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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
951

Development, metrological validation and applications of non-invasive cardiovascular exploration techniques for clinical and experimental use in canine and feline models / Mise au point, validation métrologique et applications de méthodes d'exploration cardiovasculaire non-invasives à visée expérimentale et clinique dans des modèles canins et félins

Gouni, Vassiliki 24 February 2015 (has links)
Les animaux de compagnie présentent un intérêt majeur dans les études cardiovasculaires soit comme modèles expérimentales soit comme modèles spontanées. De plus, le développement de méthodes d'exploration non invasives en médecine vétérinaire est devenu une nécessité à cause de régulations strictes concernant le bien être de l'animal. Un facteur limitant demeure l'exactitude et la fiabilité (répétabilité/reproductibilité) des techniques d'exploration pour leur utilisation répétitive chez des animaux vigiles. La mesure de la pression artérielle systémique (PA) non invasive et l'échocardiographie conventionnelle et avancée ont gagné de la place dans le domaine de recherche ; cependant, il n'existe pas de recommandations spécifiques sur la validation métrologique de méthodes quantitatives utilisées en recherche clinique ou fondamentale en médecine vétérinaire. Le présent travail a premièrement focalisé sur la validation métrologique de la mesure de la PA chez le chien et le chat en étudiant la répétabilité et la reproductibilité de la méthode Doppler (chez les deux espèces) et de la méthode oscillométrique (chez le chien) et en déterminant l'influence du niveau d'expérience de l'opérateur sur la variabilité intra- et inter-jour et le pourcentage de mesures réussies. Puis l'effet de la position de l'animal et du nombre de mesures répétées sur de variables sélectionnées d'échocardiographie bidimensionnelle (2D) et temps-mouvement (TM) a été évalué. De plus, la méthode de l'aire de la surface de l'isovélocité proximale (PISA) pour la quantification de la régurgitation mitrale (RM) ainsi que le strain (St) et strain rate (SR) dérivé du Doppler tissulaire ont été validé chez le chien par le calcul de la répétabilité et la reproductibilité des techniques. Dans un deuxième temps les techniques précédemment validées ont été appliquées chez des chiens sains, des chiens souffrant de maladie valvulaire mitrale dégénérative (MVD) spontanée et dans un modèle expérimental de myopathie centronucléaire (CNM) chez des Labradors retrievers. Toutes les études ont été réalisées à l'Unité de Cardiologie d'Alfort, à l'Ecole Nationale Vétérinaire d'Alfort. Pour les mesures de la PA, toutes les deux études ont montré que l'entrainement est important, notamment pour la mesure de la pression diastolique avec le Doppler, tandis que la répétabilité et reproductibilité sont bonnes pour un opérateur expérimenté. Concernant l'échocardiographie 2D et TM, la technique peut être réalisée chez des chiens couchés ou debout avec une répétabilité/reproductibilité similaire. La fraction régurgitée évaluée par la méthode PISA est une variable répétable et reproductible pour l'évaluation de la RM chez le chien souffrant de MVD. De façon similaire le St et SR peuvent être mesurés de manière fiable chez le chien vigile et leur utilisation combinée avec d'autres paramètres échocardiographiques offre une nouvelle approche à l'étude de la fonction systolique dans cette espèce et peut complémenter l'échocardiographie conventionnelle pour la mesure de la performance myocardique. L'intérêt de ces méthodes validées a été illustré dans des études avec des chiens souffrant de MVD de gravité variable et une différence significative des paramètres étudiés (PA et fraction régurgitée) a été retrouvée dépendant du stade de la maladie. Enfin dans le modèle de CNM, des altérations sous-cliniques ont été détectées et considérées comme significatives étant donnée les faible coefficients de variation de techniques utilisées. En conclusion, le présent travail a évalué la répétabilité et la reproductibilité de quelques techniques d'exploration cardiovasculaires et a démontré l'importance de la validation en les appliquant dans des circonstances cliniques. Cependant ces résultats ne sont valables que dans les conditions spécifiques utilisées dans ces études. / Small animais present a major interest in cardiovascular studies either as experimental or as spontaneous models. Additionally, the development of non-invasive exploration methods in veterinary medicine has been impeding since regulations applying to animais are getting stricter and animal welfare has been the subject of many debates recently. A limitation factor regarding noninvasive cardiovascular exploration by different methods remains the accuracy, and reliability of the different techniques, that is to say, if the methods are repeatable and reproducible, and able to be used in repeated manner in awake animais. Although non-invasive arterial blood pressure (ABP) measurement and conventional, as weil as, advanced echocardiographic techniques have gained place in the domain of veterinary research, there are no specifie guidelines on how to metrologically validate a quantitative imaging technique in veterinary medicine for use in clinical or fundamental research. The present work focused firstly on metrological validation of non-invasive ABP measurement in dogs and cats by assessment of repeatability and reproducibility of Doppler ultrasonography (DU, in both dogs and cats) and high definition oscillometry (in dogs) and by determination of the influence of the observer's level of experience on within-day and between-day variability and the percentage of successful measurements. Then, the effect of animal position and number of repeated measurements on selected 2-dimensional (20) and M-mode echocardiographic variables in heal~hy dogs was evaluated. Moreover, the proximal isoveJocity surface area (PISA) method for quantification of mitral regurgitation (MR) and the tissue Doppler-derived strain (St) and strain rate (SR) technique in the dog were validated by calculation of repeatability and reproducibility. In a second step, the previously validated techniques were applied to healthy dogs, dogs suffering from spontaneous mitral valve disease (MVD) and to an experimental model of centronudear myopathy (CNM) in labrador retrievers. A total of 7 studies were realized. Ali studies were conducted at the Cardiology Unit of Alfort, in the National Veterinary School of Alfort. For ABP measurements, bath studies showed that training is important especially for evaluation of diastolic ABP with DU, whereas repeatability and reproducibility are good for sufficiently experienced observers. Regarding transthoracic 20 and M-mode echocardiography, itcan be performed on dogs in both standing position and lateral recumbency, and the repeatability of measurements is similar. Regurgitant fraction assessed by the PISA method is a repeatable and reproducible variable for the non-invasive evaluation of MR in awake dogs with MVD. This Doppler index is reliable, and its assessment can therefore be recommended for use, in combination with evaluation of other Doppler echocardiographic variables, in longitudinal studies of mitral valve disease in dogs. SimilarJy, myocardial St and SR can be measured non-invasively and in real time from regional myocardial velocities by TOI with good repeatability and reproducibility in the awake dog. The combined use of. St and SR indices with other tissue Doppler parameter's offers a new ultrasound approach to the systolic function in this species and may complement conventional echocardiographic measure of myocardial performance. The interest of those validation methods was firstly iIIustrated in studies involving dogs suffering from MVD of differing severity, where a relevant difference of the evaluated parameters (ABP and regurgitant fraction) was found depending on the stage of the disease.
952

