reports and case collections about patients with haemoptysis due to pulmonary venous stenosis were detected. This review gives an overview about the case reports and discusses the underlying pathophysiology and the pros and cons of different imaging techniques for the detection of pulmonary venous stenosis. Several conditions predispose to the obstruction of the mediastinal pulmonary veins. Clinical findings are unspecific and may be misleading. Pulmonary venous stenosis can be detected using several imaging techniques, yet three-dimensional magnetic resonance-angiography and three-dimensional contrast-enhanced computed tomography are the most appropriate. Pulmonary venous stenosis should be considered in patients with haemoptysis.

  19. Cerebral venous outflow and cerebrospinal fluid dynamics

    Directory of Open Access Journals (Sweden)

    Clive B. Beggs

    2014-12-01

    Full Text Available In this review, the impact of restricted cerebral venous outflow on the biomechanics of the intracranial fluid system is investigated. The cerebral venous drainage system is often viewed simply as a series of collecting vessels channeling blood back to the heart. However there is growing evidence that it plays an important role in regulating the intracranial fluid system. In particular, there appears to be a link between increased cerebrospinal fluid (CSF pulsatility in the Aqueduct of Sylvius and constricted venous outflow. Constricted venous outflow also appears to inhibit absorption of CSF into the superior sagittal sinus. The compliance of the cortical bridging veins appears to be critical to the behaviour of the intracranial fluid system, with abnormalities at this location implicated in normal pressure hydrocephalus. The compliance associated with these vessels appears to be functional in nature and dependent on the free egress of blood out of the cranium via the extracranial venous drainage pathways. Because constricted venous outflow appears to be linked with increased aqueductal CSF pulsatility, it suggests that inhibited venous blood outflow may be altering the compliance of the cortical bridging veins.

  20. [Thrombosis of the right atrium after umbilical venous catheterization. Favourable outcome after early thrombectomy].

    Science.gov (United States)

    Paupe, A; Lenclen, R; Blanc, P; Chassevent, J; Hoenn, E; Molho, M; Zannier, D; Olivier-Martin, M

    1992-02-01

    A case of right atrial thrombosis after venous umbilical catheterization in a 21 day-old premature newborn is reported. The initiating factors of such an accident and its clinical signs are evocated. The authors emphasize the value of a systematic ultrasonographic supervision of newborns with central catheters for a long period of time and the value of surgical thrombectomy.

  1. Upper Body Venous Compliance Exceeds Lower Body Venous Compliance in Humans

    Science.gov (United States)

    Watenpaugh, Donald E.

    1996-01-01

    Human venous compliance hypothetically decreases from upper to lower body as a mechanism for maintenance of the hydrostatic indifference level 'headward' in the body, near the heart. This maintains cardiac filling pressure, and thus cardiac output and cerebral perfusion, during orthostasis. This project entailed four steps. First, acute whole-body tilting was employed to alter human calf and neck venous volumes. Subjects were tilted on a tilt table equipped with a footplate as follows: 90 deg, 53 deg, 30 deg, 12 deg, O deg, -6 deg, -12 deg, -6 deg, O deg, 12 deg, 30 deg, 53 deg, and 90 deg. Tilt angles were held for 30 sec each, with 10 sec transitions between angles. Neck volume increased and calf volume decreased during head-down tilting, and the opposite occurred during head-up tilt. Second, I sought to cross-validate Katkov and Chestukhin's (1980) measurements of human leg and neck venous pressures during whole-body tilting, so that those data could be used with volume data from the present study to calculate calf and neck venous compliance (compliance = (Delta)volume/(Delta)pressure). Direct measurements of venous pressures during postural chances and whole-body tilting confirmed that the local changes in venous pressures seen by Katkov and Chestukhin (1980) are valid. The present data also confirmed that gravitational changes in calf venous pressure substantially exceed those changes in upper body venous pressure. Third, the volume and pressure data above were used to find that human neck venous compliance exceeds calf venous compliance by a factor of 6, thereby upholding the primary hypothesis. Also, calf and neck venous compliance correlated significantly with each other (r(exp 2) = 0.56). Fourth, I wished to determine whether human calf muscle activation during head-up tilt reduces calf venous compliance. Findings from tilting and from supine assessments of relaxed calf venous compliance were similar, indicating that tilt-induced muscle activation is

  2. [Use of mesoglycan in venous pathology].

    Science.gov (United States)

    Scondotto, G; Catena, G; Aloisi, D

    1997-12-01

    Twenty-five female patients suffering from primary venous insufficiency of the lower limbs underwent parenteral and oral treatment with mesoglycan for 3 months. In addition to an evaluation of the subjective and objective parameters linked to venous insufficiency, all patients underwent lower limb venous echo colour-Doppler and videocapillaroscopy using an optic probe in a perimalleolar or periulcerous site. At the end of treatment, all patients reported an improvement in subjective parameters, which was confirmed by a reduction of distal edema in 22 out of 25 cases. There was also an improvement in capillaroscopic findings (reduction of edema of pericapillary connective tissue, reduction of capillary and venular ectasia.

  3. [Ultrasound-guided peripheral venous access].

    Science.gov (United States)

    Fuzier, Régis; Rougé, Pierre; Pierre, Sébastien

    2016-02-01

    International guidelines advocate the use of first-line ultrasound for central venous catheter, particularly for the internal jugular vein. The role of ultrasound in peripheral venous access remains questionable. In some specific situations, such as pediatrics, obesity and patients with poor venous network, problems to cannulate peripheral vein may occur. Success rate of peripheral intravenous access increases with the diameter of the vein and for a depth of the vein between 0.3 and 1.5 cm. The type of puncture (long-axis or short-axis) and the type of catheters have little influence on the success rate. Specific considerations have to be taken concerning infection control.

  4. Current opinion on iliofemoral venous thrombectomy.

    Science.gov (United States)

    Stephens, G L

    1976-02-01

    Iliofemoral venous thrombosis is discussed and a technique of iliofemoral venous thrombectomy is presented. Operative phlebography is recommended. The personal recommendations of leading American vascular surgeons in treating the patient with acute iliofemoral venous thrombosis are presented. I recommend thrombectomy for phlegmasia cerulea dolens, and in previously healthy, young ambulatory patients with phlegmasia alba dolens who are seen within 48 hours following thrombosis and have failed to show clinical improvement after a trial of bed rest, elevation of the lower extremities, and intravenous heparin. The majority of patients seen with phlegmasia alba dolens will best be served with nonoperative treatment.

  5. Current perspective of venous thrombosis in the upper extremity

    NARCIS (Netherlands)

    Flinterman, L.E.; Meer, van der F.J.M.; Rosendaal, F.R.; Doggen, C.J.M.

    2008-01-01

    Venous thrombosis of the upper extremity is a rare disease. Therefore, not as much is known about risk factors, treatment and the risk of recurrence as for venous thrombosis of the leg. Only central venous catheters and strenuous exercise are commonly known risk factors for an upper extremity venous

  6. Arterial and portal venous liver perfusion using selective spin labelling MRI

    Energy Technology Data Exchange (ETDEWEB)

    Schalkx, Hanke J.; Petersen, Esben T.; Veldhuis, Wouter B.; Leeuwen, Maarten S. van; Bosch, Maurice A.A.J. van den [University Medical Center Utrecht, Department of Radiology, HP E.01.132, Postbus 85500, Utrecht (Netherlands); Peters, Nicky H.G.M. [Atrium Medical Center Parkstad, Department of Radiology, Heerlen (Netherlands); Pluim, Josien P.W.; Stralen, Marijn van [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands)

    2015-06-01

    To investigate the feasibility of selective arterial and portal venous liver perfusion imaging with spin labelling (SL) MRI, allowing separate labelling of each blood supply. The portal venous perfusion was assessed with a pulsed EPISTAR technique and the arterial perfusion with a pseudo-continuous sequence. To explore precision and reproducibility, portal venous and arterial perfusion were separately quantified in 12 healthy volunteers pre- and postprandially (before and after meal intake). In a subgroup of 6 volunteers, the accuracy of the absolute portal perfusion and its relative postprandial change were compared with MRI flow measurements of the portal vein. The portal venous perfusion significantly increased from 63 ± 22 ml/100g/min preprandially to 132 ± 42 ml/100g/min postprandially. The arterial perfusion was lower with 35 ± 22 preprandially and 22 ± 30 ml/100g/min postprandially. The pre- and postprandial portal perfusion using SL correlated well with flow-based perfusion (r{sup 2} = 0.71). Moreover, postprandial perfusion change correlated well between SL- and flow-based quantification (r{sup 2} = 0.77). The SL results are in range with literature values. Selective spin labelling MRI of the portal venous and arterial blood supply successfully quantified liver perfusion. This non-invasive technique provides specific arterial and portal venous perfusion imaging and could benefit clinical settings where contrast agents are contraindicated. (orig.)

  7. Retinal abnormalities in multiple sclerosis patients with associated chronic cerebrospinal venous insufficiency

    Directory of Open Access Journals (Sweden)

    Aneta Adamczyk-Ludyga

    2012-06-01

    Full Text Available Optical coherence tomography (OCT is a non-invasive method for the assessment of optic nerve fibers and retinal ganglion cells. This study was aimed at the assessment of retinal abnormalities in multiple sclerosis patients in the context of chronic cerebrospinal venous insufficiency using OCT of the retina and the optic nerve. We examined 239 multiple sclerosis (MS patients, including 220 patients with associated chronic cerebrospinal venous insufficiency and 19 MS patients without venous pathology. The following OCT parameters were assessed: average ganglion cell complex thickness, global loss volume, focal loss volume and average retinal nerve fibre layer thickness. Abnormalities in the azygous and internal jugular veins were evaluated using catheter venography. We found a higher prevalence of abnormal OCT parameters in the patients with previous history of optic neuritis, not only on the side of inflammatory event, but also in the contralateral eye, which is in line with already existing body of evidence. The new and intriguing discovery is that we found statistically significant higher prevalence of abnormal OCT values in multiple sclerosis patients with unilateral stenosis of internal jugular vein. Patients who were not found venous abnormalities, as well as those presenting with pathologic azygous or bilateral internal jugular venous outflows, did not demonstrate a changed frequency of abnormal OCT parameters. Potential association between venous malformations and eye manifestations of multiple sclerosis, as has been demonstrated in this report, justifies further studies on this topic.

  8. Proposed electromagnetic wave energy converter

    Science.gov (United States)

    Bailey, R. L.

    1973-01-01

    Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.

  9. Automatic Control of Veno-Venous Extracorporeal Lung Assist.

    Science.gov (United States)

    Kopp, Ruedger; Bensberg, Ralf; Stollenwerk, Andre; Arens, Jutta; Grottke, Oliver; Walter, Marian; Rossaint, Rolf

    2016-10-01

    Veno-venous extracorporeal lung assist (ECLA) can provide sufficient gas exchange even in most severe cases of acute respiratory distress syndrome. Commercially available systems are manually controlled, although an automatically controlled ECLA could allow individualized and continuous adaption to clinical requirements. Therefore, we developed a demonstrator with an integrated control algorithm to keep continuously measured peripheral oxygen saturation and partial pressure of carbon dioxide constant by automatically adjusting extracorporeal blood and gas flow. The "SmartECLA" system was tested in six animal experiments with increasing pulmonary hypoventilation and hypoxic inspiratory gas mixture to simulate progressive acute respiratory failure. During a cumulative evaluation time of 32 h for all experiments, automatic ECLA control resulted in a peripheral oxygen saturation ≥90% for 98% of the time with the lowest value of 82% for 15 s. Partial pressure of venous carbon dioxide was between 40 and 49 mm Hg for 97% of the time with no value 49 mm Hg. With decreasing inspiratory oxygen concentration, extracorporeal oxygen uptake increased from 68 ± 25 to 154 ± 34 mL/min (P automatic control of the extracorporeal circuit. Proof of concept could be demonstrated for this novel automatically controlled veno-venous ECLA circuit. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  10. Impedance Source Power Electronic Converters

    DEFF Research Database (Denmark)

    Liu, Yushan; Abu-Rub, Haitham; Ge, Baoming

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable...... and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key...... control methods. Presents the latest power conversion solutions that aim to advance the role of power electronics into industries and sustainable energy conversion systems. Compares impedance source converter/inverter applications in renewable energy power generation and electric vehicles as well...

  11. The possibility for use of venous flaps in plastic surgery

    Energy Technology Data Exchange (ETDEWEB)

    Baytinger, V. F., E-mail: baitinger@mail.tomsknet.ru; Kurochkina, O. S., E-mail: kurochkinaos@yandex.ru; Selianinov, K. V.; Baytinger, A. V. [Research Institute of Microsurgery, Tomsk (Russian Federation); Dzyuman, A. N. [Siberian State Medical University, Tomsk (Russian Federation)

    2015-11-17

    The use of venous flaps is controversial. The mechanism of perfusion of venous flaps is still not fully understood. The research was conducted on 56 white rats. In our experimental work we studied two different models of venous flaps: pedicled venous flap (PVF) and pedicled arterialized venous flap (PAVF). Our results showed that postoperative congestion was present in all flaps. However 66.7% of all pedicled venous flaps and 100% of all pedicled arterialized venous flaps eventually survived. Histological examination revealed that postoperatively the blood flow in the skin of the pedicled arterialized venous flap became «re-reversed» again; there were no differences between mechanism of survival of venous flaps and other flaps. On the 7-14th day in the skin of all flaps were processes of neoangiogenesis and proliferation. Hence the best scenario for the clinical use of venous flaps unfolds when both revascularization and skin coverage are required.

  12. The possibility for use of venous flaps in plastic surgery

    Science.gov (United States)

    Baytinger, V. F.; Kurochkina, O. S.; Selianinov, K. V.; Baytinger, A. V.; Dzyuman, A. N.

    2015-11-01

    The use of venous flaps is controversial. The mechanism of perfusion of venous flaps is still not fully understood. The research was conducted on 56 white rats. In our experimental work we studied two different models of venous flaps: pedicled venous flap (PVF) and pedicled arterialized venous flap (PAVF). Our results showed that postoperative congestion was present in all flaps. However 66.7% of all pedicled venous flaps and 100% of all pedicled arterialized venous flaps eventually survived. Histological examination revealed that postoperatively the blood flow in the skin of the pedicled arterialized venous flap became «re-reversed» again; there were no differences between mechanism of survival of venous flaps and other flaps. On the 7-14th day in the skin of all flaps were processes of neoangiogenesis and proliferation. Hence the best scenario for the clinical use of venous flaps unfolds when both revascularization and skin coverage are required.

  13. Upper-extremity deep venous thrombosis: a review.

    Science.gov (United States)

    Mai, Cuc; Hunt, Daniel

    2011-05-01

    Upper-extremity deep venous thrombosis is less common than lower-extremity deep venous thrombosis. However, upper-extremity deep venous thrombosis is associated with similar adverse consequences and is becoming more common in patients with complex medical conditions requiring central venous catheters or wires. Although guidelines suggest that this disorder be managed using approaches similar to those for lower-extremity deep venous thrombosis, studies are refining the prognosis and management of upper-extremity deep venous thrombosis. Physicians should be familiar with the diagnostic and treatment considerations for this disease. This review will differentiate between primary and secondary upper-extremity deep venous thromboses; assess the risk factors and clinical sequelae associated with upper-extremity deep venous thrombosis, comparing these with lower-extremity deep venous thrombosis; and describe an approach to treatment and prevention of secondary upper-extremity deep venous thrombosis based on clinical evidence.

  14. The diagnostic value of plasma D-dimer and fibrinogen in lower limb deep venous thrombosis%血浆D-二聚体与纤维蛋白原在下肢深静脉血栓中的诊断价值

    Institute of Scientific and Technical Information of China (English)

    王旭东

    2014-01-01

    目的:探讨D-二聚体(DD)和纤维蛋白原(FIB)在下肢深静脉血栓形成(DVT)诊断中的临床意义。方法对52例疑似DVT患者进行血浆DD和FIB检测,并计算D-二聚体/纤维蛋白原比值(D/F值),根据彩色多普勒超声检查结果明确诊断,同时选取健康体检者50例作为对照组。结果 DVT组血浆DD、FIB及D/F值均明显高于健康对照组,差异有统计学意义(P<0.01);DVT组与非DVT组比较,DVT组DD、FIB和D/F值明显高于非DVT组具有显著性差异(P<0.01),D/F值、DD、FIB对诊断DVT的敏感度分别为98%、94%、85%,D/F值在诊断DVT中较单独应用DD或FIB有较高的敏感度。结论检测血浆DD、FIB及D/F比值可提高DVT临床诊断的特异性,对下肢深静脉血栓的早期诊断具有重要的临床意义。%Objective To explore the diagnostic value of plasma D-dimer and fibrinogen in lower limb deep venous thrombosis(DVT). Methods 52 patients with suspected DVT were selected to be carried out the test on plasma DD and FIB :and calculated d-dimer/fibrinogen ratio(D/F values).According to color doppler ultrasonography examination results determined diagnosis. At the same time: 50 healthy subjects were in the control group. Results The plasma DD and FIB levels and D/F values in DVT group were significantly higher than that of the healthy control group:the differences were statistically significant(P < 0.01). The plasma DD and FIB levels and D/F values in DVT group were higher than those in non-DVT group:and there was significant difference(P<0.01). The sensitivity of D/F values:DD and FIB were respectively 98%,94%,85%.The D/F values had higher sensitivity than the DD or FIB increased in the diagnosis of DVT. Conclusion The testing of plasma DD:FIB and D/F values could improve the specificity in DVT diagnosis and had important clinical significance on the early diagnosis of DVT.

  15. Treatment of hepatic venous stenosis by transfemoral venous balloon dilation following living donor liver transplantation: a case report

    Institute of Scientific and Technical Information of China (English)

    Weiwei Jiang; Yangsui Liu; Lianbao Kong

    2009-01-01

    Hepatic venous stenosis may be a cause of graft failure in living donor liver transplantation (LDLT). Balloon dilation and metallic frame approaches have been used successfully to treat hepatic venous stenosis. Here, we report the effect of transfemoral venous balloon dilation for treating a child with hepatic venous stenosis after LDLT.

  16. Imaging of head and neck venous malformations

    Energy Technology Data Exchange (ETDEWEB)

    Flis, Christine M.; Connor, Stephen E. [King' s College Hospital, Neuroradiology Department, London (United Kingdom)

    2005-10-01

    Venous malformations (VMs) are non proliferative lesions that consist of dysplastic venous channels. The aim of imaging is to characterise the lesion and define its anatomic extent. We will describe the plain film, ultrasound (US) (including colour and duplex Doppler), computed tomography (CT), magnetic resonance imaging (MRI), conventional angiographic and direct phlebographic appearances of venous malformations. They will be illustrated at a number of head and neck locations, including orbit, oral cavity, superficial and deep facial space, supraglottic and intramuscular. An understanding of the classification of such vascular anomalies is required to define the correct therapeutic procedure to employ. Image-guided sclerotherapy alone or in combination with surgery is now the first line treatment option in many cases of head and neck venous malformations, so the radiologist is now an integral part of the multidisciplinary management team. (orig.)

  17. A Rare Venous Port Complication: Supraventriculer Tachycardia

    Directory of Open Access Journals (Sweden)

    Tamer Yoldaş

    2016-04-01

    Full Text Available Implantable central venous port catheters are widely used in the management of children with cancer undergoing long term chemotherapy. These catheters can manifest a number of complications such as arrhythmia. Central venous port catheter was placed on a ten years old boy for chemotherapy. Before insertion of port catheter his physical examination, laboratory parameters, electrocardiography and echocardiography were normal. The patient felt palpitations shortly after the insertion of the port catheter. At that time the heart rate was 200 beats/minute but immediately normal sinus rhythm was restored. A chest roentgenogram revealed that the distal fragment of the port catheter was inside the right atrium. The port catheter was pulled back somewhat and then tachycardia attacks stopped. To our knowledge there are a few reports of supraventricular tachycardia (SVT in children associated with central venous port catheter. Here we aimed to present a pediatric case with SVT after placement of central venous port catheter and his management.

  18. [Emphysematous gastritis with concomitant portal venous air].

    Science.gov (United States)

    Jeong, Min Yeong; Kim, Jin Il; Kim, Jae Young; Kim, Hyun Ho; Jo, Ik Hyun; Seo, Jae Hyun; Kim, Il Kyu; Cheung, Dae Young

    2015-02-01

    Emphysematous gastritis is a rare form of gastritis caused by infection of the stomach wall by gas forming bacteria. It is a very rare condition that carries a high mortality rate. Portal venous gas shadow represents elevation of intestinal luminal pressure which manifests as emphysematous gastritis or gastric emphysema. Literature reviews show that the mortality rate is especially high when portal venous gas shadow is present on CT scan. Until recently, the treatment of emphysematous gastritis has been immediate surgical intervention. However, there is a recent trend of avoiding surgery because of the frequent occurrence of post-operative complications such as anastomosis leakage. In addition, aggressive surgical treatment has failed to show significant improvement in prognosis. Recently, the authors experienced a case of emphysematous gastritis accompanied by portal venous gas which was treated successfully by conservative treatment without immediate surgical intervention. Herein, we present a case of emphysematous gastritis with concomitant portal venous air along with literature review.

  19. Venous thromboembolism: awareness and practice of ...

    African Journals Online (AJOL)

    MJP

    thromboprophylaxis among physicians in a tertiary-care hospital. Ekwere TA1* ... Background: Venous thromboembolism (VTE) is a major public health challenge globally due to its ... multicenter study conducted in Canada to determine the ...

  20. Clinical quality indicators of venous leg ulcers

    DEFF Research Database (Denmark)

    Kjaer, Monica L; Mainz, Jan; Soernsen, Lars T

    2005-01-01

    and reliable evidence-based quality indicators of venous leg ulcer care. A Scandinavian multidisciplinary, cross-sectional panel of wound healing experts developed clinical quality indicators on the basis of scientific evidence from the literature and subsequent group nominal consensus of the panel......%) were assessed for venous surgery. Distal arterial pressure was measured following initial examination in 33 of the patients (34%). All patients (100%) were prescribed compression therapy. Of the 98 patients, 11 (11%) had ulcers recur in 3 months and 72 (73%) healed in 12 months, which is in line......; an independent medical doctor tested the feasibility and reliability of these clinical indicators, assessing the quality of medical technical care on 100 consecutive venous leg ulcer patients. Main outcome measures were healing, recurrence, pain, venous disease diagnosis, differential diagnosis and treatment...

  1. Links between arterial and venous disease.

    Science.gov (United States)

    Prandoni, P

    2007-09-01

    An increasing body of evidence suggests the likelihood of a link between arterial and venous disease. According to the results of recent studies, atherosclerosis and venous thromboembolism (VTE) share common risk factors, including age, obesity, diabetes mellitus and metabolic syndrome. Atherosclerosis has the potential to promote the development of thrombotic disorders in the venous system. Another scenario assumes that the two clinical conditions are simultaneously triggered by biological stimuli responsible for activating coagulation and inflammatory pathways in both the arterial and the venous system. Several recent studies have consistently shown that patients with VTE of unknown origin are at a higher risk of cardiovascular diseases, including atherosclerotic complications, than patients with secondary VTE and matched control individuals. Future studies are needed to clarify the nature of this association, to assess its extent and to evaluate its implications for clinical practice.

  2. Current perspective of venous thrombosis in the upper extremity

    OpenAIRE

    Flinterman, L.E.; Meer, van der, D; Rosendaal, F.R.; Doggen, C. J. M.

    2008-01-01

    Venous thrombosis of the upper extremity is a rare disease. Therefore, not as much is known about risk factors, treatment and the risk of recurrence as for venous thrombosis of the leg. Only central venous catheters and strenuous exercise are commonly known risk factors for an upper extremity venous thrombosis. In this review an overview of the different risk factors, possible treatments and the complications for patients with a venous thrombosis of the upper extremity is given

  3. Why Current Doppler Ultrasound Methodology Is Inaccurate in Assessing Cerebral Venous Return: The Alternative of the Ultrasonic Jugular Venous Pulse

    Directory of Open Access Journals (Sweden)

    Paolo Zamboni

    2016-01-01

    Full Text Available Assessment of cerebral venous return is growing interest for potential application in clinical practice. Doppler ultrasound (DUS was used as a screening tool. However, three meta-analyses of qualitative DUS protocol demonstrate a big heterogeneity among studies. In an attempt to improve accuracy, several authors alternatively measured the flow rate, based on the product of the time average velocity with the cross-sectional area (CSA. However, also the quantification protocols lacked of the necessary accuracy. The reasons are as follows: (a automatic measurement of the CSA assimilates the jugular to a circle, while it is elliptical; (b the use of just a single CSA value in a pulsatile vessel is inaccurate; (c time average velocity assessment can be applied only in laminar flow. Finally, the tutorial describes alternative ultrasound calculation of flow based on the Womersley method, which takes into account the variation of the jugular CSA overtime. In the near future, it will be possible to synchronize the electrocardiogram with the brain inflow (carotid distension wave and with the outflow (jugular venous pulse in order to nicely have a noninvasive ultrasound picture of the brain-heart axis. US jugular venous pulse may have potential use in neurovascular, neurocognitive, neurosensorial, and neurodegenerative disorders.

  4. Why Current Doppler Ultrasound Methodology Is Inaccurate in Assessing Cerebral Venous Return: The Alternative of the Ultrasonic Jugular Venous Pulse.

    Science.gov (United States)

    Zamboni, Paolo

    2016-01-01

    Assessment of cerebral venous return is growing interest for potential application in clinical practice. Doppler ultrasound (DUS) was used as a screening tool. However, three meta-analyses of qualitative DUS protocol demonstrate a big heterogeneity among studies. In an attempt to improve accuracy, several authors alternatively measured the flow rate, based on the product of the time average velocity with the cross-sectional area (CSA). However, also the quantification protocols lacked of the necessary accuracy. The reasons are as follows: (a) automatic measurement of the CSA assimilates the jugular to a circle, while it is elliptical; (b) the use of just a single CSA value in a pulsatile vessel is inaccurate; (c) time average velocity assessment can be applied only in laminar flow. Finally, the tutorial describes alternative ultrasound calculation of flow based on the Womersley method, which takes into account the variation of the jugular CSA overtime. In the near future, it will be possible to synchronize the electrocardiogram with the brain inflow (carotid distension wave) and with the outflow (jugular venous pulse) in order to nicely have a noninvasive ultrasound picture of the brain-heart axis. US jugular venous pulse may have potential use in neurovascular, neurocognitive, neurosensorial, and neurodegenerative disorders.

  5. A novel approach for assessing the progression of deep venous thrombosis by area of venous thrombus in ultrasonic elastography.

    Science.gov (United States)

    Wang, Chao; Wang, Lei; Zhang, Yuhui; Chen, Ming

    2014-04-01

    Exact age determination of deep venous thrombosis (DVT) is important for an appropriate treatment. The purpose of this present study is to assess the age of acute DVT with the area of venous thrombi in elasticity imaging during the thrombosis procession. The thrombus area is obtained from a specially designed program. It was applied to clot specimens induced in human great saphenous (n = 15) at selected time points following the initiation of thrombosis. The relative mean proportion of blood clots was 50.01% ± 12.44% at day 1; 69.94% ± 8.19% at day 3; 81.93% ± 6.15% at day 6; and 92.37% ± 4.06% at day 9. The results indicated that the thrombus area increased significantly over time, while the normalized strain values inside the thrombus changed only a little. The pathological analyses also showed the same results. Therefore, we conclude that the area of venous thrombi in elasticity imaging may be a novel function for acute DVT staging.

  6. Entrapment of guidewire during central venous catheterization

    Directory of Open Access Journals (Sweden)

    Tarun S.

    2016-07-01

    Full Text Available Central venous catheterization (CVC is common in the setting of ICU for various reasons like monitoring of CVP, fluid administration and vasopressor or drug infusions. Guidewires are routinely used in the Seldinger technique during central venous catheter placement CVC placement is not innocuous as numerous complications may occur, with varying frequency and severity. [Int J Res Med Sci 2016; 4(7.000: 3080-3081

  7. Prospects of Jugular Venous Pulse Assessment

    Directory of Open Access Journals (Sweden)

    M D Bhattarai

    2010-09-01

    Full Text Available There is no controversy regarding the current clinical method of examination of waveform of jugular vein pulse. However there are limitations of clinical assessment of central venous pressure by jugular vein pressure measurement from the level of sternal angle. There are variations in the reported distances from sternal angle to right atrium as well as to upper limit of JVP. In erect position, anterior end of fourth intercostal space is at about the level of mid-right atrium. In patients with visible JVP at neck in erect position, measurement of CVP can be done more accurately directly from the anterior end of fourth intercostal space. For others, the position of mid-right atrium can be marked in lateral chest wall first in erect position at the mid-point of an anteroposterior line from anterior end of fourth intercostal space to back. Subsequently in reclining position, the vertical height of venous pressure can be measured from the horizontal plane of the midpoint marked at lateral chest wall to visible upper limit of JVP. Such measurement can be done in a more reliable way with venous pressure (VP manometer with its indicator rod at the horizontal plane of mid-right atrium and with its horizontal surface at upper limit of JVP. The venous pressure manometer can also be used to measure relatively less reliable upper limb venous pressure (ULVP, as indicated by the vertical distance at which veins of upper limb collapse, especially when JVP is not visualized due to subnormal CVP as in hypovolemia. Keywords: CVP, JVP, right atrium, sternal angle, upper limp venous pressure, venous pressure, venous pressure manometer

  8. BOARD-INVITED REVIEW: Efficiency of converting digestible energy to metabolizable energy and reevaluation of the California Net Energy System maintenance requirements and equations for predicting dietary net energy values for beef cattle.

    Science.gov (United States)

    Galyean, M L; Cole, N A; Tedeschi, L O; Branine, M E

    2016-04-01

    For the past several decades, nutrient requirement systems for beef cattle in North America have recommended that dietary ME can be calculated as dietary DE × 0.82, but considerable published data suggest a variable relationship between DE and ME. We reviewed the literature and tabulated the results of 23 respiration calorimetry studies (87 treatment mean data points), in which measurements of fecal, urinary, and gaseous energy were determined with beef cattle (bulls, steers, and heifers) and growing dairy cattle. Mixed-model regression analyses to adjust for the effects of the citation from which the data were obtained suggested a strong linear relationship between ME and DE (Mcal/kg of DM; ME = 0.9611 × DE - 0.2999; = 0.986, root mean square error [RMSE] = 0.048, California Net Energy System (CNES) for beef cattle by recalculating ME intake and heat production and regressing the logarithm of heat production on ME intake (both per BW, kg daily). The resulting intercept and slope of the recalculated data did not differ ( ≥ 0.34) from those reported for the original analyses of the CNES data, suggesting that use of the linear equation for calculating ME concentration was consistent with NEm and NEg values as derived in the CNES. Nonetheless, because the cubic equations recommended by the NRC to calculate dietary NEm and NEg from ME were based on conversion of DE to ME using 0.82, these equations were mathematically recalculated to account for the linear relationship between DE and ME. Overall, our review and analyses suggested that there is a strong linear relationship between DE and ME, which seems to be consistent across a wide range of dietary conditions, cattle types, and levels of intake. Applying this linear relationship to predict ME concentrations agreed with the original CNES calculations for NE requirements, thereby allowing the development of new equations for predicting dietary NEm and NEg values from ME.

  9. Radiation tolerant power converter controls

    CERN Document Server

    Todd, B; King, Q; Uznanski, S

    2012-01-01

    The Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN) is the world's most powerful particle collider. The LHC has several thousand magnets, both warm and super-conducting, which are supplied with current by power converters. Each converter is controlled by a purpose-built electronic module called a Function Generator Controller (FGC). The FGC allows remote control of the power converter and forms the central part of a closed-loop control system where the power converter voltage is set, based on the converter output current and magnet-circuit characteristics. Some power converters and FGCs are located in areas which are exposed to beam-induced radiation. There are numerous radiation induced effects, some of which lead to a loss of control of the power converter, having a direct impact upon the accelerator's availability. Following the first long shut down (LS1), the LHC will be able to run with higher intensity beams and higher beam energy. This is expected to lead to signifi...

  10. Power converter simulation and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ghazy, M.A.

    1989-01-01

    There has been a great deal of progress made in computer aided design and analysis in the power electronic field. Many of the simulation packages are inefficient and time consuming in simulating switching converters. This thesis proposes an efficient, simple, general simulation approach to simulate any power converter with less computation time and space requirements on computer. In this approach the equations of power converters are formulated using network topology. In this thesis several procedures have been explained for the steady-state computation of power electronic circuits. Also, the steady-state analyses have been accomplished by a new technique called Fourier series method. For a complete system consisting of converters, filters, and electric machines, the simulation is complicated if a frequency domain technique is used. This thesis introduces a better technique which decouples the system into subsystems and simulates it in the time domain. The design of power converters using optimization techniques is presented in this thesis. Finally, the theory of Variable Structured Systems has been applied to power converters. Sliding mode control for DC-DC and DC-AC power converters is introduced as a tool to accomplish desired characteristics.

  11. Microcirculation and venous ulcers: a review.

    Science.gov (United States)

    Pascarella, Luigi; Schönbein, Geert W Schmid; Bergan, John J

    2005-11-01

    Recent histological and immunocytochemical analyses of venous leg ulcers suggest that lesions observed in the different stages of chronic venous insufficiency (CVI) may be related to an inflammatory process. This inflammatory process leads to fibrosclerotic remodeling of the skin and then to ulceration. The vascular network of the most superficial layers of the skin appears to be the target of the inflammatory reaction. Hemodynamic forces such as venous hypertension, circulatory stasis, and modified conditions of shear stress appear to play an important role in an inflammatory reaction accompanied by leukocyte activation which clinically leads to CVI: venous dermatitis and venous ulceration. The leukocyte activation is accompanied by the expression of integrins and by synthesis and release of many inflammatory molecules, including proteolytic enzymes, leukotrienes, prostaglandin, bradykinin, free oxygen radicals, cytokines, and possibly other classes of inflammatory mediators. The inflammatory reaction perpetuates itself, leading to liposclerotic skin and subcutaneous tissue remodeling. In light of the mechanisms of venous ulcer formation cited above, therapy in the future might be directed against leukocyte activation in order to diminish the magnitude of the inflammatory response. With this in mind, the attention of many investigators has been drawn to two different drugs with an anti-inflammatory effect: pentoxifylline and flavonoids.

  12. The chronic cerebrospinal venous insufficiency syndrome.

    Science.gov (United States)

    Zamboni, P; Galeotti, R

    2010-12-01

    Chronic cerebrospinal venous insufficiency (CCSVI) is a syndrome characterized by stenosies of the internal jugular and/or azygous veins (IJVs-AZ) with opening of collaterals and insufficient drainage proved by reduced cerebral blood flow and increased mean transit time in cerebral MRI perfusional study. The present review is aimed to give a comprehensive overview of the actual status of the art of the diagnosis and treatment of this condition. As far as the origin of venous narrowing is concerned, phlebographic studies of the IJVs and AZ systems demonstrated that venous stenoses were likely to be truncular venous malformations; mostly, they are intraluminal defects such as malformed valve, septa webs. CCSVI condition has been found to be strongly associated with multiple sclerosis (MS), a disabling neurodegenerative and demyelinating disease considered autoimmune in nature. In several epidemiological observations performed at different latitudes on patients with different genetic backgrounds, the prevalence of CCSVI in MS ranges from 56% to 100%. To the contrary, by using venous MR and/or different Doppler protocols, CCSVI was not detected with the same prevalence. Two pilot studies demonstrated the safety and feasibility in Day Surgery of the endovascular treatment of CCSVI by means of balloon angioplasty (PTA). It determines a significant reduction of postoperative venous pressure. Restenosis rate was found out elevated in the IJVs, but negligible in the AZ. However, PTA seems to positively influence clinical and QoL parameters of the associated MS and warrants further randomized control trials.

