Tesis sobre el tema "Arterial blood pressure estimation"
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Zakrzewski, Aaron Michael. "Arterial blood pressure estimation using ultrasound". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111743.
Texto completoCataloged from PDF version of thesis.
Includes bibliographical references (pages 155-163).
While blood pressure is commonly used by doctors as an indicator of patient health, the available techniques to measure the quantity suffer from many inconveniences such as cutting off blood flow, being cumbersome to use, being invasive, or being inaccurate. The research addresses many of these inconveniences by developing and evaluating a novel ultrasound-based blood pressure measurement technique that is non-invasive and non-occlusive. The technique proceeds in three steps: data acquisition, data reduction, and optimization. In the data acquisition step, an ultrasound probe is placed on a patient's artery and a force sweep is conducted such that the contact force gradually increases; both the applied force and B-Mode images are recorded. In the data-reduction step, the Star-Kalman filter is applied in order to find the size of the artery in each image frame captured. The segmentation data and contact force data are inputs into the optimization step which consists of two sequential optimizations; the first makes many modeling assumptions and gives an estimate of pulse pressure while the second makes less assumptions and uses the approximation of pulse pressure to obtain absolute values of systolic and diastolic blood pressure. Central to the optimization algorithm is a computational biomechanical model of the artery and surrounding tissue, which is numerically modeled using finite elements. The impact of major modeling assumptions is corrected with a one time calibration. The technique is validated on a number of different data sets. Major data sets discussed include data taken on the carotid artery of (1) 24 single-visit nominally healthy volunteers, (2) two multi-visit nominally healthy volunteers, (3) one multi-visit hypertensive volunteer, and (4) one multi-visit hypotensive volunteer; additional miscellaneous data sets are taken and analyzed as part of this dissertation. The algorithm performance is quantified against readings from an automatic oscillometric cuff. Results show that systolic and diastolic blood pressures can be predicted by the algorithm. The technology discussed in this dissertation represents a proof-of-concept of a blood pressure measurement technique that could occupy a clinical middle ground between the invasive catheter and cuff-based techniques.
by Aaron Michael Zakrzewski.
Ph. D.
Baktash, Seddigheh. "Ratio-Independent Arterial Stiffness-Based Blood Pressure Estimation". Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30971.
Texto completoSun, James Xin. "Cardiac output estimation using arterial blood pressure waveforms". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/41625.
Texto completoIncludes bibliographical references (p. 73-74).
Cardiac output (CO) is a cardinal parameter of cardiovascular state, and a fundamental determinant of global oxygen delivery. Historically, measurement of CO has been limited to critically-ill patients, using invasive indicator-dilution methods such as thermodilution via Swan-Ganz lines, which carry risks. Over the past century, the premise that CO could be estimated by analysis of the arterial blood pressure (ABP) waveform has captured the attention of many investigators. This approach of estimating CO is minimally invasive, cheap, and can be done continuously as long as ABP waveforms are available. Over a dozen different methods of estimating CO from ABP waveforms have been proposed and some are commercialized. However, the effectiveness of this approach is nebular. Performance validation studies in the past have mostly been conducted on a small set of subjects under well-controlled laboratory conditions. It is entirely possible that there will be circumstances in real world clinical practice in which CO estimation produces inaccurate results. In this thesis, our goals are to (1) build a computational system that estimates CO using 11 of the established methods; (2) evaluate and compare the performance of the CO estimation methods on a large set clinical data, using the simultaneously available thermodilution CO measurements as gold-standard; and (3) design and evaluate an algorithm that identifies and eliminates ABP waveform segments of poor quality. Out of the 11 CO estimation methods studied, there is one method (Liljestrand method) that is clearly more accurate than the rest. Across our study population of 120 subjects, the Liljestrand method has an error distribution with a 1 standard deviation error of 0.8 L/min, which is roughly twice that of thermodilution CO. These results suggest that although CO estimation methods may not generate the most precise values, they are still useful for detecting significant (>1 L/min) changes in CO.
by James Xin Sun.
M.Eng.
Beeks, Kyle A. "Arterial blood pressure estimation using ultrasound technology and transmission line arterial model". Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/121663.
Texto completoThesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 67-69).
This thesis describes the application of a transmission line model to arterial measurements in order to derive useful cardiovascular parameters. Non-invasive ultrasound techniques are used to make these measurements, which has several benefits over invasive methods such as arterial catheterization. However, invasive methods are seen as the "gold standard" measurements and therefore the most accurate. Having accurate measurements that can be done non-invasively would be very desirable for cardiologists to determine their patients' risk of developing cardiovascular disease. This work details how to obtain the blood flow and pulse pressure waveforms using ultrasound transducers. Two transducers, one for imaging and one for Doppler, can be used together to derive these waveforms from distension and blood flow velocity measurements. Unfortunately, the only blood pressure waveform that can be obtained is the pulse pressure, which does not contain diastolic information. By decomposing the backward and forward pulse and flow waves and using the transmission line model, the diastolic pressure can be determined and the complete arterial blood pressure waveform can be obtained.
by Kyle A. Beeks.