Verenpainepotilaiden hoitoon sitoutumisen arviointi ja edistäminen multimediaohjelman avulla

Lahdenperä, T. (Tiina) 16 August 2002 (has links)
Abstract The study is part of a project titled Self-motivated control of hypertension. The project is multidisciplinary, and the participants were from the Department of Nursing and Health Administration, University of Oulu, the Department of Internal Medicine, Oulu University Hospital, the health centers of the Liminka and Rantsila municipalities, Polar Electro Oy and The National Technology Agency (TEKES). The main purpose of the study was to evaluate the compliance and the blood pressure control of the intervention patients and the positive effect of the intervention on the compliance and the control of blood pressure. A further purpose was to develop a scale for measuring hypertensive patients' compliance and to test the reliability and validity of the scale. The intervention included the use of a multimedia-based computer program and a heart rate monitor, home measurements of blood pressure and two walking tests as a support of hypertension care. The study consisted of four phases. In the first phase, the patients in the intervention group (n = 21) were interviewed. The topics were: the patients' compliance and attitude towards hypertension and its care and the patients' attitude towards information technology and its use as a support of hypertension care. The material was analysed using the method of content analysis. In the second phase, the Compliance of Hypertensive Patients' Scale (= CHPS) was developed and its reliability and validity were assessed. Data were collected from five health centers (n = 103). Dimensionality was explored using principal component analysis and internal consistency was estimated according to a standard item analysis approach and Theta coefficient. Validity was assessed using face validity, content validity and criterion-related validity (through the use of concurrent validity). In the third phase, by using the CHPS, the compliance of the intervention (n = 14) and control patients (n = 21) was evaluated and the groups were compared. Data were analysed using Mann Whitney's U-test. The control of blood pressure of intervention (n = 16) and control (n = 18) groups was also evaluated and compared. Data were analysed using T-test. In the fourth phase, the patients were interviewed for an evaluation of how the intervention had improved their (n = 16) compliance. The material was analyzed using content analysis. The patients' attitude towards information technology as a support of hypertension care and their attitude towards hypertension and its care were more positive at the end than at the beginning of the intervention. The intervention improved the patients' compliance. They used less sodium (p = .014), exercised more effectively (p = .017) and needed fewer follow-up appointments with nurses than the patients in the control group. The most important part of the intervention consisted of the measurement of blood pressure at home, sending the readings to the health center and the use of a heart rate monitor to improve the effectiveness of exercise. The program illustrated and made more concrete the things connected with lifestyle. The patients who felt that hypertension was caused by stress did not find the setting of the goals and the use of the program meaningful. The variation of diastolic blood pressure at home was statistically almost significant (p = .057) at the end of the project and the blood pressure values were lower in the intervention group than in the control group. The blood pressure readings recorded at home were lower than the measurements recorded by the physician at the health center (SBP p = .000, DBP p = .003). / Tiivistelmä Tutkimus oli osa Omatoiminen verenpaineen hallinta -projektia (OVH-projekti). Projekti on monitieteinen, ja siihen ovat osallistuneet Oulun yliopiston hoitotieteen ja terveyshallinnon laitos, Oulun yliopistollisen sairaalan sisätautien klinikka, Limingan ja Rantsilan terveyskeskukset, Polar Electro Oy ja Tekes. Tutkimuksen päätarkoituksena oli arvioida interventioryhmän potilaiden hoitoon sitoutumista ja hoitotasapainoa sekä sitä, miten kyseinen interventio edisti hoitoon sitoutumista. Lisäksi tarkoituksena oli kehittää hoitoon sitoutumista arvioiva mittari ja testata sen luotettavuutta. Projektissa toteutettuun interventioon kuului kohonneen verenpaineen hoidon tueksi suunnitellun multimediapohjaisen tietokoneohjelman (OVH-ohjelma) ja sykemittarin käyttö, verenpaineen kotimittaukset sekä kaksi kävelytestiä. Tutkimus sisälsi neljä vaihetta. Ensimmäisessä vaiheessa interventioryhmän (n = 21) potilaat haastateltiin. Aiheina olivat potilaiden hoitoon sitoutuminen ja suhtautuminen kohonneeseen verenpaineeseen sekä suhtautuminen tietotekniikkaan ja sen käyttöön kohonneen verenpaineen hoidon tukena. Aineisto analysoitiin sisällönanalyysillä. Toisessa vaiheessa kehitettiin hoitoon sitoutumista arvioiva mittari, jonka luotettavuutta testattiin viiden eri terveyskeskuksen verenpainepotilailla (n = 103). Luotettavuuden arvioinnissa käytettiin osioiden välisiä korrelaatiokertoimia, face-validiteettia, faktorianalyysiä, osioiden välisiä korjattuja korrelaatiokertoimia, theeta-arvoa ja Pearsonin tulomomenttikorrelaatiokerrointa. Kolmannessa vaiheessa arvioitiin ja verrattiin interventio- ja vertailuryhmän potilaiden hoitoon sitoutumista (n = 14, n = 21) kehitetyn mittarin avulla sekä hoitotasapainoa (n = 16, n = 18). Aineiston analyysissä käytettiin kuvailevia arvoja, Mann Whitneyn U-testiä ja T-testiä. Neljännessä vaiheessa arvioitiin haastattelujen avulla sitä, miten interventio edisti potilaiden (n = 16) hoitoon sitoutumista. Aineisto analysoitiin sisällönanalyysillä. Potilaiden suhtautuminen tietotekniikkaan ja sen käyttöön kohonneen verenpaineen hoidon tukena sekä suhtautuminen kohonneeseen verenpaineeseen ja sen hoitoon oli intervention lopussa myönteisempää kuin sen alussa. Interventio edisti tutkittavien hoitoon sitoutumista. He käyttivät suolaa vähemmän (p = .014), liikkuivat tehokkaammin (p = .017) ja kävivät hoitajan vastaanotolla harvemmin (p = .000) kuin vertailuryhmän potilaat. Tärkeimmät intervention osa-alueet olivat verenpaineen mittaus kotona ja arvojen lähettäminen terveyskeskukseen sekä sykemittarin käyttö. Sykemittarin käyttö lisäsi liikunnan tehokkuutta. OVH-ohjelman käyttö havainnollisti ja konkretisoi elintapoihin liittyviä asioita. Potilaat, jotka pitivät stressiä kohonneen verenpaineen syynä, eivät kokeneet tavoitteiden asettamista eivätkä myöskään ohjelman käyttöä mielekkääksi. Interventioryhmän diastolisen verenpaineen muutos kotimittauksissa oli intervention lopussa tilastollisesti melkein merkitsevä (p = .057) ja verenpainearvot olivat matalammat kotimittauksissa kuin vertailuryhmän potilaiden arvot. Tutkittavien verenpainearvot olivat kotimittauksissa matalammat kuin lääkärin mittauksissa terveysasemalla (SVP p = .000, DVP p = .003).
953