  13. What happens after venous thromboembolism?

    Science.gov (United States)

    Baglin, T

    2009-07-01

    Venous thromboembolism (VTE) comprises deep vein thrombosis (DVT) with or without symptomatic pulmonary embolus (PE). The incidence of a first episode of VTE is 1.5 per 1000 person-years [1] (J Thromb Haemost, 2007;5:692-9) with a per-person lifetime incidence of 5% [2] (Arch Intern Med 1998;158:585-93). The risk of recurrence after DVT and PE is similar but the pattern of recurrence tends to reflect the initial event, for example recurrence with PE is more common in patients with previous PE [3] (Circulation 2003;107:122-30). At least 50% of patients, who present with symptomatic DVT, have asymptomatic PE and conversely, a majority presenting with symptomatic PE have asymptomatic DVT [3] (Circulation 2003;107:122-30). This suggests that whilst DVT and PE are manifestations of the same pathology, the phenotypic expression of the disease is predetermined. This may be an important consideration for long-term anticoagulant therapy as the risk of fatal PE is the greatest in patients with previous PE [4] (Ann Intern Med 2007;147:766-74). At present, the only factor reported to be associated with the pattern of VTE is the factor V Leiden mutation [5] (Thromb Haemost 1999;81:345-8). This suggests that the kinetics of thrombin generation and the resulting fibrinolytic response may influence clot structure and likelihood of embolization.

  14. Venous catheterization with ultrasound navigation

    Science.gov (United States)

    Kasatkin, A. A.; Urakov, A. L.; Nigmatullina, A. R.

    2015-11-01

    By ultrasound scanning it was determined that respiratory movements made by chest of healthy and sick person are accompanied by respiratory chest rise of internal jugular veins. During the exhalation of an individual diameter of his veins increases and during the breath it decreases down to the complete disappearing if their lumen. Change of the diameter of internal jugular veins in different phases can influence significantly the results of vein puncture and cauterization in patients. The purpose of this research is development of the method increasing the efficiency and safety of cannulation of internal jugular veins by the ultrasound visualization. We suggested the method of catheterization of internal jugular veins by the ultrasound navigation during the execution of which the puncture of venous wall by puncture needle and the following conduction of J-guide is carried out at the moment of patient's exhalation. This method decreases the risk of complications development during catheterization of internal jugular vein due to exclusion of perforating wound of vein and subjacent tissues and anatomical structures.

  15. Venous catheterization with ultrasound navigation

    Energy Technology Data Exchange (ETDEWEB)

    Kasatkin, A. A., E-mail: ant-kasatkin@yandex.ru; Nigmatullina, A. R. [Izhevsk State Medical Academy, Kommunarov street, 281, Izhevsk, Russia, 426034 (Russian Federation); Urakov, A. L., E-mail: ant-kasatkin@yandex.ru [Institute of Mechanics Ural Branch of Russian Academy of Sciences, T.Baramzinoy street 34, Izhevsk, Russia, 426067, Izhevsk (Russian Federation); Izhevsk State Medical Academy, Kommunarov street, 281, Izhevsk, Russia, 426034 (Russian Federation)

    2015-11-17

    By ultrasound scanning it was determined that respiratory movements made by chest of healthy and sick person are accompanied by respiratory chest rise of internal jugular veins. During the exhalation of an individual diameter of his veins increases and during the breath it decreases down to the complete disappearing if their lumen. Change of the diameter of internal jugular veins in different phases can influence significantly the results of vein puncture and cauterization in patients. The purpose of this research is development of the method increasing the efficiency and safety of cannulation of internal jugular veins by the ultrasound visualization. We suggested the method of catheterization of internal jugular veins by the ultrasound navigation during the execution of which the puncture of venous wall by puncture needle and the following conduction of J-guide is carried out at the moment of patient’s exhalation. This method decreases the risk of complications development during catheterization of internal jugular vein due to exclusion of perforating wound of vein and subjacent tissues and anatomical structures.

  16. PWM DC/DC Converter

    OpenAIRE

    Chen, Juan

    2008-01-01

    This report is the result of a Master Thesis work done at Seaward Electronics Inc. in Beijing, China from June to December in 2007. The main goal for this thesis is to verify and improve the performance of Honey-PWM DC-DC converter, which has been fabricated by a standard 0.6um CMOS processes. The project was started with studying of Buck converter structure. After the understanding of the converter structure, the project goes in to the analyses phase for each sub-cells, including the theory,...

  17. Computer-assisted venous thrombosis volume quantification.

    Science.gov (United States)

    Puentes, John; Dhibi, Mounir; Bressollette, Luc; Guias, Bruno; Solaiman, Basel

    2009-03-01

    Venous thrombosis (VT) volume assessment, by verifying its risk of progression when anticoagulant or thrombolytic therapies are prescribed, is often necessary to screen life-threatening complications. Commonly, VT volume estimation is done by manual delineation of few contours in the ultrasound (US) image sequence, assuming that the VT has a regular shape and constant radius, thus producing significant errors. This paper presents and evaluates a comprehensive functional approach based on the combination of robust anisotropic diffusion and deformable contours to calculate VT volume in a more accurate manner when applied to freehand 2-D US image sequences. Robust anisotropic filtering reduces image speckle noise without generating incoherent edge discontinuities. Prior knowledge of the VT shape allows initializing the deformable contour, which is then guided by the noise-filtering outcome. Segmented contours are subsequently used to calculate VT volume. The proposed approach is integrated into a system prototype compatible with existing clinical US machines that additionally tracks the acquired images 3-D position and provides a dense Delaunay triangulation required for volume calculation. A predefined robust anisotropic diffusion and deformable contour parameter set enhances the system usability. Experimental results pertinence is assessed by comparison with manual and tetrahedron-based volume computations, using images acquired by two medical experts of eight plastic phantoms and eight in vitro VTs, whose independently measured volume is the reference ground truth. Results show a mean difference between 16 and 35 mm(3) for volumes that vary from 655 to 2826 mm(3). Two in vivo VT volumes are also calculated to illustrate how this approach could be applied in clinical conditions when the real value is unknown. Comparative results for the two experts differ from 1.2% to 10.08% of the smallest estimated value when the image acquisition cadences are similar.

  18. M RI在诊断退变期脑实质型脑囊虫病同小转移瘤的鉴别价值%Value of convertional MRI in detecting degenerative phase of cerebral cysticerlosis and small metastases

    Institute of Scientific and Technical Information of China (English)

    王立源; 曾睿; 黄红芳; 张雪; 侯仲军

    2014-01-01

    目的:通过常规M RI序列与DWI序列,鉴别退变期脑实质型脑囊虫病与小病灶环形强化转移瘤。方法回顾29例脑囊虫病患者与30例多发小病灶转移瘤患者的M R检查,观察两者的影像学表现及测量ADC值进行统计学处理。结果常规T2 WI退变期脑囊虫病组和小转移瘤组病灶出现低信号环的比例分别为91.9%和9.1%,诊断敏感性为90.7%(78/86)、特异性90.9%(60/66)、准确性90.8%(138/152);DWI退变期脑囊虫病组和转移瘤组病灶出现低信号所占比例分别为95.4%和69.7%,诊断敏感性95.4%(82/86)、特异性30.3%(20/66)、准确性67.1%(102/152)。退变期脑囊虫组病灶ADC值(1.54±0.42)×10-3 s/mm2,脑转移瘤病灶组ADC值(1.12±0.36)×10-3 s/mm2,两者比较具有统计学差异( P <0.01)。结论 T2 WI病灶周围连续的低信号和完整规则的环形强化是退变期脑囊虫病的特殊表现。DWI序列对退变期脑囊虫病和小病灶转移瘤的鉴别具有一定的价值。%Objective To study the difference of degeno-death stage cerebral neurocysticercosis lesions and brain metas-tasis nodules through the conventional MR scan and DWI sequence .Methods MRI data of 29 patients with degeno-death stage cerebral neurocysticercosis and 30 patients with brain metastasis were reviewed .The imaging features were studied and the ADC value of the lesions ,were measured with spss 16 .0 statistical software as data analysis .Results 91 .9% le-sions of degeno-death stage cerebral nerocyticercosis displayed surrounding hypointense signal on T 2 WI ,while ,the brain metastasis nodules was 9 .1% .The diagnostic sensitivety ,specificity and accuracy of T2WI low signal intensity surround-ing were 90 .7% (78/86) ,90 .9% (60/66) and 90 .8% (138/152) respectively .Among those ,95 .4% lesions of degeno-death stage cerebral nerocyticercosis were shown hypointense signal on

  19. New Multiphase Hybrid Boost Converter with Wide Conversion Ratio for PV System

    Directory of Open Access Journals (Sweden)

    Ioana-Monica Pop-Calimanu

    2014-01-01

    Full Text Available A new multiphase hybrid boost converter, with wide conversion ratio as a solution for photovoltaic energy system, is presented in this paper. To ensure that all the phases of the converter operate at the same switching frequency we use interleaving topology. The proposed converter can be used as an interface between the PV system and the DC load/inverter. This multiphase converter has the advantage of reduced value and physical size of the input and output capacitor as well as the effort for the inductors. To validate the operation of the converter we provide the analyses and the simulation results of the converter.

  20. A Variational Inequality from Pricing Convertible Bond

    Directory of Open Access Journals (Sweden)

    Yan Huiwen

    2011-01-01

    Full Text Available The model of pricing American-style convertible bond is formulated as a zero-sum Dynkin game, which can be transformed into a parabolic variational inequality (PVI. The fundamental variable in this model is the stock price of the firm which issued the bond, and the differential operator in PVI is linear. The optimal call and conversion strategies correspond to the free boundaries of PVI. Some properties of the free boundaries are studied in this paper. We show that the bondholder should convert the bond if and only if the price of the stock is equal to a fixed value, and the firm should call the bond back if and only if the price is equal to a strictly decreasing function of time. Moreover, we prove that the free boundaries are smooth and bounded. Eventually we give some numerical results.

  1. Analysis of central venous pressure (CVP) signals using mathematical methods.

    Science.gov (United States)

    Atefvahid, Parham; Hassani, Kamran; Jafarian, Kamal; Doyle, D John; Ahmadi, Hessam

    2017-06-01

    Central venous pressure (CVP) is an important clinical parameter for physicians but only the absolute CVP value is typically monitored in the intensive care unit (ICU). In this study, we propose a novel mathematical method to present and analyze CVP signals. A total of 44 suitable samples were chosen from a total of 65 collected in an ICU. Pre-processing of the samples included rate reduction and digital filtering. The statistical features of time and frequency domain, wavelet, and empirical mode decomposition of these signals were extracted. We found no significant difference among the CVP signals regarding sex, smoking, coronary disease, and respiration mode of the samples.

  2. Laser system with wavelength converter

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention relates to an apparatus comprising a diode laser (10) providing radiation in a first wavelength interval, a radiation conversion unit (12) having an input and an output, the radiation converter configured to receive the radiation in the first wavelength interval from the diode...... laser at the input, the radiation conversion unit configured to convert the radiation in the first wavelength interval to radiation in a second wavelength interval and the output configured to output the converted radiation, the second wavelength interval having one end point outside the first...... wavelength interval. Further, the invention relates to a method of optically pumping a target laser (14) in a laser system, the laser system comprising a laser source providing radiation at a first frequency, the laser source being optically connected to an input of a frequency converter, the frequency...

  3. Time-to-digital converters

    CERN Document Server

    Henzler, Stephan

    2010-01-01

    This text covers the fundamentals of time-to-digital converters on analog and digital conversion principles. It includes a theoretical investigation into quantization, linearity, noise and variability, and it details a range of advanced TDC architectures.

  4. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriette; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michael A.; Spronk, Peter E.

    2012-01-01

    Objective:  The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design:  Prospective observational controlled study. Setting:  Nonacademic university-affiliated t

  5. Boron nitride converted carbon fiber

    Science.gov (United States)

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  6. Photoelectric converters with quantum coherence

    OpenAIRE

    Su, Shan-He; Sun, Chang-Pu; Li, Sheng-Wen; Chen, Jin-Can

    2016-01-01

    Photon impingement is capable of liberating electrons in electronic devices and driving the electron flux from the lower chemical potential to higher chemical potential. Previous studies hinted that the thermodynamic efficiency of a nano-sized photoelectric converter at maximum power is bounded by the Curzon-Ahlborn efficiency. In this study, we apply quantum effects to design a photoelectric converter based on a three-level quantum dot (QD) interacting with fermionic baths and photons. We sh...

  7. Radiation tolerant power converter controls

    Science.gov (United States)

    Todd, B.; Dinius, A.; King, Q.; Uznanski, S.

    2012-11-01

    The Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN) is the world's most powerful particle collider. The LHC has several thousand magnets, both warm and super-conducting, which are supplied with current by power converters. Each converter is controlled by a purpose-built electronic module called a Function Generator Controller (FGC). The FGC allows remote control of the power converter and forms the central part of a closed-loop control system where the power converter voltage is set, based on the converter output current and magnet-circuit characteristics. Some power converters and FGCs are located in areas which are exposed to beam-induced radiation. There are numerous radiation induced effects, some of which lead to a loss of control of the power converter, having a direct impact upon the accelerator's availability. Following the first long shut down (LS1), the LHC will be able to run with higher intensity beams and higher beam energy. This is expected to lead to significantly increased radiation induced effects in materials close to the accelerator, including the FGC. Recent radiation tests indicate that the current FGC would not be sufficiently reliable. A so-called FGClite is being designed to work reliably in the radiation environment in the post-LS1 era. This paper outlines the concepts of power converter controls for machines such as the LHC, introduces the risks related to radiation and a radiation tolerant project flow. The FGClite is then described, with its key concepts and challenges: aiming for high reliability in a radiation field.

  8. Transformerless dc-Isolated Converter

    Science.gov (United States)

    Rippel, Wally E.

    1987-01-01

    Efficient voltage converter employs capacitive instead of transformer coupling to provide dc isolation. Offers buck/boost operation, minimal filtering, and low parts count, with possible application in photovoltaic power inverters, power supplies and battery charges. In photovoltaic inverter circuit with transformerless converter, Q2, Q3, Q4, and Q5 form line-commutated inverter. Switching losses and stresses nil because switching performed when current is zero.

  9. Wave energy converter test application

    OpenAIRE

    Hottola, Niko

    2016-01-01

    This thesis was made for wave energy company Wello Oy. Given assignment was to find the suitable generator and frequency converter for a wave energy converter test application. The primary objective was to find a suitable generator for direct drive, in order to avoid the weight of the test application rising too high. In this thesis the possible machine types for test application are presented and what are their advenatages and disadvantages. In addition, the operation of the frequency co...

  10. Pharmacologic treatment of venous leg ulcers.

    Science.gov (United States)

    Dormandy, J A

    1995-01-01

    In terms of prevalence, total cost and morbidity, venous leg ulcers are probably by far the most important type of ulcerations in the leg. The macrocirculatory defect leading to a raised ambulatory venous pressure is now accepted as a common initial pathologic pathway. Most current treatment modalities, such as surgery or external compression, are designed to control the macrovascular defect. However, it is the microcirculatory consequences of the venous hypertension that give rise to the trophic skin changes and ultimately to ulceration. At this microcirculatory level, pharmacotherapy may be a useful adjunct in the treatment of venous leg ulcers. The microcirculatory pathophysiologic changes include decreased fibrinolytic activity, elevated plasma fibrinogen, microcirculatory thrombi, and inappropriate activation of the white blood cells. The oxidative burst from the activated white cells probably plays a key role by releasing locally leukocyte-derived free radicals, proteolytic enzymes, cytokines, platelet-activating factor, and a number of other noxious mediators. An important additional component in recalcitrant venous ulcers is co-existing arterial disease, which is probably present in 15-20% of cases. Decreased arterial perfusion pressure will further aggravate the ischemic changes caused by the venous hypertension. Pentoxifylline downregulates leukocyte activation, reduces leukocyte adhesion, and also has fibrinolytic effects. A number of clinical studies have therefore been carried out to examine the clinical efficacy of pentoxifylline in treatment of venous leg ulcers. Probably the largest published placebo-controlled, double-blind randomized study was reported in 1990. In this study, 80 patients received either pentoxifylline 400 mg three times a day orally or matching placebo for 6 months or until their reference ulcer healed if this occurred sooner. Complete healing of the reference ulcer occurred in 23 of the 38 patients treated with pentoxifylline

  11. 连续性血液滤过在肝移植术后并发急性肾功能衰竭中的治疗价值%The therapeutic value of continuous veno-venous hemofiltration in acute renal failure after liver transplantation

    Institute of Scientific and Technical Information of China (English)

    沈清; 梁少梅; 甘华; 杜小刚; 李正荣

    2011-01-01

    Objective To evaluate the therapeutic value of continuous veno venous hemofiltration(CVVH) in the treatment of acute renal failure(ARF) after liver transplantation. Methods 22 patients with ARF after liver transplantation were treated with CVVH. Their vital signs, hemodynamic, hepatic and renal functions, sera electrolyte, blood gas analysis, thromboxane function and blood platelet count were compared before and after the treatment. The mortality was observed and the efficacy and safety of the treatment were evaluated. Results After CVVH,the vital signs and hemodynamic were irnproved(P<0. 05) ;serum BUN, Ct, TB and DB were significantly decreased (P<0. 05); hyperkalemia, hyponatremia and metabolic acidosis were corrected(P<0. 05). But there were no remarkable changes in coagulogram and blood platelet count before and after the treatment(P>0. 05). The mortality was to some extent reduced. During the treatment of CVVH, the survivability of the patients was good, without obvious side effects. Conclusion CVVH is an effective and safe treatment for patients with acute renal failure after liver transplantation.%目的 探讨连续性静脉-静脉血液滤过(CVVH)对肝移植术后并发急性肾功能衰竭的临床应用价值.方法 应用CVVH对该院的22例肝移植术后并发急性肾功能衰竭的患者进行治疗,比较治疗前、后患者的生命体征,血流动力学,肾、肝功能,电解质,动脉血气分析,凝血象,血小板计数的变化,并观察其病死率,以评价CVVH的治疗效果及不良反应.结果 CVVH治疗后患者生命体征和血流动力学平稳(P0.05);患者病死率有所下降.CVVH治疗过程中,患者耐受性好,无明显不良反应.结论 CVVH是肝移植术后并发急性肾功能衰竭的有效治疗方法之一.

  12. [Correlation between arterial and venous blood gas analysis parameters in patients with acute exacerbation of chronic obstructive pulmonary disease].

    Science.gov (United States)

    Novović, Miloš; Topić, Vesna

    2012-01-01

    Arterial blood gas (ABG) analyses have an important role in the assessment and monitoring of the metabolic and oxygen status of patients with acute exacerbation of chronic obstructive pulmonary disease (COPD). Arterial puncture could have a lot of adverse effects, while sampling of venous blood is simpler and is not so invasive. The aim of this study was to evaluate whether venous blood gas (VBG) values of pH, partial pressure of carbon dioxide (PCO2), partial oxygen pressure (PO2), bicarbonate (HCO3), and venous and arterial blood oxygen saturation (SO2) can reliably predict ABG levels in patients with acute exacerbation of COPD. Forty-seven patients with a prior diagnosis of COPD were included in this prospective study. The patients with acute exacerbation of this disease were examined at the General Hospital EMS Department in Prijepolje. ABG samples were taken immediately after venous sampling, and both were analyzed. The Pearson correlation coefficients between arterial and venous parameters were 0.828, 0.877, 0.599, 0.896 and 0.312 for pH, PCO2, PO2, HCO3 and SO2, respectively. The statistically significant correlation between arterial and venous pH, PCO2 and HCO3, values was found in patients with acute exacerbation of COPD (parterial blood for analysis, venous values of the pH, Pv,CO2 and HCO3 parameters can be an alternative to their arterial equivalents in the interpretation of the metabolic status in patients with acute exacerbation of COPD, while the values of venous Pv,O, and Sv,O2 cannot be used as predictors in the assessment of oxygen status of such patients.

  13. Correlation between arterial and venous blood gas analysis parameters in patients with acute exacerbation of chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Novović Miloš

    2012-01-01

    Full Text Available Introduction. Arterial blood gas (ABG analyses have an important role in the assessment and monitoring of the metabolic and oxygen status of patients with acute exacerbation of chronic obstructive pulmonary disease (COPD. Arterial puncture could have a lot of adverse effects, while sampling of venous blood is simpler and is not so invasive. Objective. The aim of this study was to evaluate whether venous blood gas (VBG values of pH, partial pressure of carbon dioxide (PCO2, partial oxygen pressure (PO2, bicarbonate (HCO3, and venous and arterial blood oxygen saturation (SO2 can reliably predict ABG levels in patients with acute exacerbation of COPD. Methods. Forty-seven patients with a prior diagnosis of COPD were included in this prospective study. The patients with acute exacerbation of this disease were examined at the General Hospital EMS Department in Prijepolje. ABG samples were taken immediately after venous sampling, and both were analyzed. Results. The Pearson correlation coefficients between arterial and venous parameters were 0.828, 0.877, 0.599, 0.896 and 0.312 for pH, PCO2, PO2, HCO3 and SO2, respectively. The statistically significant correlation between arterial and venous pH, PCO2 and HCO3, values was found in patients with acute exacerbation of COPD (p<0.001. Conclusion. When we cannot provide arterial blood for analysis, venous values of the pH, Pv,CO2 and HCO3 parameters can be an alternative to their arterial equivalents in the interpretation of the metabolic status in patients with acute exacerbation of COPD, while the values of venous Pv,O2 and Sv,O2 cannot be used as predictors in the assessment of oxygen status of such patients.

  14. CT and MR imaging of non-cavernous cranial dural arteriovenous fistulas: Findings associated with cortical venous reflux

    Energy Technology Data Exchange (ETDEWEB)

    Letourneau-Guillon, Laurent; Cruz, Juan Pablo; Krings, Timo, E-mail: Timo.Krings@uhn.ca

    2015-08-15

    Highlights: • The conventional neuroimaging manifestations of dural arteriovenous fistulas are highly variable. • Identification of cortical venous reflux is important to prevent complications. • Tortuous and dilated vessels without a nidus are associated with cortical venous reflux. • Digital subtraction angiography remains the gold standard for DAVF diagnosis. - Abstract: Purpose: To compare the conventional CT and MR findings of DAVFs in relation to the venous drainage pattern on digital subtraction angiography (DSA). Materials and Methods: Cross-sectional imaging findings (CT and/or MR) in 92 patients were compared to the presence of cortical venous reflux (CVR) on DSA. Results: Imaging features significantly more prevalent in patients with CVR included: abnormally dilated and tortuous leptomeningeal vessels (92% vs. 4%, p < 0.001) or medullary vessels (69% vs. 0%, p < 0.001), venous ectasias (45% vs. 0%, p < 0.001) and focal vasogenic edema (38% vs. 0%, p < 0.001). The following findings trended towards association but did not reach the p value established following Bonferroni correction: dilated external carotid artery branches (71% vs. 38%, p = 0.005), cluster of vessels surrounding dural venous sinus (50% vs. 19%, p = 0.009), presence of hemorrhage (33 vs. 12%, p = 0.040), and parenchymal enhancement (21% vs. 0%, p = 0.030). Conclusion: In the appropriate clinical setting, recognition of ancillary signs presumably related to venous arterialization and congestion as well as arterial feeder hypertrophy should prompt DSA confirmation to identify DAVFs associated with CVR.

  15. Familial risk of venous thromboembolism: a nationwide cohort study

    DEFF Research Database (Denmark)

    Sørensen, H T; Riis, A H; Diaz, L J

    2011-01-01

    Background: Venous thromboembolism has genetic determinants, but population-based data on familial risks are limited. Objectives: To examine the familial risk of venous thromboembolism. Methods: We undertook a nationwide study of a cohort of patients with deep venous thrombosis or pulmonary...... and expected number of venous thromboembolism cases among siblings, using population-specific, gender-specific and age-specific incidence rates. Results: We identified 30 179 siblings of 19 599 cases of venous thromboembolism. The incidence among siblings was 2.2 cases per 1000 person-years, representing...... with pulmonary embolism. Conclusion: Venous thromboembolism has a strong familial component....

  16. Venous injury in abusive head trauma

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, Arabinda K. [Nemours A. I. duPont Hospital for Children, Department of Radiology, Wilmington, DE (United States); Bradford, Ray; Thamburaj, K.; Boal, Danielle K.B. [Hershey Medical Center, Department of Radiology, Hershey, PA (United States); Dias, Mark S. [Hershey Medical Center, Department of Neurosurgery, Hershey, PA (United States)

    2015-11-15

    Abusive head trauma (AHT) is an important cause of serious brain injury in infants and young children who have characteristic clinical and imaging findings that are discordant with the clinical history provided. Recent attention has focused on abnormalities of the cranial venous sinuses and cortical veins, both on MRI and at autopsy. Although many have interpreted these to be secondary to the AHT, some have recently argued that these venous abnormalities represent primary cortical sinus and venous thrombosis that leads secondarily to subdural hemorrhage and secondary brain injury. Direct trauma to the veins and sinuses has been reported at autopsy in AHT, but there has been no systematic study of venous abnormalities in cases of AHT. The purpose of this study was to define the incidence and characteristics of venous and sinus abnormalities in AHT. We included all children <36 months of age who were diagnosed with abusive head trauma between 2001 and 2012 and who had MRI and magnetic resonance (MR) venography as part of their diagnostic workup. We analyzed age, gender and clinical findings. MRI and MR venography were analyzed independently by two neuroradiologists with a focus on abnormalities involving the intracranial veins and venous sinuses. A total of 45 children were included. The median age was 3 months (range 15 days to 31 months) and 28 were boys (62%). Clinical findings included retinal hemorrhage in 71% and extracranial fractures in 55%. CT or MRI demonstrated subdural hemorrhage in 41 (91%); none had subdural effusions. In 31 cases (69%) MR venography demonstrated mass effect on the venous sinuses or cortical draining veins, with either displacement or partial or complete effacement of the venous structures from an adjacent subdural hematoma or brain swelling. We also describe the lollipop sign, which represents direct trauma to the cortical bridging veins and was present in 20/45 (44%) children. Evidence of displacement or compression of cortical veins

  17. [The concentration of free lidocaine in arterial, central venous and peripheral vein plasma following intravenous injection].

    Science.gov (United States)

    Nolte, H; al Saydali, B; Weissenberg, W

    1990-03-01

    Ten intensive care patients and five healthy volunteers each received a bolus injection of lidocaine HCl (100 mg, 2%) over an injection period of 5 s. After 0.5, 1, 2, 4, 8, 15 and 25 min arterial, central venous and peripheral venous blood samples were collected. In four of the volunteers, arterial and central venous samples were also taken about 10 s after the end of injection. The fluorescence polarization method by means of the Abbott-TDx system was used, and plasma concentrations of lidocaine were determined. The measurements showed that lidocaine levels in central venous plasma 10 s after the end of administration were higher than those in arterial plasma. By 30 s after administration the opposite situation had developed, so that arterial concentrations were higher than those in central venous plasma. This relation did not change throughout the study, though the two levels became closer, as is shown by the ratios (Table 3, Fig. 2). Concentrations in peripheral venous plasma increased more slowly but remained far below those in arterial and central venous plasma, at least for the first 8 min. After 15 min lidocaine levels were almost the same in all three samples. During the entire study there were no ECG changes, and neither heart rate nor blood pressure showed any significant deviation from the values obtained at the beginning. The volunteers had minor toxic manifestations, such as dizziness, tinnitus and a metallic taste in the mouth; one person had a sensation of pressure in his chest, which improved following oxygen administration.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Binary/BCD-to-ASCII data converter

    Science.gov (United States)

    Miller, A. J.

    1977-01-01

    Converter inputs multiple precision binary words, converts data to multiple precision binary-coded decimal, and routes data back to computer. Converter base can be readily changed without need for new gate structure for each base changeover.

  19. Radiologic placement of tunneled central venous catheter

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, Seong Tae; Yang, Po Song; Yang, Dong Hunn; Kim, Ki Tae; Kim, Choon Yul; Shinn, Kyung Sub [The Catholic Univ. College of Medicine, Seoul (Korea, Republic of); Yun, Eun Joo [Korea Veterans Hospital, Seoul (Korea, Republic of)

    1996-01-01

    To evaluate the efficacy and safety of fluoroscopy-guided, radiologic placement of a tunneled central venous catheter into the superior vena cava (SVC). Thirty five patients underwent tunneled central venous catheter placement to facilitate long-term chemotherapy. They included 33 leukemic patients, one colon cancer patient, and one multiple myeloma patient. After confirming central venous patency with a injection of contrast media via the peripheral cephalic or basilic vein in the wrist joint, the subclavian vein was punctured under fluoroscopic guidance. A 7F double lumen TPN catheter was placed into the SVC through a subcutaneous tunnel in the anterior chest wall. Catheter placements were successful in all patients. The mean procedure time was 17.2minutes, mean fluooscopy time was 1.3minutes, mean number of punctures was 1.4, and mean volume of injhected contrast media was 43.5cc. Only two of all leukemic patients developed mild hematomas at the puncture site, but these soon resolved themselves. None of the patients developed pneumothorax or hemothorax. But late complications included local infection in two patients (6%) and thrombotic occlusion of the catheter in one (3%). The occluded catheter was successfully recanalized with Urokinase infusion. Fluoroscopy-guided, radiologic placement of a tunneled central venous catheter is an easy and safe method, and useful for patients requiring long-term venous access.

  20. The pricing of perpetual convertible bond with credit risk

    Institute of Scientific and Technical Information of China (English)

    WANG Le-le; BIAN Bao-jun

    2010-01-01

    Convertible bond gives holder the right to choose a conversion strategy to maximize the bond value,and issuer also has the right to minimize the bond value in order to maximize equity value.When there is default occurring,conversion and calling strategies are invalid.In the framework of reduced form model,we reduce the price of convertible bond to variational inequalities,and the coefficients of variational inequalities are unbounded at the original point.Then the existence and uniqueness of variational inequality are proven.Finally,we prove that the conversion area,the calling area and the holding area are connected subsets of the state space.

  1. PWM Converter Power Density Barriers

    Science.gov (United States)

    Kolar, Johann W.; Drofenik, Uwe; Biela, Juergen; Heldwein, Marcelo; Ertl, Hans; Friedli, Thomas; Round, Simon

    Power density of power electronic converters has roughly doubled every 10 years since 1970. Behind this trajectory is the continuous advancement of power semiconductor devices, which has increased the converter switching frequencies by a factor of 10 every decade. However, today's cooling concepts and passive components are major barriers for a continuation of this trend. To identify such technological barriers, this paper investigates the volume of the cooling system and passive components as a function of the switching frequency for power electronic converters and determines the switching frequency that minimizes the total volume. A power density limit of 28kW/dm3 at 300kHz is calculated for an isolated DC-DC converter, 44kW/dm3 at 820kHz for a three-phase unity power factor PWM rectifier, and 26kW/dm3 at 21kHz for a sparse matrix converter. For single-phase AC-DC conversion a general limit of 35kW/dm3 results from the DC link capacitor. These power density limits highlight the need to broaden the scope of power electronics research to include cooling systems, high frequency electromagnetics, interconnection and packaging technology, and multi-domain modelling and simulation to ensure further advancement along the power density trajectory.

  2. A classic learning opportunity from Arthur Guyton and colleagues (1955): circuit analysis of venous return.

    Science.gov (United States)

    Curran-Everett, Douglas

    2007-06-01

    The circuit analysis of an electric analog of the systemic circulation, the focus of a classic paper by Guyton, Lindsey, and Kaufmann, provides a framework for understanding the factors that impact venous return and for appreciating the value of modeling physiological systems. The classic 1955 paper by Guyton, Lindsey, and Kaufmann gives your students an opportunity to learn about modeling from the physiologist who pioneered it (Guyton) and demonstrates that mathematics and data graphics are fundamental tools with which to learn about the regulation of the cardiovascular system. In this essay, I outline avenues of discovery by which your students can explore the factors that impact venous return.

  3. [Heparan sulfate: efficacy and safety in patients with chronic venous insufficiency].

    Science.gov (United States)

    Agrati, A M; De Bartolo, G; Palmieri, G

    1991-10-01

    Fifty patients suffering from chronic venous disease were treated for 30 days with heparan sulphate 100 mg per os, b.i.d., or mesoglycan 50 mg per os, t.i.d., in a single blind random study. Both therapies led to a marked improvement in comparison to basal clinical values, but patients treated with heparan sulphate showed the greatest and most rapid regression of symptoms, associated with a significant improvement in plethysmographic index of capacitance and venous flow. Patients treated with heparan sulphate also showed an increased fibrinolytic activity and a reduced antithrombin III consumption, both of which were statistically significant.

  4. Optical analog-to-digital converter

    Science.gov (United States)

    Evanchuk, Vincent L. (Inventor)

    1984-01-01

    A method and apparatus for converting the intensity of an unknown optical signal (B) into an electrical signal in digital form utilizes two elongated optical attenuators (11, 13), one for the unknown optical signal from a source (10) and one for a known optical signal (A) from a variable source (12), a plurality of photodetectors (e.g., 17, 18) along each attenuator for detecting the intensity of the optical signals, and a plurality of comparators (e.g., 21) connected to the photodetectors in pairs to determine at what points being compared the attenuated known signal equals the attenuated unknown signal. The intensity of the unknown relative to the known is thus determined by the output of a particular comparator. That output is automatically encoded to a relative intensity value in digital form through a balancing feedback control (24) and encoder (23). The digital value may be converted to analog form in a D-to-A converter (27) and used to vary the source of the known signal so that the attenuated intensity of the known signal at a predetermined point (comparator 16) equals the attenuated intensity of the unknown signal at the predetermined point of comparison. If the known signal is then equal to the unknown, there is verification of the analog-to-digital conversion being complete. Otherwise the output of the comparator indicating equality at some other point along the attenuators will provide an output which is encoded and added, through an accumulator comprised of a register (25) and an adder (26), to a previous relative intensity value thereby to further vary the intensity of the known signal source. The steps are repeated until full conversion is verified.

  5. Central Venous Catheter-Related Hydrothorax

    Directory of Open Access Journals (Sweden)

    Se Hun Kim

    2015-11-01

    Full Text Available This report describes a case of 88-year-old women who developed central venous catheter-related bilateral hydrothorax, in which left pleural effusion, while right pleural effusion was being drained. The drainage prevented accumulation of fluid in the right pleural space, indicating that there was neither extravasation of infusion fluid nor connection between the two pleural cavities. The only explanation for bilateral hydrothorax in this case is lymphatic connections. Although vascular injuries by central venous catheter can cause catheter-related hydrothorax, it is most likely that the positioning of the tip of central venous catheter within the lymphatic duct opening in the right sub-clavian-jugular confluence or superior vena cava causes the catheter-related hydrothorax. Pericardial effusion can also result from retrograde lymphatic flow through the pulmonary lymphatic chains.