M. Eng.
M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
Koohi, Iraj. "Methods for Non-invasive Trustworthy Estimation of Arterial Blood Pressure". Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35830.
Texto completoTannous, Milad. "Robust Estimation of Mean Arterial Pressure in Atrial Fibrillation Using Oscillometry". Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31707.
Texto completoArai, Tatsuya. "Estimation of cardiovascular indices by analysis of the arterial blood pressure signal". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67751.
Texto completoCataloged from PDF version of thesis.
Includes bibliographical references (p. 175-177).
This thesis introduces novel mathematical algorithms that track changes in stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) by analysis of the arterial blood pressure (ABP) signal. The algorithms incorporate cardiovascular physiology within the framework of a generalized Windkessel model, which is a widely accepted cardiovascular model. Algorithms to identify end systole were also developed and implemented in the new and existing SV, CO, and TPR estimation algorithms. The algorithms were validated by applying them to previously recorded Yorkshire swine data sets that include directly measured aortic blood flow (ABF), SV, CO, as well as central and peripheral ABP. Among the algorithms using the end systole identification algorithms, Parabolic Method, Modified Herd's Method, Kouchoukos Correction Method, and Corrected Impedance Method achieved low root normalized mean squared errors (RNMSEs). This thesis also introduces and validates a novel algorithm to reconstruct instantaneous ABF waveforms from the ABP signal. The algorithm utilizes an auto-regressive with exogenous input (ARX) model to describe the filter between ABF and ABP. Because ABF (the exogenous input to the peripheral circulation) is approximately zero during diastole, the diastolic ABP waveforms can be regarded as auto-regressive (AR). By the AR analysis of multiple diastolic ABP waveforms, the AR parameters are obtained. The AR parameters were applied to the ABP waveforms (both systolic and diastolic) to compute beat-to-beat ABF waveforms. The errors of skewness and kurtosis of the estimated ABF waveforms were statistically smaller than those estimated by the standard Windkessel model. The estimated ABF waveforms were further processed to estimate SV, CO, and TPR. The algorithm achieved RNMSEs of 15.3, 19.6, and 21.8% in SV estimation; 12.7, 15.2, and 15.8% in CO estimation; and 14.3, 20.9, and 19.4 % in TPR estimation derived from central, femoral, and radial ABP, respectively.
by Tatsuya Arai.
Ph.D.
Dastmalchi, Azadeh. "Beat-to-Beat Estimation of Blood Pressure by Artificial Neural Network". Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/31962.
Texto completoChen, Tiffany. "Cardiac output estimation from arterial blood pressure waveforms using the MIMIC II database". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53096.
Texto completoIncludes bibliographical references (p. 115-118).
The effect of signal quality on the accuracy of cardiac output (CO) estimation from arterial blood pressure (ABP) was evaluated using data from the Multi-Parameter Intelligent Patient Monitoring for Intensive Care (MIMIC) II database. Thermodilution CO (TCO) was the gold standard, and a total of 121 records with 1,497 TCO measurements were used. Six lumped-parameter and systolic area CO estimators were tested, using ABP features and a robust heart rate (HR) estimate. Signal quality indices for ABP and HR were calculated using previously described metrics. For retrospective analysis, results showed that the Liljestrand estimator yielded the lowest error for all levels of signal quality and for any single estimator when using five or more calibration points. Increasing signal quality decreased error and only marginally reduced the amount of available data, as a signal quality level of 90% preserved sufficient data for almost continuous CO estimation. At the recommended signal quality thresholds, the lowest gross root mean square normalized error (RMSNE) was found to be 15.4% (or 0.74 L/min) and average RMSNE was 13.7% (0.71 L/min). Based on these results, a linear combination (LC) of the six CO estimation methods was developed and proved superior to all other methods when up to 13 TCO calibration values were used. The clinical utility of the CO estimates were examined by correlating changes in four vasoactive medication doses with corresponding changes in estimated resistance, which was derived from mean ABP and estimated CO.
(cont.) Both the Liljestrand estimator and the LC estimator were used to estimate CO. Regression analysis failed to show a clear correlation between dose level and estimated resistance for either estimator except for neosynephrine, revealing the limitations of current SQI methods in ensuring signal fidelity. Examples of types of non-physiological or artifactual ABP waveforms are shown, and a potential damping detection method is proposed.
by Tiffany Chen.
M.Eng.
Francis, Said Elias. "Continuous estimation of cardiac output and arterial resistance from arterial blood pressure using a third-order Windkessel model". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41641.
Texto completoIncludes bibliographical references (p. 85-89).