Non-invasive Estimation of Blood Pressure using Harmonic Components of Oscillometric Pulses

Abolarin, David January 2016 (has links)
This research presents a pulse-by-pulse analysis of Oscillometric blood pressure waveform at systolic, diastolic and mean arterial pressure points. Using a mathematical optimization technique, pulses are characterized into component harmonic by minimizing the least square error. The results at the important pressure points are analyzed and compared for different subject using different waveform extraction techniques. Blood pressure is estimated using the harmonic parameters. The approach studies changes in the parameters as oscillometric blood pressure recording is done. 8 harmonic parameters are obtained from the pulse characterization and are used to estimate Systolic arterial Blood Pressure, Mean arterial Blood Pressure, and Diastolic arterial Blood Pressure. The estimates are compared with our reference value to determine which has the best agreement. The proposed method is further compared with Maximum Amplitude Algorithm and Pulse Morphology Algorithm. The effect of oscillometric waveform extraction methods on the proposed method is observed. The experiment established the fact that the extraction technique can alter the shape of oscillometric pulses. The methods were compared and it was observed that the used extraction methods did not make any significant difference on the accuracy, using this technique.
954

Longitudinal Assessment of Blood Pressure in Late Stage Chronic Kidney Disease

Sood, Manish January 2017 (has links)
The worldwide population of patients with chronic kidney disease (CKD) is growing, with estimated prevalence at 12-15% of adults. Of particular concern are those with late stage CKD, defined as an estimated glomerular filtration rate (eGFR)of less than 30 ml/min/1.73m2, as they are susceptible to the highest risk of adverse outcomes such as progression to end stage kidney disease (ESKD), cardiovascular disease and all-cause mortality (1, 2). As such, late stage CKD patients are often managed in specialized clinics with set clinical targets, standardized education and multi-disciplinary care(3). A key clinical target for therapeutic intervention and prevention of the progression of CKD is blood pressure (BP) reduction(4). Yet, multiple relevant questions remain regarding the strength and nature of association of BP with clinical outcomes in late stage CKD. As the risks of hypotension-related complications are high in late stage CKD, it remains unclear whether strict BP control delays CKD progression in a real world clinic population(5). Furthermore, it is unclear how to appropriately specify the nature of the longitudinal association between BP and clinical outcomes of ESKD and mortality. The overall objective of this thesis is to examine the longitudinal association of BP and adverse clinical outcomes in a cohort of 1203 patients (mean eGFR 17.8 ml/min/1.73m2; mean of 6.7 BP measures per patient) with late stage CKD. In our first paper we examined the association of repeat measures of BP with CKD progression, defined as a decline in eGFR. When modeling eGFR using longitudinal linear regression, we found that its over-time trajectory was non-linear and that this trajectory was modified by BP; thus, we found a significant time-dependant association between BP and eGFR. When modeling time to eGFR decline ≥ 30% using Cox proportional hazards regression with categorized BP specified as a time-dependent exposure, BP was significantly associated with risk of eGFR decline; in particular, extremes of low and high systolic blood pressure (SBP) and high diastolic blood pressure (DBP) significantly increased the risk of eGFR decline. In our second paper, we examined different methods of modelling longitudinal BP and its association with time to mortality and ESKD. We found that elevations in SBP and DBP, in particular, when expressed as current (most recent visit), lag (previous visit), and cumulative exposure were significantly associated with increased risk of ESKD while low SBP (current, lag and cumulative exposure) was significantly associated with increased risk of mortality. Baseline BP measures were not statistically significantly associated with any outcomes. In patients with more moderate ranges of SBP (121-140) or DBP (60-85) at baseline, a subsequent rise to >160 or > 85 respectively, was associated with an increased risk of ESKD. Thus, longitudinal BP measures in late-stage CKD are significantly associated with adverse outcomes and convey important information beyond baseline BP measures.
955