  6. Infections associated with the central venous catheters.

    Science.gov (United States)

    Drasković, Biljana; Fabri, Izabella; Benka, Anna Uram; Rakić, Goran

    2014-01-01

    Central venous catheters are of an essential importance to critically ill patients who require long-term venous access for various purposes. Their use made the treatment much easier, but still they are not harmless and are prone to numerous complications. Catheter infections represent the most significant complication in their use. The frequency of infections varies in different patient care settings, but their appearance mostly depends on the patient's health condition, catheter insertion time, localization of the catheter and type of the used catheter. Since they are one of the leading causes of nosocomial infections and related to significant number of morbidity and mortality in intensive care units, it is very important that maximal aseptic precautions are taken during the insertion and the maintenance period. Prevention of infection of the central venous catheters demands several measures that should be applied routinely.

  7. Increased rheumatoid factor and deep venous thrombosis

    DEFF Research Database (Denmark)

    Meyer-Olesen, Christine L; Nielsen, Sune F; Nordestgaard, Børge G

    2015-01-01

    in the general population. METHODS: We included 54628 participants from the Copenhagen City Heart Study (1981-83) and the Copenhagen General Population Study (2004-12), all with a measured concentration of IgM rheumatoid factor and without autoimmune rheumatic disease or venous thromboembolism. The main outcome...... was incident deep venous thrombosis. There were no losses to follow-up. RESULTS: During 368381 person-years, 670 individuals developed deep venous thrombosis. A rheumatoid factor concentration ≥ vs ... ratios of 9.0 (95% CI 3.1-26) for 1-year follow-up, 4.3 (2.2-8.5) for 5-year follow-up, and 3.1 (1.7-5.6) for up to 32 years of follow-up. Compared with rheumatoid factor concentrations

  8. Complex central venous catheter insertion for hemodialysis.

    Science.gov (United States)

    Powell, Steven; Belfield, Jane

    2014-01-01

    Despite the introduction of payment by results in the UK, there has been no decrease in central venous catheter (CVC) use. In part, this may relate to a requirement to dialyse through a CVC while autogenous access matures. Mortality data have improved in parallel and patients on hemodialysis live longer, which may lead to an increased exposure to CVCs.Exposure to CVCs carries a significant risk of infection and occlusion requiring their repositioning or exchange. The mid to long-term sequelae of CVC use is central venous occlusion leaving clinical teams with an ever increasing challenge to find adequate venous access.In this article, we will discuss the challenges faced by operators inserting CVCs into the hemodialysis-dependent patient who has exhausted more tradition insertion sites. These include translumbar caval catheters, transocclusion and transcollateral catheters, transjugular Inferior Vena Cava catheter positioning, and transhepatic catheters. We will demonstrate the techniques employed, complications, and anticipated longevity of function.

  9. Experimental extracorporeal membrane oxygenation reduces central venous pressure: an adjunct to control of venous hemorrhage?

    Science.gov (United States)

    Larsson, Magnus; Talving, Peep; Palmér, Kenneth; Frenckner, Björn; Riddez, Louis; Broomé, Michael

    2010-07-01

    Venoarterial ECMO has been utilized in trauma patients to improve oxygenation, particularly in the setting of pulmonary contusions and ARDS. We hypothesized that venoarterial ECMO could reduce the central venous pressure in the trauma scenario, thus, alleviating major venous hemorrhage. Ten swine were cannulated for venoarterial ECMO. Central venous pressure, mean arterial pressure, portal vein pressure and portal vein flow were recorded at three different flow rates in both a hemodynamic normal state and a setting of increased central venous pressure and right ventricular load, mimicking acute lung injury. Venoarterial ECMO reduced the central venous pressure (CVP( sup)) from 9.4+/-0.8 to 7.3+/-0.7 mmHg (p<0.01) and increased the mean arterial pressure from 103+/-8 to 119+/-10 mmHg (p<0.01) in the normal hemodynamic state. In the state of increased right ventricular load, the CVP(sup) declined from 14.3+/-0.4 to 11.0+/-0.7mmHg (p<0.01) and the mean arterial pressure (MAP) increased from 66+/-6 to 113 +/-5 mmHg (p<0.01). Venoarterial ECMO reduces systemic venous pressure while maintaining or improving systemic perfusion in both a normal circulatory state and in the setting of increased right ventricular load associated with acute lung injury. ECMO may be a useful tool in reducing blood loss during major venous hemorrhage in both trauma and selected elective surgery.

  10. Novel optoacoustic system for noninvasive continuous monitoring of cerebral venous blood oxygenation

    Science.gov (United States)

    Petrov, Yuriy; Petrov, Irene Y.; Prough, Donald S.; Esenaliev, Rinat O.

    2012-02-01

    Traumatic brain injury (TBI) and spinal cord injury are a major cause of death for individuals under 50 years of age. In the USA alone, 150,000 patients per year suffer moderate or severe TBI. Moreover, TBI is a major cause of combatrelated death. Monitoring of cerebral venous blood oxygenation is critically important for management of TBI patients because cerebral venous blood oxygenation below 50% results in death or severe neurologic complications. At present, there is no technique for noninvasive, accurate monitoring of this clinically important variable. We proposed to use optoacoustic technique for noninvasive monitoring of cerebral venous blood oxygenation by probing cerebral veins such as the superior sagittal sinus (SSS) and validated it in animal studies. In this work, we developed a novel, medical grade optoacoustic system for continuous, real-time cerebral venous blood oxygenation monitoring and tested it in human subjects at normal conditions and during hyperventilation to simulate changes that may occur in patients with TBI. We designed and built a highly-sensitive optoacoustic probe for SSS signal detection. Continuous measurements were performed in the near infrared spectral range and the SSS oxygenation absolute values were automatically calculated in real time using a special algorithm developed by our group. Continuous measurements performed at normal conditions and during hyperventilation demonstrated that hyperventilation resulted in approximately 12% decrease of cerebral venous blood oxygenation.

  11. Internal jugular versus subclavian vein catheterization for central venous catheterization in orthotopic liver transplantation.

    Science.gov (United States)

    Torgay, A; Pirat, A; Candan, S; Zeyneloglu, P; Arslan, G; Haberal, M

    2005-09-01

    The aim of this study was to compare incidence rates of mechanical and infectious complications associated with central venous catheterization via the internal jugular vein (IJV) versus the subclavian vein (SV) among 45 consecutive patients undergoing orthotopic liver transplantation (OLT) between January 2000 and June 2004. The subjects were divided into two groups according to the site of central venous catheterization (IJV or SV). We recorded each patient's physical characteristics, international normalized ratio (INR), partial thromboplastin time, platelet levels, number of puncture attempts, success/failure of central venous catheterization, duration of catheter placement, occurrence of catheter tip misplacement, arterial puncture, incidence of hematoma or pneumothorax, catheter-related infection, or bacterial colonization of the catheter. Senior staff anesthesiologists performed 22 SV and 23 IJV catheterizations for the 45 OLT procedures. The SV and IVJ groups both had minor coagulation abnormalities with slightly increased INR values at the time of catheterization. There were no significant differences between the groups with respect to success of central venous catheterization (100% for both), numbers of attempted punctures, duration of catheter placement, and incidence rates of mechanical and infectious complications. Both groups showed high frequencies of catheter tip misplacement, with right atrium as the site of misplacement in all cases. Two patients in the IJV group (8.7%) developed hematomas after accidental carotid artery puncture. The results suggest that, when performed by experienced anesthesiologists, central venous catheterization via the SV is an acceptable alternative to IJV catheterization for patients undergoing OLT.

  12. Acutely altered hemodynamics following venous obstruction in the early chick embryo.

    Science.gov (United States)

    Stekelenburg-de Vos, Sandra; Ursem, Nicolette T C; Hop, Wim C J; Wladimiroff, Juriy W; Gittenberger-de Groot, Adriana C; Poelmann, Robert E

    2003-03-01

    In the venous clip model specific cardiac malformations are induced in the chick embryo by obstructing the right lateral vitelline vein with a microclip. Clipping alters venous return and intracardiac laminar blood flow patterns, with secondary effects on the mechanical load of the embryonic myocardium. We investigated the instantaneous effects of clipping the right lateral vitelline vein on hemodynamics in the stage-17 chick embryo. 32 chick embryos HH 17 were subdivided into venous clipped (N=16) and matched control embryos (N=16). Dorsal aortic blood flow velocity was measured with a 20 MHz pulsed Doppler meter. A time series of eight successive measurements per embryo was made starting just before clipping and ending 5h after clipping. Heart rate, peak systolic velocity, time-averaged velocity, peak blood flow, mean blood flow, peak acceleration and stroke volume were determined. All hemodynamic parameters decreased acutely after venous clipping and only three out of seven parameters (heart rate, time-averaged velocity and mean blood flow) showed a recovery to baseline values during the 5h study period. We conclude that the experimental alteration of venous return has major acute effects on hemodynamics in the chick embryo. These effects may be responsible for the observed cardiac malformations after clipping.

  13. The Same Angiographic Factors Predict Venous and Arterial Graft Patency: A Retrospective Study.

    Science.gov (United States)

    Gaudino, Mario; Niccoli, Giampaolo; Roberto, Marco; Cammertoni, Federico; Cosentino, Nicola; Falcioni, Elena; Panebianco, Mario; D'Amario, Domenico; Crea, Filippo; Massetti, Massimo

    2016-01-01

    To evaluate the value of angiographic factors in predicting failure of both venous and arterial coronary artery bypass graft. We retrieved from our angiographic database 148 patients who underwent venous and/or arterial CABG and for whom a control coronary angiography at more than 1 month after surgery was available. Pre-CABG and follow-up angiographies were analyzed in order to evaluate diameter stenosis (DS,%), stenosis length (mm), Bogaty score (extent index), Sullivan score, and Gensini score for the extent of coronary artery disease, and Jeopardy Duke score for the extent of myocardial area supplied by an artery. Thirty-nine patients (26%) experienced graft failure at follow-up (mean follow-up 11.3 ± 4.6 months). Patients with venous graft failure [26 (20%)] had significantly smaller DS (P = 0.013), shorter stenosis length (P = 0.01), and lower extent index (P = 0.015), Sullivan score (P = 0.013), Gensini score (P = 0.04) as compared with those without venous graft failure. Patients with arterial graft failure [13 (11%)] had significantly lower DS (P = 0.008), shorter stenosis length (P = 0.001), and lower extent index (P = 0.03) and Sullivan score (P = 0.023) as compared with those without arterial graft failure. Venous and arterial graft failure are associated with less severe stenosis and less extensive atherosclerosis of the grafted vessel.

  14. Doppler assessment of hepatic venous waves for predicting large varices in cirrhotic patients

    Directory of Open Access Journals (Sweden)

    Thomas Joseph

    2011-01-01

    Full Text Available Background/Aim: Color Doppler examination of changes in hepatic venous waveforms is being evaluated as a means of prediction of severity of portal hypertension and presence of esophageal varices. Normal hepatic venous waveform shows a triphasic pattern. In cirrhosis, this pattern changes to a biphasic or monophasic pattern. We aimed to study the sensitivity of loss of normal hepatic venous waveforms in predicting large varices in a cross-sectional analysis. Materials and Methods: All patients, admitted or attending the outpatient department, with a diagnosis of cirrhosis were included in the study. All patients were subjected to oesophagogastroduodenoscopy and Color Doppler examination, and waveform patterns in hepatic vein were recorded. The sensitivity and specificity of changes in waveform in detecting large varices were studied. Results : A total of 51 cases were examined. Triphasic waves were seen in 4 (7.8% cases, biphasic in 26 (51% cases, and monophasic in 21 (41.2% cases. Small varices were seen in 30 (58.8% cases and large varices in 21 (41.2% cases. The sensitivity of loss of the triphasic wave pattern in detecting significant varices (Grade 3 or 4 was very high (95.23% and negative predictive value was also high (75%. Severity of liver disease as indicated by Child-Pugh and MELD scores did not correlate with changes in hepatic venous waveforms. Conclusion : Loss of triphasic hepatic venous waveform is highly sensitive in predicting significant varices in patients with cirrhosis.

  15. Limits and possibilities experienced by nurses in the treatment of women with chronic venous ulcers

    Directory of Open Access Journals (Sweden)

    Marcelo Henrique da Silva

    2014-08-01

    Full Text Available Objective To understand the experiences and expectations of nurses in the treatment of women with chronic venous ulcers. Method Phenomenological research was based on Alfred Schütz, whose statements were obtained in January, 2012, through semi-structured interviews with seven nurses. Results The nurse reveals the difficulties presented by the woman in performing self-care, the perceived limitations in the treatment anchored in motivation, and the values and beliefs of women. It showed professional frustration because venous leg ulcer recurrence, lack of inputs, interdisciplinary work and training of nursing staff. There was an expected adherence to the treatment of women, and it emphasized the need for ongoing care, supported self-care and standard practices in treatment. Conclusion That treatment of chronic venous leg ulcers constitutes a challenge that requires collective investment, involving women, professionals, managers and health institutions.

  16. Post combustion in converter steelmaking

    Energy Technology Data Exchange (ETDEWEB)

    Oghbasilasie, H.; Holappa, L.

    1997-12-31

    The purpose of this work is to study the fundamentals of post combustion and the effect of different process parameters on the post combustion ratio (PCR) and heat transfer efficiency (HTE) in converter steelmaking process. The PCR and HTE have been determined under normal operating conditions. Trials assessed the effect of lance height, vessel volume, foaming slag and pellet additions on PCR and HTE. Based on enthalpy considerations, post combustion of CO gas is regarded as one of the most effective means of increasing the heat supply to the BOP. The thermodynamic study of gas-metal-slag reactions gives the limiting conditions for post combustion inside the converter reactor. Different process parameters influencing both thermodynamic equilibria and kinetic conditions can greatly affect the post combustion ratio. Different features of converter processes as well smelting reduction processes utilizing post combustion have been reviewed. (orig.) SULA 2 Research Programme; 26 refs.

  17. News in Pathogenesis of Chronic Venous Insufficiency

    Directory of Open Access Journals (Sweden)

    Mazuchova J

    2016-08-01

    Full Text Available This review article is concentrating on the news in the pathophysiology of chronic venous insufficiency (CVD. Despite ongoing progress in understanding the molecular aspects of CVD the exact mechanism of its development remains unclear. Many different factors may play role in the pathogenesis of CVD, including changes in hydrostatic pressure, valvular incompetence, increased capillary permeability, endothelial dysfunction, activation of leukocytes, deep venous obstruction, capillary microthrombosis, ineffective function of calf muscle pump, biochemical and structural changes in the vessel wall, extracellular matrix alteration, and several other mechanisms. A better understanding of the pathophysiology is an important step in the finding of new potential treatment.

  18. Lay Stress on Study of Venous Thromboembolism

    Institute of Scientific and Technical Information of China (English)

    刘泽霖

    2002-01-01

    @@ Venous thromboembolism (VTE) including deep vein thrombosis(DVT) and pulmonary embolism(PE).Its occurs in about 1 per 1 000 individuals per years.Thrombosis is a serious disorder. It may be fatal by PE (case fatality rate of venous thrombosis is estimated at 1% to 2%)(Figure 1 ). A substantial proportion of these deaths occur in the postoperative period, and many events are fatal before diagnosis can be made and therapy initiated. Just as well, the prophylactic treatment of thrombosis is focused on preventing first events and recurrences through adequate knowledge about risks and risk factors.

  19. Management of Peripheral and Truncal Venous Injuries

    Directory of Open Access Journals (Sweden)

    Triantafillos G. Giannakopoulos

    2017-08-01

    Full Text Available Civilian injuries are increasing according to the World Health Organization, and this is attributed mainly to road traffic accidents and urban interpersonal violence. Vascular injuries are common in these scenarios and are associated with high morbidity and mortality rates. Associated peripheral venous trauma is less likely to lead to death and controversy remains whether ligation or repair should be the primary approach. Conversely, non-compressible truncal venous insult can be lethal due to exsanguination, thus a high index of suspicion is crucial. Operative management is demanding with fair results but recent endovascular adjuncts demonstrate promising results and seem to be the way forward for these serious conditions.

  20. Venous thrombosis: the history of knowledge.

    Science.gov (United States)

    Mannucci, P M

    2002-01-01

    Venous thrombosis is a frequent disease. It is surprising, therefore, that no case truly compatible with a diagnosis of venous thrombosis was apparently reported in the antiquity. There is no case that could be reasonably attributed to a venous thrombus in the writings of Hippocrates, Galenus, Celius Aurelianus, Ibn an-Nafiz, Avicenna and others. Venous thrombosis is not among the many diseases mentioned in the Bible. The term "leucophlegmasia", first used by Hippocrates and then by Celius Aurelianus, refers to cases of bilateral leg edema, most likely due to conditions such as heart failure, liver cirrhosis and renal insufficiency. Nothing compatible with a diagnosis of venous thrombosis can be found in pieces of art from ancient Egypt, Greece, Rome, Persia and South America. While in these sources there are sometimes representations of varicose veins and ulcers, unilateral leg edema or other pictures compatible with venous thrombosis are not featured. The first well documented case of venous thrombosis is depicted in a beautifully illustrated manuscript written in the 13th century and currently preserved in Paris at the Bibliothèque Nationale (MS Fr 2829, Folio 87). The manuscript describes the case of a young man from Normandy named Raoul who at the age of twenty developed unilateral edema in the right ankle that subsequently extended up to the thigh, with no obvious symptoms in the contralateral leg. Raoul was advised to visit the tomb of Saint Louis who was buried in the church of Saint Denis, where the patient spent several days confessing his sins and praying the saint. Afterwards he chose to collect the dust accumulating below the stone that covered the tomb and to apply it on the fistulae and ulcers of his foot. The openings stopped running and were filled with flesh. He was first obliged to use crutches but subsequently he could walk with a cane, to be eventually able to dispose of all devices, even though his foot throbbed a little. Raoul was cured as

  1. Assessment of Venous Thrombosis in Animal Models.

    Science.gov (United States)

    Grover, Steven P; Evans, Colin E; Patel, Ashish S; Modarai, Bijan; Saha, Prakash; Smith, Alberto

    2016-02-01

    Deep vein thrombosis and common complications, including pulmonary embolism and post-thrombotic syndrome, represent a major source of morbidity and mortality worldwide. Experimental models of venous thrombosis have provided considerable insight into the cellular and molecular mechanisms that regulate thrombus formation and subsequent resolution. Here, we critically appraise the ex vivo and in vivo techniques used to assess venous thrombosis in these models. Particular attention is paid to imaging modalities, including magnetic resonance imaging, micro-computed tomography, and high-frequency ultrasound that facilitate longitudinal assessment of thrombus size and composition.

  2. Imaging characteristics of two patients with isolated cortical venous thrombosis

    Institute of Scientific and Technical Information of China (English)

    Shunchang Han; Hui Zhang; Guoguang Fan; Baohai Sun

    2008-01-01

    BACKGROUND:Over the past twenty years, improvements in neuroimaging have greatly improved the ability to diagnose cerebral venous sinus thrombosis, as well as isolated cortical venous thrombosis. Neuroimaging allows for variations to be detected in the cortical vein and venous sinus. Diagnosis of thromboses in the venous system should not depend entirely on angiography of undeveloped veins or venous sinus. Currently, the combination of magnetic resonance imaging and magnetic resonance venography is the gold standard for diagnosing cerebral venous sinus thrombosis, rather than digital subtraction angiography. This article summarizes clinical manifestations, results from computed tomography and magnetic resonance imaging in two cases of isolated cortical venous thrombosis, analyzed relevant literature, and discussed the clinical and imaging characteristics of isolated cortical venous thromboses.

  3. Complement C3 and High Risk of Venous Thromboembolism

    DEFF Research Database (Denmark)

    Nørgaard, Ina; Nielsen, Sune Fallgaard; Nordestgaard, Børge Grønne

    2016-01-01

    BACKGROUND: Complement activation may contribute to venous thromboembolism, including deep venous thrombosis and pulmonary embolism. We tested the hypothesis that high complement C3 concentrations are associated with high risk of venous thromboembolism in the general population. METHODS: We...... similar for deep venous thrombosis and pulmonary embolism separately. The multivariable-adjusted hazard ratio for venous thromboembolism for a 1-g/L increase in complement C3 was 2.43 (1.74-3.40). CONCLUSIONS: High concentrations of complement C3 were associated with high risk of venous thromboembolism...... included 80 517 individuals without venous thromboembolism from the Copenhagen General Population Study recruited in 2003-2012. Plasma complement C3 concentrations were measured at baseline, and venous thromboembolism (n = 1176) was ascertained through April 2013 in nationwide registries. No individuals...

  4. Effect of Pingyangmycin on human venous malformation endothelial cells

    Institute of Scientific and Technical Information of China (English)

    Yi Fang Zhao; Zhi Jun Sun; Yu Lin Jia; Jun Jia; Ya Meng Si; Ji Hong Zhao; Wen Feng Zhang

    2008-01-01

    @@ Purpose: Venous malformations are common vascular anomalies with a propensity of the head and neck. Intralesional injection of Pingyangmycin (PYM, bleomycin A5 hydrochloride) is a widely used sclerotherapy method for the treatment of venous malformation.

  5. [Lower limb venous angiodysplasia as a cause of chronic venous insufficiency: specific diagnosis and treatment].

    Science.gov (United States)

    Dan, V N; Sapelkin, S V; Karmazanovskiĭ, G G; Kuntsevich, G I

    2007-01-01

    The paper presents a current understanding of chronic venous insufficiency that develops in venous forms of dysplasia. Management of venous dysplasia must be based on multidisciplinary approach including comprehensive diagnosis (predominantly noninvasive), integrative surgical and non-surgical treatment. Modern therapy must be complex and carried out in highly specialized facilities. Best functional and esthetic results can be achieved only through combined therapy. When surgical or non-surgical interventions are inappropriate or impossible, management focus must be placed on clinical control of vascular anomaly (follow-up and compression-based conservative treatment) aimed at minimization of its unfavorable impact on vital functions and at quality of life improvement.

  6. Stirling Converters For Solar Power

    Science.gov (United States)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    1993-01-01

    Two designs expected to meet long-term goals for performance and cost. Proposed for advanced systems to convert solar thermal power to electrical power. Each system, designed to operate with 11-m-diameter paraboloidal reflector, includes solar-energy receiver, liquid-metal heat-transport subsystem, free-piston Stirling engine, cooling subsystem, alternator or generator coupled directly or indirectly to commercial electric-power system, and control and power-conditioning circuitry. System converts approximately 75 kW of input solar thermal power falling on collector to about 25 kW of output electrical power.

  7. Family history of venous thromboembolism and identifying factor V Leiden carriers during pregnancy.

    Science.gov (United States)

    Horton, Amanda L; Momirova, Valerija; Dizon-Townson, Donna; Wenstrom, Katharine; Wendel, George; Samuels, Philip; Sibai, Baha; Spong, Catherine Y; Cotroneo, Margaret; Sorokin, Yoram; Miodovnik, Menachem; O'Sullivan, Mary J; Conway, Deborah; Wapner, Ronald J

    2010-03-01

    To estimate whether there is a correlation between family history of venous thromboembolism and factor V Leiden mutation carriage in gravid women without a personal history of venous thromboembolism. This is a secondary analysis of a prospective observational study of the frequency of pregnancy-related thromboembolic events among carriers of the factor V Leiden mutation. Family history of venous thromboembolism in either first- or second-degree relatives was self-reported. Sensitivity, specificity, and positive and negative predictive values of family history to predict factor V Leiden mutation carrier status were calculated. Women without a personal venous thromboembolism history and with available DNA were included (n=5,168). One hundred forty women (2.7% [95% confidence interval (CI) 2.3-3.2%]) were factor V Leiden mutation-positive. Four hundred twelve women (8.0% [95% CI 7.3-8.7%]) reported a family history of venous thromboembolism. Women with a positive family history were twofold more likely to be factor V Leiden mutation carriers than those with a negative family history (23 of 412 [5.6%] compared with 117 of 4,756 [2.5%], Pfactor V Leiden carriers were 16.4% (95% CI 10.7-23.6%), 92.3% (95% CI 91.5-93.0%), and 5.6% (95% CI 3.6-8.3%), respectively. Although a family history of venous thromboembolism is associated with factor V Leiden mutation in thrombosis-free gravid women, the sensitivity and positive predictive values are too low to recommend screening women for the factor V Leiden mutation based solely on a family history.

  8. Design and Control for the Buck-Boost Converter Combining 1-Plus-D Converter and Synchronous Rectified Buck Converters

    OpenAIRE

    2015-01-01

    In this paper, a design and control for the buck-boost converter, i.e., 1-plus-D converter with a positive output voltage, is presented, which combines the 1-plus-D converter and the synchronous rectified (SR) buck converter. By doing so, the problem in voltage bucking of the 1-plus-D converter can be solved, thereby increasing the application capability of the 1-plus-D converter. Since such a converter operates in continuous conduction mode inherently, it possesses the nonpulsating output cu...

  9. Risk factors for a first and recurrent venous thrombosis

    OpenAIRE

    Flinterman, Linda Elisabeth

    2013-01-01

    The aim of this thesis was to identify new risk factors for first and recurrent venous thrombosis of both the upper and lower extremity, and assess the incidence of recurrence and mortality after a first venous thrombosis. An overview was provided of the current literature on risk factors and treatment for a first venous thrombosis of the upper extremity (chapter 2). We investigated the association between levels of coagulation factors, blood group and a first venous thrombosis of the upper e...

  10. AC-DC PFC Converter Using Combination of Flyback Converter and Full-bridge DC-DC Converter

    Directory of Open Access Journals (Sweden)

    Moh. Zaenal Efendi

    2014-06-01

    Full Text Available This paper presents a combination of power factor correction converter using Flyback converter and Full-bridge dc-dc converter in series connection. Flyback converter is operated in discontinuous conduction mode so that it can serve as a power factor correction converter and meanwhile Full-bridge dc-dc converter is used for dc regulator. This converter system is designed to produce a 86 Volt of output voltage and 2 A of output current. Both simulation and experiment results show that the power factor of this converter achieves up to 0.99 and meets harmonic standard of IEC61000-3-2. Keywords: Flyback Converter, Full-bridge DC-DC Converter, Power Factor Correction.

  11. Pain and efficacy of local anesthetics for central venous access

    Directory of Open Access Journals (Sweden)

    William C Culp Jr

    2008-11-01

    Full Text Available William C Culp Jr1, Mohammed Yousaf2, Benjamin Lowry1, Timothy C McCowan3, William C Culp21Division of Cardiothoracic Anesthesiology, Scott and White Hospital, The Texas A&M University College of Medicine, Temple, TX, USA; 2Division of Interventional Radiology, University of Arkansas for Medical Sciences, Little Rock, AR, USA; 3Department of Radiology, University of Mississippi Medical Center, Jackson, MS, USAPurpose: To compare pain during injection and efficacy of analgesia of local anesthetics during central venous line placement.Methods: Sixty-two patients were studied in a randomized, double-blinded prospective fashion. Patients received 1% lidocaine (L, buffered 1% lidocaine (LB, or 2% chloroprocaine (CP injected around the internal jugular vein for procedural analgesia for central venous access. Patients reported pain via a standard linear visual analog scale, with 0 representing no pain and 10 being the worst pain imaginable.Results: Overall patient perception of pain was better with CP and L than LB with mean scores of CP 2.4, L 2.6, LB 4.2. Pain with injection mean scores were CP 2.1, L 2.5, LB 3.2. Pain with catheter placement scores were CP 2.5, L 1.7, LB 3.4. Operator assessment of overall pain values were CP 1.9, L 2.2, LB 3.4. LB consistently scored the worst, though compared with CP, this only reached statistical significance in overall patient pain and pain at catheter insertion compared with L.Conclusion: Though chloroprocaine scored better than lidocaine in 3 of 4 parameters, this trend did not achieve statistical significance. Adding sodium bicarbonate to lidocaine isn’t justified in routine practice, nor is routine replacement of lidocaine with chloroprocaine.Keywords: local anesthesia, analgesia, central venous access, lidocaine, chloroprocaine

  12. Proof of concept non-invasive estimation of peripheral venous oxygen saturation.

    Science.gov (United States)

    Khan, Musabbir; Pretty, Chris G; Amies, Alexander C; Balmer, Joel; Banna, Houda E; Shaw, Geoffrey M; Geoffrey Chase, J

    2017-05-19

    Pulse oximeters continuously monitor arterial oxygen saturation. Continuous monitoring of venous oxygen saturation (SvO2) would enable real-time assessment of tissue oxygen extraction (O2E) and perfusion changes leading to improved diagnosis of clinical conditions, such as sepsis. This study presents the proof of concept of a novel pulse oximeter method that utilises the compliance difference between arteries and veins to induce artificial respiration-like modulations to the peripheral vasculature. These modulations make the venous blood pulsatile, which are then detected by a pulse oximeter sensor. The resulting photoplethysmograph (PPG) signals from the pulse oximeter are processed and analysed to develop a calibration model to estimate regional venous oxygen saturation (SpvO2), in parallel to arterial oxygen saturation estimation (SpaO2). A clinical study with healthy adult volunteers (n = 8) was conducted to assess peripheral SvO2 using this pulse oximeter method. A range of physiologically realistic SvO2 values were induced using arm lift and vascular occlusion tests. Gold standard, arterial and venous blood gas measurements were used as reference measurements. Modulation ratios related to arterial and venous systems were determined using a frequency domain analysis of the PPG signals. A strong, linear correlation (r (2)  = 0.95) was found between estimated venous modulation ratio (RVen) and measured SvO2, providing a calibration curve relating measured RVen to venous oxygen saturation. There is a significant difference in gradient between the SpvO2 estimation model (SpvO2 = 111 - 40.6*R) and the empirical SpaO2 estimation model (SpaO2 = 110 - 25*R), which yields the expected arterial-venous differences. Median venous and arterial oxygen saturation accuracies of paired measurements between pulse oximeter estimated and gold standard measurements were 0.29 and 0.65%, respectively, showing good accuracy of the pulse oximeter system. The main outcome

  13. Physical activity, immobilization and the risk of venous thrombosis

    NARCIS (Netherlands)

    Stralen, Karlijn Janneke van

    2008-01-01

    Deep venous thrombosis is a common disease. Already in 1856 it was suggested that immobilization could cause venous thrombosis. However, so far little research has shown whether exercise or ambulation could decrease the risk of venous thrombosis. We performed a historical review regarding the role o

  14. The recalcitrant venous leg ulcer - A never ending story?

    NARCIS (Netherlands)

    S.W.I. Reeder (Suzan); M.B. Maessen-Visch (Birgitte); S.I. Langendoen; K.P. de Roos; H.A.M. Neumann (Martino)

    2013-01-01

    textabstractIntroduction: In general, four particular causes of recalcitrant venous leg ulcers may be distinguished. These are foot pump insufficiency, chronic venous compartment syndrome and non-re-canalized popliteal vein thrombosis. The fourth cause of recalcitrant venous leg ulcers is lipodermat

  15. XML Docbook to Mediawiki Converter

    Directory of Open Access Journals (Sweden)

    Maria Chiara Pievatolo

    2013-05-01

    Full Text Available A Perl script, based on the work of Stefano Selleri, to migrate XML-Docbook 4.X documents to Wiki markup. I added some lines to meet my need to convert my Kant translations from Docbook to MediaWiki. A sample of the output can be...

  16. Charge-pump voltage converter

    Science.gov (United States)

    Brainard, John P.; Christenson, Todd R.

    2009-11-03

    A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.

  17. High-Performance Data Converters

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    Novel techniques for multi-bit oversampled data conversion are described. State-of-the-art oversampled data converters are analyzed, leading to the conclusion that their performance is limited mainly by low-resolution signal representation. To increase the resolution, high-performance, high...

  18. Accuracy of Venous Filling Index on Standing (VFIst) and Pure Regurgitation Index (PRI), a Novel Index Obtained by Air Plethysmography, for Detecting Venous Reflux.

    Science.gov (United States)

    Shiraishi, Yasushi

    2015-01-01

    To evaluate the accuracy of venous filling index on standing (VFIst) and a new index named pure regurgitation index (PRI), obtained by air plethysmography, for detecting venous reflux. One hundred and sixty-one healthy subjects (161 limbs) and 180 varicose vein patients (180 limbs) were investigated. All subjects underwent duplex ultrasonography for verifying venous reflux and air plethysmography to obtain hemodynamic parameters such as VFIst, VFI in the supine position (VFIsu), and the maximum arterial inflow rate. To evaluate the accuracy of VFIst and PRI (= (VFIst - VFIsu)/body mass index), receiver operating characteristics curves were created. The optimal cut-off value, sensitivity, specificity, and area under the curve, obtained from analyzing the receiver operating characteristics curves, of VFIst vs. PRI were 2.058 mL/s vs. 0.059 mL · m(2)/s · kg, 93.3% vs. 90.3%, 88.8% vs. 91.3%, and 0.954 vs. 0.964, respectively. This study indicates that while both VFIst and PRI are highly accurate indicators of venous reflux, PRI, which is not affected by the arterial inflow rate and body mass index, is slightly superior to VFIst, especially in subjects with greater body mass index.

  19. Microalbuminuria and Risk of Venous Thromboembolism

    NARCIS (Netherlands)

    Mahmoodi, Bakhtawar K.; Gansevoort, Ron T.; Veeger, Nic J. G. M.; Matthews, Abigail G.; Navis, Gerjan; Hillege, Hans L.; van der Meer, Jan

    2009-01-01

    Context Microalbuminuria (albuminuria 30-300 mg per 24-hour urine collection) is a well-known risk marker for arterial thromboembolism. It is assumed that microalbuminuria reflects generalized endothelial dysfunction. Hence, microalbuminuria may also predispose for venous thromboembolism (VTE). Obje

  20. Treatment of Cancer-Associated Venous Thrombosis

    NARCIS (Netherlands)

    G.L. van Sluis; H.R. Buller

    2009-01-01

    Venous thromboembolism (VTE) is an important complication in cancer patients, which is associated with bad outcome. Increased recurrence rates and bleeding complications as compared to non-cancer patients during the treatment of VTE, require special attention. This review aims to summarize the avail

  1. [Femoral venous catheter: an unusual complication].

    Science.gov (United States)

    Garcia, P; Mora, A; Trambert, P; Maler, E; Courant, P

    2000-08-01

    We report an erratic course of a venous femoral catheter which was in the abdominal cavity in a patient with an haemoperitoneum and an hepatic injury. This complication led to an inefficiency of the transfusion and a worsening of the haemoperitoneum.

  2. Arterial and venous blood gas analyses.

    Science.gov (United States)

    Rieser, Teresa M

    2013-08-01

    Arterial and venous blood gases provide useful information regarding pulmonary function as well as acid-base balance. The goal of this article is to discuss the collection of blood gases, common errors in analysis, and what information can be gleaned from a blood gas analysis. © 2013 Elsevier Inc. All rights reserved.

  3. Arterial and Venous Thrombosis in Cancer Patients

    Directory of Open Access Journals (Sweden)

    Andrew D. Blann

    2011-01-01

    Full Text Available The most frequent ultimate cause of death is myocardial arrest. In many cases this is due to myocardial hypoxia, generally arising from failure of the coronary macro- and microcirculation to deliver enough oxygenated red cells to the cardiomyocytes. The principle reason for this is occlusive thrombosis, either by isolated circulating thrombi, or by rupture of upstream plaque. However, an additionally serious pathology causing potentially fatal stress to the heart is extra-cardiac disease, such as pulmonary hypertension. A primary cause of the latter is pulmonary embolus, considered to be a venous thromboembolism. Whilst the thrombotic scenario has for decades been the dominating paradigm in cardiovascular disease, these issues have, until recently, been infrequently considered in cancer. However, there is now a developing view that cancer is also a thrombotic disease, and notably a disease predominantly of the venous circulation, manifesting as deep vein thrombosis and pulmonary embolism. Indeed, for many, a venous thromboembolism is one of the first symptoms of a developing cancer. Furthermore, many of the standard chemotherapies in cancer are prothrombotic. Accordingly, thromboprophylaxis in cancer with heparins or oral anticoagulation (such as Warfarin, especially in high risk groups (such as those who are immobile and on high dose chemotherapy, may be an important therapy. The objective of this communication is to summarise current views on the epidemiology and pathophysiology of arterial and venous thrombosis in cancer.