A Modeling Approach for Coefficient-Free Oscillometric Blood Pressure Estimation

Forouzanfar, Mohamad 27 June 2014 (has links)
Oscillometry is the most common measurement method used in automatic blood pressure (BP) monitors. However, most of the oscillometric algorithms are without physiological and theoretical foundation, and rely on empirically derived coefficients for systolic and diastolic pressure evaluation which affects the reliability of the technique. In this thesis, the oscillometric BP estimation problem is addressed using a comprehensive modeling approach, based on which coefficient-free estimation of BP becomes possible. A feature-based neural network approach is developed to find an implicit relationship between BP and the oscillometric waveform (OMW). The modeling approach is then extended by developing a mathematical model for the OMW as a function of the arterial blood pressure, cuff pressure, and cuff-arm-artery system parameters. Based on the developed model, the explicit relationship between the OMW and the systolic and diastolic pressures is found and a new coefficient-free oscillometric BP estimation method using the trust region reflective algorithm is proposed. In order to improve the reliability of BP estimates, the electrocardiogram signal is recorded simultaneously with the OMW, as another independent source of information. The electrocardiogram signal is used to identify the true oscillometric pulses and calculate the pulse transit time (PTT). By combining our developed model of oscillomtery with an existing model of the pulse wave velocity, a new mathematical model is derived for the PTT during the cuff deflation. The derived model is incorporated to study the PTT-cuff pressure dependence, based on which a new coefficient-free BP estimation method is proposed. In order to obtain accurate and robust estimates of BP, the proposed model-based BP estimation method sare fused by computing the weighted arithmetic mean of their estimates. With fusion of the proposed methods, it is observed that the mean absolute error (MAE) in estimation of systolic and diastolic pressures is 4.40 and 3.00 mmHg, respectively, relative to the Food and Drug Administration-approved Omron monitor. In addition, the proposed feature-based neural network was compared with auscultatory measurements by trained observers giving MAE of 6.28 and 5.73 mmHg in estimation of systolic and diastolic pressures, respectively. The proposed models thus show promise toward developing robust BP estimation methods.
956

Analyse et traitement des signaux oscillomètriques pour la mesure de la pression artérielle systolique et la détermination des caractéristiques biomécaniques de la paroi artérielle. / Analysis and processing of oscillometric signals for the measurement of systolic arterial blood pressure and assessment of arterial wall biomechanics.

Benmira, Amir Mokhfi 04 July 2016 (has links)
Notre travail de thèse est consacré au développement d’une nouvelle approche d’analyse du signal oscillométrique pour mesurer la pression artérielle systolique et identifier les personnes dont la paroi artérielle est anormalement rigide. L’oscillométrie, largement exploitée pour la mesure automatique non-vulnérante de la pression artérielle, repose sur l’amplitude des variations dynamiques de pression du brassard pneumatique générées par l’expansion de l’artère brachiale sous l’effet de l’onde de pouls. Nous avons d’abord effectué une revue de la littérature sur les méthodes auscultatoire et oscillométrique. La méthode auscultatoire, fondée sur la détection des bruits produits par l’artère brachiale sous le brassard, reste la référence pour la validation des moniteurs oscillométriques. Depuis la description de ces bruits par Nicolaï Korotkoff en 1905, de nombreux auteurs ont tenté d’en expliquer l’origine et d’en identifier les limites et pièges en comparaison avec la mesure intra-artérielle directe. La technique oscillométrique dérive de l’invention du sphygmographe par Etienne-Jules Marey en 1859. Les constructeurs procèdent à la validation de leurs appareils en référence aux normes internationales (ISO) sans dévoiler les algorithmes mise en œuvre. De très nombreuses approches ont été proposées, depuis des rapports déterminés empiriquement jusqu’à des réseaux de neurones en passant par divers modèles mathématiques, pour déterminer les pressions systolique et diastolique à partir de la pression moyenne mesurée sur la courbe oscillométrique. Cependant, l’oscillométrie donne des résultats variables et présente des erreurs significatives, en particulier pour la détermination de la pression systolique, notamment chez les sujets ayant des facteurs de risque cardiovasculaires.Sur la base de cette analyse, considérant que la référence reste la détection des bruits de Korotkoff, nous avons cherché à en mieux comprendre les mécanismes. Nous avons enregistré les images échographiques et le signal Doppler de l’artère brachiale sous le brassard lors de la mesure de pression artérielle chez des sujets volontaires, en synchronisation avec l’ECG, la pression du brassard et les bruits de Korotkoff. Nous avons pu observer les variations cycliques du diamètre de l’artère brachiale pendant le dégonflage du brassard, et mesurer la vitesse locale de propagation de l’onde de pouls, ainsi que les délais entre le signal oscillométrique, l’ECG et les bruits de Korotkoff. Nous avons pu ainsi démontrer que les bruits de Korotkoff sont produits par la vibration de la paroi artérielle sous l’impact de l’onde de pouls, puis par la turbulence de l’écoulement flux sanguin, et nous avons montré la diminution marquée de la vitesse locale de l’onde de pouls lorsque la pression du brassard réduit la pression artérielle transmurale. L’observation de ces enregistrements nous a montré l’intérêt de l’analyse de la forme de l’onde de pouls enregistrée par oscillométrie. Nous en avons tiré une approche innovante fondée sur l’analyse temporelle pour la détermination directe de la pression artérielle systolique. Nous avons réalisé une étude clinique prospective, selon un protocole approuvé par le Comité d’éthique du CHU de Nîmes, pour valider notre nouvelle approche. Nous avons comparé notre technique à la méthode auscultatoire chez 145 sujets avec ou sans facteurs de risque cardiovasculaire, et à la pression mesurée par cathéter radial chez 35 patients hospitalisés en réanimation. Nous avons obtenu une excellente concordance avec le premier bruit de Korotkoff, avec des résultats très supérieurs à l’oscillométrie réalisée à l’aide d’un appareil validé. De plus, notre technique s’est montrée capable d’identifier les sujets porteurs de facteurs de risque cardiovasculaires, se comparant favorablement à la vitesse de l’onde de pouls aortique. / Our thesis is devoted to the development of a new oscillometric signal analysis approach to measure systolic blood pressure and identify subjects with abnormal arterial wall rigidity. Oscillometry, widely used for the non-invasive automatic measurement of blood pressure, is based on the amplitude of the dynamic cuff-pressure oscillations generated by the expansion of the brachial artery at the arrival of the pulse wave.We first conducted a literature review on the auscultatory and oscillometric methods. The auscultatory method, based on the detection of the sounds emitted by the brachial artery under the cuff, remains the reference for the validation of oscillometric monitors. Since the description of these sounds by Nicolai Korotkoff in 1905, many authors attempted to explain their origin and assess their limits and pitfalls in comparison with direct intra-arterial blood pressure measurement.Oscillometric technique derive from the sphygmograph built by Etienne-Jules Marey in 1859. Manufacturers validate their oscillometric devices in reference to the international standards (ISO) without revealing the algorithms they use. Numerous approaches have been proposed, from fixed empirical ratios to neural networks to various mathematical models, for the calculation of systolic and diastolic pressure since only the mean arterial pressure is actually measured on the oscillometric curve. However, oscillometry yields variable results and produces significant errors, especially for systolic pressure, notably in patients with cardiovascular risk factors.Based on this analysis, and considering that the reference remains the detection of Korotkoff sounds, we sought to better understand their mechanisms. We recorded ultrasound images and the Doppler signal of the brachial artery under the cuff when measuring blood pressure in volunteers, simultaneously with ECG, cuff pressure and Korotkoff sounds. We could record the systolic diameter changes of the brachial artery during cuff deflation, and measure the local pulse wave velocity, as well as the time delay between the oscillometric signal, the ECG and the Korotkoff sounds. We were able to demonstrate that the Korotkoff sounds are produced by arterial wall vibration under the impact of the pulse wave, then by blood flow turbulence, and we measured the marked decrease in local pulse wave velocity when the cuff inflation reduces the brachial artery transmural pressure.We concluded to the interest of pulse waveform analysis, and designed an innovative approach based on its temporal characteristics for the direct determination of systolic blood pressure. We conducted a prospective clinical study, according to a protocol approved by the Ethics Committee of the Nîmes University Hospital Center, to validate our new approach. We compared our technique to the auscultation method in 145 subjects with or without cardiovascular risk factors, and to direct blood pressure measurement with a radial catheter in 35 patients hospitalized in the intensive care unit. We obtained an excellent correlation with the first Korotkoff sound, with better results than conventional oscillometry. In addition, our technique has proven able to identify subjects with cardiovascular risk factors with an accuracy favorably comparable to aortic pulse wave velocity.
957