  4. Lymphatic and venous function in lipoedema.

    Science.gov (United States)

    Harwood, C A; Bull, R H; Evans, J; Mortimer, P S

    1996-01-01

    Lipoedema is a common but infrequently recognized condition causing bilateral enlargement of the legs in women. Although generally considered to be the result of an abnormal deposition of subcutaneous fat with associated oedema, the precise mechanisms responsible for oedema formation have yet to be fully established. In order to evaluate the possible role of lymphatic or venous dysfunction in the pathogenesis of lipoedema, 10 patients were investigated by photoplethysmography (venous function) and quantitative lymphoscintigraphy (lymphatic function). The results were compared with those from patients with primary lymphoedema and those from healthy volunteers. The results demonstrated minor abnormalities of venous function in only two patients. One patient had moderately impaired lymphatic function in both legs and seven patients had a marginal degree of impairment in one or both legs. However, in none of these cases did the impairment attain the low levels seen in true lymphoedema. Lipoedema appears to be a distinct clinical entity best classified as a lipodystrophy rather than a direct consequence of any primary venous or lymphatic insufficiency.

  5. Diagnosing deep venous thrombosis in primary care

    NARCIS (Netherlands)

    Oudega, Rudolphus

    2005-01-01

    In patients suspected of deep venous thrombosis (DVT) in primary care, it is a challenge to discriminate the patients with DVT from those without DVT. The risk of missing the diagnosis and the risk of unnecessary referral and treatment with a potential harmful therapy has to be balanced by the prima

  6. Nonclinical aspects of venous thrombosis in pregnancy.

    Science.gov (United States)

    Struble, Evi; Harrouk, Wafa; DeFelice, Albert; Tesfamariam, Belay

    2015-09-01

    Pregnancy is a hypercoagulable state which carries an excess risk of maternal venous thrombosis. Endothelial injury, alterations in blood flow and activation of the coagulation pathway are proposed to contribute to the hypercoagulability. The risk for thrombosis may be accentuated by certain drugs and device implants that directly or indirectly affect the coagulation pathway. To help ensure that these interventions do not result in adverse maternal or fetal outcomes during pregnancy, gravid experimental animals can be exposed to such treatments at various stages of gestation and over a dosage range that would identify hazards and inform risk assessment. Circulating soluble biomarkers can also be evaluated for enhancing the assessment of any increased risk of venous thrombosis during pregnancy. In addition to traditional in vivo animal testing, efforts are under way to incorporate reliable non-animal methods in the assessment of embryofetal toxicity and thrombogenic effects. This review summarizes hemostatic balance during pregnancy in animal species, embryofetal development, biomarkers of venous thrombosis, and alterations caused by drug-induced venous thrombosis.

  7. Venous infraction of developmental venous anomaly: A case report with perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Youn; Kim, Hye Jeong; Hyun, Su Jeong; Kim, Hee Yeong; Kim, Han Myun; Hwang, Ji Young; Hong, Hye Suk; Woo, Ji Young; Yang, Ik [Dept. of Radiology, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul (Korea, Republic of); Kim, Eun Soo [Dept. of Radiology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang (Korea, Republic of)

    2017-06-15

    Developmental venous anomaly (DVA) is a common congenital venous malformation characterized by dilated medullary veins in caput medusa configuration and a draining vein. Despite the high incidence of DVAs, they are benign anatomic variations and rarely cause symptoms. Here, we report computed tomography and magnetic resonance imaging findings with perfusion images of acute infarction from underlying DVA in a 63-year-old female patient who presented with acute onset of neurologic symptoms and recovered without any neurologic deficit.

  8. To what extent might deep venous thrombosis and chronic venous insufficiency share a common etiology?

    Science.gov (United States)

    Malone, P Colm; Agutter, P S

    2009-08-01

    According to the valve cusp hypoxia hypothesis (VCHH), deep venous thrombosis is caused by sustained non-pulsatile (streamline) venous blood flow. This leads to hypoxemia in the valve pockets; hypoxic injury to the inner (parietalis) endothelium of the cusp leaflets activates the elk-1/egr-1 pathway, leading to leukocyte and platelet swarming at the site of injury and, potentially, blood coagulation. Here, we propose an extension of the VCHH to account for chronic venous insufficiency. First, should the foregoing events not proceed to frank thrombogenesis, the valves may nevertheless be chronically injured and become incompetent. Serial incompetence in lower limb valves may then generate ''passive'' venous hypertension. Second, should ostial valve thrombosis obstruct venous return from muscles via tributaries draining into the femoral vein, as Virchow illustrated, ''active'' venous hypertension may supervene: muscle contraction would force the blood in the vessels behind the blocked ostial valves to re-route. Passive or active venous hypertension opposes return flow, leading to luminal hypoxemia and vein wall distension, which in turn may impair vasa venarum perfusion; the resulting mural endothelial hypoxia would lead to leukocyte invasion of the wall and remodelling of the media. We propose that varicose veins result if gross active hypertension stretches the valve ''rings'', rendering attached valves incompetent caudad to obstructed sites, replacing normal centripetal flow in perforating veins with centrifugal flow and over-distending those vessels. We also discuss how hypoxemia-related venous/capillary wall lesions may lead to accumulation of leukocytes, progressive blockage of capillary blood flow, lipodermosclerosis and skin ulceration.

  9. Architecture for a High-to-Medium-Voltage Power Converter

    Science.gov (United States)

    Vorpenian, Vatche

    2008-01-01

    A power converter now undergoing development is required to operate at a DC input potential ranging between 5.5 and 10 kV and a DC output potential of 400 V at a current up to 25 A. This power converter is also required to be sufficiently compact and reliable to fit and operate within the confines of a high-pressure case to be lowered to several miles (approx.5 km) below the surface of the ocean. The architecture chosen to satisfy these requirements calls for a series/ parallel arrangement of 48 high-frequency, pulse-width-modulation (PWM), transformer-isolation DC-to-DC power converter blocks. The input sides of the converter blocks would be connected in series so that the input potential would be divided among them, each of them being exposed to an input potential of no more than 10 kV/48 . 210 V. The series connection of inputs would also enforce a requirement that all the converter blocks operate at the same input current. The outputs of the converter blocks would be connected in a matrix comprising 6 parallel legs, each leg being a cascade of eight outputs wired in series (see figure). All the converter blocks would be identical within the tolerances of the values of their components. A single voltage feedback loop would regulate the output potential. All the converter blocks would be driven by the same PWM waveform generated by this feedback loop. The power transformer of each converter block would have a unity turns ratio and would be capable of withstanding as much as 10 kVDC between its primary and secondary windings. (Although, in general, the turns ratio could be different from unity, the simplest construction for minimizing leakage and maximizing breakdown voltage is attained at a turns ratio of unity.)

  10. Bidirectional dc-to-dc Power Converter

    Science.gov (United States)

    Griesbach, C. R.

    1986-01-01

    Solid-state, series-resonant converter uses high-voltage thyristors. Converter used either to convert high-voltage, low-current dc power to lowvoltage, high current power or reverse. Taking advantage of newly-available high-voltage thyristors to provide better reliability and efficiency than traditional converters that use vacuum tubes as power switches. New converter essentially maintenance free and provides greatly increased mean time between failures. Attractive in industrial applications whether or not bidirectional capability is required.

  11. Parametric study of laser photovoltaic energy converters

    Science.gov (United States)

    Walker, G. H.; Heinbockel, J. H.

    1987-01-01

    Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

  12. Pycnogenol® in chronic venous insufficiency and related venous disorders.

    Science.gov (United States)

    Gulati, Om P

    2014-03-01

    The present review provides an update of the biological profile of Pycnogenol in the light of its use in the treatment of chronic venous insufficiency (CVI) and related venous disorders such as deep vein thrombosis (DVT), post-thrombotic syndrome, long haul air-travel-related leg oedema, venous ulcers and acute haemorrhoids. Pycnogenol is a French maritime pine bark extract produced from the outer bark of Pinus pinaster Ait. subsp. atlantica. Its strong antioxidant, anti-inflammatory and vasodilator activities, antithrombotic effects and collagen stabilizing properties make it uniquely able to target the multi facet pathophysiology of CVI and related venous disorders. Clinical studies have shown that it can reduce oedema of the legs in CVI, reduce the incidence of deep venous thrombosis during long haul flights and enhance the healing of venous ulcers and haemorrhoidal episodes by topical application and/or oral administration. This review highlights clinical research findings on the safety, compliance and efficacy of Pycnogenol, including its use in combination products.

  13. Variations in plasma free radicals with topical aescin + essential phospholipids gel in venous hypertension: new clinical data.

    Science.gov (United States)

    Ricci, A; Ruffini, I; Cesarone, M R; Cornelli, U; Corsi, M; Belcaro, G; Ippolito, E; Dugall, M

    2004-01-01

    The aim of this study was the evaluation of the effects of Aescin + essential phospholipids (AEPL) gel on plasma free radicals (PFRs). In this study, ten patients with venous hypertension, no ulcerations or infections, venous microangiopathy, and varicose veins were treated with topical AEPL applied in a standard protocol. AEPL was applied for 2 weeks, three times daily at the same skin region (perimalleolar internal region at defined distance from the medial malleolus and from the anterior edge of the tibia). In subjects with venous hypertension, PFR values were higher than 420 Carr units. After treatment, the values of PRF decreased to almost normal as an effect of the massage with AEPL gel. The decrease in value was observed in all treatment subjects. A ranking system indicates that the AEPL preparation is active in all subjects who have venous microangiopathy. The decrease in PFR value was greater than 30% in all treatment subjects (p < 0.05). The decrease in PFR can be considered an important indication of an improvement in skin perfusion, which protects the skin from deterioration and eventually from venous ulcerations. The evaluation of PFR is an important new physiologic parameter that can be associated with other noninvasive tests to study the microcirculation and its evolution and improvement with systemic or topical medical treatment.

  14. Cerebral venous thrombosis presenting with cerebellar ataxia and cortical blindness.

    Science.gov (United States)

    Ben Sassi, Samia; Mizouni, Habiba; Nabli, Fatma; Kallel, Lamia; Kefi, Mounir; Hentati, Fayçal

    2010-01-01

    Venous infarction in the cerebellum has been reported only rarely, probably because of the abundant venous collateral drainage in this region. Bilateral occipital infarction is a rare cause of visual loss in cerebral venous thrombosis. We describe a 50-year-old woman with a history of ulcerative colitis who developed acute cerebellar ataxia and cortical blindness. She had bilateral cerebellar and occipital lesions related to sigmoid venous thrombosis and achieved complete recovery with anticoagulation therapy. Cerebral venous thrombosis should be considered in cases of simultaneous cerebellar and occipital vascular lesions.

  15. Can venous blood gas analysis be used for predicting seizure recurrence in emergency department?

    Science.gov (United States)

    Kılıc, Turgay Yılmaz; Yesilaras, Murat; Atilla, Ozge Duman; Sever, Mustafa; Aksay, Ersin

    2014-01-01

    Epileptic seizures account for 1%-2% of all admissions of patients to the emergency department (ED). The present study aimed to determine whether venous blood pH, bicarbonate, base excess, and lactate levels taken within 1 hour of the last seizure episode help to determine seizure recurrence in emergency departments. A cross-sectional study was conducted in the emergency department (ED) between January and July, 2012. Patients who were admitted to the emergency department consecutively were included in the study if they were 14 years or older and within 1 hour after last seizure. Demographics, seizure type, use of antiepileptic drugs, observation period at the emergency department, seizure recurrence, pH, bicarbonate, base excess, and lactate levels from venous blood gas analysis were determined. A total of 94 patients aged 14 years or older were included in the study. Of these patients, 10.6% (n=10) experienced recurrent seizures in the observation period at the emergency department. To predict recurrent seizures in ED, threshold venous blood gas values were determined as follows: pH7.65 mmol/L [sensitivity 80% (95%CI: 44-96), negative predictive value 96.6% (95%CI: 87-99)]. If venous blood gas analysis is made on pH, base excess, lactate and bicarbonate immediately one hour after the last epileptic seizure episode, it is possible to predict whether the patient will have seizure recurrence.

  16. Normal venous anatomy and physiology of the lower extremity.

    Science.gov (United States)

    Notowitz, L B

    1993-06-01

    Venous disease of the lower extremities is common but is often misunderstood. It seems that the focus is on the exciting world of arterial anatomy and pathology, while the topic of venous anatomy and pathology comes in second place. However, venous diseases such as chronic venous insufficiency, leg ulcers, and varicose veins affect much of the population and may lead to disability and death. Nurses are often required to answer complex questions from the patients and his or her family about the patient's disease. Patients depend on nurses to provide accurate information in terms they can understand. Therefore it is important to have an understanding of the normal venous system of the legs before one can understand the complexities of venous diseases and treatments. This presents an overview of normal venous anatomy and physiology.

  17. Advances in diagnosis and treatment of cerebral venous system diseases

    Directory of Open Access Journals (Sweden)

    Xiao-yun LIU

    2016-11-01

    Full Text Available Cerebral venous system diseases include cerebral venous thrombosis (CVT, venous sinus stenosis, carotid cavernous fistula (CCF, intracranial arteriovenous malformation (AVM and so on. In recent years, due to the rapid development of neuroimaging and interventional technology, more and more cerebral venous system diseases have been timely diagnosed and treated, such as magnetic resonance black-blood thrombus imaging (MRBTI in the diagnosis of CVT, stenting in the treatment of venous sinus stenosis, micro coil plus Onyx glue or covered stents in the treatment of CCF, which allow us to make a deeper recognition of cerebral venous system diseases. Therefore, this paper will introduce the latest diagnosis and treatment of cerebral venous system diseases. DOI: 10.3969/j.issn.1672-6731.2016.11.006

  18. Photoelectric converters with quantum coherence

    Science.gov (United States)

    Su, Shan-He; Sun, Chang-Pu; Li, Sheng-Wen; Chen, Jin-Can

    2016-05-01

    Photon impingement is capable of liberating electrons in electronic devices and driving the electron flux from the lower chemical potential to higher chemical potential. Previous studies hinted that the thermodynamic efficiency of a nanosized photoelectric converter at maximum power is bounded by the Curzon-Ahlborn efficiency ηCA. In this study, we apply quantum effects to design a photoelectric converter based on a three-level quantum dot (QD) interacting with fermionic baths and photons. We show that, by adopting a pair of suitable degenerate states, quantum coherences induced by the couplings of QDs to sunlight and fermion baths can coexist steadily in nanoelectronic systems. Our analysis indicates that the efficiency at maximum power is no longer limited to ηCA through manipulation of carefully controlled quantum coherences.

  19. Photoelectric converter; Koden henkan soshi

    Energy Technology Data Exchange (ETDEWEB)

    Sawayama, I.

    1995-04-07

    The conventional solar cell module wherein plural photovoltaic elements formed on a metal substrate are connected and coated by weatherproof and translucent resin has defects such as pinholes, and separation because moisture infiltrating from the outside causes dissolution of such conductive matrix as silver in the collecting electrode. This invention relates to a photoelectric converter which has little decrease in the output under the environment of light irradiation, wherein a photoelectric converting semiconductor, a transparent conductive layer on the above-mentioned semiconductor, and conductive member containing water repellent fine powder grains on this transparent conductive layer are laminated successively. Polytetrafluoroethylene, polydimethyl siloxane, polyethylene, and nylon are desirable to be employed as the water repellent fine powder grains. The fine powder grains are mixed with conductive filler and binder to produce conductive paste, pattern-applied by a screen printing machine, and subjected to thermal treatment to form a conductive member. 3 figs., 1 tab.

  20. Photoelectric converters with quantum coherence.

    Science.gov (United States)

    Su, Shan-He; Sun, Chang-Pu; Li, Sheng-Wen; Chen, Jin-Can

    2016-05-01

    Photon impingement is capable of liberating electrons in electronic devices and driving the electron flux from the lower chemical potential to higher chemical potential. Previous studies hinted that the thermodynamic efficiency of a nanosized photoelectric converter at maximum power is bounded by the Curzon-Ahlborn efficiency η_{CA}. In this study, we apply quantum effects to design a photoelectric converter based on a three-level quantum dot (QD) interacting with fermionic baths and photons. We show that, by adopting a pair of suitable degenerate states, quantum coherences induced by the couplings of QDs to sunlight and fermion baths can coexist steadily in nanoelectronic systems. Our analysis indicates that the efficiency at maximum power is no longer limited to η_{CA} through manipulation of carefully controlled quantum coherences.

  1. In utero magnetic resonance imaging for diagnosis of dural venous sinus ectasia with thrombosis in the fetus

    Energy Technology Data Exchange (ETDEWEB)

    Fanou, Evgenia Maria [University Hospital of North Staffordshire, Stoke-on-Trent (United Kingdom); Reeves, Mike J.; Griffiths, Paul D. [Royal Hallamshire Hospital, University of Sheffield, Academic Unit of Radiology, Sheffield (United Kingdom); Howe, David T. [Princess Anne Hospital, Wessex Fetal Medicine Unit, Southampton (United Kingdom); Joy, Harriet [University Hospital of Southampton, Department of Radiology, Southampton (United Kingdom); Morris, Susan [University Hospital of Wales, Radiology Department, Cardiff, Wales (United Kingdom); Russell, Sarah [St. Mary' s Hospital, Radiology Department, Manchester (United Kingdom)

    2013-12-15

    Dural venous sinus ectasia with thrombosis (DVSET) in the fetus is a rare condition that can be diagnosed prenatally with the use of fetal MR imaging, yet with limited indication of long-term clinical significance. To describe and evaluate the diagnostic value of fetal MR imaging in the prenatal diagnosis of dural venous sinus ectasia with thrombosis and its clinical significance. We report a series of nine fetuses with dural venous sinus ectasia with thrombosis. The mothers, located in four feto-maternal centres, were referred for fetal MR imaging due to space occupying lesions identified on second-trimester antenatal ultrasound. In all but one case the dural venous sinus ectasia with thrombosis was in the vicinity of the venous confluence (VC) with various extension in the posterior dural sinuses. Antenatal follow-up imaging was performed in seven cases and showed progression in one, stable appearances in one and regression in five cases. Three pregnancies were terminated. In the remaining six cases there was no reported neurological deficit at up to 44 months of clinical follow-up. This is among the largest series of postnatal clinical follow-up in cases of prenatal diagnosis of dural venous sinus ectasia with thrombosis in the literature. Clinical follow-up suggests a good prognosis when antenatal follow-up shows partial or complete thrombus resolution. (orig.)

  2. Simplified dc to dc converter

    Science.gov (United States)

    Gruber, R. P. (Inventor)

    1984-01-01

    A dc to dc converter which can start with a shorted output and which regulates output voltage and current is described. Voltage controlled switches directed current through the primary of a transformer the secondary of which includes virtual reactance. The switching frequency of the switches is appropriately varied to increase the voltage drop across the virtual reactance in the secondary winding to which there is connected a low impedance load. A starting circuit suitable for voltage switching devices is provided.

  3. Biomass compounds converted to gasoline

    Energy Technology Data Exchange (ETDEWEB)

    1979-10-08

    It is claimed that corn, castor, and jojoba oils as well as Hevea latex can be converted in high yields to gasoline by passage over zeolite catalysts at 450 degrees to 500 degrees centigrade. Gasoline yields are 60% from corn oil (essentially tristearin), compared with 50% yields from methanol. Latex depolymerizes before conversion. Fat and oil molecules adopt conformations that enable them to enter zeolite interstices, resulting in high yields of C6 to C9 aromatics.

  4. Workshop 4 Converter cooling & recuperation

    Science.gov (United States)

    Iles, Peter; Hindman, Don

    1995-01-01

    Cooling the PV converter increases the overall TPV system efficiency, and more than offsets the losses incurred in providing cooling systems. Convective air flow methods may be sufficient, and several standard water cooling systems, including thermo-syphon radiators, capillary pumps or microchannel plates, are available. Recuperation is used to increase system efficiency, rather than to increase the emitter temperature. Recuperators operating at comparable high temperatures, such as in high temperature turbines have worked effectively.

  5. Low perfusion index affects the difference in glucose level between capillary and venous blood

    Directory of Open Access Journals (Sweden)

    Acar N

    2014-11-01

    Full Text Available Nurdan Acar,1 Hamit Ozcelik,1 Arif Alper Cevik,1 Engin Ozakin,1 Goknur Yorulmaz,2 Nur Kebapci,2 Ugur Bilge,3 Muzaffer Bilgin4 1Emergency Department, 2Endocrinology Department, 3Family Medicine Department, 4Biostatistics Department, Medical School, Eskisehir Osmangazi University, Eskisehir, Turkey Aim: In emergency cases, finger stick testing is primarily used to check the blood glucose value of patients since it takes longer to obtain the venous value. In critical patients, under conditions that cause an increase in metabolic state and level of stress, there occurs considerable difference in glucose levels between capillary and venous measurements. This study aimed to investigate the comparability of capillary and venous glucose values, according to the perfusion index level obtained with the Masimo Radical-7® device, in critical patients aged 18 years and over.Method: We conducted this prospective and observational study in the emergency department of the Eskisehir Osmangazi University hospital between November 3, 2008 and February 2, 2009.Results: The blood glucose of 300 critical patients was checked by finger stick in the emergency unit. The participants with normal vital signs had perfusion index between 0 and 5; the results obtained by the two methods were more consistent for perfusion index values of 6 and over. The results were most consistent in aged participants with normal vital sign findings and low perfusion index and in young patients with high perfusion index. In the cases where at least one of the vital signs was abnormal, the glucose values obtained by the two methods were more consistent when the perfusion index was 6 or over. In this group, independently from the perfusion index value, the consistency was higher in younger patients compared with aged patients.Conclusion: In the emergency department, perfusion index value measured by Masimo Radical-7 and capillary blood glucose levels can serve in blood sugar management in

  6. Analysis of energy processes in pulse converters of AC electric power

    Directory of Open Access Journals (Sweden)

    Kadatsky A.F.

    2015-02-01

    Full Text Available The article presents the analysis of energy processes in switched-mode AC-AC converters of buck, boost and buck-boost types. The mathematical model of energy processes is obtained. The mathematical model is generalized to DC-DC and AC-AC converters, to three basic types of converters and considers possibility of autotransformer inclusion of an inductor. It is shown that the use of bi-directional switches allows both DC and AC conversion of electrical energy regardless of the load type and also supports recuperation of electrical energy back to the source. It is shown that the maximum value of instant power in a load circuit in AC—AC converters exceeds twice the rated value of load power in comparison with DC—DC converters. It is shown that the energy capacity of an inductor in AC—AC converters exceeds twice the energy capacity of DC—DC converters at the identical rated power of conversion. It is shown that the energy capacity of an inductor in converters of buck and boost types depends on the ratio of input and output voltage. Also, the energy capacity of an inductor in converters of buck-boost type does not depend on the ratio of input and output voltage. It is shown that the energy capacity of an inductor in converters of buck and boost types is lower than the energy capacity of an inductor in the converter of buck-boost type.

  7. Do Factor V Leiden and Prothrombin G20210A Mutations Predict Recurrent Venous Thromboembolism in Older Patients?

    Science.gov (United States)

    Méan, Marie; Limacher, Andreas; Stalder, Odile; Angelillo-Scherrer, Anne; Alberio, Lorenzo; Fontana, Pierre; Beer, Hans-Jürg; Rodondi, Nicolas; Lämmle, Bernhard; Aujesky, Drahomir

    2017-10-01

    The value of genetic thrombophilia testing in elderly patients with an unprovoked venous thromboembolism is unclear. We assessed whether the Factor V Leiden and the prothrombin G20210A mutation are associated with recurrent venous thromboembolism in elderly patients in a prospective multicenter cohort study. We genotyped the Factor V Leiden and the prothrombin G20210A mutation in 354 consecutive in- and outpatients aged ≥65 years with a first unprovoked venous thromboembolism from 9 Swiss hospitals. Patients and managing physicians were blinded to testing results. The outcome was recurrent symptomatic venous thromboembolism during follow-up. We examined the association between the Factor V Leiden and the prothrombin G20210A mutation and venous thromboembolism recurrence using competing risk regression, adjusting for age, sex, and periods of anticoagulation as a time-varying covariate. Overall, 9.0% of patients had a Factor V Leiden and 3.7% had a prothrombin G20210A mutation. At 36 months of follow-up, patients with a Factor V Leiden and a prothrombin G20210A mutation had a cumulative incidence of recurrent venous thromboembolism of 12.9% (95% confidence interval [CI], 5.1%-30.8%) and 18.5% (95% CI, 4.9%-56.5%), respectively, compared with 16.7% (95% CI, 12.5%-22.1%) of patients without mutation (P = .91 by the log-rank test). After adjustment, neither the Factor V Leiden (sub-hazard ratio 0.98; 95% CI, 0.35-2.77) nor the prothrombin G20210A mutation (sub-hazard ratio 1.15; 95% CI, 0.25-5.19) was associated with recurrent venous thromboembolism. Our results suggest that testing for genetic thrombophilia may not be beneficial in elderly patients with a first unprovoked venous thromboembolism. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Computerized simulation of converter process

    Energy Technology Data Exchange (ETDEWEB)

    Jalkanen, H.; Suomi, M.L.; Wallgren, M. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Metallurgy

    1996-12-31

    Converter process is essentially an oxidising refining process aiming in addition to (1) the primary refining action, decarburisation of high carbon iron melt, also to (2) maximal elimination of impurity elements, especially silicon, phosphorus and sulphur, (3) melting of substantial amounts of scrap using the extra heat released in oxidation reactions and (4) to exact final steel temperature control, optimal for further treatments. `Quantitative modelling of such a complex non-stationary chemical process as oxygen converting necessitates extensive formulation of chemical and thermal evolution of the process in connection with the technological properties of the reactor and the process control measures. A comprehensive converter simulation program like CONSIM-3. 1 and its preceding versions that is based on the theoretical and practical knowledge on the process can be used for (1) educating specialists and smelter personnel, (2) planning of the blowing programs, (3) developing and testing of process control systems and after some elaboration and restructuring (4) it can be integrated to static or dynamic process control systems. (orig.) SULA 2 Research Programme; 10 refs.

  9. Design and Control for the Buck-Boost Converter Combining 1-Plus-D Converter and Synchronous Rectified Buck Converters

    Directory of Open Access Journals (Sweden)

    Jeevan Naik

    2015-06-01

    Full Text Available In this paper, a design and control for the buck-boost converter, i.e., 1-plus-D converter with a positive output voltage, is presented, which combines the 1-plus-D converter and the synchronous rectified (SR buck converter. By doing so, the problem in voltage bucking of the 1-plus-D converter can be solved, thereby increasing the application capability of the 1-plus-D converter. Since such a converter operates in continuous conduction mode inherently, it possesses the nonpulsating output current, thereby not only decreasing the current stress on the output capacitor but also reducing the output voltage ripple. Above all, both the 1-plus-D converter and the SR buck converter, combined into a buck–boost converter with no right-half plane zero, use the same power switches, thereby causing the required circuit to be compact and the corresponding cost to be down. Furthermore, during the magnetization period, the input voltage of the 1-plus-D converter comes from the input voltage source, whereas during the demagnetization period, the input voltage of the 1-plus-D converter comes from the output voltage of the SR buck converter.

  10. [Medial venous catheter or midline (MVC)].

    Science.gov (United States)

    Carrero Caballero, Ma Carmen; Montealegre Sanz, María; Cubero Pérez, Ma Antonia

    2014-01-01

    Current clinical practice is characterised for importance of the patient's quality of life and the need to reduce the costs of their treatment. We search intravenous therapy alternatives that meet the needs of the patient, reducing the complications associated with the use of venous catheters. Scientific evidence shows that there are midline venous catheters that offer patients and professionals the possibility of extending the duration of infusion therapy, using more venous compatibility materials, and with less risk of infection. The Midlines are becoming in a safe an efficient device for intravenous therapy, continuous and intermittent infusion, provided the necessary care by expert nurses. Midline catheters are peripheral venous access devices between 3 to 10 inches in length (8 to 25 cm). Midlines are usually placed in an upper arm vein, such as the brachial or cephalic, and the distal extreme ends below the level of the axillary line. Midlines catheters implanted in the cephalic or deep basilica veins get more blood flow. This large blood volume justifies the lower risk of mechanical or chemical phlebitis. Midlines are routinely used for two to six weeks. Due that the extrem of these catheters does not extend beyond the axillary line, there are limitations for its use: type of infused drugs, velocity of infusion, etc. In general, solutions that have pH 5 to 9, or an osmolarity less than 500 mOsm are appropriate for infusion through a Midline. Its use is recommended in case of treatments over 7 days with low irritant capacity fluids. According to the Infusion Nurses Society's standards of practice, Midline catheters are appropriate for all intravenous fluids that would normally be administered through a short peripheral IV Importantly, due that the catheter does not pass through the central veins, Midlines can be placed without a chest X-ray to confirm placement. For certain situations, Midlines are suitable for acute units and even for care home settings

  11. Computed Tomograpy Venography diagnosis of iliocaval venous obstruction in advanced chronic venous insufficiency

    Directory of Open Access Journals (Sweden)

    Fabio Henrique Rossi

    2014-12-01

    Full Text Available Objective:Iliocaval obstruction is associated with venous hypertension symptoms and may predispose to deep venous thrombosis (DVT. Ultrasonography may fail to achieve noninvasive diagnosis of these obstructions. The possibility of using Computed Tomography Venography (CTV for these diagnoses is under investigation.Methods:Patients with CVI graded at CEAP clinical classes 3 to 6 and previous treatment failure underwent evaluation with CTV. Percentage obstruction was rated by two independent examiners. Obstruction prevalence and its associations with risk factors and CEAP classification were analyzed.Results:A total of 112 limbs were prospectively evaluated. Mean patient age was 55.8 years and 75.4% were women. Obstructions involved the left lower limb in 71.8% of cases and 35.8% of patients reported a medical history of deep venous thrombosis. Overall, 57.1% of imaging studies demonstrated venous obstruction of at least 50% and 10.7% showed obstruction of >80%. The only risk factor that was found to be independently associated with a significantly higher incidence of >50% venous obstruction was a medical history of DVT (p=0.035 (Fisher's exact test. There was a positive relationship between clinical classification (CEAP and degree of venous obstruction in the limbs studied (Chi-square test for linear trend; p=0.011.Conclusion:Patients with advanced CVI are often affected by obstructions in the iliocaval venous territory and CTV is able to diagnose the degree of obstruction. There is a positive association between degree of obstruction and both previous history of DVT and severity of symptoms of CVI.

  12. Risk factors for venous thrombosis associated with peripherally inserted central venous catheters.

    Science.gov (United States)

    Pan, Longfang; Zhao, Qianru; Yang, Xiangmei

    2014-01-01

    To evaluate the risk factors associated with an increased risk of symptomatic peripherally inserted central venous catheter (PICC)-related venous thrombosis. Retrospective analyses identified 2313 patients who received PICCs from 1 January 2012 to 31 December 2013. All 11 patients with symptomatic PICC-related venous thrombosis (thrombosis group) and 148 who did not have thromboses (non-thrombosis group) were selected randomly. The medical information of 159 patients (age, body mass index (BMI), diagnosis, smoking history, nutritional risk score, platelet count, leucocyte count as well as levels of D-dimer, fibrinogen, and degradation products of fibrin) were collected. Logistic regression analysis was undertaken to determine the risk factors for thrombosis. Of 2313 patients, 11 (0.47%) were found to have symptomatic PICC-related venous thrombosis by color Doppler ultrasound. Being bedridden for a long time (odds ratio [(OR]), 17.774; P=0.0017), D-dimer >5 mg/L (36.651; 0.0025) and suffering from one comorbidity (8.39; 0.0265) or more comorbidities (13.705; 0.0083) were the major risk factors for PICC-catheter related venous thrombosis by stepwise logistic regression analysis. Among 159 patients, the prevalence of PICC-associated venous thrombosis in those with ≥1 risk factor was 10.34% (12/116), in those with ≥2 risk factors was 20.41% (10/49), and in those with >3 risk factors was 26.67% (4/15). Being bedridden >72 h, having increased levels of D-dimer (>5 mg/L) and suffering from comorbidities were independent risk factors of PICC-related venous thrombosis.

  13. Comparison of intramuscular and venous blood pH, PCO(2) and PO(2) during rhythmic handgrip exercise.

    Science.gov (United States)

    Soller, Babs R; Hagan, R Donald; Shear, Michael; Walz, J Matthias; Landry, Michelle; Anunciacion, Dulce; Orquiola, Alan; Heard, Stephen O

    2007-06-01

    Oxygen and acid-base status during exercise is well established for the lungs, large arteries and veins. However, values for these parameters in exercising muscle are less frequently reported. In this study we examined the relationship between intramuscular PO(2), pH, PCO(2) and the comparable venous values during rhythmic isometric handgrip exercise at target levels of 15%, 30% and 45% of maximum voluntary contraction (MVC). A small fiber optic sensor was inserted into the flexor digitorum profundus (FDP) muscle for continuous measurement of intramuscular (IM) PO(2), pH and PCO(2). Venous blood samples were taken from the forearm every minute during each exercise bout. IM pH and PCO(2) were similar to their venous counterparts at baseline, but the difference between IM and venous values increased when exercise exceeded 30% MVC. During exercise at 15% MVC and greater, venous PO(2) declined from 40 to 21 Torr (approximately 5.3 to 2.8 kPa). IM PO(2) declined from 24 to 8 Torr with 15% MVC, and approached 0 Torr at 30% MVC and 45% MVC. IM pH declined rapidly when IM PO(2) reached 10 Torr and continued to decrease with increasing exertion, despite an IM PO(2) near 0 Torr.

  14. Thermal heat-balance mode flow-to-frequency converter

    Science.gov (United States)

    Pawlowski, Eligiusz

    2016-11-01

    This paper presents new type of thermal flow converter with the pulse frequency output. The integrating properties of the temperature sensor have been used, which allowed for realization of pulse frequency modulator with thermal feedback loop, stabilizing temperature of sensor placed in the flowing medium. The system assures balancing of heat amount supplied in impulses to the sensor and heat given up by the sensor in a continuous way to the flowing medium. Therefore the frequency of output impulses is proportional to the heat transfer coefficient from sensor to environment. According to the King's law, the frequency of those impulses is a function of medium flow velocity around the sensor. The special feature of presented solution is total integration of thermal sensor with the measurement signal conditioning system. Sensor and conditioning system are not the separate elements of the measurement circuit, but constitute a whole in form of thermal heat-balance mode flow-to-frequency converter. The advantage of such system is easiness of converting the frequency signal to the digital form, without using any additional analogue-to-digital converters. The frequency signal from the converter may be directly connected to the microprocessor input, which with use of standard built-in counters may convert the frequency into numerical value of high precision. Moreover, the frequency signal has higher resistance to interference than the voltage signal and may be transmitted to remote locations without the information loss.

  15. Simulation Results of Double Forward Converter

    Directory of Open Access Journals (Sweden)

    P. Vijaya KUMAR

    2009-12-01

    Full Text Available This work aims to find a better forward converter for DC to DC conversion.Simulation of double forward converter in SMPS system is discussed in this paper. Aforward converter with RCD snubber to synchronous rectifier and/or to current doubleris also discussed. The evolution of the forward converter is first reviewed in a tutorialfashion. Performance parameters are discussed including operating principle, voltageconversion ratio, efficiency, device stress, small-signal dynamics, noise and EMI. Itscircuit operation and its performance characteristics of the forward converter with RCDsnubber and double forward converter are described and the simulation results arepresented.

  16. Agreement and Correlation between Arterial and Central Venous Blood Gas Following Coronary Artery Bypass Graft Surgery.

    Science.gov (United States)

    Esmaeilivand, Masoumeh; Khatony, Alireza; Moradi, Gholamreza; Najafi, Farid; Abdi, Alireza

    2017-03-01

    Arterial blood sampling, used to assess patients in acute conditions, may result in complications such as thrombosis and embolism. However, it can be replaced by venous blood sampling, but there is a dearth of information on this. To assess the correlation and agreement between the arterial and central venous blood gases analyses in patients undergoing elective Coronary Artery Bypass Graft (CABG) surgery. In this cross-sectional study, 100 ICU patients undergoing elective CABG surgery were recruited. 2 mm arterial and a 2 mm venous blood samples were obtained from each patient's arterial and central venous lines, respectively. To predict Arterial Blood Gas (ABG) values based on central Venous Blood Gas (VBG) values, the linear regression analysis was used and for evaluating their agreement Bland-Altman method was used. In total of 200 samples were obtained. The mean and Standard Deviation (SD) of age was 58.9±9.1 years and 51% of the participants were female. There was a strong correlation between ABG and central VBG values regarding pH, partial Pressure of Carbon Dioxide (PCO2), Bicarbonate (HCO3) and Base Excess (BE) (r= 0.73, r=0.74, r=0.67 and r=0.71, respectively; parterial and venous Partial Pressure of Oxygen (PO2) and Oxygen Saturation (SO2) was moderate (r=0.29, p=0.005 and r=0.27, p=0.006, respectively). The Bland-Altman analysis showed an excellent agreement between all the variables (panalysis cannot replace ABG analysis in measuring exact PO2 status, necessitating arterial sampling in some matters, but with respect to the accuracy of pulse oximetry measurements in determining the exact PO2 status, for the rest of the indices a central VBG rather than an ABG can be utilised for determining patient's acid-base status. Particularly in patients who are hospitalised for a long time and have a central venous catheter in place like patients who have undergone CABG, thus reducing the risk and need for invasive arterial sampling.

  17. Comparison of four clinical scores for the predicting lower limb deep venous thrombosis in Chinese patients

    Institute of Scientific and Technical Information of China (English)

    Li Zhua; Min Liu; Xiaojuan Guo; Jianguo Wang; Youmin Guo; Chen Wang; Hongxia Ma; Yulin Guo

    2008-01-01

    To evaluate Wells, Kahn, St.Andr é and Constans scores for the prediction of deep venous thrombosis in Chinese patients.Methods:One hundred and seventy-two patients, prospectively, blinded referred for evaluation with four clinical-score systems for suspected deep venous thrombosis, were examined by ultrasonography.Sensitivity, specificity, positive predictive value, nega- tive predictive value and receiver operation curves were calculated for four clinical scores.The difference between areas of the ROC curve for each of the scores was compared with others and reference line.Results:Forty-six of 172 patients had deep venous throm- bosis proven by sonography.The sensitivity, specificity, positive predictive value and negative predictive value for Wells score was 91.3%, 27.4% and 74.2% respectively, for Constans score; 95.7%, 34.9%, 34.9% and 95.7% respectively.Area under ROV curve of Constans with the reference line.Conclusion:Based on the results of our study, the sensitivity, negative prediction value and area under ROC Considering the aim of the clinical assessment, Constans score and Wells score are more efficient for Chinese hospitalized patients.

  18. Forback DC-to-DC converter

    Science.gov (United States)

    Lukemire, Alan T.

    1995-05-01

    A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

  19. Forback DC-to-DC converter

    Science.gov (United States)

    Lukemire, Alan T. (Inventor)

    1993-01-01

    A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

  20. CCLIBS: The CERN Power Converter Control Libraries

    CERN Document Server

    AUTHOR|(SzGeCERN)404953; Lebioda, Krzysztof Tomasz; Magrans De Abril, Marc; Martino, Michele; Murillo Garcia, Raul; Nicoletti, Achille

    2015-01-01

    Accurate control of power converters is a vital activity in large physics projects. Several different control scenarios may coexist, including regulation of a circuit’s voltage, current, or field strength within a magnet. Depending on the type of facility, a circuit’s reference value may be changed asynchronously or synchronously with other circuits. Synchronous changes may be on demand or under the control of a cyclic timing system. In other cases, the reference may be calculated in real-time by an outer regulation loop of some other quantity, such as the tune of the beam in a synchrotron. The power stage may be unipolar or bipolar in voltage and current. If it is unipolar in current, it may be used with a polarity switch. Depending on the design, the power stage may be controlled by a firing angle or PWM duty-cycle reference, or a voltage or current reference. All these cases are supported by the CERN Converter Control Libraries (CCLIBS). These open-source C libraries include advanced reference generati...

  1. Central venous obstruction in the thorax.

    Science.gov (United States)

    Collin, G; Jones, R G; Willis, A P

    2015-06-01

    Central venous stenosis and occlusion can occur secondary to a spectrum of conditions ranging from aggressive malignancy to benign extrinsic anatomical compression in otherwise healthy individuals. Irrespective of aetiology, significant morbidity in the acute setting and long term can occur unless prompt accurate diagnosis and appropriate management is initiated, the radiologist being central to both. The present review will provide radiologists with a thorough illustration and explanation of the range of central venous conditions in the thorax (including deep vein thrombosis, thoracic outlet syndrome, haemodialysis, and malignancy related causes), the salient imaging findings and interventional management using case examples from the authors' practice. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  2. [Venous thromboembolism in patients with cancer].

    Science.gov (United States)

    Lecumberri, Ramón; Feliu, Jesús; Rocha, Eduardo

    2006-06-03

    The association between neoplastic diseases and venous thromboembolism (VTE) is known since long time ago. The nature of this association is bidirectional. On one hand, cancer increases the incidence of venous thrombosis and, on the other hand, the hemostatic system does play a key role in the tumorigenesis process. However, despite recent advances in the field, prophylaxis and treatment of VTE in cancer patients is still a challenge, due to the complexity of this type of patients. This review is focused on some important points regarding management of VTE in cancer patients such as physiopathology, epidemiology, search for hidden malignancy, prognostic impact, prophylaxis in the medical and surgical setting, or initial and long-term treatment.

  3. [Prevention of venous thromboembolism in musculoskeletal surgery].

    Science.gov (United States)

    Pabinger-Fasching, Ingrid; Eichinger-Hasenauer, Sabine; Grohs, Josef; Hochreiter, Josef; Kastner, Norbert; Korninger, Hans Christian; Kozek-Langenecker, Sibylle; Marlovits, Stefan; Niessner, Herwig; Rachbauer, Franz; Ritschl, Peter; Wurnig, Christian; Windhager, Reinhard

    2014-05-01

    Musculoskeletal surgery is associated with a high risk of venous thrombosis and pulmonary embolism. The introduction of direct oral anticoagulants (DOAK) has broadened the possibilities for prevention of venous thromboembolism in the course of orthopedic and trauma surgery. Addressing this recent development, the Austrian Societies of Orthopedics and Orthopedic Surgery (ÖGO), Trauma Surgery (ÖGU), Hematology and Oncology (OeGHO) and of Anaesthesiology, Reanimation und Intensive Care Medicine (ÖGARI) have taken the initiative to create Austrian guidelines for the prevention of thromboembolism after total hip and knee replacement, hip fracture surgery, interventions at the spine and cases of minor orthopedic and traumatic surgery. Furthermore, the pharmacology of the DOAK and the pivotal trial data for each of the three currently available substances - apixaban, dabigatran, and rivaroxaban - are briefly presented. Separate chapters are dedicated to "anticoagulation and neuroaxial anesthesia" and "bridging".

  4. External jugular venous aneurysm: A clinical curiosity

    Science.gov (United States)

    Mohanty, Debajyoti; Jain, Bhupendra Kumar; Garg, Pankaj Kumar; Tandon, Anupama

    2013-01-01

    Jugular venous aneurysm is an extremely rare condition. The patients presented with a painless swelling in the neck that appears while coughing, straining, bending, or breath holding. Detection of a soft and compressible swelling in the course of an external jugular vein (EJV) superficial to the sternomastoid muscle, non-filling on compression of the EJV during Valsalva maneuver clinches the diagnosis of EJV aneurysm. Color Doppler ultrasound allows precise delineation of the lesion and is considered the gold standard for confirming the diagnosis. Surgical excision is indicated mostly for cosmetic reasons and symptomatic aneurysms. We, herein, report a patient with saccular external jugular venous aneurysm to highlight the typical clinical presentation and diagnosis of this rare entity. PMID:23633867

  5. Venous Thromboembolism in Patients With Thrombocytopenia

    DEFF Research Database (Denmark)

    Baelum, Jens Kristian; Moe, Espen Ellingsen; Nybo, Mads

    2017-01-01

    . OBJECTIVES: To identify VTE risk factors and describe treatment and outcome (bleeding episodes and mortality) in patients with thrombocytopenia. PATIENTS/METHODS: Patients with thrombocytopenia (platelet count ... with anticoagulants. There was no difference in bleeding incidence between cases and controls. CONCLUSIONS: Several known VTE risk factors also seems to apply in patients with thrombocytopenia. Also, patients with thrombocytopenia may be VTE risk stratified based on platelet count and comorbidities. Finally, patients......BACKGROUND: Venous thromboembolism (VTE) is a frequent and potentially lethal condition. Venous thrombi are mainly constituted of fibrin and red blood cells, but platelets also play an important role in VTE formation. Information about VTE in patients with thrombocytopenia is, however, missing...

  6. Deep venous thrombosis of the upper extremity

    DEFF Research Database (Denmark)

    Klitfod, Lotte; Broholm, R; Baekgaard, N

    2013-01-01

    to the condition. Malignancy and therapeutic interventions are major risk factors for the secondary deep vein thrombosis in combination with the patient's characteristics, comorbidities and prior history of deep vein thrombosis. Complications: recurrent deep venous thrombosis, pulmonary embolism and Post......Upper extremity deep venous thrombosis (UEDVT) occurs either spontaneously, as a consequence of strenuous upper limb activity (also known as the Paget-Schroetter syndrome) or secondary to an underlying cause. Primary and secondary UEDVT differs in long-term sequelae and mortality. This review...... will focus on the clinical presentation, risk factors, diagnosis, and treatment strategies of UEDVT. In the period from January to October 2012 an electronic literature search was performed in the PubMed/MEDLINE database, and 27 publications were included. Clinical presentation: swelling, pain and functional...

  7. Si Bule Masuk Islam: Western Converts to Islam in Indonesia - more than just Converts of Convenience?

    OpenAIRE

    M. A. Kevin Brice

    2015-01-01

    In discussing converts to Islam, two different types of converts are often identified based on the reason for conversion: converts of convenience and converts of conviction. The common view is that in most (if not all) cases, conversion to Islam in Indonesia by Westerners is about facilitating marriage and so the converts should be classified as converts of convenience. Evidence of the commonality of this view is considered by reference to advice offered to Westerners about marriage to Indone...

  8. Congenital pseudoarthrosis associated with venous malformation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hadidy, A.; Haroun, A.; Al-Ryalat, N. [Jordan University Hospital, Radiology Department, P.O. Box 340621, Amman (Jordan); Hamamy, H. [Endocrinology and Genetics, National Center for Diabetes, Amman (Jordan); Al-Hadidi, S. [Jordan University Hospital, Departments of Orthopedics, Amman (Jordan)

    2007-06-15

    Congenital pseudoarthrosis is a pathologic entity that may be isolated, or may be associated with neurofibromatosis. We report the case of a 3-year-old female with congenital pseudoarthrosis involving the right tibia and fibula. Magnetic resonance imaging (MRI) and complementary magnetic resonance angiogram (MRA) revealed a lobulated mass with vivid enhancement, which led to the diagnosis of venous malformation. This is the first report of congenital pseudoarthrosis caused by the presence of a vascular malformation. (orig.)

  9. Epidemiology and Risk Factors for Venous Thrombosis

    OpenAIRE

    Cushman, Mary

    2007-01-01

    Venous thrombosis, including deep vein thrombosis and pulmonary embolism, occurs at an annual incidence of about 1 per 1000 adults. Rates increase sharply after around age 45 years, and are slightly higher in men than women in older age. Major risk factors for thrombosis, other than age, include exogenous factors such as surgery, hospitalization, immobility, trauma, pregnancy and the puerperium and hormone use, and endogenous factors such as cancer, obesity, and inherited and acquired disorde...

  10. Cerebral venous sinus thrombosis with autoimmune thyroiditis

    Directory of Open Access Journals (Sweden)

    Sameer Aggarwal

    2013-01-01

    Full Text Available Cerebral Venous Thrombosis ( CVT is a multifactorial condition which is described as idiopathic in 12.5% of patients. Hyperthyroidism has been associated with CVT in many case reports, and increased levels of factor VIII and von Willebrand factor (vWF have been proposed as the possible link in this association, but only few rare case reports have described an association of hypothyroidism with CVT. We report here a case of autoimmune thyroiditis presenting with CVT.

  11. Venous malformations: clinical diagnosis and treatment.

    Science.gov (United States)

    Behravesh, Sasan; Yakes, Wayne; Gupta, Nikhil; Naidu, Sailendra; Chong, Brian W; Khademhosseini, Ali; Oklu, Rahmi

    2016-12-01

    Venous malformation (VM) is the most common type of congenital vascular malformation (CVM). They are present at birth and are often symptomatic, causing morbidity and pain. VMs can be challenging to diagnose and are often confused with hemangioma in terminology as well as with imaging. An accurate clinical history and cross-sectional imaging are critical for diagnosis and for devising management. This manuscript will review imaging approaches to diagnosing VMs and current treatment strategies.

  12. The controversy on chronic cerebrospinal venous insufficiency

    Directory of Open Access Journals (Sweden)

    Paolo Zamboni

    2013-08-01

    Full Text Available The objective of this review is to analyze the actual scientific controversy on chronic cerebrospinal venous insufficiency (CCSVI and its association with both neurodegenerative disorders and multiple sclerosis (MS. We revised all published studies on prevalence of CCSVI in MS patients, including ultrasound and catheter venography series. Furthermore, we take into consideration other publications dealing with the pathophysiologic consequences of CCSVI in the brain, as well as ecent data characterizing the pathology of the venous wall in course of CCSVI. Finally, safety and pilot data on effectiveness of endovascular CCSVI treatment were further updated. Studies of prevalence show a big variability in prevalence of CCSVI in MS patients assessed by established ultrasonographic criteria. This could be related to high operator dependency of ultrasound. However, 12 studies, by the means of more objective catheter venography, show a prevalence >90% of CCSVI in MS. Global hypo-hypoperfusion of the brain, and reduced cerebral spinal fluid dynamics in MS was shown to be related to CCSVI. Postmortem studies and histology corroborate the 2009 International Union of Phlebology (UIP Consensus decision to insert CCSVI among venous malformations. Finally, safety of balloon angioplasty of the extracranial veins was certainly demonstrated, while prospective data on the potential effectiveness of endovascular treatment of CCSVI support to increase the level of evidence by proceeding with a randomized control trial (RCT. Taking into account the current epidemiological data, including studies on catheter venography, the autoptic findings, and the relationship between CCSVI and both hypo-perfusion and cerebro-spinal fluid flow, we conclude that CCSVI can be definitively inserted among the medical entities. Research is still inconclusive in elucidating the CCSVI role in the pathogenesis of neurological disorders. The controversy between the vascular and the

  13. What's new: Management of venous leg ulcers: Approach to venous leg ulcers.

    Science.gov (United States)

    Alavi, Afsaneh; Sibbald, R Gary; Phillips, Tania J; Miller, O Fred; Margolis, David J; Marston, William; Woo, Kevin; Romanelli, Marco; Kirsner, Robert S

    2016-04-01

    Leg ulcerations are a common problem, with an estimated prevalence of 1% to 2% in the adult population. Venous leg ulcers are primarily treated in outpatient settings and often are managed by dermatologists. Recent advances in the diagnosis and treatment of leg ulcers combined with available evidence-based data will provide an update on this topic. A systematized approach and the judicious use of expensive advanced therapeutics are critical. Specialized arterial and venous studies are most commonly noninvasive. The ankle brachial pressure index can be performed with a handheld Doppler unit at the bedside by most clinicians. The vascular laboratory results and duplex Doppler findings are used to identify segmental defects and potential operative candidates. Studies of the venous system can also predict a subset of patients who may benefit from surgery. Successful leg ulcer management requires an interdisciplinary team to make the correct diagnosis, assess the vascular supply, and identify other modifiable factors to optimize healing. The aim of this continuing medical education article is to provide an update on the management of venous leg ulcers. Part I is focused on the approach to venous ulcer diagnostic testing.

  14. Multiple venous thrombosis complicating central venous cannulation in a non cancer patient - a case report.

    Science.gov (United States)

    Peters, Ce; Menkiti, Id; Desalu, I; Thomas, Mo

    2013-01-01

    Central venous catheterization is a common procedure for critically ill patients. Like all procedures, it has its complications, one of which is thrombosis. Reports of thrombosis are commoner among cancer patients. We present a 37 year old non cancer patient who developed thrombi in both right and left internal jugular veins, 10 and 13 days respectively after insertion of central venous catheter. This was detected by ultrasound scans of the neck while attempting re-cannulation for parenteral feeding. She also had left lower limb deep venous thrombosis, confirmed by doppler scan, which was managed with low molecular weight heparin and warfarin. The patient was subsequently treated with streptokinase. A repeat scan of the internal jugular veins 4 days after thrombolysis revealed a reduction in size of the thrombi. Symptoms of deep venous thrombosis improved and she was transferred to the wards where she made remarkable improvement. This case illustrates the potential usefulness of ultrasound guided-central line insertion in patients who have had central venous lines inserted previously in order to detect thrombi.

  15. Venous access: options, approaches and issues

    Energy Technology Data Exchange (ETDEWEB)

    Asch, M.R. [Univ. of Toronto, Mount Sinai Hospital, Dept. of Medical Imaging, Toronto, Ontario (Canada)

    2001-06-01

    Venous access is an essential part of medical practice. It is needed to obtain blood samples to make the diagnosis and to administer fluids or medicines as part of treatment. Although relatively new in the history of medicine, the placement and maintenance of the various venous access devices now occupies a significant portion of many vascular and interventional radiology practices. Thus, it is important to have a thorough understanding of these devices and their uses. The first long-term venous access devices were used in 1973. These were placed via a surgical cut-down on the subclavian vein. In 1982, the first subcutaneous implantable ports were described. These procedures were initially performed by surgeons, but over the last 5-10 years, both the insertion and management of these devices has shifted to interventional radiologists. Peripherally inserted central catheter (PICC) lines have almost completely supplanted the use of standard central lines (Fig. 1). A number of factors have facilitated this - namely, ready and less expensive room access, outpatient procedure and radiologists' accessibility and familiarity with image-guidance procedures and catheters and guide wires. (author)

  16. Developmental venous anomaly in the newborn brain

    Energy Technology Data Exchange (ETDEWEB)

    Horsch, S. [Erasmus MC-Sophia Children' s Hospital, Department of Neonatology, Rotterdam (Netherlands); Helios Klinikum Berlin-Buch, Department of Neonatology, Berlin (Germany); Govaert, P. [Erasmus MC-Sophia Children' s Hospital, Department of Neonatology, Rotterdam (Netherlands); Cowan, F.M. [Hammersmith Hospital, Department of Paediatrics, Imperial College Healthcare NHS Trust, London (United Kingdom); Benders, M.J.N.L.; Groenendaal, F.; Vries, L.S. de [University Medical Centre Utrecht, Wilhelmina Children' s Hospital, Department of Neonatology, Utrecht (Netherlands); Lequin, M.H. [Erasmus MC/Sophia Children' s Hospital, Department of Paediatric Radiology, Rotterdam (Netherlands); Saliou, G. [University Hospital, Department of Neuroradiology, Le Kremlin-Bicetre (France)

    2014-07-15

    Cerebral developmental venous anomaly (DVA) is considered a benign anatomical variant of parenchymal venous drainage; it is the most common vascular malformation seen in the adult brain. Despite its assumed congenital origin, little is known about DVA in the neonatal brain. We report here the first cohort study of 14 neonates with DVA. Fourteen infants (seven preterm) with DVA diagnosed neonatally using cranial ultrasound (cUS) and magnetic resonance imaging (MRI) from three tertiary neonatal units over 14 years are reviewed. DVA was first detected on cUS in 6 and on MRI in 8 of the 14 infants. The cUS appearances of DVA showed a focal fairly uniform area of increased echogenicity, often (86 %) adjacent to the lateral ventricle and located in the frontal lobe (58 %). Blood flow in the dilated collector vein detected by Doppler ultrasound (US) varied between cases (venous flow pattern in ten and arterialized in four). The appearance on conventional MRI was similar to findings in adults. Serial imaging showed a fairly constant appearance to the DVAs in some cases while others varied considerably regarding anatomical extent and flow velocity. This case series underlines that a neonatal diagnosis of DVA is possible with carefully performed cUS and MRI and that DVA tends to be an incidental finding with a diverse spectrum of imaging appearances. Serial imaging suggests that some DVAs undergo dynamic changes during the neonatal period and early infancy; this may contribute to why diagnosis is rare at this age. (orig.)

  17. Ethanol sclerotherapy of peripheral venous malformations

    Energy Technology Data Exchange (ETDEWEB)

    Rimon, U. E-mail: rimonu@sheba.health.gov.il; Garniek, A.; Galili, Y.; Golan, G.; Bensaid, P.; Morag, B

    2004-12-01

    Background: venous malformations are congenital lesions that can cause pain, decreased range of movement, compression on adjacent structures, bleeding, consumptive coagulopathy and cosmetic deformity. Sclerotherapy alone or combined with surgical excision is the accepted treatment in symptomatic malformations after failed treatment attempts with tailored compression garments. Objectives: to report our experience with percutaneous sclerotherapy of peripheral venous malformations with ethanol 96%. Patients and methods: 41 sclerotherapy sessions were performed on 21 patients, aged 4-46 years, 15 females and 6 males. Fourteen patients were treated for painful extremity lesions, while five others with face and neck lesions and two with giant chest malformations had treatment for esthetic reasons. All patients had a pre-procedure magnetic resonance imaging (MRI) study. In all patients, 96% ethanol was used as the sclerosant by direct injection using general anesthesia. A minimum of 1-year clinical follow-up was performed. Follow-up imaging studies were performed if clinically indicated. Results: 17 patients showed complete or partial symptomatic improvement after one to nine therapeutic sessions. Four patients with lower extremity lesions continue to suffer from pain and they are considered as a treatment failure. Complications were encountered in five patients, including acute pulmonary hypertension with cardiovascular collapse, pulmonary embolus, skin ulcers (two) and skin blisters. All patients fully recovered. Conclusion: sclerotherapy with 96% ethanol for venous malformations was found to be effective for symptomatic improvement, but serious complications can occur.

  18. Venous thromboembolism prophylaxis in the pediatric trauma patient.

    Science.gov (United States)

    Petty, John K

    2017-02-01

    Although venous thromboembolism (VTE) occurs in less than 1% of hospitalized pediatric trauma patients, care providers must make decisions about VTE prophylaxis on a daily basis. The consequences of VTE are significant; the risks of developing VTE are variable; and the effectiveness of prophylaxis against VTE is not conclusive in children. While the value of VTE prophylaxis is well defined in adult trauma care, it is unclear how this translates to the care of injured children. This review evaluates the incidence and risks of VTE in pediatric trauma and assesses the merits of prophylaxis in children. Pharmacologic prophylaxis against VTE is a reasonable strategy in critically injured adolescent trauma patients. Further study is needed to establish the risks and benefits of VTE prophylaxis across the spectrum of injured children. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. multilevel buck converter for automotive electrical load

    African Journals Online (AJOL)

    user

    development of DCM based buck converter and its applications in the HEVs/EVs using ... The paper also highlights the implications of implementing a single stage buck converter, and ..... instance when the saw tooth signal within the internal.

  20. An upgraded camera-based imaging system for mapping venous blood oxygenation in human skin tissue

    Science.gov (United States)

    Li, Jun; Zhang, Xiao; Qiu, Lina; Leotta, Daniel F.

    2016-07-01

    A camera-based imaging system was previously developed for mapping venous blood oxygenation in human skin. However, several limitations were realized in later applications, which could lead to either significant bias in the estimated oxygen saturation value or poor spatial resolution in the map of the oxygen saturation. To overcome these issues, an upgraded system was developed using improved modeling and image processing algorithms. In the modeling, Monte Carlo (MC) simulation was used to verify the effectiveness of the ratio-to-ratio method for semi-infinite and two-layer skin models, and then the relationship between the venous oxygen saturation and the ratio-to-ratio was determined. The improved image processing algorithms included surface curvature correction and motion compensation. The curvature correction is necessary when the imaged skin surface is uneven. The motion compensation is critical for the imaging system because surface motion is inevitable when the venous volume alteration is induced by cuff inflation. In addition to the modeling and image processing algorithms in the upgraded system, a ring light guide was used to achieve perpendicular and uniform incidence of light. Cross-polarization detection was also adopted to suppress surface specular reflection. The upgraded system was applied to mapping of venous oxygen saturation in the palm, opisthenar and forearm of human subjects. The spatial resolution of the oxygenation map achieved is much better than that of the original system. In addition, the mean values of the venous oxygen saturation for the three locations were verified with a commercial near-infrared spectroscopy system and were consistent with previously published data.

  1. Converting pest insects into food

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim; Wiwatwittaya, Decha

    2010-01-01

    on management, 32-115 kg ant brood (mainly new queens) was harvested per ha per year without detrimental effect on colony survival and worker ant densities. This suggest that ant biocontrol and ant harvest can be sustainable integrated in plantations and double benefits derived. As ant production is fuelled...... by pest insects, problematic pests are converted into food and additional earnings. To assess the profitability of providing additional food for the ants, O. smaragdina food conversion efficiency (ECI) was estimated in the laboratory. This estimate suggests the feeding of weaver ants in ant farms...

  2. Power electronics converters and regulators

    CERN Document Server

    Dokić, Branko L

    2015-01-01

    This book is the result of the extensive experience the authors gained through their year-long occupation at the Faculty of Electrical Engineering at the University of Banja Luka. Starting at the fundamental basics of electrical engineering, the book guides the reader into this field and covers all the relevant types of converters and regulators. Understanding is enhanced by the given examples, exercises and solutions. Thus this book can be used as a textbook for students, for self-study or as a reference book for professionals.

  3. Converting pest insects into food

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim; Wiwatwittaya, Decha

    2010-01-01

    Canopy dwelling weaver ants (Oecophylla spp.) are used to control a variety of pests in a number of tropical tree crops. What is less familiar is the existence of commercial markets where these ants and their brood are sold for (i) human consumption, (ii) pet food or (iii) traditional medicine...... by pest insects, problematic pests are converted into food and additional earnings. To assess the profitability of providing additional food for the ants, O. smaragdina food conversion efficiency (ECI) was estimated in the laboratory. This estimate suggests the feeding of weaver ants in ant farms...

  4. OAM mode converter in twisted fibers

    DEFF Research Database (Denmark)

    Usuga Castaneda, Mario A.; Beltran-Mejia, Felipe; Cordeiro, Cristiano

    2014-01-01

    We analyze the case of an OAM mode converter based on a twisted fiber, through finite element simulations where we exploit an equivalence between geometric and material transformations. The obtained converter has potential applications in MDM. © 2014 OSA.......We analyze the case of an OAM mode converter based on a twisted fiber, through finite element simulations where we exploit an equivalence between geometric and material transformations. The obtained converter has potential applications in MDM. © 2014 OSA....

  5. Analysis and design of converters in Matlab

    OpenAIRE

    Lorente Sanjurjo, Rodrigo

    2010-01-01

    This project will try to provide better understanding of data converters, more specifically in the mathematical representation and coding of non idealities of the converter. As programming tool it will be used the MATLAB environment, with which will carry out the coding and the analysis of the behavior of the converters by adding diverse nonlinearities, taking advantage of the simplicity, clarity, and extensibility that provides this environment. Summarizing, it is going to study the converte...

  6. Venous hemodynamic changes in lower limb venous disease: the UIP consensus according to scientific evidence.

    Science.gov (United States)

    Lee, Byung B; Nicolaides, Andrew N; Myers, Kenneth; Meissner, Mark; Kalodiki, Evi; Allegra, Claudio; Antignani, Pier L; Bækgaard, Niels; Beach, Kirk; Belcaro, Giovanni; Black, Stephen; Blomgren, Lena; Bouskela, Eliete; Cappelli, Massimo; Caprini, Joseph; Carpentier, Patrick; Cavezzi, Attilio; Chastanet, Sylvain; Christenson, Jan T; Christopoulos, Demetris; Clarke, Heather; Davies, Alun; Demaeseneer, Marianne; Eklöf, Bo; Ermini, Stefano; Fernández, Fidel; Franceschi, Claude; Gasparis, Antonios; Geroulakos, George; Gianesini, Sergio; Giannoukas, Athanasios; Gloviczki, Peter; Huang, Ying; Ibegbuna, Veronica; Kakkos, Stavros K; Kistner, Robert; Kölbel, Tilo; Kurstjens, Ralph L; Labropoulos, Nicos; Laredo, James; Lattimer, Christopher R; Lugli, Marzia; Lurie, Fedor; Maleti, Oscar; Markovic, Jovan; Mendoza, Erika; Monedero, Javier L; Moneta, Gregory; Moore, Hayley; Morrison, Nick; Mosti, Giovanni; Nelzén, Olle; Obermayer, Alfred; Ogawa, Tomohiro; Parsi, Kurosh; Partsch, Hugo; Passariello, Fausto; Perrin, Michel L; Pittaluga, Paul; Raju, Seshadri; Ricci, Stefano; Rosales, Antonio; Scuderi, Angelo; Slagsvold, Carl E; Thurin, Anders; Urbanek, Tomasz; M VAN Rij, Andre; Vasquez, Michael; Wittens, Cees H; Zamboni, Paolo; Zimmet, Steven; Ezpeleta, Santiago Z

    2016-06-01

    There are excellent guidelines for clinicians to manage venous diseases but few reviews to assess their hemodynamic background. Hemodynamic concepts that evolved in the past have largely remained unchallenged in recent decades, perhaps due to their often complicated nature and in part due to emergence of new diagnostic techniques. Duplex ultrasound scanning and other imaging techniques which evolved in the latter part of the 20th century have dominated investigation. They have greatly improved our understanding of the anatomical patterns of venous reflux and obstruction. However, they do not provide the physiological basis for understanding the hemodynamics of flow, pressure, compliance and resistance. Hemodynamic investigations appear to provide a better correlation with post-treatment clinical outcome and quality of life than ultrasound findings. There is a far better prospect for understanding the complete picture of the patient's disability and response to management by combining ultrasound with hemodynamic studies. Accordingly, at the instigation of Dr Angelo Scuderi, the Union Internationale de Phlebologie (UIP) executive board commissioned a large number of experts to assess all aspects of management for venous disease by evidence-based principles. These included experts from various member societies including the European Venous Forum (EVF), American Venous Forum (AVF), American College of Phlebology (ACP) and Cardiovascular Disease Educational and Research Trust (CDERT). Their aim was to confirm or dispel long-held hemodynamic principles and to provide a comprehensive review of venous hemodynamic concepts underlying the pathophysiology of lower limb venous disorders, their usefulness for investigating patients and the relevant hemodynamic changes associated with various forms of treatment. Chapter 1 is devoted to basic hemodynamic concepts and normal venous physiology. Chapter 2 presents the mechanism and magnitude of hemodynamic changes in acute deep vein

  7. Spiral CT venography in central venous obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Jin Wook; Park, Jae Hyung; Im, Jung Gi; Han, Moon Hee; Kim, In One; Chang, Kee Hyun; Yeon, Kyung Mo [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of); Song, Chi Sung [Boramae Hospital, Seoul (Korea, Republic of)

    1998-11-01

    To determine the clinical usefulness of spiral computed tomographic (CT) venography for the evaluation of central venous obstruction. The authors prospectively performed a total of 29 spiral CT venography procedures in 25 consecutive patients with suspected central venous obstrucion. Diluted contrast media were directly injected into the peripheral veins of the hand or the foot. Scan parameters were 3mm X-ray beam collimation, table speed of 4-6cm/sec, scan time of 32-40sec, and injection delay of 20 sec. Axial images were reconstructed at 2-mm intervals, and using shaded surface display(SSD), maximum intensity projection(MIP), and multiplanar reformation(MPR), 3-D reconstruction was performed. In all cases, ascending venograp-hy(n=3D13) and/or direct catheter venography (n=3D21) was performed within 2 days of CT venography. With regard to site, extent, extent, severity, and cause of obstruction and collateral circulation, we compared the results of CT and contrast venography. In 24 patients, a total of 56 sites of central venous obstruction or stenosis (>50%) were demonstrated. The causes of obstruction were venous thrombosis(n=3D6), malignant tumors(n=3D4), arteriovenous fistula for hemodialysis(n=3D5), extrinsic compression(n=3D2), coincidence of extrinsic compression and arteriovenous fistula(n=3D1), pacemaker(n=3D1), mediastinal inflammatory pseudotumor(n=3D1), spinal tuberculosis(n=3D1), membranous obstruction of the hepatic inferior vena cava(n=3D1), Behcet's disease(n=3D1), or unknown cause(n=3D1). When compared with ascending venography(n=3D13), CT venography was superior for evaluation of the extent and cause of obstruction and collateral circulation in two, four and one case(s), respectively. For the evaluation of site and severity of obstruction, CT venography was equal to ascending venography. In two cases, direct catheter venography (n=3D21) was superior to CT venography for evaluating the obstruction site, but in three, five and one case

  8. Chronic cerebrospinal venous insufficiency: current perspectives

    Directory of Open Access Journals (Sweden)

    Simka M

    2014-03-01

    Full Text Available Marian Simka Department of Nursing, College of Applied Sciences, Ruda Slaska, Poland Abstract: This review summarizes the research to date on chronic cerebrospinal venous insufficiency (CCSVI. CCSVI was initially defined as a clinical syndrome comprising stenoses of the internal jugular and/or azygos veins, characterized by collateral venous outflows and reduced cerebral blood flow, and was found primarily in patients with multiple sclerosis. However, the published evidence on CCSVI is very discordant. Catheter venography studies gave a regular picture, with the majority of patients with multiple sclerosis presenting with demonstrable outflow abnormalities in the veins draining the central nervous system. The prevalence of these lesions was over 50%, and even higher (about 90% when more liberal definition of an abnormality or intravascular sonography was used. Further, the results of magnetic resonance venography studies have been quite consistent, in that stenoses of the internal jugular veins have been found in 25%–70% of patients with multiple sclerosis. In contrast, Doppler sonography studies have revealed CCSVI in 0% to 100% of patients. The research is currently suggesting that CCSVI is not a single entity, but rather a group of different anatomic and functional venous abnormalities. Regarding venous outflow from the brain, a patient can present either with diminished inflow to the internal jugular veins resulting from decreased cerebral circulation or with externally compressed or hypoplastic internal jugular veins or stenotic jugular valves. Considering these many faces of CCSVI, it becomes more comprehensible as to why the results of the studies, especially those utilizing Doppler sonography, have been so discordant. Not only were investigators using different diagnostic modalities and distinct protocols, but they were not looking for the same pathology. Since these abnormalities were indeed differently prevalent in patients and

  9. Correlation between Arterial Lactate and Central Venous Lactate in Children with Sepsis

    Directory of Open Access Journals (Sweden)

    Jaime Fernández Sarmiento

    2016-01-01

    Full Text Available Introduction. Lactate is an important indicator of tissue perfusion. The objective of this study is to evaluate if there are significant differences between the arterial and central venous measurement of lactate in pediatric patients with sepsis and/or septic shock. Methods. Longitudinal retrospective observational study. Forty-two patients were included between the age of 1 month and 17 years, with a diagnosis of sepsis and septic shock, who were admitted to the intensive care unit of a university referral hospital. The lactate value obtained from an arterial blood sample and a central venous blood sample drawn simultaneously, and within 24 hours of admission to the unit, was recorded. Results. The median age was 2.3 years (RIC 0,3–15, with a predominance of males (71.4%, having a 2.5 : 1 ratio to females. Most of the patients had septic shock (78.5% of pulmonary origin (50.0%, followed by those of gastrointestinal origin (26.1%. Using Spearman’s Rho, a 0.872 (p<0.001 correlation was found between arterial and venous lactate, which did not vary when adjusted for age (p<0.05 and the use of vasoactive drugs (p<0.05. Conclusion. There is a good correlation between arterial and venous lactate in pediatric patients with sepsis and septic shock, which is not affected by demographic variables or type of vasoactive support.