Qualidade de vida relacionada à saúde do indivíduo com hipertensão arterial integrante de um grupo de convivência / Health-related quality of life of high blood patients participating in a gathering group

Patrícia Magnabosco 08 August 2007 (has links)
A Hipertensão Arterial Sistêmica (HAS) é uma doença crônica não transmissível com etiologia multifatorial e uma das principais causas de doenças cardiovasculares que são responsáveis pela maioria das mortes mundiais. Por ser tratar de uma doença de alta prevalência e na maioria das vezes assintomática, a adesão do hipertenso ao tratamento tem uma representação muito baixa, o que requer a intervenção educacional dos profissionais da saúde no tratamento, na prevenção das complicações e na manutenção da vida. A qualidade de vida relacionada à saúde (QVRS) dos indivíduos com hipertensão arterial é menor comparada com a população geral. A avaliação dos fatores que influenciam na QVRS dos hipertensos pode servir de subsídios no planejamento de estratégias de tratamento mais eficazes para essa população. Objetivos: Caracterizar os indivíduos com hipertensão arterial participantes do grupo de convivência educativa segundo as variáveis: sócio-demográficas e econômica; hábitos de vida (atividade física, tabagismo, consumo de bebida alcoólica); dados relacionados a HAS(co-morbidades, uso de medicamentos anti-hipertensivos, controle dos níveis pressóricos, tempo de progressão da HAS) e tempo de participação nas atividades educativas em grupo, comparar a QVRS entre hipertensos participantes do grupo de convivência educativa com as variáveis sócio-demográficas, econômicas e clínicas e avaliar a contribuição do grupo de convivência na qualidade de vida dos hipertensos. Material e Métodos: Foi realizado um estudo descritivo do tipo transversal com 131 sujeitos com idade superior a 18 anos e diagnóstico de hipertensão arterial, residentes no município de Sacramento-MG, cadastrados no grupo de convivência no período mínimo de um ano anterior a data da entrevista. Os instrumentos utilizados para a coleta de dados foram: instrumento para caracterização da população quanto aos dados clínicos e sóciodemográficos e econômicos e o Medical Outcomes Short-Form Health Survey (SF-36) para avaliação da QVRS. Resultados: Dos pacientes, 98 eram mulheres e 33 homens, a maioria idosa 88(67,2%), com predomínio na faixa etária de 60 a 69 anos 43(32,8%) e ganham igual ou menos que um salário mínimo por mês 88(67,2%). As dimensões do SF-36 que obtiveram menores escores foram: vitalidade (64,4) e dor (70,3), enquanto as dimensões que apresentaram maiores escores foram: aspectos sociais (86,7) e capacidade funcional (79,4). Os fatores que apresentaram relação com a variação dos escores médios e correlação das dimensões do SF-36 foram: renda, atividade física, número de morbidades, diabetes, obesidade. A participação no grupo apresentou relação estatisticamente significante apenas no domínio saúde mental. Conclusão: Clinicamente os resultados mostraram relevância para intervenções educativas pela equipe de saúde. Os enfermeiros como elementos constituintes destas equipes devem estar presentes e ativos em todas as etapas desse trabalho, desde o planejamento, execução e avaliação colaborando na busca de meios efetivos que vão de encontro com a melhoria da qualidade de vida dessa população. / Arterial Hypertension is a non-transmissible chronic disease with multifactorial etiology and it is one of the main causes of cardiovascular diseases which are the leading cause of death in the world. Since the disease is characterized as having a high prevalence rate and in most cases it is asymptomatic, the treatment adherence rate is low, therefore requiring educational intervention from health professionals during the treatment in order to prevent complications and to keep the patient alive. Health-related quality of life (HRQoL) in patients with high blood pressure is reduced when compared to the general population. The evaluation of factors influencing on the HRQoL of high blood pressure patients point to the strategic planning of more efficient treatments to this population. Aims: Characterize the high blood pressure patients participating in the educational gathering group according to the following variables: socio-demographics and economics; lifestyles (physical activity, smoking, drinking); data related to systemic arterial hypertension (comorbidity, use of antidepressive drugs, blood pressure rate control, systemic arterial hypertension progression rate) and participation time in educational group activities, comparison of HRQoL among the group participating patients with the socio-demographical, economical and clinical variables and evaluate the contribution of the group to the quality of life of the participating patients. Methods and Materials: It was performed a descriptive cross-sectional study with 131 individuals over 18 years of age who suffered from high blood pressure. The patients lived in the city of Sacramento ? MG and had been participating in the gathering group for at least one year prior to the interview. The following tools were used to collect the data: Tools to characterize the population according to clinical, socio-demographical and economical data; Medical Outcomes Short-Form Health Survey (SF-36) to evaluate HRQoL. Results: From the total of 131 patients, 98 were female and 33 were male. Most of them (88 patients or 67.2%) were in an advanced age ranging from 60 to 69 years old (43 patients or 32.8%) and earned minimal wage or less (88 patients or 67.2%). The SF-36 dimensions with the lowest scores were: Vitality (64.4) and pain (70.3), whereas the dimensions with the highest scores were: Social functioning (86.7) and functional status (79.4). The factors presenting relation to the average score variation and dimension correlation in the SF-36 were: Income; physical activity; death rate; diabetes, obesity. The participation in the group was statiscally significant relation only to the mental health dimension. Conclusion: The results clinically showed the relevance of educational interventions performed by the health team. The nurses, as part of this team, must be present and active in all the stages of this work, planning, performing and searching for effective methods that lead to the improvement of life quality for this population.
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Efeito do treinamento de caminhada sobre o risco, a função e a regulação cardiovasculares em indivíduos com claudicação intermitente / Effect of walking training on cardiovascular risk, function and regulation in patients with intermittent claudication