  10. Ecologically Optimal Solution of Power Semiconductors Converters

    Directory of Open Access Journals (Sweden)

    Ivan Lokseninec

    2003-01-01

    Full Text Available One of the relevant scientific programs of Department of Power Electrical Systems is research of ecologically optimal topologies main circuits of power converters. This paper presents some methods how to reduce unfavourable influences of power converters on the grid. The achieved results were applieed in praxis, especially in the power converters produced by Electrotechnical Research and Projecting Institute in Nova Dubnica.

  11. Clinical features of venous insufficiency and the risk of venous thrombosis in older people.

    Science.gov (United States)

    Engbers, Marissa J; Karasu, Alev; Blom, Jeanet W; Cushman, Mary; Rosendaal, Frits R; van Hylckama Vlieg, Astrid

    2015-11-01

    Venous thrombosis is common in older age, with an incidence of 0·5-1% per year in those aged >70 years. Stasis of blood flow is an important contributor to the development of thrombosis and may be due to venous insufficiency in the legs. The risk of thrombosis associated with clinical features of venous insufficiency, i.e., varicose veins, leg ulcers and leg oedema, obtained with a standardized interview was assessed in the Age and Thrombosis Acquired and Genetic risk factors in the Elderly (AT-AGE) study. The AT-AGE study is a case-control study in individuals aged 70 years and older (401 cases with a first-time venous thrombosis and 431 control subjects). We calculated odds ratios (ORs) and corresponding 95% confidence intervals (CI) adjusted for age, sex and study centre. Varicose veins and leg ulcer were associated with a 1·6-fold (95% CI 1·2-2·3) and 3·3-fold increased risk of thrombosis (95% CI 1·6-6·7), respectively, while the risk was increased 3·0-fold (95% CI 2·1-4·5) in the presence of leg oedema. The risk of thrombosis was highest when all three risk factors occurred simultaneously (OR: 10·5; 95% CI 1·3-86·1). In conclusion, clinical features of venous insufficiency, i.e., varicose veins, leg ulcers and leg oedema, are risk factors for venous thrombosis in older people.

  12. Leukocytic Response and Peripheral Venous Blood Lymphocyte Apoptosis as a Marker of Tissue Ischemia in Acute Massive Blood Loss

    Directory of Open Access Journals (Sweden)

    N. V. Borovkova

    2013-01-01

    Full Text Available Objective: to estimate the level of peripheral venous blood lymphocyte apoptosis and intraoperative hypoxia in victims with acute massive blood loss. Subjects and methods. Twenty-two patients with open and close chest and abdominal traumas complicated by acute massive blood loss were examined. All the patients were emergently operated on to stop bleeding. Tissue metabolism was evaluated from gases, acid-base parameters, and plasma lactate, glucose, potassium, and sodium levels. Apoptosis of mononuclear cells was studied and dead leukocytes were counted using flow cytometry. Results. Preoperatively, the victims were found to have venous hypoxemia, hyperlactatemia, hyperglycemia, moderate leukocytosis, and higher dead leukocyte counts. There were also raised counts of lymphocytes coming into the process of apoptosis. A significant relationship was found between monocyte counts and hypoxia values. At the end of surgery, oxygen balance values became stable and exerted an effect on the count of leukocytes, the relative level of granulocytes, the relative and absolute counts of dead and damaged leukocytes, and the concentration of lymphocytes in the victims’ venous blood during the early stages of apoptosis, as evidenced by nonlinear regression models. Conclusion. The indicators of immunocompetent cell apoptosis and the count of venous blood dead leukocytes along with lactate levels and venous hypoxemia parameters reflect the degree of tissue hypoxia and may be used as specific markers.

  13. Compression therapies for chronic venous leg ulcers: interventions and adherence

    Directory of Open Access Journals (Sweden)

    Latz CA

    2015-01-01

    Full Text Available Christopher A Latz,1 Kellie R Brown,2 Ruth L Bush11Texas A&M Health Science Center College of Medicine, Bryan, TX, USA; 2Medical College of Wisconsin, Milwaukee, WI, USAAbstract: Compression therapy has been the mainstay for the treatment of lower extremity edema, venous insufficiency, and particularly, venous ulcerative disease. Though modern surgical treatments exist, none are completely effective without good compressive options to allow for decreased swelling and better oxygenation of damaged tissues. This review article will describe the pathophysiology and presentation of lower extremity venous ulcerations, as well as current options for compression therapy. The benefits, along with the major pitfall of nonadherence, will also be discussed.Keywords: venous disease, chronic venous insufficiency, venous ulceration

  14. Single Phase Online UPS Design Using Three Leg Converters

    Directory of Open Access Journals (Sweden)

    R. Ramesh,

    2014-03-01

    Full Text Available The single phase online UPS integrate with the three leg type converter which operate with battery charger and the inverter. The first leg controls the ability of charging battery. The third leg controls the output voltage. The common leg is used to control the line frequency. The battery charger has the ability of making the correction of power factor during the battery charging. The inverter is used to maintain the output voltage and to limit the output current. The main feature of the three leg converter is used to reduce the number of switching devices. So that the system has the low value of power loss and low cost.

  15. "Assessment of Potentially-Efficient DC-AC Converter Architectures"

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Jamie

    2004-04-29

    Two alternate and potentially-efficient power electronic architectures are assessed and compared with a conventional, three-phase, voltage-source converter. The comparisons are in terms of a 750 kVA converter as might be used with a variable-speed wind turbine or a photovoltaic array, The two architectures are projected to cost 1.15 and 1.39 times the comparable (factory) cost of the conventional system. However the present value of the recovered energy stream may justify the added cost.

  16. "Assessment of Potentially-Efficient DC-AC Converter Architectures"

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Jamie

    2004-04-29

    Two alternate and potentially-efficient power electronic architectures are assessed and compared with a conventional, three-phase, voltage-source converter. The comparisons are in terms of a 750 kVA converter as might be used with a variable-speed wind turbine or a photovoltaic array, The two architectures are projected to cost 1.15 and 1.39 times the comparable (factory) cost of the conventional system. However the present value of the recovered energy stream may justify the added cost.

  17. A dc to dc converter

    Science.gov (United States)

    Willis, A. E.; Gould, J. M.; Matheney, J. L.; Garrett, H. (Inventor)

    1984-01-01

    The object of the invention is to provide an improved converter for converting one direct current voltage to another. A plurality of phased square wave voltages are provided from a ring counter through amplifiers to a like plurality of output transformers. Each of these transformers has two windings, and S(1) winding and an S(2) winding. The S(1) windings are connected in series, then the S(2) windings are connected in series, and finally, the two sets of windings are connected in series. One of six SCRs is connected between each two series connected windings to a positive output terminal and one of diodes is connected between each set of two windings of a zero output terminal. By virtue of this configuration, a quite high average direct current voltage is obtained, which varies between full voltage and two-thirds full voltage rather than from full voltage to zero. Further, its variation, ripple frequency, is reduced to one-sixth of that present in a single phase system. Application to raising battery voltage for an ion propulsion system is mentioned.

  18. Human cerebral venous outflow pathway depends on posture and central venous pressure

    DEFF Research Database (Denmark)

    Gisolf, J; van Lieshout, J J; van Heusden, K

    2004-01-01

    and central venous pressure (CVP) on the distribution of cerebral outflow over the internal jugular veins and the vertebral plexus, using a mathematical model. Input to the model was a data set of beat-to-beat cerebral blood flow velocity and CVP measurements in 10 healthy subjects, during baseline rest...... and during a Valsalva manoeuvre in both body positions, correlate highly with model simulation of the jugular cross-sectional area (R(2) = 0.97). The results suggest that the cerebral venous flow distribution depends on posture and CVP: in supine humans the internal jugular veins are the primary pathway...

  19. [Venous thrombosis associated with central venous catheter use in patients with cancer].

    Science.gov (United States)

    Iglesias Rey, Leticia; Fernández Pérez, Isaura; Barbagelata López, Cristina; Rivera Gallego, Alberto

    2015-01-01

    The use of central venous catheters for various applications (administration of chemotherapy, blood products and others) in patients with cancer is increasingly frequent. The association between thrombosis and catheter use has been fully established but aspects such as its causes, diagnosis, prophylaxis and treatment have not. We describe a case of thrombosis in a patient with cancer treated with chemotherapy who carried a central venous catheter. We also perform a review of the risk factors, the role of the prophylaxis and the treatment. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

  20. Venous Return and Clinical Hemodynamics: How the Body Works during Acute Hemorrhage

    Science.gov (United States)

    Shen, Tao; Baker, Keith

    2015-01-01

    Venous return is a major determinant of cardiac output. Adjustments within the venous system are critical for maintaining venous pressure during loss in circulating volume. This article reviews two factors that are thought to enable the venous system to compensate during acute hemorrhage: 1) changes in venous elastance and 2) mobilization of…

  1. Venous Return and Clinical Hemodynamics: How the Body Works during Acute Hemorrhage

    Science.gov (United States)

    Shen, Tao; Baker, Keith

    2015-01-01

    Venous return is a major determinant of cardiac output. Adjustments within the venous system are critical for maintaining venous pressure during loss in circulating volume. This article reviews two factors that are thought to enable the venous system to compensate during acute hemorrhage: 1) changes in venous elastance and 2) mobilization of…

  2. Antithrombotic Agents in the Prevention and Treatment of Venous Thromboembolism

    Institute of Scientific and Technical Information of China (English)

    包承鑫

    2004-01-01

    @@ Venous thromboembolism is a major health problem,carrying significant morbidity and mortality, with an incidence that exceeds I per 1 000. Independent risk factors for venous thromboembolism include increasing age, male gender, surgery, trauma, hospital or nursing home confinement, neurologic disease with extremity paresis, central venous catheter/transvenous pacemaker, prior superficial vein thrombosis, and varicose, among women, the risk factors include pregnancy, oral contraceptives, and hormone replacement therapy.

  3. An unusual cause of hydrocephalus: aqueductal developmental venous anomaly

    Energy Technology Data Exchange (ETDEWEB)

    Yagmurlu, Banu; Fitoz, Suat; Atasoy, Cetin; Erden, ilhan [Ankara University School of Medicine, Department of Radiology, Ankara (Turkey); Deda, Gulhis; Unal, Ozlem [Ankara University School of Medicine, Division of Pediatric Neurology, Ankara (Turkey)

    2005-06-01

    Vascular malformations are infrequent causes of aqueductal stenoses, developmental venous anomaly (DVA) being the rarest among them. DVAs, also known as venous angiomas, are congenital in origin and characterized by dilatation of vessels in the superficial and deep venous system. Although they are usually clinically silent, they can be complicated by hemorrhage, seizures and neurologic deficits. Herein, we report MR imaging findings of a 7-year-old girl whose hydrocephalus was due to an abnormal vein coursing through the aqueduct. (orig.)

  4. Venous ulcers of the lower limb: Where do we stand?

    Science.gov (United States)

    Chatterjee, Sasanka S

    2012-05-01

    Venous ulcers are the most common ulcers of the lower limb. It has a high morbidity and results in economic strain both at a personal and at a state level. Chronic venous hypertension either due to primary or secondary venous disease with perforator paucity, destruction or incompetence resulting in reflux is the underlying pathology, but inflammatory reactions mediated through leucocytes, platelet adhesion, formation of pericapillary fibrin cuff, growth factors and macromolecules trapped in tissue result in tissue hypoxia, cell death and ulceration. Duplex scan with colour flow is the most useful investigation for venous disease supplying information about patency, reflux, effects of proximal and distal compression, Valsalva maneuver and effects of muscle contraction. Most venous disease can be managed conservatively by leg elevation and compression bandaging. Drugs of proven benefit in venous disease are pentoxifylline and aspirin, but they work best in conjunction with compression therapy. Once ulceration is chronic or the patient does not respond to or cannot maintain conservative regime, surgical intervention treating the underlying venous hypertension and cover for the ulcer is necessary. The different modalities like sclerotherapy, ligation and stripping of superficial varicose veins, endoscopic subfascial perforator ligation, endovenous laser or radiofrequency ablation have similar long-term results, although short-term recovery is best with radiofrequency and foam sclerotherapy. For deep venous reflux, surgical modalities include repair of incompetent venous valves or transplant or transposition of a competent vein segment with normal valves to replace a post-thrombotic destroyed portion of the deep vein.

  5. Levoatriocardinal vein with normal intracardiac anatomy and pulmonary venous return

    Directory of Open Access Journals (Sweden)

    Ender Odemis

    2011-01-01

    Full Text Available Levoatriocardinal vein (LACV is characterized by an abnormal connection between pulmonary and systemic venous return. This extremely rare cardiac malformation is usually associated with left-sided obstructive lesions including mitral atresia, hypoplastic left-heart syndrome, and abnormal pulmonary venous connection. Patients may have low systemic cardiac output and pulmonary venous obstruction symptoms. In this manuscript, we report a case with LACV and normal pulmonary venous return with absence of any intracardiac pathology. LACV was demonstrated with echocardiography, angiography, and computed tomography. Surgical correction was made successfully.

  6. Venous ulcers of the lower limb: Where do we stand?

    Directory of Open Access Journals (Sweden)

    Chatterjee S Sasanka

    2012-01-01

    Full Text Available Venous ulcers are the most common ulcers of the lower limb. It has a high morbidity and results in economic strain both at a personal and at a state level. Chronic venous hypertension either due to primary or secondary venous disease with perforator paucity, destruction or incompetence resulting in reflux is the underlying pathology, but inflammatory reactions mediated through leucocytes, platelet adhesion, formation of pericapillary fibrin cuff, growth factors and macromolecules trapped in tissue result in tissue hypoxia, cell death and ulceration. Duplex scan with colour flow is the most useful investigation for venous disease supplying information about patency, reflux, effects of proximal and distal compression, Valsalva maneuver and effects of muscle contraction. Most venous disease can be managed conservatively by leg elevation and compression bandaging. Drugs of proven benefit in venous disease are pentoxifylline and aspirin, but they work best in conjunction with compression therapy. Once ulceration is chronic or the patient does not respond to or cannot maintain conservative regime, surgical intervention treating the underlying venous hypertension and cover for the ulcer is necessary. The different modalities like sclerotherapy, ligation and stripping of superficial varicose veins, endoscopic subfascial perforator ligation, endovenous laser or radiofrequency ablation have similar long-term results, although short-term recovery is best with radiofrequency and foam sclerotherapy. For deep venous reflux, surgical modalities include repair of incompetent venous valves or transplant or transposition of a competent vein segment with normal valves to replace a post-thrombotic destroyed portion of the deep vein.

  7. Isolation of human liver angiotensin-converting enzyme by chromatofocusing.

    Science.gov (United States)

    Sakharov IYu; Danilov, S M; Sukhova, N V

    1987-10-01

    Angiotensin-converting enzyme (EC 3.4.15.1) has been isolated from human liver by chromatofocusing. The isolation procedure permitted us to obtain a 9000-fold purified enzyme with a 22% yield. Specific activity of the angiotensin-converting enzyme was 10 units/mg of protein. The molecular mass of enzyme determined by polyacrylamide gel electrophoresis under denaturing conditions was 150,000. The isoelectric point (4.2-4.3) was also determined by chromatofocusing. The Km values of the enzyme for hippuryl-L-histidyl-L-leucine and N-benzyloxycarbonyl-L-phenylalanyl-L-histidyl-L-leucine are 5000 and 125 microM, respectively. The human liver angiotensin-converting enzyme is inhibited by bradykinin-potentiating factor SQ 20881 (IC50 = 18 nM).

  8. Energy Evaluation for DC/DC Converters in DC-Based Wind Farms

    Energy Technology Data Exchange (ETDEWEB)

    Max, Lena

    2007-02-15

    to be the most suitable choice for the wind farm application. A measurement verification is conducted for the fullbridge converter, and the result found is that the simulated waveforms and the calculated losses agree with the measured values.

  9. Efficiency of Capacitively Loaded Converters

    DEFF Research Database (Denmark)

    Andersen, Thomas; Huang, Lina; Andersen, Michael A. E.;

    2012-01-01

    This paper explores the characteristic of capacitance versus voltage for dielectric electro active polymer (DEAP) actuator, 2kV polypropylene film capacitor as well as 3kV X7R multi layer ceramic capacitor (MLCC) at the beginning. An energy efficiency for capacitively loaded converters...... is introduced as a definition of efficiency. The calculated and measured efficiency curves for charging DEAP actuator, polypropylene film capacitor and X7R MLCC are provided and compared. The attention has to be paid for the voltage dependent capacitive load, like X7R MLCC, when evaluating the charging...... polypropylene film capacitor can be the equivalent capacitive load. Because of the voltage dependent characteristic, X7R MLCC cannot be used to replace the DEAP actuator. However, this type of capacitor can be used to substitute the capacitive actuator with voltage dependent property at the development phase....

  10. Reliability of Wave Energy Converters

    DEFF Research Database (Denmark)

    Ambühl, Simon

    . Structural reliability considerations and optimizations impact operation and maintenance (O&M) costs as well as the initial investment costs. Furthermore, there is a control system for WEC applications which defines the harvested energy but also the loads onto the structure. Therefore, extreme loads but also...... WEPTOS. Calibration of safety factors are performed for welded structures at theWavestar device including different control systems for harvesting energy from waves. In addition, a case study of different O&M strategies for WECs is discussed, and an example of reliability-based structural optimization......There are many different working principles for wave energy converters (WECs) which are used to produce electricity from waves. In order for WECs to become successful and more competitive to other renewable electricity sources, the consideration of the structural reliability of WECs is essential...

  11. Reliability of Wave Energy Converters

    DEFF Research Database (Denmark)

    Ambühl, Simon

    for welded structures at the Wavestar device includingdifferent control systems for harvesting energy from waves. In addition, a casestudy of different O&M strategies for WECs is discussed, and an example ofreliability-based structural optimization of the Wavestar foundation ispresented. The work performed......There are many different working principles for wave energy converters (WECs) which are used to produce electricity from waves. In order for WECs tobecome successful and more competitive to other renewable electricity sources,the consideration of the structural reliability of WECs is essential.......Structural reliability considerations and optimizations impact operation andmaintenance (O&M) costs as well as the initial investment costs.Furthermore, there is a control system for WEC applications which defines theharvested energy but also the loads onto the structure. Therefore, extremeloads but also fatigue loads...

  12. Reliability of Wave Energy Converters

    DEFF Research Database (Denmark)

    Ambühl, Simon

    There are many different working principles for wave energy converters (WECs) which are used to produce electricity from waves. In order for WECs to become successful and more competitive to other renewable electricity sources, the consideration of the structural reliability of WECs is essential....... Structural reliability considerations and optimizations impact operation and maintenance (O&M) costs as well as the initial investment costs. Furthermore, there is a control system for WEC applications which defines the harvested energy but also the loads onto the structure. Therefore, extreme loads but also...... of the Wavestar foundation is presented. The work performed in this thesis focuses on the Wavestar and WEPTOS WEC devices which are only two working principles out of a large diversity. Therefore, in order to gain general statements and give advice for standards for structural WEC designs, more working principles...

  13. Manufacturing method of photoelectric converter

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Koji; Niwa, Yasuo

    1987-06-24

    In a method of making a thin film for a photoelectric converter by a method to form an electroconductive layer by burning a mixture of lead oxide and chromic oxide, thickness of the film was limited and the poreless uniform film was not obtainable. The intransparency of the film gave low conversion efficiency only. This invention enabled to obtain a transparent film wherein an oxide (containing lead and chrome) is used as a target to form, in vacuum, a thin film of the oxide, and then this thin film is heat-treated in an atmosphere at least containing lead. Thin transparent film was obtained enhancing the conversion efficiency. High quality and high reliability are ensured because a poreless uniform film can be obtained. Cost was reduced because mass-production was made possible by the use of a vacuum technique. (5 figs)

  14. The SSG Wave Energy Converter

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Margheritini, Lucia; Kofoed, Jens Peter

    2012-01-01

    The Sea-wave Slot-cone Generator concept (SSG) is a Wave Energy Converter based on the wave overtopping principle utilizing several reservoirs placed on top of each other, in which the energy of the incoming wave will be stored as potential energy. The water captured in the reservoirs will then run...... through turbines for electricity production. The system utilizes a wide spectrum of different wave conditions by means of multiple reservoirs, located at different levels above the still water level. Thereby, it obtains a high overall efficiency and it can be suitable for shoreline and breakwater...... applications, presenting particular advantages such as: sharing structure costs, availability of grid connection and infrastructures, recirculation of water inside the harbor, as the outlet of the turbines is on the rear part of the system. Recently, plans for the SSG pilot installation were in progress...

  15. Non-invasive bedside assessment of central venous pressure: scanning into the future.

    Directory of Open Access Journals (Sweden)

    Jacques Rizkallah

    Full Text Available Noninvasive evaluation of central venous pressure (CVP can be achieved by assessing the Jugular Venous Pressure (JVP, Peripheral Venous Collapse (PVC, and ultrasound visualization of the inferior vena cava. The relative accuracy of these techniques compared to one another and their application by trainees of varying experience remains uncertain. We compare the application and utility of the JVP, PVC, and handheld Mini Echo amongst trainees of varying experience including a medical student, internal medicine resident, and cardiology fellow. We also introduce and validate a new physical exam technique to assess central venous pressures, the Anthem sign.Patients presenting for their regularly scheduled echocardiograms at the hospital echo department had clinical evaluations of their CVP using these non-invasive bedside techniques. The examiners were blinded to the echo results, each other's assessments, and patient history; their CVP estimates were compared to the gold standard level 3 echo-cardiographer's estimates at the completion of the study.325 patients combined were examined (mean age 65, s.d. 16 years. When compared to the gold standard of central venous pressure by a level 3 echocardiographer, the JVP was the most sensitive at 86%, improving with clinical experience (p<0.01. The classic PVC technique and Anthem sign had better specificity compared to the JVP. Mini Echo estimates were comparable to physical exam assessments.JVP evaluation is the most sensitive physical examination technique in CVP assessments. The PVC techniques along with the newly described Anthem sign may be of value for the early learner who still has not mastered the art of JVP assessment and in obese patients in whom JVP evaluation is problematic. Mini Echo estimates of CVPs are comparable to physical examination by trained clinicians and require less instruction. The use of Mini Echo in medical training should be further evaluated and encouraged.

  16. Low-dose midazolam sedation: an option for patients undergoing serial hepatic venous pressure measurements.

    Science.gov (United States)

    Steinlauf, A F; Garcia-Tsao, G; Zakko, M F; Dickey, K; Gupta, T; Groszmann, R J

    1999-04-01

    The hepatic venous pressure gradient (HVPG) is becoming increasingly used clinically. It is useful in the differential diagnosis of portal hypertension and provides a prognostic index in cirrhotic patients. Performance of serial measurements has been shown to be useful in guiding pharmacological therapy of portal hypertension and variceal hemorrhage. The technique is safe to perform; however, many patients are anxious and reluctant to undergo serial measurements. The effects of sedatives on portal pressure measurements have not yet been defined. The objective of this study was to evaluate the effects of midazolam on the HVPG. Twenty patients with compensated cirrhosis were included in this prospective, double-blind study. The HVPG was determined by subtracting the free hepatic venous pressure (FHVP) from the wedged hepatic venous pressure (WHVP). Patients were randomized to receive either placebo, 0.02 mg/kg midazolam, or 0.03 mg/kg midazolam, administered intravenously over 3 minutes. Immediately after drug administration and every 3 minutes thereafter, for a total of 30 or 40 minutes, measurements were repeated. Three hours later, patients were asked to state whether the sedative affected their state of comfort/relaxation. The effects of both doses of midazolam on HVPG did not differ significantly from those of placebo. Furthermore, neither dose of midazolam induced significant changes in HVPG as compared with baseline values. However, higher-dose midazolam (0.03 mg/kg) was associated with significant reductions in FHVP from baseline and a tendency for a reduction in WHVP. Both doses significantly increased patient comfort and relaxation during the test. Midazolam, used at a dose of 0.02 mg/kg, is effective in increasing patient comfort and relaxation during hepatic venous pressure measurements, without significantly affecting pressures (HVPG, WHVP, or FHVP). It is therefore an acceptable option for patients undergoing serial hepatic venous pressure measurements.

  17. Chlorhexidine and gauze and tape dressings for central venous catheters: a randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Edivane Pedrolo

    2014-10-01

    Full Text Available OBJECTIVE: to assess the effectiveness of the chlorhexidine antimicrobial dressing in comparison to the gauze and tape dressing in the use of central venous catheters.METHOD: a randomized clinical trial was conducted in the intensive care and adult semi intensive care units of a university hospital in the south of Brazil. The subjects were patients using short-term central venous catheters, randomly assigned to the intervention (chlorhexidine antimicrobial dressing or control (gauze and micro porous tape groups.RESULTS: a total of 85 patients were included: 43 in the intervention group and 42 in the control group. No statistically significant differences were found between dressings in regard to the occurrence of: primary bloodstream infections (p-value = 0.5170; local reactions to the dressing (p-value = 0.3774; and dressing fixation (p-value = 0.2739.CONCLUSION: both technologies are effective in covering central venous catheters in regard to the investigated variables and can be used for this purpose. Registry ECR: RBR-7b5ycz.

  18. Venous vs arterial blood gases in the assessment of patients presenting with an exacerbation of chronic obstructive pulmonary disease.

    Science.gov (United States)

    McCanny, Peter; Bennett, Kath; Staunton, Paul; McMahon, Geraldine

    2012-07-01

    The purpose of this study was to investigate the clinical correlation between arterial and venous blood gas (VBG) values in patients presenting to the emergency department (ED) with acute exacerbation of chronic obstructive pulmonary disease. A prospective study of patients with chronic obstructive pulmonary disease presenting to the ED with acute ventilatory compromise was done. Patients were included if their attending physician considered arterial blood gas sampling important in their initial assessment. Data from arterial and venous samples were compared using Spearman correlation and bias plot (Bland-Altman) methods. Ninety-four patients were enrolled in the study. Eighty-nine patients had complete data sets for analysis. Arterial hypercarbia was present in 30 patients (33.7%; range, 51-140.19 mm Hg). All cases of arterial hypercarbia were detected using VBG sampling when a screening cutoff of 45 mm Hg was applied (sensitivity, 100%; 95% confidence interval, 88.7%-100% and specificity, 34%; 95% confidence interval, 23.1%-46.6%). Bias plot revealed moderate agreement between arterial and venous Pco(2) with an average difference of 8.6 mm Hg and 95% limits of agreement of -7.84 to 25.05 mm Hg. For pH, mean difference between each group was 0.039 (range, -0.12 to 0.03). Linear regression analysis for pH demonstrated very close equivalence with a regression coefficient of 0.955, and Spearman correlation showed significant correlation of 0.826 (P = .001). Venous pH and HCO(3) values show excellent correlation with arterial values. Using a previously validated screening cutoff of 45 mm Hg, venous CO(2) has 100% sensitivity in detecting arterial hypercarbia. There is insufficient agreement between venous and arterial CO(2) for VBG to replace arterial blood gas in determining the degree of hypercarbia. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. MRA for diagnosis of venous thromboembolism

    Energy Technology Data Exchange (ETDEWEB)

    Sostman, H. D. [Cornell University, Weill Medical College, Chair of Radiology, New York (United States)

    2001-12-01

    Direct imaging of pulmonary embolism (PE) and deep vein thrombosis (DVT) with CT, and potentially with MR, will continue to replace V/Q scintigraphy. Venous imaging with MR far detecting DVT is used in a few centers, and their published accuracy figures are impressive. Recent studies of MR pulmonary angiography for PE reported that sensitivity of MRA was 85-100%, specificity 95-96%, but this data must be confirmed in other centers and patient populations. MR has advantages compared with CT, which make it worthwhile to continue MR development. Ionizing radiation and iodinated contrast material are not used. Imaging the pulmonary arteries and then imaging whichever venous region is of clinical interest is practical in a single examination. Repeated examinations can be performed safely. New contrast materials will facilitate the practically and accuracy of the MR technique and perfusion imaging may increase sensitivity. MR also has disadvantages compared with CT. It does not image effectively the non-vascular compartment of the lungs. It is more expensive, patient monitoring is more cumbersome, and a routine technique, which embodies all of MR's potential advantages, has not been packaged and tested. Accordingly, helical CT is a realistic option in clinical management of patients with suspected PE in most centers, while clinical application of MR is limited to centers with appropriate MR expertise and technology. However, MR has a number of fundamental characteristics that make it potentially ideal modality for evaluating patients with suspected acute venous thromboembolic disease and further clinical research with MRA is warranted.

  20. Daily nursing care on patients undergoing venous-venous extracorporeal membrane oxygenation: a challenging procedure!

    Science.gov (United States)

    Redaelli, Sara; Zanella, Alberto; Milan, Manuela; Isgrò, Stefano; Lucchini, Alberto; Pesenti, Antonio; Patroniti, Nicolò

    2016-12-01

    Daily nursing in critical care patients may alter vital parameters, especially in the most critically ill patients. The aim of our study was to evaluate feasibility and safety of daily nursing on patients undergoing venous-venous extracorporeal membrane oxygenation (vv-ECMO) for severe respiratory failure. Daily nursing was performed following defined phases (sponge bath, elevation with scooping stretcher, change position of endotracheal tube, dressing replacement). We recorded physiological and ECMO parameters before and during daily nursing in 5 patients for several days (total: 25 daily nursing) and adverse events: desaturation, hypertension, reduction of mixed venous oxygen saturation, arterial oxygen saturation or ECMO blood flow and elevation in minute ventilation. Sedative drug dosage and additional bolus were recorded. Daily nursing was performed in 92 % of cases (23/25), with a minimum of two adverse events per daily nursing. Hypertension and tachycardia were mostly recorded at the beginning, while desaturation, reduction in mixed venous oxygen saturation and blood flow were recorded during elevation with scooping stretcher. Increase in minute ventilation was frequent in spontaneous breathing patients. Additional bolus of sedation was required before and/or during nursing. Daily nursing significantly alters physiologic parameters; thus, it should be performed only when physicians are readily available to treat adverse events.

  1. Predictors of Venous Thromboembolic Events Associated with Central Venous Port Insertion in Cancer Patients

    Directory of Open Access Journals (Sweden)

    Christine Hohl Moinat

    2014-01-01

    Full Text Available Insertion of central venous port (CVP catheter in the cancer population is associated with increased incidence of venous thromboembolic events (VTE. However, trials have shown limited benefit of antithrombotic treatment to prevent catheter-related venous thrombosis. This prospective observational cohort study was designed to assess the incidence of VTE closely related to CVP implantation in patients with cancer and undergoing chemotherapy, and to identify a high risk subgroup of patients. Between February 2006 and December 2011, 1097 consecutive cancer patients with first CVP implantation were included. Catheter-related VTE were defined as deep venous thrombosis in the arm, with or without pulmonary embolism (PE, or isolated PE. The incidence of CVP-associated VTE was 5.9% (IC95 4.4–7.3% at 3 months, and 11.3% (IC95 9.4–13.2% at 12 months. The incidence of any VTE was 7.6% (IC95 6.0–9.3% at 3 months, and 15.3% (IC95 13.1–17.6% at 12 months. High Khorana risk score and lung cancer were significant predictors of 3 month VTE. In conclusion, this large cohort study of patients with first CVP catheter implantation confirms the high incidence of VTE associated with the CVP implantation and allow identifying high risk patients who may benefit from thromboprophylaxis.

  2. Recent research on venous thromboembolism in China: a brief report from China Venous Thromboembolism Study Group

    Institute of Scientific and Technical Information of China (English)

    ZHAI Zhen-guo; ZHAN Xi; YANG Yuan-hua; WANG Chen

    2010-01-01

    @@ Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary thrombo-embolism (PTE), carries significant mortality and morbidity. As a result of the increasing awareness and improvement in diagnostic facilities, the hospital admissions have increased dramatically in China. Recent publications have reported the increasing incidences of PTE and DVT in hospitalized patients.~(1-3)

  3. Mean Platelet Volume in Patients with Chronic Venous Insufficiency

    Directory of Open Access Journals (Sweden)

    Mehmet Akif Sarıca

    2016-03-01

    Full Text Available Objective: the mean platelet volume (MPV is a good indicator of platelet activity; it is reported to increase in diseases associated with inflammatory processes and in vascular diseases. This study investigated the importance of mean platelet volume in patients with chronic venous insufficiency (CVI and whether the MPV was likely to be a predictor of the CVI. Methods: 117 patients who were diagnosed as CVI by colored Doppler Ultrasound (CDU method and 49 healthy volunteers (forming the control group were en­rolled to this study, which was planned retrospectively. The patients’ blood count values taken within one month before and after the CDU evaluation were recorded by the hospital information system. The complete blood count, routine biochemical tests and thyroid function tests of the patients diagnosed with CVI were compared to the control group. Results: Significant differences were not detected be­tween the patients and the control group in terms of the levels of creatinine, aspartate aminotransferase, total cholesterol, LDL cholesterol, HDL cholesterol, triglycer­ides, erythrocyte, sedimentation speed, leukocyte, hae­moglobin and thrombocyte (p>0.05. The thyroid stimulat­ing hormone and the MPV levels were significantly lower in the control group (p<0.05. Conclusion: MPV levels as an easy, cheap and practi­cal data extracted from complete blood count, were found higher in patients diagnosed with CVI compared to the control group. This may be originated from endothelium changes as an answer to venous hypertension and dila­tation in CVI. MPV can be used as a follow-up marker in CVI patients. J Clin Exp Invest 2016; 7 (1: 73-77

  4. Liver CT with portal-venous contrast

    Energy Technology Data Exchange (ETDEWEB)

    Schild, H.; Mildenberger, P.; Schweden, F.; Eckmann, A.; Nagel, K.; Knuth, A.; Boerner, N.; Thelen, M.; Junginger, T.