Marcel da Rocha Chehuen 18 November 2014 (has links)
O treinamento de caminhada (TC) é recomendado para o tratamento de indivíduos com claudicação intermitente (CI) porque melhora a capacidade de caminhada. Além disso, seria interessante que o TC também promovesse modificações benéficas no sistema cardiovascular, pois os eventos cardiovasculares são a principal causa de morte nestes indivíduos. No entanto, os efeitos cardiovasculares do TC em indivíduos com CI foi pouco estudado. Assim, o objetivo deste estudo foi verificar o efeito do TC sobre o risco, a função e a regulação cardiovasculares em indivíduos com CI. Quarenta e dois indivíduos com CI foram divididos de forma aleatória em 2 grupos: controle (GC, n=20, sessões de 30 min de alongamento) e treinamento de caminhada (GT, n=22, 15 séries de 2 min de caminhada em intensidade correspondente à frequência cardíaca (FC) do limiar de dor intercalados por 2 min de repouso passivo). Nos dois grupos, a intervenção foi realizada 2 vezes/semana durante 12 semanas consecutivas. No início e ao final do estudo, os indivíduos realizaram as seguintes avaliações: glicemia e perfil lipídico de jejum; índice de massa corporal; capacidade de caminhada; consumo de oxigênio no 1º estágio e no pico do teste de esforço; índice tornozelo-braço (ITB) de repouso; janela isquêmica após teste ergoespirométrico; pressão arterial (PA) em repouso (auscultatória) e de 24 horas (oscilométrica); débito cardíaco (DC - reinalação de CO2); FC (ECG); volume sistólico (VS); resistência vascular (RV) sistêmica, do antebraço e da perna (plestismografia); componentes de alta (AF) e baixa (BF) frequência da variabilidade da FC; e sensibilidade barorreflexa espontânea (SBR). Mudanças significantes (P<0,05) ao longo do tempo e entre os grupos foram verificadas pela análise de variância ANOVA de dois fatores para medidas repetidas. O TC aumentou significantemente a capacidade de caminhada (&Delta;=+302±85m) e a SBR (&Delta;=+2.13±1.07 ms/mmHg), e diminuiu o VO2) no 1º estágio do teste (&Delta;=-1,8±0,4ml.kg-1.min-1), a janela isquêmica (&Delta;=- 0,40±0,38mmHg.min.m-1), a PA média (&Delta;=-5±2mmHg), a variabilidade da PA média de 24h (&Delta;=-0,8±0,2mmHg), o DC (&Delta;=-0.37±0.24L/min), a FC (&Delta;=- 4±2bpm), a RV do antebraço (&Delta;=-8.5±2.8 U) e a razão BF/AF (&Delta;=-1.24±0.99). A glicemia, o perfil lipídico, o índice de massa corporal, o VO2) pico, o ITB de repouso e a RV sistêmica e da perna não foram modificadas pelo TC. Não houve mudança em nenhuma variável no GC. Em conclusão, o TC melhorou a capacidade de caminhada, a economia de caminhada e a janela isquêmica. Além disso, o TC melhorou a função (PA, DC, FC e RV antebraço) e a regulação (BF/AF e SBR) cardiovasculares em indivíduos com CI. Estas alterações fornecem suporte adicional para a utilização do TC no tratamento de indivíduos com CI / Walking training (WT) is recommended for the treatment of patients with intermittent claudication (IC) because it improves walking capacity. Moreover, it would be interesting that WT also promotes beneficial changes on cardiovascular system, since cardiovascular events are the main causes of death in these patients. Nevertheless, the effects of WT on cardiovascular system in patients with IC have been poorly studied. Thus, the objective of this study was to investigate the effects of WT on cardiovascular risk, function and regulation in patients with IC. Forty-two IC patients were randomly divided into 2 groups: Control (CG, n=20, 30 min of stretching exercises) and walking training (TG, n=22, 15 sets of 2:2-min walk:rest at the heart rate (HR) of pain threshold). In both groups, the intervention was performed twice/week for 12 consecutive weeks. At the beginning and end of the study, the following measured were done: fasting glycemia and lipid profile; body mass index; walking capacity; VO2 at the first stage and the peak of a treadmill test; ankle brachial index (ABI); ischemic window after maximal test; resting (auscultatory) and 24-hour (oscillometric) blood pressure (BP); cardiac output (CO - CO2 rebreathing); heart rate (HR - ECG); stroke volume (SV); systemic, forearm and leg vascular resistance (VR - plethysmography); low- (LF) and high-frequency (HF) components of HR variability; and spontaneous baroreflex sensitivity (SBS). Significant changes (P<0.05) over time and between groups were assessed by 2-way ANOVA for repeated measures. WT significantly increased walking capacity (&Delta;=+302±85m) and SBS (&Delta;=+2.13±1.07 ms/mmHg), and decreased VO2 at the first stage of treadmill test (&Delta;=-1.8±0.4ml.kg-1.min-1), ischemic window (&Delta;=-0.40±0.38mmHg.min.m-1), mean BP (&Delta;=-5±2mmHg), ambulatory mean BP variability (&Delta;=-0,8±0,2 mmHg), CO (&Delta;=-0.37±0.24 L/min), HR (&Delta;=- 4±2bpm), forearm VR (&Delta;=-8.5±2.8 U) and LF/HF (&Delta;=-1.24±0.99). Glycemia, lipid profile, body mass index, VO2 peak, ABI, systemic and leg VR were unchanged following WT. There was no significant change for any variable in CG. In conclusion, WT enhanced walking capacity, walking economy and ischemic window. In addition, WT improved cardiovascular function (BP, CO, HR and forearm VR) and autonomic regulation (LF/HF, SBS) in patients with IC. These changes provide further support for the use of regular WT in treating patients with IC
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Efeito do treinamento resistido progressivo de alta intensidade sobre a pressão arterial e seus mecanismos hemodinâmicos e neurais em idosos / Progressive high-intensity resistance training on blood pressure and its hemodynamic and neural mechanisms in elderly subjects