    1987-12-01

    Contrast administration through the superior mesenteric or splenic arteries provided additional information in 22 out of 31 patients, when compared with intravenous contrast bolus for CT of the liver. In 11 patients, the demonstration of a tumour lead to a change in treatment. False positive findings occurred in four of the 31 patients. In 2 patients intrahepatic lesions were overlooked, but were found during angiography carried out at the same examination. The diagnosis of intrahepatic space-occupying lesions is discussed as well as the CT appearances of portal-venous liver perfusion.

  5. Cerebral venous thrombosis: An Indian perspective

    Directory of Open Access Journals (Sweden)

    Deepa Dash

    2015-01-01

    Full Text Available Cerebral venous thrombosis (CVT is an uncommon cause of stroke with extremely varied clinical presentations, predisposing factors, imaging findings, and outcomes, and thus can be extremely challenging to diagnose. Accurate and prompt diagnosis of CVT is crucial because timely and appropriate therapy can reverse the disease process and significantly reduce the risk of acute complications and long-term squel. In this article, we have reviewed the epidemiology, causative factors, clinical features, diagnosis and treatment of CVT from an Indian perspective. Over the last decade, a change in trends in the causative factors has been noted from India.

  6. Unilateral Pseudotumoral Presentation of Cerebral Venous Thrombosis

    Directory of Open Access Journals (Sweden)

    Leonardo Halley Carvalho Pimentel

    2014-09-01

    Full Text Available Cerebral venous thrombosis (CVT is an unusual cause of stroke. It is more common in middle-aged women and deep CVT lesions are usually bilateral. CVT can have very diverse clinical presentations and mimic other conditions. We report two women with CVT initially diagnosed as tumors (unilateral pseudotumoral presentation of CVT successfully treated with intravenous heparin. Early diagnosis was important and completely reversed the symptoms. The diagnosis of CVT should be remembered when clinical picture is compatible even if brain imaging suggests unilateral tumor.

  7. Sickle Cell Trait Causing Splanchnic Venous Thrombosis

    Directory of Open Access Journals (Sweden)

    Priyanka Saxena

    2015-01-01

    Full Text Available Sickle cell trait is considered as a benign condition as these individuals carry only one defective gene and typically have their life span similar to the normal population without any health problems related to sickle cell. Only under extreme conditions, red cells become sickled and can cause clinical complications including hematuria and splenic infarction. Although twofold increased risk of venous thrombosis has been described in African Americans, there is no data available from Indian population. We here report a case of sickle cell trait from India whose index presentation was thrombosis of unusual vascular territory.

  8. Direct oral anticoagulants and venous thromboembolism

    Directory of Open Access Journals (Sweden)

    Massimo Franchini

    2016-09-01

    Full Text Available Venous thromboembolism (VTE, consisting of deep vein thrombosis and pulmonary embolism, is a major clinical concern associated with significant morbidity and mortality. The cornerstone of management of VTE is anticoagulation, and traditional anticoagulants include parenteral heparins and oral vitamin K antagonists. Recently, new oral anticoagulant drugs have been developed and licensed, including direct factor Xa inhibitors (e.g. rivaroxaban, apixaban and edoxaban and thrombin inhibitors (e.g. dabigatran etexilate. This narrative review focusses on the characteristics of these direct anticoagulants and the main results of published clinical studies on their use in the prevention and treatment of VTE.

  9. The Value of Value

    DEFF Research Database (Denmark)

    Sørensen, Asger

    parts of business ethics given prominence to especially one term, namely `value'. The question that interests me is the following: What does the articulation of ethics and morality in terms of values mean for ethics and morality as such. Or, to put the question in a more fashionably way: What...... is the value of value for morality and ethics?To make things a bit more precise, we can make use of the common distinction between ethics and morality, i.e. that morality is the immediate, collective and unconscious employment of morals, whereas ethics is the systematic, individual and conscious reflections...

  10. Central venous-arterial pCO(2) difference as a tool in resuscitation of septic patients

    NARCIS (Netherlands)

    van Beest, Paul A.; Lont, Mariska C.; Holman, Nicole D.; Loef, Bert; Kuiper, Michael A.; Boerma, E. Christiaan

    2013-01-01

    To investigate the interchangeability of mixed and central venous-arterial carbon dioxide differences and the relation between the central difference (pCO(2) gap) and cardiac index (CI). We also investigated the value of the pCO(2) gap in outcome prediction. We performed a post hoc analysis of a wel

  11. Venous rupture complicating hemodialysis access angioplasty: percutaneous treatments and outcomes

    Energy Technology Data Exchange (ETDEWEB)

    La, Young Jong; Goo, Dong Erk; Kim, Dae Ho; Lee, Hae Kyoung; Hong, Hyun Suk; Kwon, Gui Hyang; Choi, Duk Lin; Ynag, Sung Boo [College of Medicine, Soonchunhyang Univ., Seoul (Korea, Republic of)

    2002-03-01

    To evaluate the usefulness of percutaneous management and prognosis in venous rupture during angioplasty of hemodialytic arteriovenous fistulas. Among 814 patients who underwent angioplasty on account of inadequate hemodialysis, 63(39 women and 24 men aged 20-78 (mean, 55.8) years) were included in this study. All 63 had peripheral venous stenosis. Venous rupture was diagnosed when contrast leakage was seen at venography after percutaneous angioplasty (PTA). In order to manage venous rupture, the sites at which this occurred were compressed manually for 3-5 minutes or blood flow was blocked with a balloon catheter for the same period. In one case, a stent was inserted at the rupture site. Using the Kaplan-Meier method, we investigated the patency rate of arteriovenous fistula (AVF) in cases of successful PTA. We also compared PTA patency rates in cases with and without peripheral venous rupture. Venous rupture occurred in 38 cephalic, 16 brachial, and 9 basilic veins. In 63 patients, bleeding stopped and in 54 (85.7 %) of thee, PTA was successful. Among the nine failed cases, dilatation was incomplete in five, though bleeding had stopped. In patients with brachial and cephalic vein rupture the venous tract at the rupture site was not located. Two patients underwent surgery: one of these experienced brachial venous rupture, with incontrollable bleeding, and the other had nerve compression symptoms due to hematoma. Among 54 patients in whom PTA was successful, the primary and secondary six-months rates for angioaccess were 47.9% and 81.2%, and the mean patency period was 6.1 and 15.8 months, respectively. In cases of non-venous rupture, the mean patency period was 9.6 months, significantly longer than in cases involving venous rupture (p=0.02). Venous rupture occurring during the PTA of hemodialytic AVF can be managed percutaneously.

  12. Altered Venous Function during Long-Duration Spaceflights

    Directory of Open Access Journals (Sweden)

    Jacques-Olivier Fortrat

    2017-09-01

    Full Text Available Aims: Venous adaptation to microgravity, associated with cardiovascular deconditioning, may contribute to orthostatic intolerance following spaceflight. The aim of this study was to analyze the main parameters of venous hemodynamics with long-duration spaceflight.Methods: Venous plethysmography was performed on 24 cosmonauts before, during, and after spaceflights aboard the International Space Station. Venous plethysmography assessed venous filling and emptying functions as well as microvascular filtration, in response to different levels of venous occlusion pressure. Calf volume was assessed using calf circumference measurements.Results: Calf volume decreased during spaceflight from 2.3 ± 0.3 to 1.7 ± 0.2 L (p < 0.001, and recovered after it (2.3 ± 0.3 L. Venous compliance, determined as the relationship between occlusion pressure and the change in venous volume, increased during spaceflight from 0.090 ± 0.005 to 0.120 ± 0.007 (p < 0.01 and recovered 8 days after landing (0.071 ± 0.005, arbitrary units. The index of venous emptying rate decreased during spaceflight from −0.004 ± 0.022 to −0.212 ± 0.033 (p < 0.001, arbitrary units. The index of vascular microfiltration increased during spaceflight from 6.1 ± 1.8 to 10.6 ± 7.9 (p < 0.05, arbitrary units.Conclusion: This study demonstrated that overall venous function is changed during spaceflight. In future, venous function should be considered when developing countermeasures to prevent cardiovascular deconditioning and orthostatic intolerance with long-duration spaceflight.

  13. Radiographic signs of non-venous placement of intended central venous catheters in children

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Erin C. [Boston Children' s Hospital, Department of Radiology, Boston, MA (United States); Taylor, George A. [Boston Children' s Hospital, Department of Radiology, Boston, MA (United States); Harvard Medical School, Department of Radiology, Boston, MA (United States)

    2016-02-15

    Central venous catheters (CVCs) are commonly used in children, and inadvertent arterial or extravascular cannulation is rare but has potentially serious complications. To identify the radiographic signs of arterial placement of CVCs. We retrospectively reviewed seven cases of arterially malpositioned CVCs on chest radiograph. These cases were identified through departmental quality-assurance mechanisms and external consultation. Comparison of arterial cases was made with 127 age-matched chest radiographs with CVCs in normal, expected venous location. On each anteroposterior (AP) radiograph we measured the distance of the catheter tip from the right lateral border of the thoracic spine, and the angle of the vertical portion of the catheter relative to the midline. On each lateral radiograph we measured the angle of the vertical portion of each catheter relative to the anterior border of the thoracic spine. When bilateral subclavian catheters were present, the catheter tips were described as crossed, overlapping or uncrossed. On AP radiographs, arterially placed CVCs were more curved to the left, with catheter tip positions located farther to the left of midline than normal venous CVCs. When bilateral, properly placed venous catheters were present, all catheters crossed at the level of the superior vena cava (SVC). When one of the bilateral catheters was in arterial position, neither of the catheters crossed or the inter-catheter crossover distance was exaggerated. On lateral radiographs, there was a marked anterior angulation of the vertical portion of the catheter (mean angle 37 ± 15 standard deviation [SD] in arterial catheters versus 5.9 ± 8.3 SD in normally placed venous catheters). Useful radiographic signs suggestive of unintentional arterial misplacement of vascular catheters include leftward curvature of the vertical portion of the catheter, left-side catheter tip position, lack of catheter crossover on the frontal radiograph, as well as exaggerated

  14. Exploration of the Chaotic Behaviour in a Buck-Boost Converter Depending on the Converter and Load Elements

    Science.gov (United States)

    Demirbaş, Şevki; Fidanboy, Hikmet; Kurt, Erol

    2016-08-01

    In this paper, detailed analyses of the chaotic behavior observed in a buck-boost converter are presented. Although this basic converter system is already known world-wide for the purpose of dc-dc conversion of the output of renewable energy systems, it indicates certain chaotic regimes where both the output amplitude and frequency change randomly. This chaotic regime can yield an unstable output over the resistive or resistive/inductive electrical loads. This study presents a detailed map for the regular and chaotic regions in terms of material parameters, such as converter capacitance C, resistive load R, and inductive load L. Thus, the stable area of operation for efficient and renewable electricity production will be ascertained for the studied converter system. We emphasize that the material parameters C, R, and L play important roles in generating energy from the solar cell; indeed, the stability increases with higher values of the converter capacitor and load inductance, whereas it decreases according to the resistive load. A number of periodic windows have been observed and the output frequency gives a broad-band spectrum of up to 50 kHz.

  15. Three-phase AC-AC power converters based on matrix converter topology matrix-reactance frequency converters concept

    CERN Document Server

    Szczesniak, Pawel

    2013-01-01

    AC voltage frequency changes is one of the most important functions of solid state power converters. The most desirable features in frequency converters are the ability to generate load voltages with arbitrary amplitude and frequency, sinusoidal currents and voltages waveforms; the possibility of providing unity power factor for any load; and, finally, a simple and compact power circuit. Over the past decades, a number of different frequency converter topologies have appeared in the literature, but only the converters with either a voltage or current DC link are commonly used in industrial app

  16. Adding value(s)

    DEFF Research Database (Denmark)

    Carré, David

    2015-01-01

    , 1992). In response, behavioral economics (Camerer, 1999) has shown that agents have values other than optimization underpinning their decisions. Therefore, concerns arose regarding which values are guiding the agent but not about how such values became relevant for the agent. In this presentation, I......Most economic inquires revolve around agents making decisions. Getting the ‘best value’, it is assumed, drives such decisions: gaining most while risking least. This assumption has been debunked by showing that people does not always choose neither maximum benefit nor less risk (Kahneman & Tversky...... will explore the consequences of shifting to the latter perspective, i.e. looking for the generative framework of values. Here I argue that economic behavior should also be seen as a sense-making process, guided by values that are chosen/rejected along with fellow human beings, in specific socio...

  17. Venous pCO(2) and pH can be used to screen for significant hypercarbia in emergency patients with acute respiratory disease.

    Science.gov (United States)

    Kelly, Anne-Maree; Kyle, Elizabeth; McAlpine, Ross

    2002-01-01

    This prospective study of patients with acute respiratory illness or potential ventilatory compromise compared pCO(2) and pH on an arterial and a venous blood sample with the aims of determining whether venous pH and pCO(2) can replace arterial values in the management of patients with acute respiratory disease and to determine whether there is a cut-off level of venous pCO(2) that can accurately screen for significant hypercarbia (pCO(2) > 50 mm Hg). Data were analyzed using bias plot and receiver operator characteristic (ROC) curve methods. There were 196 sample-pairs analyzed; 56 (29%) had significant hypercarbia. For pH, there was very good agreement with venous samples being an average of 0.034 pH units lower than arterial samples. With respect to pCO(2), there was only fair agreement, with the pCO(2) on average 5.8 mm Hg higher in venous samples and 95% limits of agreement -8.8 to +20.5 mm Hg. The ROC curve analysis showed that a venous pCO(2) level of 45 mm Hg was a potential screening cutoff (sensitivity for the detection of hypercarbia of 100%, specificity 57%). This study shows that venous pH is an acceptable substitute for arterial measurement but there is not sufficient agreement for venous pCO(2) to be able to replace arterial pCO(2) in the clinical evaluation of ventilatory function. Venous pCO(2) may be able to be used as a screening test for hypercarbia using a screening cut-off of 45 mm Hg.

  18. The influence of venous blood flow on the retinal ganglion cell complex in patients with primary open angle glaucoma

    Directory of Open Access Journals (Sweden)

    N. I. Kurysheva

    2014-07-01

    Full Text Available Purpose: To study the influence of venous blood flow on the ganglion cell complex (GCC in patients with preperimetric and perimetric open angle glaucoma.Methods: 74 patients were included in the research. 59 eyes and 62 eyes were diagnosed with preperimetric and perimetric open angle glaucoma respectively. The mean age was 56.5±10.5 years. 22 (12 female and 10 male healthy individuals constituted the control group. The ganglion cell complex and retinal nerve fibre layer were evaluated with the help of optical coherence tomography (RTVue-100 OCT, Optovue, Inc., Fremont, CA. Ocular blood flow was measured by Color Doppler Imaging (multifunctional VOLUSON 730 ProSystem. The statistical analysis included correlation between GCC and RNFL thickness in both glaucoma groups.Results: The results showed a statistically significant reduction of venous blood flow velocity in both glaucoma groups compared to the control group. No difference in venous blood flow parameters between two glaucoma groups was found, except resistance index, which was higher in perimetric group in comparison to preperimetric group. A correlation was also obtained between venous blood flow parameters and GCC and RNFL thickness in both glaucoma groups.Conclusion: Early GCC damage in glaucoma might occur due to venous blood flow reduction. This fact may be of great value in understanding glaucoma pathogenesis and search for novel treatment options.

  19. Mesenteric and splenic venous thrombosis in a female patient with essential thrombocytosis and the resistance to activated protein C

    Directory of Open Access Journals (Sweden)

    Marisavljević Dragomir

    2003-01-01

    Full Text Available Splenic venous thrombosis is a rare disease in which an underlying hypercoagulable state can often be found. A 27-years old female patient with recurrent mesenteric venous and splenic thrombosis as a severe complication of an association of resistance to activated protein C and essential thrombocythemia is presented in this report. Establishing the diagnosis of essential thrombocytosis was particularly difficult because this was the case of the so called "silent" myeloproliferative disorder. The number of thrombocytes was almost normal before the splenectomy performed because of the splenic venous thrombosis. Thus, spontaneous growth of erythroid and megakaryocyte colonies in vitro and the clinical course of the disease were the clues for establishing the diagnosis, because the number of thrombocytes reached the values over 1500×109/l after only 1.5 years of the follow-up. The case of this patient was interesting particularly from the surgical point of view because of the management strategy.

  20. Compression Stockings for Treating Venous Leg Ulcers

    Directory of Open Access Journals (Sweden)

    J. P. Benigni

    2013-01-01

    Full Text Available Background. In order to treat venous leg ulcers, it is recommended to use high pressure compression (30–40 mmHg at the ankle. Compression stockings which are not operator dependant could be the best option because of their pressure control. However 30–40 mmHg compression stockings are often hard to put on. Putting two lower pressure compression stockings over each other could be a good therapeutic alternative. Objectives. To compare the in vitro pressures given by the manufacturers of 2 antiulcer kits with the in vivo interface pressures measured in healthy subjects and to evaluate the stiffness and friction indices from those kits based on the interface pressure in order to assess their clinical properties. Material and Methods. Using a Kikuhime pressure device, interface pressure was measured in 12 healthy subjects at the reference point B1. One stiffness index (Static Stiffness Index (SSI and a friction index have been calculated. Results. Mediven Ulcer kit gets the recommended pressures whereas Jobst’s Ulcer Care kit does not for treating a venous leg ulcer. Jobst’s Ulcer Care transmits entirely the pressure in relation to a friction index close to 1. Conclusion. This antiulcer kit study underlines that in vivo and in vitro pressures can be different (Jobst’s Ulcer Care kit and Mediven Ulcer kit. In order not to lose pressure, it is important to take into account the friction index when superimposing two stockings.

  1. Chronic Infection and Venous Thromboembolic Disease.

    Science.gov (United States)

    Epaulard, Olivier; Foote, Alison; Bosson, Jean-Luc

    2015-09-01

    Venous thromboembolic disease often arises as a complication of another pathological condition and/or triggering event. Infectious diseases result from both the direct action of the pathogens themselves and their effect on the immune system. The resulting inflammatory process and the coagulation and fibrinolysis processes share common pathways, explaining why infection is associated with thrombosis. In this brief overview, besides certain chronic infectious diseases, we also consider some acute infections, as the mechanisms are likely to be similar, particularly in the initial infective stage or the more acute episodes of a chronic infection. The infectious agent can be viral, bacterial, fungal, or parasitic. However, the literature on the link between infections and venous thromboembolism (VTE) is uneven, favoring infections that are found in more developed countries where physicians have access to VTE diagnostic tools. Thus, large epidemiological studies in this field are restricted to a limited number of the common chronic infectious diseases such as tuberculosis, while for other infections, particularly parasitic and fungal infections, the link with VTE is only evoked in a few scattered case reports.

  2. Risk Factors for Cerebral Venous Thrombosis.

    Science.gov (United States)

    Silvis, Suzanne M; Middeldorp, Saskia; Zuurbier, Susanna M; Cannegieter, Suzanne C; Coutinho, Jonathan M

    2016-09-01

    Cerebral venous thrombosis (CVT) is a rare thrombotic disorder involving the cerebral veins and dural sinuses. In contrast to more common sites of venous thromboembolism (VTE), such as the legs and lungs, CVT mainly affects young adults and children, and women are affected three times more often than men. Although presenting symptoms are variable, headache is usually the first symptom, often in combination with focal neurologic deficits and epileptic seizures. The primary therapy for CVT consists of heparin followed by oral anticoagulation for at least 3 to 6 months. The mortality in the acute phase is 5 to 10% and a substantial proportion of survivors suffer from long-term disabilities. A large number of risk factors have been linked to CVT, although the scientific evidence for an association varies considerably between risk factors. Some risk factors, such as hereditary thrombophilia, correspond with risk factors for more common sites of VTE, whereas others, such as head trauma, are specific to CVT. In most patients, at least one risk factor can be identified. In this review, we provide an overview of the risk factors for CVT.

  3. Central Vein Preservation in Critical Venous Access.

    Science.gov (United States)

    Davidson, J; Paul, A; Patel, S; Davenport, M; Ade-Ajayi, N

    2016-08-01

    Introduction The lack of suitable veins in children with critical central venous access requirements is a major obstacle to optimal care and is potentially life-threatening. We present outcomes following the use of vein-preserving (VP) surgical techniques, notably the sheath exchange for tunneled lines (SETL). Materials and Methods A retrospective, single observer analysis of a prospectively maintained departmental logbook as well as the medical records of patients. Two broad groups of central line replacements were identified; those inserted following removal of a previous line and a traditional "plastic-free" (PF) period and those exchanged without such an interval. Results Overall, 19 lines were directly exchanged during the study period and compared with 34 inserted after a PF period. Similar catheter life spans and infection rates were demonstrated in each group; 125 (range, 78-173) days in VP exchanges versus 122 (range, 70-175) days in PF replacements (p = 0.41). Line Sepsis resulting in removal or change of line occurred at 103 (range, 60-147) days in VP group versus 104 (range, 45-164) days in PF (p = 0.73). Conclusion For children with critical venous access requirements, direct line exchange procedures are a robust and reproducible means of vein preservation. The outcomes compare favorably with those following the more traditional removal, a PF period and reinsertion.

  4. [Association between venous thrombosis and dyslipidemia].

    Science.gov (United States)

    García Raso, Aránzazu; Ene, Gabriela; Miranda, Carolina; Vidal, Rosa; Mata, Raquel; Llamas Sillero, M Pilar

    2014-07-07

    Venous and arterial thrombosis, despite being historically considered as distinct conditions, share certain risk factors. Dyslipidemia is a clinical condition with a relatively high prevalence in the population and has been associated with an increased thrombotic risk. Lipids and lipoproteins modulate the expression and/or function of thrombotic, fibrinolytic and rheological factors. We have developed a descriptive, retrospective, comparative, cross-sectional study including a group of 313 patients with venous thromboembolism (VTE). We collected basic demographic data, cardiovascular risk factors and thrombotic complications. All patients were subjected to a lipid profile study with determination of total cholesterol, high density lipoprotein cholesterol (cHDL), low density lipoprotein cholesterol (cLDL) and triglycerides. The multivariable analysis showed that dyslipidemia was a risk factor for VTE (odds ratio [OR] 3.87, 95% confidence interval [95% CI] 2.72-5.56; Pcomplications, recurrence and post-thrombotic syndrome. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  5. Epidemiological study of venous thromboembolism in a big Danish cohort

    DEFF Research Database (Denmark)

    Severinsen, Marianne Tang; Kristensen, Søren Risom; Overvad, Kim

    Introduction: Epidemiological data on venous thromboembolism (VT), i.e. pulmonary emboli (PE) and deep venous thrombosis (DVT) are sparse. We have examined VT-diagnoses registered in a big Danish Cohort study.  Methods: All first-time VT diagnoses in The Danish National Patient Register were...

  6. Venous aneurysm complicating arteriovenous fistula access and matrix metalloproteinases

    Directory of Open Access Journals (Sweden)

    Serra Raffaele

    2015-01-01

    Full Text Available Introduction: An arteriovenous fistula (AVF for placed for hemodialysis may be burdened by one particular complication-the formation of a venous aneurysm. It has been shown that matrix metalloproteinases (MMPs and neutrophil gelatinase-associated lipocalin (NGAL could represent markers of disease in both venous and arterial vessels.

  7. Venous Thrombosis and Atherosclerosis is There a link

    Institute of Scientific and Technical Information of China (English)

    LIU MIN-JUAN; LiU Ze-lin

    2008-01-01

    @@ Venous thrombosis and arterial thrombotic disorders have long been viewed as separate pathophysiological entities, partly as a result of the obvious anatomical differences, as well as their distinct clinical presentations. Recently, the potential association between venous thromboembolism(VTE) and atherosclerosis was described for the first time in 2003. Subsequently, numerous investigations have addressed the topic.

  8. Do we have to anticoagulated patients with cerebral venous thrombosis?

    DEFF Research Database (Denmark)

    Feher, G; Illes, Z; Hargroves, D

    2016-01-01

    INTRODUCTION: Cerebral venous thrombosis (CVT) is a rare form of venous thromboembolism (VTE). Although anticoagulation is recommended for the initial and long term treatment with regards to thrombotic risks for patients with CVT, the role of anticogalution has not been fully elucidated. The aim...... and the outcome of a second event as good as that of the first one irrespective of underlying risk factors....

  9. Risk factors for a first and recurrent venous thrombosis

    NARCIS (Netherlands)

    Flinterman, Linda Elisabeth

    2013-01-01

    The aim of this thesis was to identify new risk factors for first and recurrent venous thrombosis of both the upper and lower extremity, and assess the incidence of recurrence and mortality after a first venous thrombosis. An overview was provided of the current literature on risk factors and treatm

  10. Central venous oxygen saturation during hypovolaemic shock in humans

    DEFF Research Database (Denmark)

    Madsen, P; Iversen, H; Secher, N H

    1993-01-01

    We compared central venous oxygen saturation and central venous pressure (CVP) as indices of the effective blood volume during 50 degrees head-up tilt (anti-Trendelenburg's position) induced hypovolaemic shock in eight healthy subjects. Head-up tilt increased thoracic electrical impedance from 31...

  11. Central venous catheters and catheter locks in children with cancer

    DEFF Research Database (Denmark)

    Handrup, Mette Møller; Møller, Jens Kjølseth; Schrøder, Henrik

    2013-01-01

    To determine if the catheter lock taurolidine can reduce the number of catheter-related bloodstream infections (CRBSI) in pediatric cancer patients with tunneled central venous catheters (CVC).......To determine if the catheter lock taurolidine can reduce the number of catheter-related bloodstream infections (CRBSI) in pediatric cancer patients with tunneled central venous catheters (CVC)....

  12. Thrombin Avtivable Fibrinolysis Inhibitor in Venous and Arterial Thrombosis

    NARCIS (Netherlands)

    E.L.E. de Bruijne

    2011-01-01

    textabstractVenous and arterial thromboses are major causes of morbidity and mortality. Venous thrombosis is the result of pathological occlusive clot formation in the veins. It occurs mainly in the deep veins of the leg (deep vein thrombosis), from which parts of the clot frequently embolize to the

  13. Radiation-Tolerant DC-DC Converters

    Science.gov (United States)

    Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn

    2012-01-01

    A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).

  14. Converting Relational Database Into Xml Document

    Directory of Open Access Journals (Sweden)

    Kanagaraj.S

    2012-03-01

    Full Text Available XML (Extensible Markup Language is emerging and gradually accepted as the standard for data interchange in the Internet world. Interoperation of relational database and XML database involves schema and data translations. Through EER (extended entity relationship model can convert the schema of relational database into XML. The semantics of the relational database, captured in EER diagram, are mapped to XML schema using stepwise procedures and mapped to XML document under the definitions of the XML schema. Converting Relational Database into XML Document is a process of converting the existing databases into XML file format. Existing conversion techniques convert a single database into xml. The proposed approach performs the conversion of databases like Ms-Access, MS-SQL to XML file format. Read the tables information from the corresponding database and generate code for the appropriate databases and convert the tables into XML flat file format. This converted XML file is been presented to the user.

  15. Ocean floor mounting of wave energy converters

    Science.gov (United States)

    Siegel, Stefan G

    2015-01-20

    A system for mounting a set of wave energy converters in the ocean includes a pole attached to a floor of an ocean and a slider mounted on the pole in a manner that permits the slider to move vertically along the pole and rotate about the pole. The wave energy converters can then be mounted on the slider to allow adjustment of the depth and orientation of the wave energy converters.

  16. Development of a Modular Power Converter

    Science.gov (United States)

    Stepanov, A.; Biesenieks, L.; Sokolovs, A.; Galkin, I.

    2009-01-01

    This report describes the most important details of elaboration of a versatile power module that can be utilized as a part of various converters. Two or more modules connected together can form a frequency converter or multilevel converter or 3-phase inverter/rectifier etc. Initially the module was developed for fast prototyping of uninterruptible power supplies and energy systems with alternative energy sources. The module can be used also as a basis for laboratory equipment of the power electronics course.

  17. Regeneration of ZVS converter with Resonant inductor

    Directory of Open Access Journals (Sweden)

    J.Sivavara Prasad

    2011-09-01

    Full Text Available This paper presents an analysis of the regeneration of zero-voltage-switching converter with resonant inductor, quasi-resonant converters, and full-bridge zero-voltage-switched PWM Converter. The design of a clamping circuit considering a saturable resonant inductor is presented and compared with the design of a clamping circuit with a linear resonant inductor. A diode model with reverse recovery is employed to simulate the effects.

  18. CEREBRAL VENOUS THROMBOSIS AND TURNER SYNDROME: A RARE REPORTED ASSOCIATION.

    Science.gov (United States)

    Guler, A; Alpaydin, S; Bademkiran, F; Sirin, H; Celebisoy, N

    2015-01-01

    Turner Syndrome is the only known viable chromosomal monosomy, characterised by the complete or partial absence of an X chromosome. It's the most common chromosomal abnormality in females. Apart from the well known dysmorphic features of the syndrome, it has been associated with a number of vascular pathologies; mainly involving the cardiovascular, renovascular, peripheral vascular and cerebrovascular system. It seems striking that thromboembolism is not considered as a feature of the syndrome. Most of the thromboembolism cases are related to the arterial vascular system; except for some rare reported portal venous thrombosis cases, peripheral venous thrombosis cases and to the best of our knowledge a single case of cerebral venous thrombosis with Dandy Walker malformation and polymicrogyria. We herein report a cerebral venous thrombosis case with Turner Syndrome. With no other found underlying etiology, we want to highlight that Turner Syndrome, itself, may have a relationship not only with the cerebral arterial vascular system pathologies but also with the cerebral venous thrombosis.

  19. Unilateral Loss of Spontaneous Venous Pulsations in an Astronaut

    Science.gov (United States)

    Mader, Thomas H.; Gibson, C. Robert; Lee, Andrew G.; Patel, Nimesh; Hart, Steven; Pettit, Donald R.

    2014-01-01

    Spontaneous venous pulsations seen on the optic nerve head (optic disc) are presumed to be caused by fluctuations in the pressure gradient between the intraocular and retrolaminar venous systems. The disappearance of previously documented spontaneous venous pulsations is a well-recognized clinical sign usually associated with a rise in intracranial pressure and a concomitant bilateral elevation of pressure in the subarachnoid space surrounding the optic nerves. In this correspondence we report the unilateral loss of spontaneous venous pulsations in an astronaut 5 months into a long duration space flight. We documented a normal lumbar puncture opening pressure 8 days post mission. The spontaneous venous pulsations were also documented to be absent 21 months following return to Earth.. We hypothesize that these changes may have resulted from a chronic unilateral rise in optic nerve sheath pressure caused by a microgravity-induced optic nerve sheath compartment syndrome.

  20. Fundamentals and hard-switching converters

    CERN Document Server

    Ioinovici, Adrian

    2013-01-01

    Volume 1 Fundamentals and Hard-switching Converters introduces the key challenges in power electronics from basic components to operation principles and presents classical hard- and soft-switching DC to DC converters, rectifiers and inverters. At a more advanced level, it provides comprehensive analysis of DC and AC models comparing the available approaches for their derivation and results. A full treatment of DC to DC hard-switching converters is given, from fundamentals to modern industrial solutions and practical engineering insight. The author elucidates various contradictions and misunderstandings in the literature, for example, in the treatment of the discontinuous conduction operation or in deriving AC small-signal models of converters.

  1. DC/DC Converter Stability Testing Study

    Science.gov (United States)

    Wang, Bright L.

    2008-01-01

    This report presents study results on hybrid DC/DC converter stability testing methods. An input impedance measurement method and a gain/phase margin measurement method were evaluated to be effective to determine front-end oscillation and feedback loop oscillation. In particular, certain channel power levels of converter input noises have been found to have high degree correlation with the gain/phase margins. It becomes a potential new method to evaluate stability levels of all type of DC/DC converters by utilizing the spectral analysis on converter input noises.

  2. Commutation Processes in Multiresonant ZVS Bridge Converter

    Directory of Open Access Journals (Sweden)

    Miroslaw Luft

    2008-01-01

    Full Text Available The analysis of the multiresonant ZVS DC/DC bridge converter is presented. The control system of the converter is basedon the method of frequency control at the constant time of transistor turn-off with a phase shift. The operation of the circuit is givenand the operating range of the converter is defined where ZVS switching operation is assured. Control characteristics are given andthe converter’s efficiency is defined. The circuit’s operation is analysed on the basis of results of the converter simulation tests using Simplorer programme.

  3. Reliability of Power Electronic Converter Systems

    DEFF Research Database (Denmark)

    -link capacitance in power electronic converter systems; wind turbine systems; smart control strategies for improved reliability of power electronics system; lifetime modelling; power module lifetime test and state monitoring; tools for performance and reliability analysis of power electronics systems; fault......-tolerant adjustable speed drive systems; mission profile oriented reliability design in wind turbine and photovoltaic systems; reliability of power conversion systems in photovoltaic applications; power supplies for computers; and high-power converters. Reliability of Power Electronic Converter Systems is essential...... reading for researchers, professionals and students working with power electronics and their applications, particularly those specializing in the development and application of power electronic converters and systems....

  4. Calculating acid-base and oxygenation status during COPD exacerbation using mathematically arterialised venous blood

    DEFF Research Database (Denmark)

    Rees, Stephen Edward; Rychwicka-Kielek, Beate A; Andersen, Bjarne F

    2012-01-01

    Abstract Background: Repeated arterial puncture is painful. A mathematical method exists for transforming peripheral venous pH, PCO2 and PO2 to arterial eliminating the need for arterial sampling. This study evaluates this method to monitor acid-base and oxygenation during admission for exacerbat......Abstract Background: Repeated arterial puncture is painful. A mathematical method exists for transforming peripheral venous pH, PCO2 and PO2 to arterial eliminating the need for arterial sampling. This study evaluates this method to monitor acid-base and oxygenation during admission...... were assessed with previously defined rules. Differences between maximal changes of calculated and measured values were compared using a t-test, with trends analysed by inspection of plots. Results: Fifty-four patients, median age 67 years (range 62-75), were studied on average 3 days. Mean values of p......H, PCO2 and PO2 were 7.432±0.047, 6.8±1.7 kPa and 9.2±1.5 kPa, respectively. Calculated and measured arterial pH and PCO2 agreed well, differences having small bias and SD (0.000±0.022 pH, -0.06±0.50 kPa PCO2), significantly better than venous blood alone. Calculated PO2 obeyed the clinical rules...

  5. Periodontal disease as a risk factor of recurrence of venous thromboembolic disease: a prospective study.

    Science.gov (United States)

    Sánchez-Siles, Mariano; Rosa-Salazar, Vladimir; Salazar-Sánchez, Noemi; Camacho-Alonso, Fabio

    2015-01-01

    In recent years, periodontal disease has been related to a large number of systemic disorders. To study the possible relationship between periodontal disease and high levels of D-dimer in a group of patients with venous thromboembolic disease. A study was made of 142 patients diagnosed with unprovoked venous thromboembolic disease. All patients underwent oral examination consecutively and randomly. Finally, two groups were obtained: (a) patients with periodontal disease (n = 71); and (b) patients without periodontal disease (n = 71). All patients were subjected to periodontal study, with evaluation of the number of teeth, bleeding index, gingival index, simplified oral hygiene index, community periodontal index of treatment needs, clinical attachment level, probe depth, number of pockets ≥4 mm, number of pockets ≥6 mm. The D-dimer values were evaluated in both groups. D-dimer values were higher in the study group than the control group, with statistically significant differences (p = 0.010). A relationship is observed between the presence of periodontal disease and high D-dimer levels. Patients with venous thromboembolic disease and periodontal disease could have more risk of a new thromboembolism episode.

  6. Speed Control of DC Motor using AC/AC/DC Converter Based on Intelligent Techniques

    Directory of Open Access Journals (Sweden)

    Rakan Kh Antar

    2013-05-01

    Full Text Available    This paper describes the application of ac/ac/dc and ac/dc converters to control the speed of a separately excited DC motor. Artificial neural network and PI controller are trained to select the desired values of firing angles for triggering thyristors of the ac/ac/dc and ac/dc bridge converters in order to control the speed of the dc motor at a desired value with constant and different load torques in order to obtain the best speed response. Simulation results show that the rising time for ac/dc and ac/ac/dc converters at 250rpm are reduced about 79% and 89% respectively, while delay time it reduced about 69% and 64% respectively. Therefore, speed response of the dc motor is more efficient for closed loop system compared with open loop also the response of ac/ac/dc converter is better than ac/dc converter.

  7. THE AZYGOS VENOUS SYSTEM AND ITS ANATOMICAL VARIATIONS

    Directory of Open Access Journals (Sweden)

    Madiki Sudhakara Rao

    2016-06-01

    Full Text Available AIMS AND OBJECTIVES Azygos veins are important cavocaval and portacaval junctions, which form a collateral circulation in caval vein occlusion and in portal hypertension, cirrhosis of liver. The unpaired azygos venous system consists of azygos vein, hemiazygos vein and accessory azygos vein. This system of veins, along with its mediastinal, bronchial and oesophageal tributaries drains most of the body wall of trunk, namely posterior abdominal and thoracic wall. Anatomical variations of this unpaired azygos venous system are clinically important. AIMS To study and report the occurrence of anatomical variations of the unpaired azygos venous system in the region of East Godavari District, Andhra Pradesh (India. METHODS The present study was carried out in the Department of Anatomy, KIMS & RF, Amalapuram and G.S.L. Medical College, Rajahmundry over a period of 2 years. The present study was conducted on 60 cadavers (irrespective of age and sex. The entire course of the azygos venous system in these 60 cadavers was carefully observed and documented. RESULTS Anatomical variations were present in 16.66% of cases, out of which three distinct types were identified. 6.6% exhibited two separate azygos venous systems with no communications, 5% with communication between the left brachiocephalic vein and the azygos vein and 5% presence of post-aortic venous channels. CONCLUSION Variations of azygos venous system may be wrongly dubbed as aneurysm, lymphadenopathy or other abnormalities while reporting a CT scan of mediastinum. Venous anomalies are also detected only during surgery. The most troublesome intraoperative hazard is haemorrhage, which is mainly of venous origin. To avoid such situations is to have an awareness and knowledge of the expected venous anomalies.

  8. Cerebral venous etiology of intracranial hypertension and differentiation from idiopathic intracranial hypertension

    Directory of Open Access Journals (Sweden)

    Stefan Mircea Iencean

    2015-03-01

    Full Text Available This study presents the characteristics that distinguish between idiopathic intracranial hypertension (ICH and ICH caused by intracranial vascular damage. Twenty-one patients with ICH were included in this study. The analysis of the symptomatology correlated with the values of intracranial pressure, and the imaging findings revealed significant differences between these two types of ICH. ICH caused by intracranial venous vascular damage is named vascular ICH. Vascular ICH has a known etiology, such as cerebral vascular illness, and a relatively rapid increase in intracranial pressure of approximately 21 cmH2O and imaging findings show characteristic images of thrombosis or stenosis of the intracranial venous system, while all brain images (computed tomography, magnetic resonance imaging, angio-magnetic resonance imaging are normal in idiopathic ICH. The treatment of vascular ICH is etiologic, pathogenic, and symptomatic, but that of idiopathic ICH is only symptomatic.

  9. Cerebral venous etiology of intracranial hypertension and differentiation from idiopathic intracranial hypertension.

    Science.gov (United States)

    Iencean, Stefan Mircea; Poeata, Ion; Iencean, Andrei Stefan; Tascu, Alexandru

    2015-03-01

    This study presents the characteristics that distinguish between idiopathic intracranial hypertension (ICH) and ICH caused by intracranial vascular damage. Twenty-one patients with ICH were included in this study. The analysis of the symptomatology correlated with the values of intracranial pressure, and the imaging findings revealed significant differences between these two types of ICH. ICH caused by intracranial venous vascular damage is named vascular ICH. Vascular ICH has a known etiology, such as cerebral vascular illness, and a relatively rapid increase in intracranial pressure of approximately 21 cmH2O and imaging findings show characteristic images of thrombosis or stenosis of the intracranial venous system, while all brain images (computed tomography, magnetic resonance imaging, angio-magnetic resonance imaging) are normal in idiopathic ICH. The treatment of vascular ICH is etiologic, pathogenic, and symptomatic, but that of idiopathic ICH is only symptomatic. Copyright © 2015. Published by Elsevier Taiwan.

  10. Association of varicosities and concomitant deep venous thrombosis in patients with superficial venous thrombosis, a systematic review

    NARCIS (Netherlands)

    Baggen, Vivan J M; Chung, Kaman; Koole, Koos; Sarneel, Michelle H J; Rutten, Frans H; Hajer, Gideon R

    2015-01-01

    BACKGROUND: In patients with superficial venous thrombosis (SVT) co-existence of deep venous thrombosis (DVT) can be present. Varicosities are considered as a risk factor for both SVT and DVT separately. However, current evidence is contradictory whether varicosities are associated with an increased

  11. Improvements of venous tone with pycnogenol in chronic venous insufficiency: an ex vivo study on venous segments.

    Science.gov (United States)

    Belcaro, Gianni; Dugall, Mark; Luzzi, Roberta; Hosoi, M; Corsi, Marcello

    2014-03-01

    This study evaluated the stretching and dilatation of venous segments ex vivo in subjects with primary varicose veins in comparison with comparable segments from subjects that used the supplement Pycnogenol (150 mg/d) for 3 months before surgery. Subjects with varicose veins and chronic venous insufficiency voluntarily used Pycnogenol for a period of at least 3 months. The segments of veins removed with surgery (in 30 subjects that had used Pycnogenol and in 10 comparable control subjects that had not used the supplement) were compared with normal, unused vein segments harvested for bypass grafting. The segments were suspended and a weight was attached to the distal part of the veins for 3 minutes and dilated with pressurized water. Digital images were recorded; the veins were measured before and after stretching to evaluate elongation. The manipulation of the vein segment was minimal. Tests were completed within 20 minutes after harvesting the veins. All segments were 4 cm long. The stretching test indicated a significantly higher level of passive elongation in control, varicose segments (2.29; 0.65 mm) in comparison with 1.39; 0.2 mm in vein segments from Pycnogenol-using patients. The dilation test showed an average higher dilation (2.19; 0.3 mm) in control varicose veins in comparison with varicose veins from Pycnogenol-using patients (1.32; 0.7 mm) (p Pycnogenol-using subjects (p Pycnogenol. Varicose segments had a more significant persistent dilatation and elongation in comparison with normal vein segments. Pycnogenol seems to decrease passive dilatation and stretching and gives vein walls a greater tonic recovery and elasticity that allows the vein to recover its original shape after dynamic stresses.

  12. Multicenter Trial of the VenaTech Convertible Vena Cava Filter.

    Science.gov (United States)

    Hohenwalter, Eric J; Stone, James R; O'Moore, Paul V; Smith, Steven J; Selby, J Bayne; Lewandowski, Robert J; Samuels, Shaun; Kiproff, Paul M; Trost, David W; Madoff, David C; Handel, Jeremy; Gandras, Eric J; Vlahos, Athanasios; Rilling, William S

    2017-08-16

    To demonstrate rates of successful filter conversion and 6-month major device-related adverse events in subjects with converted caval filters. An investigational device exemption multicenter, prospective, single-arm study was performed at 11 sites enrolling 149 patients. The VenaTech Convertible Vena Cava Filter (B. Braun Interventional Systems, Inc, Bethlehem, Pennsylvania) was implanted in 149 patients with venous thromboembolism and contraindication to or failure of anticoagulation (n = 119), with high-risk trauma (n = 14), and for surgical prophylaxis (n = 16). When the patient was no longer at risk for pulmonary embolism as determined by clinical assessment, an attempt at filter conversion was made. Follow-up of converted patients (n = 93) was conducted at 30 days, 3 months, and 6 months after conversion. Patients who did not undergo a conversion attempt (n = 53) had follow-up at 6 months after implant. All implants were successful. One 7-day migration to the right atrium required surgical removal. Technical success rate for filter conversion was 92.7% (89/96). Mean time from placement to conversion was 130.7 days (range, 15-391 d). No major conversion-related events were reported. The mean conversion procedure time was 30.7 minutes (range, 7-135 min). There were 89 converted and 32 unconverted patients who completed 6-month follow-up with no delayed complications. The VenaTech Convertible filter has a high conversion rate and low 6-month device-related adverse event rate. Further studies are necessary to determine long-term safety and efficacy in both converted and unconverted patients. Copyright © 2017 SIR. Published by Elsevier Inc. All rights reserved.

  13. Deep Venous Thrombosis Associated With Inferior Vena Cava Abnormalities And Hypoplastic Kidney In Siblings

    Directory of Open Access Journals (Sweden)

    Duicu Carmen

    2016-06-01

    Full Text Available Congenital inferior vena cava anomalies have a reduced frequency in general population, many times being an asymptomatic finding. Patients caring such anomalies are at risk to develop deep vein thrombosis. In this paper, we present 2 siblings with deep venous thrombosis and inferior vena cava abnormalities, with a symptomatic onset at similar age. The inferior vena cava abnormality was documented by an angio-CT in each case. The thrombophilic workup was negative. Patients were treated with conservative therapy: low molecular weight heparin anticoagulants converted later to oral anticoagulant with resolution of symptoms and disappearance of the thrombus. Finally, in the absence of any risk factor in a young patient admitted with deep vein thrombosis investigations to exclude inferior vena cava anomalies are mandatory.

  14. Expression of the Components of the Renin-Angiotensin System in Venous Malformation

    Directory of Open Access Journals (Sweden)

    Sam eSiljee

    2016-05-01

    Full Text Available Background Venous malformation (VM is the most common form of vascular malformation, consisting of a network of thin-walled ectatic venous channels with deficient or absent media. This study investigated the expression of the components of the renin-angiotensin system (RAS, namely (prorenin receptor (PRR, angiotensin converting enzyme (ACE, angiotensin II receptor 1 (ATIIR1 and angiotensin II receptor 2 (AIITR2 in subcutaneous (SC and intramuscular (IM VM. Materials and Methods SC (n=7 and IM (n=7 VM were analyzed for the expression of PRR, ACE, ATIIR1, and ATIIR2 using 3,3-diaminobenzidine (DAB and immunofluorescent (IF immunohistochemical (IHC staining and NanoString gene expression analysis. Results IHC staining showed expression of PRR, ACE, ATIIR1 and faint expression of ATIIR2 in the endothelium of SC and IM VM. Furthermore, ATIIR2 was expressed by cells away from the endothelium in both SC and IM VM lesions examined. NanoString analysis demonstrated the presence of PRR, ACE and ATIIR1 but not ATIIR2.Conclusions The presence of PRR, ACE, ATIIR1 and potentially ATIIR2, in both SC and IM VM suggests a role for the RAS in the biology of VM. This novel finding may lead to a mechanism-based therapy for VM.

  15. Lack of association between potential prothrombotic genetic risk factors and arterial and venous thrombosis.

    Science.gov (United States)

    Evangelista, F C G; Rios, D R A; Ribeiro, D D; Carvalho, M G; Dusse, L M S; Fernandes, A P; Sabino, A P

    2015-08-14

    Recent studies have shown an association between thrombosis and factor VII (FVII), tissue factor (TF), and angiotensin-converting enzyme (ACE). This suggests that individuals with FVII-402 G/A, FVII-401 G/T, TF+5466 A/G, and ACE-287 insertion/deletion (I/D) polymorphisms present an increased risk of venous thrombosis, heart disease, and ischemic stroke compared with controls. In this study, we investigated the frequencies of these polymorphisms and their association with arterial and venous thrombosis. For the FVII-402 G/A polymorphism, there were 57.3% heterozygote (HT) genotypes and 8.3% homozygote (HM) genotypes in the patients, and 45.2% HT genotypes and 15.4% HM genotypes in the controls. For the FVII-401 G/T polymorphism, there were 37.5% HT genotypes and 3.1% HM genotypes in the patients, and 32.7% HT genotypes and 4.8% HM genotypes in the controls. The polymorphism TF+5466 A/G was not found in any of the samples analyzed. For the ACE-287 I/D polymorphism, there were 43 (40.6%) HT genotypes and 63 (59.4%) HM genotypes in the controls and 28 (45.2%) HT genotypes and 34 (54.8%) HM genotypes in the patients. No significant difference was observed by comparing patients and controls. In this study, no association was found between the presence of the evaluated polymorphisms and the occurrence of thrombotic events.

  16. The role of venous blood gas in the emergency department: a systematic review and meta-analysis.

    Science.gov (United States)

    Bloom, Benjamin M; Grundlingh, Johann; Bestwick, Jonathan P; Harris, Tim

    2014-04-01

    The aim of this study is to provide a systematic review of the literature reporting agreement between arterial and venous pH, partial pressure of carbon dioxide (PCO2), bicarbonate (HCO3⁻), base excess and lactate; and to perform a meta-analysis of the differences. Medline and Embase searches using Eduserv Athens from 1950 to present were conducted using the terms 'VBG', 'ABG', 'arterial', 'venous', 'blood', 'gas', 'lactate', 'emergency' and 'department'. References of the published papers were hand searched and full-text versions of those deemed helpful to the question were obtained. Mean difference (MD) and 95% limits of agreement (LOA) were either reported or calculated from the published data. Pooled MDs with 95% confidence intervals (CIs) were calculated for differences between arterial and venous pH, PCO2, bicarbonate and lactate. Thirteen articles relevant to pH, 12 relevant to PCO2, 10 relevant to bicarbonate and three relevant to lactate were found. The pooled MD (venous-arterial) for pH was -0.033 pH units (95% CI -0.039 to 0.027) with narrow 95% LOA, the pooled MD for PCO2 was 4.41 mmHg (95% CI 2.55-6.27) with 95% LOA ranging from -20.4 to 25.8 mmHg, the pooled MD for bicarbonate was 1.03 mmol/l (95% CI 0.56-1.50) with 95% LOA ranging from -7.1 to 10.0 mmol/l and the pooled MD for lactate was 0.25 mmol/l (95% CI 0.15-0.35) with 95% LOA ranging from -2.0 to 2.3 mmol/l. Venous and arterial pH and bicarbonate agree reasonably at all values, but the agreement is highest at normal values. Arteriovenous agreement for PCO2 is poor and PvCO2 cannot be relied upon as an absolute representation of PaCO2. However, normal peripheral PvCO2 has a good negative predictive value for normal arterial PCO2, and a normal PvCO2 can be used as a screen to exclude hypercapnic respiratory disease. There may be a poor agreement between arterial and venous lactate at abnormal values; however, if the venous lactate is normal, it is likely the arterial values of this parameter

  17. VENOUS INSUFFICIENCY AND THROMBOEMBOLIC DISEASE IN BARIATRIC SURGERY PATIENTS

    Directory of Open Access Journals (Sweden)

    Bonno van BELLEN

    2013-09-01

    Full Text Available Context Morbid obesity is associated with various co-morbidities, including chronic venous insufficiency. Bariatric surgery is the only effective treatment for morbid obesity, but with potential risks and possible complications, including venous thromboembolism. Objective To determine the prevalence of clinical and ultrasonographic signs of chronic venous insufficiency in morbid obese patients in preparation for bariatric surgery and the incidence of post-operative venous thromboembolic disease. Methods Patients on work-up for bariatric surgery of Centro Terapêutico Especializado em Fígado (CETEFI and Pro-Gastro surgical teams of the Hospital Beneficência Portuguesa de São Paulo were included. The analysed data were pre-operative findings for venous insufficiency (CEAP - clinical, etiological, anatomical, physiopathologic - classification and venous ultrassonographic findings, type of surgery (open or laparoscopic, abdominal circumference, body mass index (BMI and post-operative ultrassonography search for venous insufficiency and deep venous thrombosis. Results Between March 2007 and December 2009, 95 patients candidates for bariatric surgery had clinical and duplex scan evaluation of the lower limbs venous system. Of the 95 patients, 53 were submitted to the surgical procedure. There was a predominance of women (77.9%, the average age was 38.5 years, average preoperative weight 124.6 kg and average BMI of 45.5 kg/m2. Regarding obesity, 16.8% were obese, and 83.1% were morbidly obese. In relation to the venous findings, 86.3% of the patients did fit CEAP classification less than 3 and 13.7% greater than or equal to 3. Among the post-operative complications, there were four cases of wound infection. Three patients developed post-operative distal venous thrombosis (7.5%, but no one had clinically manifested pulmonary embolism. Conclusion No relation between BMI, CEAP classification and venous ultrassonographic findings were found. Although

  18. Obesity and lower limb venous disease - The epidemic of phlebesity.

    Science.gov (United States)

    Davies, Huw Ob; Popplewell, Matthew; Singhal, Rishi; Smith, Neil; Bradbury, Andrew W

    2017-05-01

    Introduction Lower limb venous disease affects up to one half, and obesity up to one quarter, of the adult population. Many people are therefore affected by, and present to health services for the treatment of both conditions. This article reviews the available evidence of pathophysiological and clinical relationship between obesity and varicose veins, chronic venous insufficiency and ulceration and deep vein thrombosis. Methods A literature search of PubMed and Cochrane libraries was performed in accordance with PRISMA statement from 1946 to 2015, with further article identification from following cited references for articles examining the relationship between obesity and venous disease. Search terms included obesity, overweight, thrombosis, varicose veins, CEAP, chronic venous insufficiency, treatment, endovenous, endothermal, sclerotherapy, bariatric surgery and deep vein thrombosis. Results The proportion of the population suffering from lower limb venous disease and obesity is increasing. Obesity is an important risk factor for all types of lower limb venous disease, and obese patients with lower limb venous disease are more likely to be symptomatic as a result of their lower limb venous disease. The clinical diagnosis, investigation, imaging and treatment of lower limb venous disease in obese people present a number of challenges. The evidence base underpinning medical, surgical and endovenous management of lower limb venous disease in obese people is limited and such treatment may be associated with worse outcomes and increased risks when compared to patients with a normal body mass index. Conclusion Lower limb venous disease and obesity are both increasingly common. As such, phlebologists will be treating ever greater numbers of obese patients with lower limb venous disease, and clinicians in many other specialties are going to be treating a wide range of obesity-related health problems in people with or at risk of lower limb venous disease. Unfortunately

  19. Human cerebral venous outflow pathway depends on posture and central venous pressure

    DEFF Research Database (Denmark)

    Gisolf, J; van Lieshout, J J; van Heusden, K

    2004-01-01

    and central venous pressure (CVP) on the distribution of cerebral outflow over the internal jugular veins and the vertebral plexus, using a mathematical model. Input to the model was a data set of beat-to-beat cerebral blood flow velocity and CVP measurements in 10 healthy subjects, during baseline rest...... and a Valsalva manoeuvre in the supine and standing position. The model, consisting of 2 jugular veins, each a chain of 10 units containing nonlinear resistances and capacitors, and a vertebral plexus containing a resistance, showed blood flow mainly through the internal jugular veins in the supine position...... and during a Valsalva manoeuvre in both body positions, correlate highly with model simulation of the jugular cross-sectional area (R(2) = 0.97). The results suggest that the cerebral venous flow distribution depends on posture and CVP: in supine humans the internal jugular veins are the primary pathway...

  20. Compensation for electrical converter nonlinearities

    Science.gov (United States)

    Perisic, Milun; Ransom, Ray M; Kajouke, Lateef A

    2013-11-19

    Systems and methods are provided for delivering energy from an input interface to an output interface. An electrical system includes an input interface, an output interface, an energy conversion module between the input interface and the output interface, an inductive element between the input interface and the energy conversion module, and a control module. The control module determines a compensated duty cycle control value for operating the energy conversion module to produce a desired voltage at the output interface and operates the energy conversion module to deliver energy to the output interface with a duty cycle that is influenced by the compensated duty cycle control value. The compensated duty cycle control value is influenced by the current through the inductive element and accounts for voltage across the switching elements of the energy conversion module.

  1. Multilevel converters for 10 MW Wind Turbines

    DEFF Research Database (Denmark)

    Ma, Ke; Blaabjerg, Frede

    2011-01-01

    Several promising multi-level converter configurations for 10 MW Wind Turbines both with direct drive and one-stage gear box drive using Permanent Magnet Synchronous Generator (PMSG) are proposed, designed and compared. Reliability is a crucial indicator for large scale wind power converters...

  2. Present trends in HVDC converter station design

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Lennart; Asplund, Gunnar; Bjorklund, Hans; Flisberg, Gunnar [ABB Power Systems AB, Ludvika (Sweden)

    1994-12-31

    HVDC converter station technology has developed rapidly to satisfy increasing requirements during past 10 - 15 years, but there has not been any dramatic changes since thyristor valves were introduced in the mid 70s. This paper describes some recent and expected future developments, that will substantiality change and simplify future converter stations. (author) 4 refs., 7 figs.

  3. High-Efficiency dc/dc Converter

    Science.gov (United States)

    Sturman, J.

    1982-01-01

    High-efficiency dc/dc converter has been developed that provides commonly used voltages of plus or minus 12 Volts from an unregulated dc source of from 14 to 40 Volts. Unique features of converter are its high efficiency at low power level and ability to provide output either larger or smaller than input voltage.

  4. Power Converters Secure Electronics in Harsh Environments

    Science.gov (United States)

    2013-01-01

    In order to harden power converters for the rigors of space, NASA awarded multiple SBIR contracts to Blacksburg, Virginia-based VPT Inc. The resulting hybrid DC-DC converters have proven valuable in aerospace applications, and as a result the company has generated millions in revenue from the product line and created four high-tech jobs to handle production.

  5. High Precision Current Measurement for Power Converters

    CERN Document Server

    Cerqueira Bastos, M

    2015-01-01

    The accurate measurement of power converter currents is essential to controlling and delivering stable and repeatable currents to magnets in particle accelerators. This paper reviews the most commonly used devices for the measurement of power converter currents and discusses test and calibration methods.

  6. Time-Interleaved Analog to Digital Converters

    NARCIS (Netherlands)

    Louwsma, S.M.; van Tuijl, Adrianus Johannes Maria; Nauta, Bram

    2010-01-01

    This book describes the research carried out by our PhD student Simon Louwsma at the University of Twente, The Netherlands in the field of high-speed Analogto- Digital (AD) converters. AD converters are crucial circuits for modern systems where information is stored or processed in digital form. Due

  7. Input-output rearrangement of isolated converters

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Kovacevic, Milovan; Mønster, Jakob Døllner;

    2015-01-01

    is not a requirement. The proposed technique is particularly valuable in power conversion at very high frequencies, and may be combined with other stress reduction methods. Finally, the new arrangements are experimentally verified both on off the shelf converters and on a VHF resonant SEPIC converter. All results...

  8. Modeling and Simulation of Matrix Converter

    DEFF Research Database (Denmark)

    Liu, Fu-rong; Klumpner, Christian; Blaabjerg, Frede

    2005-01-01

    This paper discusses the modeling and simulation of matrix converter. Two models of matrix converter are presented: one is based on indirect space vector modulation and the other is based on power balance equation. The basis of these two models is• given and the process on modeling is introduced...

  9. Venous thromboembolism: have we made headway?

    Science.gov (United States)

    Fitzgerald, Jan

    2010-01-01

    Venous thromboembolism (VTE) is a primary cause of preventable hospital death. The need for effective VTE prophylaxis has been recognized by the Surgical Care Improvement Program (SCIP) and the Joint Commission, which is offering VTE prevention as a core measure set, starting October 1, 2009. The adoption of SCIP VTE measures and mandate to publicly report these rates offers the opportunity to improve the use of prophylaxis in surgical patients and reduce VTE-related morbidity, mortality, and costs. Essential to this reduction is a team approach to implementing real-time interventions. Crucial to the success of the team is early identification of each patient's VTE risk and a mechanism to provide key information to ensure that the physician prescribes appropriate prophylaxis. In addition, it may be the nurse who is responsible for ensuring that a patient receives the appropriate prophylaxis, as well as being the first clinician to observe the clinical signs of a VTE event.

  10. Management of varicose veins and venous insufficiency.

    Science.gov (United States)

    Hamdan, Allen

    2012-12-26

    Chronic venous disease, reviewed herein, is manifested by a spectrum of signs and symptoms, including cosmetic spider veins, asymptomatic varicosities, large painful varicose veins, edema, hyperpigmentation and lipodermatosclerosis of skin, and ulceration. However, there is no definitive stepwise progression from spider veins to ulcers and, in fact, severe skin complications of varicose veins, even when extensive, are not guaranteed. Treatment options range from conservative (eg, medications, compression stockings, lifestyle changes) to minimally invasive (eg, sclerotherapy or endoluminal ablation), invasive (surgical techniques), and hybrid (combination of ≥1 therapies). Ms L, a 68-year-old woman with varicose veins, is presented. She has had vein problems over the course of her life. Her varicose veins recurred after initial treatment, and she is now seeking guidance regarding her current treatment options.

  11. Venous thromboembolism with inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    Hugh James Freeman

    2008-01-01

    Venous thrombosis and thromboembolism appear to be increased in patients with inflammatory bowel disease.Although several acquired and genetic risk factors are known,about half that develop a thromboembolic event have no identifiable risk factor.Control of the inflammatory process is thought to be the key factor in risk reduction for thrombotic events.Prophylactic use of anticoagulants is not universally recommended,but possible use should be reviewed in an individual patient after evaluation of the risks,such as hemorrhage,compared to potential benefits.Particular consideration should be given if there has been a prior thrombotic event,if hospitalization will require surgery,or if an underlying coagulation disorder is present.

  12. Controversies in the diagnosis of venous thromboembolism.

    Science.gov (United States)

    Le Gal, G; Righini, M

    2015-06-01

    Over the last decades, important advances have been made in the diagnosis of venous thromboembolism (VTE). Current diagnostic strategies rely on the sequential use of non-invasive diagnostic tests, based on the pretest clinical probability of disease. Diagnostic tests include D-dimer measurement, leg vein compression ultrasonography, chest computed tomography pulmonary angiography, or ventilation perfusion (V/Q) lung scan. The safety and cost-effectiveness of these strategies have been extensively validated. They have been widely implemented in clinical practice and have replaced the historical gold standard diagnostic tests (venography and pulmonary angiography). However, new challenges arise, including a lower clinical suspicion threshold and concerns on potential over-diagnosis of VTE. Moreover, the diagnostic management remains suboptimal in many subgroups of patients with suspected VTE: patients with prior VTE, pregnant women, or elderly patients.

  13. [Prophylaxis of venous thromboembolism after severe stroke].

    Science.gov (United States)

    Riabinkina, Iu V; Gnedovskaia, E V; Piradov, M A; Kuntsevich, G I

    2010-01-01

    Venous thromboembolism (VTE), a deep and superficial thrombosis and pulmonary embolism, is a very important problem of severe stroke. Pulmonary embolism (PE) significantly influences the course and outcome of severe stroke. The cause of this effect lies not only in severe patient's condition, high risk of VTE and difficulties in diagnosis of VTE but in still common limits in prophylaxis and treatment of PE in severe stroke, first of all, in brain hemorrhages and large brain infarctions with secondary hemorrhage. The paper presents the main principles and methods of prophylaxis of VTE in severe stroke. The suggested approach allows to decrease the frequency of VTE and fatal outcomes in severe stroke in the modern neuro-intensive care units.

  14. Hepatic venous outflow obstruction: Three similar syndromes

    Institute of Scientific and Technical Information of China (English)

    Ulas Darda Bayraktar; Soley Seren; Yusuf Bayraktar

    2007-01-01

    Our goal is to provide a detailed review of venoocclusive disease (VOD), Budd-Chiari syndrome (BCS),and congestive hepatopathy (CH), all of which results in hepatic venous outflow obstruction. This is the first article in which all three syndromes have been reviewed,enabling the reader to compare the characteristics of these disorders. The histological findings in VOD, BCS,and CH are almost identical: sinusoidal congestion and cell necrosis mostly in perivenular areas of hepatic acini which eventually leads to bridging fibrosis between adjacent central veins. Tender hepatomegaly with jaundice and ascites is common to all three conditions.However, the clinical presentation depends mostly on the extent and rapidity of the outflow obstruction.Although the etiology and treatment are completely different in VOD, BCS, and CH; the similarities in clinical manifestations and liver histology may suggest a common mechanism of hepatic injury and adaptation in response to increased sinusoidal pressure.

  15. Contraception-related venous thromboembolism in adolescents.

    Science.gov (United States)

    O'Brien, Sarah H

    2014-02-01

    Venous thromboembolism (VTE) is a rare but serious complication of combined hormonal contraception. While the absolute risk of VTE is low in adolescents, thrombotic events in contraception users younger than the age of 20 years account for 5 to 10% of total contraception-related VTE events in population studies, because of the high frequency of contraception use in adolescents. An increased risk of VTE exists not only with oral contraceptives, but also the contraceptive patch and vaginal ring. Most adolescents who experience contraception-related VTE have additional transient or inherited thrombotic risk factors at the time of VTE. Although the presence of inherited thrombophilia impacts the risk of contraception-related VTE, thrombophilia screening before contraception prescribing should be targeted only to high-risk populations. Pediatric institutions, caregivers, and young women need to be aware of the risk of VTE with estrogen-containing contraception, and maintain a high index of suspicion for this complication in women using these agents.

  16. Role of surgery in iliofemoral venous thrombosis.

    Science.gov (United States)

    Rutherford, R B

    1986-05-01

    Thrombectomy has a limited but definite role in the clinical management of patients with iliofemoral venous thrombosis. It is best applied selectively to achieve specific goals in two different groups of patients at either end of the disease spectrum. In relatively active healthy young patients with phlegmasia alba dolens operated on relatively soon after thrombosis, better protection against the late postthrombotic sequelae can be achieved. Patients with malignancy, underlying coagulopathy, or those who are inactive or have a limited life expectancy due to age or concurrent disease should not be operated on for bland thrombosis. At the other extreme, when phlegmasia cerulea dolens causes painful tense swelling, increases compartmental or decreases ankle pressures, and threatens limb viability in spite of heparinization and leg elevation, thrombectomy should be performed.

  17. Provisional Matrix Deposition in Hemostasis and Venous Insufficiency: Tissue Preconditioning for Nonhealing Venous Ulcers

    Science.gov (United States)

    Parker, Tony J.; Broadbent, James A.; McGovern, Jacqui A.; Broszczak, Daniel A.; Parker, Christina N.; Upton, Zee

    2015-01-01

    Significance: Chronic wounds represent a major burden on global healthcare systems and reduce the quality of life of those affected. Significant advances have been made in our understanding of the biochemistry of wound healing progression. However, knowledge regarding the specific molecular processes influencing chronic wound formation and persistence remains limited. Recent Advances: Generally, healing of acute wounds begins with hemostasis and the deposition of a plasma-derived provisional matrix into the wound. The deposition of plasma matrix proteins is known to occur around the microvasculature of the lower limb as a result of venous insufficiency. This appears to alter limb cutaneous tissue physiology and consequently drives the tissue into a ‘preconditioned’ state that negatively influences the response to wounding. Critical Issues: Processes, such as oxygen and nutrient suppression, edema, inflammatory cell trapping/extravasation, diffuse inflammation, and tissue necrosis are thought to contribute to the advent of a chronic wound. Healing of the wound then becomes difficult in the context of an internally injured limb. Thus, interventions and therapies for promoting healing of the limb is a growing area of interest. For venous ulcers, treatment using compression bandaging encourages venous return and improves healing processes within the limb, critically however, once treatment concludes ulcers often reoccur. Future Directions: Improved understanding of the composition and role of pericapillary matrix deposits in facilitating internal limb injury and subsequent development of chronic wounds will be critical for informing and enhancing current best practice therapies and preventative action in the wound care field. PMID:25785239

  18. Radiation Effects on DC-DC Converters

    Science.gov (United States)

    Zhang, De-Xin; AbdulMazid, M. D.; Attia, John O.; Kankam, Mark D. (Technical Monitor)

    2001-01-01

    In this work, several DC-DC converters were designed and built. The converters are Buck Buck-Boost, Cuk, Flyback, and full-bridge zero-voltage switched. The total ionizing dose radiation and single event effects on the converters were investigated. The experimental results for the TID effects tests show that the voltages of the Buck Buck-Boost, Cuk, and Flyback converters increase as total dose increased when using power MOSFET IRF250 as a switching transistor. The change in output voltage with total dose is highest for the Buck converter and the lowest for Flyback converter. The trend of increase in output voltages with total dose in the present work agrees with those of the literature. The trends of the experimental results also agree with those obtained from PSPICE simulation. For the full-bridge zero-voltage switch converter, it was observed that the dc-dc converter with IRF250 power MOSFET did not show a significant change of output voltage with total dose. In addition, for the dc-dc converter with FSF254R4 radiation-hardened power MOSFET, the output voltage did not change significantly with total dose. The experimental results were confirmed by PSPICE simulation that showed that FB-ZVS converter with IRF250 power MOSFET's was not affected with the increase in total ionizing dose. Single Event Effects (SEE) radiation tests were performed on FB-ZVS converters. It was observed that the FB-ZVS converter with the IRF250 power MOSFET, when the device was irradiated with Krypton ion with ion-energy of 150 MeV and LET of 41.3 MeV-square cm/mg, the output voltage increased with the increase in fluence. However, for Krypton with ion-energy of 600 MeV and LET of 33.65 MeV-square cm/mg, and two out of four transistors of the converter were permanently damaged. The dc-dc converter with FSF254R4 radiation hardened power MOSFET's did not show significant change at the output voltage with fluence while being irradiated by Krypton with ion energy of 1.20 GeV and LET of 25

  19. Modelling, analyses and design of switching converters

    Science.gov (United States)

    Cuk, S. M.; Middlebrook, R. D.

    1978-01-01

    A state-space averaging method for modelling switching dc-to-dc converters for both continuous and discontinuous conduction mode is developed. In each case the starting point is the unified state-space representation, and the end result is a complete linear circuit model, for each conduction mode, which correctly represents all essential features, namely, the input, output, and transfer properties (static dc as well as dynamic ac small-signal). While the method is generally applicable to any switching converter, it is extensively illustrated for the three common power stages (buck, boost, and buck-boost). The results for these converters are then easily tabulated owing to the fixed equivalent circuit topology of their canonical circuit model. The insights that emerge from the general state-space modelling approach lead to the design of new converter topologies through the study of generic properties of the cascade connection of basic buck and boost converters.

  20. Qualitative model of a plasma photoelectric converter

    Science.gov (United States)

    Gorbunov, N. A.; Flamant, G.

    2009-01-01

    A converter of focused optical radiation into electric current is considered on the basis of the photovoltaic effect in plasmas. The converter model is based on analysis of asymmetric spatial distributions of charge particle number density and ambipolar potential in the photoplasma produced by external optical radiation focused in a heat pipe filled with a mixture of alkali vapor and a heavy inert gas. Energy balance in the plasma photoelectric converter is analyzed. The conditions in which the external radiation energy is effectively absorbed in the converter are indicated. The plasma parameters for which the energy of absorbed optical radiation is mainly spent on sustaining the ambipolar field in the plasma are determined. It is shown that the plasma photoelectric converter makes it possible to attain a high conversion efficiency for focused solar radiation.