Hélcio Kanegusuku 16 December 2011 (has links)
O treinamento resistido progressivo de alta intensidade tem sido empregado para aumentar a massa e força musculares de indivíduos idosos. Entretanto, existe na área clínica alguma preocupação de que esse treinamento possa promover efeitos adversos sobre o sistema cardiovascular envelhecido. Assim, o objetivo do presente estudo foi avaliar os efeitos do treinamento resistido progressivo de alta intensidade sobre a pressão arterial clínica e ambulatorial e seus mecanismos hemodinâmicos e neurais de idosos. Para tanto, 25 indivíduos com idade entre 60 e 80 anos foram divididos aleatoriamente em dois grupos: Grupo Treinamento Resistido (N=12, 7 mulheres, 64±1 anos - 2 sessões/semana, 7 exercícios, 2-4 séries, 10-4 RM) e Grupo Controle (N=13, 11 mulheres, 63±1 anos - nenhum treinamento). Antes e após 4 meses, a força dinâmica máxima, a área de secção transversa do músculo quadríceps, a pressão arterial clínica (posição deitada e sentada) e ambulatorial, os determinantes hemodinâmicos e a modulação autonômica cardiovascular (posição deitada com respiração livre e controlada e posição sentada com respiração livre) foram avaliados nos dois grupos. Comparando-se os valores medidos no início e no final do estudo, a força dinâmica máxima de membros superiores e inferiores e a área de secção transversa do músculo quadríceps aumentaram no Grupo Treinamento Resistido (+32, +46 e +5%, respectivamente, P<0,05) e não se modificaram no Grupo Controle. As pressões arteriais sistólica e diastólica não se alteraram no Grupo Treinamento Resistido (posição deitada, 119±10 vs. 120±10 e 74±6 vs. 74±7 mmHg; posição sentada, 125±8 vs. 121±9 e 78±6 vs. 76±7 mmHg, respectivamente, P>0,05) e nem no Grupo Controle (posição deitada, 121±11 vs. 119±10 e 73±5 vs. 72±4 mmHg; posição sentada, 125±11 vs. 124±9 e 75±8 vs. 74±5 mmHg, respectivamente, P>0,05). Da mesma forma, a resistência vascular periférica, o débito cardíaco, o volume sistólico e a frequência cardíaca não se alteraram em nenhum dos grupos (Treinamento Resistido = 26±5 vs. 30±5 mmHg/L.min-1; 3,8±0,9 vs. 3,2±0,4 L/min; 54±11 vs. 43±10 ml e 70±9 vs. 75±12 bpm; Controle = 29±8 vs. 31±10 mmHg/L.min-1; 3,5±1,0 vs. 3,1±0,7 L/min; 54±16 vs. 50±14 ml e 66±11 vs. 65±10 bpm, respectivamente, P>0,05). Com relação aos mecanismos neurais, o balanço simpatovagal (BF/AFR-R) não se modificou em nenhuma das três situações (posição deitada com respiração livre e controlada e posição sentada com respiração livre) no Grupo Treinamento Resistido (4,1±5,4 vs. 1,9±1,3; 0,7±0,6 vs. 0,9±0,9 e 3,5±5,7 vs. 5,0±8,1, respectivamente, P>0,05) nem no Grupo Controle (2,3±2,8 vs. 2,0±1,6; 0,4±0,4 vs. 0,4±0,4 e 3,0±3,7 vs. 2,8±2,8, respectivamente, P>0,05). A sensibilidade barorreflexa espontânea e a pressão arterial ambulatorial também não se alteraram em nenhum dos grupos. Em conclusão, o treinamento resistido de alta intensidade foi efetivo em aumentar a força dinâmica máxima e a área de secção transversa muscular de indivíduos idosos audáveis, sem modificar a pressão arterial clínica e ambulatorial, nem seus determinantes hemodinâmicos e mecanismos de regulação neural / Progressive high-intensity resistance training has been performed to increase of muscle mass and strength in elderly subjects. However, some clinical concerns exist about the possible adverse cardiovascular effects of this training on cardiovascular function and regulation in elderly. Thus, the aim of this study was to evaluate the effects of progressive high-intensity resistance training on blood pressure and its hemodynamic and neural mechanisms in elderly subjects. To investigate this issue, 25 subjects aged between 60 and 80 years were randomly divided into two groups: Resistance Training Group (N=12, 7 females, 64±1 years 2 sessions/week, 7 exercises, 2-4 sets, 10-4 RM) and Control Group (N=13, 11 females, 63±1 years no training). Before and after 4 months, maximal strength, quadriceps cross-sectional area, clinical (supine and sitting position) and ambulatory blood pressure, hemodynamic determinants, and cardiovascular autonomic modulation (supine position with free and controlled breathing and sitting position with free breathing) were measured. Comparing values measured at the beginning and the end of the study, maximal strength of upper and lower limbs, and quadriceps cross-sectional area increased in the Resistance Training Group (+32, +46 e +5%, respectively, P>0.05). Similarly, peripheral vascular resistance, cardiac output, stroke volume and heart rate also did not change in neither of the groups (Resistance Training = 26±5 vs. 30±5 mmHg/L.min-1; 3.8±0.9 vs. 3.2±0.4 L/min; 54±11 vs. 43±10 ml; and 70±9 vs. 75±12 bpm; Control Group = 29±8 vs. 31±10 mmHg/L.min-1; 3.5±1.0 vs. 3.1±0.7 L/min; 54±16 vs. 50±14 ml; and 66±11 vs. 65±10 bpm, respectively, P>0.05). In regard to the neural mechanisms, cardiac sympathovagal balance (LF/HFR-R) also did not change in any of the situations (supine position with free and controlled breathing, and sitting position with free breathing) in the Resistance Training Group (4.1±5.4 vs. 1.9±1.3; 0.7±0.6 vs. 0.9±0.9; 3.5±5.7 vs. 5.0±8.1, respectively, P>0.05) nor in the Control Group (2.3±2.8 vs. 2.0±1.6; 0.4±0.4 vs. 0.4±0.4; 3.0±3.7 vs. 2.8±2.8, respectively, P>0.05). The spontaneous baroreflex sensitivity and ambulatory blood pressure also did not change in neither of the groups. In conclusion, the progressive high-intensity resistance training was effective in increasing muscle mass and strength in healthy elderly subjects, without changing clinic and ambulatory blood pressure as well as their hemodynamic and neural mechanisms. respectively, P<0.05), and did not change in the Control Group. Systolic and diastolic blood pressure did not change in the Resistance Training Group (supine, 119±10 vs. 120±10 and 74±6 vs. 74±7 mmHg; sitting 125±8 vs. 121±9 and 78±6 vs. 76±7 mmHg, respectively, P>0.05) nor in the Control Group (supine, 121±11 vs. 119±10 and 73±5 vs. 72±4 mmHg; sitting, 125±11 vs. 124±9 and 75±8 vs. 74±5 mmHg
960

Herdabilidade dos fatores envolvidos na síndrome metabólica / The heritability of metabolic syndrome factors

Camila Maciel de Oliveira 11 December 2007 (has links)
Muitos estudos têm sido conduzidos em diferentes populações visando a identificação da proporção da variância fenotípica total atribuída a efeitos genéticos. A herdabilidade de fatores de risco relacionados à Síndrome Metabólica apresenta variações entre populações, tanto por causa da diferente distribuição de fatores de risco ambientais quanto pela variação genética presente em populações distintas. O objetivo desta análise foi avaliar as influências genéticas e ambientais dos componentes da Síndrome Metabólica, usando uma análise de componentes de variância, estimando a herdabilidade destes fatores em uma amostra de extensas famílias. Nós examinamos 1.712 indivíduos de 119 famílias selecionadas randomicamente da população geral de uma cidade do Brasil. Um total de 1.666 indivíduos de 81 famílias foi usado para análises. O tamanho das famílias variou de 3 a 156 indivíduos com uma média de 21 indivíduos por família. Antes de ajustes, as herdabilidades poligênicas da pressão sistólica (PAS) e diastólica (PAD) foram de 15 e 16,4%, circunferência abdominal de 26,1%, glicemia de 32,8%, triglicérides de 25,7% e HDL-c de 31,2%. Ajuste para idade, sexo, idade2 e interação sexo x idade aumentou as estimativas de herdabilidade para todos os traços: PAS (25,9%), PAD (26,2%), circunferência abdominal (40,1%), glicemia de jejum (34,5%), triglicérides (28,8%) e HDL-c (32,0%). Quando os fatores de risco para Síndrome Metabólica foram tratados como traços discretos, utilizando pontos de corte segundo critérios do ATPIII, as estimativas de herdabilidade, após ajuste para covariáveis, foram: 24,5% para SM, 37,5% para pressão arterial, 40,6% para circunferência abdominal, 54,5% para glicemia, 25,5% para triglicérides e 37,8% para HDL-c. Em conclusão, as estimativas de herdabilidade para os traços da síndrome metabólica em uma amostra da população brasileira são altas e não significativamente diferente de outros estudos em populações mundiais / Many studies have been conducted in different populations aiming at the identification of the proportion of total phenotypic variance that is attributable to genetic effects. The heritability of Metabolic Syndrome (MS) factors is expected to differ between populations because of the different distribution of environmental risk factors, as well as the genetic make-up of different human populations. The purpose of this analysis was to evaluate genetic and environmental influences on metabolic syndrome traits, using a variance component analysis, by estimating the heritability of these traits in a sample of extended pedigrees. We examined 1,712 individuals of 119 randomly selected families from the general population of a city of Brazil. A total of 1,666 individuals of 81 families were used for analysis. Family size varied from 3 to 156 individuals with a mean of 21 subjects per family. Before adjustment, polygenic heritability of systolic (SBP) and diastolic (DBP) blood pressure were 15% and 16.4%, waist circumference 26.1%, fasting glucose 32.8%, triglycerides 25.7%, and HDL-c 31.2%. Adjustment for age, sex, age2, age and sex interaction increased polygenic heritability estimates for all traits: SBP (25.9%), DBP (26.2%), waist circumference (40.1%), fasting glucose (34.5%), triglycerides (28.8%), and HDL-c (32,0%). When the Metabolic Syndrome factors were treated as discrete traits, using ATPIII cut off, the estimates of heritability after adjusting for covariates were: 24.5% for MS, 37.5% for blood pressure, 40.6% for abdominal circumference, 54.5% for fasting glucose, 25.5% for triglycerides, and 37.8% for HDL-cholesterol. In conclusion, heritability estimates for metabolic syndrome traits in a sample of Brazilian population are high and not significantly different from other studied worldwide populations

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