Intensive Care Units (ICUs) have high impact on the survival of critically-ill patients in hospitals. Recent statistics have shown that only 10% of the 5 million patients admitted to ICUs in the United States die each year. In modern ICUs, the heart's electrical and mechanical activity is routinely monitored using various sensors. Arterial blood pressure (ABP) and heart rate (HR) are the most commonly recorded waveforms which provide key information to the ICU clinical staff. However, clinicians find themselves in many cases unable to determine the causes behind abnormal behavior of the cardiovascular system because they lack frequent measures of cardiac output (CO), the average blood flow out of the left ventricle. CO is monitored via intermittent thermodilution measurements which are highly invasive and only applied to the sickest ICU patients. The lack of frequent CO measurements has encouraged researchers to develop estimation methods for cardiac output from routinely measured arterial blood pressure waveforms. The prospects of estimating cardiac output from minimally-invasive blood pressure measurements has resulted in numerous estimation algorithms, however, there is no consensus on the performance of the algorithms that have been proposed. In this thesis, we investigate the use of a third-order variation of the Windkessel model, which is referred to as the modified Windkessel model. We validate its ability to generate well-behaved proximal and distal pressure waveforms for a given flow waveform and thus characterize the arterial tree. We also develop a model-based CO estimation algorithm which uses central and peripheral blood pressure waveforms to obtain reliable estimates of CO and the total peripheral resistance (TPR). We applied the estimation algorithm to a porcine data set.
(cont.) The results of our estimation algorithm are promising: the weighted-mean root-mean-squared-normalized-error (RMSNE) is about 13.8% over four porcine records. In each porcine experiment, intravenous drug infusions were used to vary CO, ABP, and HR over wide ranges. Our results suggest that the modified Windkessel model is a good representation of the arterial tree and that the estimation algorithm yields reliable estimates of CO and TPR under various hemodynamic conditions.
by Said Elias Francis.
M.Eng.
Swoboda, Marek Lec Ryszard Joseph Jeffrey. "Implantable arterial blood pressure sensor /". Philadelphia, Pa. : Drexel University, 2004. http://hdl.handle.net/1860/2968.
Texto completoCitty, Sandra Wolfe. "Ambulatory blood pressure biosituational feedback and systolic blood pressure estimation". [Gainesville, Fla.]: University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0000663.
Texto completoSoueidan, Karen. "Augmented blood pressure measurement through the estimation of physiological blood pressure variability". Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28828.
Texto completoEmeagwali, Ijeoma. "Using distributed machine learning to predict arterial blood pressure". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91441.
Texto completo3
Cataloged from PDF version of thesis.
Includes bibliographical references (page 57).
This thesis describes how to build a flow for machine learning on large volumes of data. The end result is EC-Flow, an end to end tool for using the EC-Star distributed machine learning system. The current problem is that analysing datasets on the order of hundreds of gigabytes requires overcoming many engineering challenges apart from the theory and algorithms used in performing the machine learning and analysing the results. EC-Star is a software package that can be used to perform such learning and analysis in a highly distributed fashion. However, there are many complexities to running very large datasets through such a system that increase its difficulty of use because the user is still exposed to the low level engineering challenges inherent to manipulating big data and configuring distributed systems. EC-Flow attempts to abstract a way these difficulties, providing users with a simple interface for each step in the machine learning pipepline.
by Ijeoma Emeagwali.
M. Eng.
Mafi, Majid. "Blood Pressure Estimation Using Oscillometric Pulse Morphology". Thesis, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/20630.
Texto completoSridharan, Mathura J. "Risk stratification of ICU patients using arterial blood pressure waveforms". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/85506.
Texto completoCataloged from PDF version of thesis. "May 24, 2013."
Includes bibliographical references (pages 109-110).
Identifying patients at high risk for adverse events is very important to the practice of clinical medicine. Non-invasive ECG-based methods of risk stratification such as T wave Alterans, Morphological Variability, and Heart Rate Variability extract prognostic information from the electrocardiograph. However, there is still a wealth of data collected from ICU patients and left unused every year that can augment risk-stratification methods. This thesis extends non-invasive risk stratification to Arterial Blood Pressure (ABP) Waveforms. We derive and analyze classifiers based on the morphological distance time series (derived from beat-to-beat morphology changes in the ABP waveform) including ASDNNmd, SDANNmd, rMSSDmd, the MVABP score etc. We also derive and analyze classifiers based on the Downstroke Time Series (derived from the decay from peak systole to diastole) including ASDNNDownstroke, SDANNDownstroke, rMSSDDownstroke, etc. While this body of work suggests the classifiers we developed are not effective in risk stratification of ICU patients, we discuss other methods which may extract prognostic information from the ABP waveform more effectively.
by Mathura J. Sridharan.
M. Eng.
McGowan, Cheri L. McCartney Neil MacDonald Maureen J. "Isometric handgrip training and arterial blood pressure : effects and mechanisms /". *McMaster only, 2006.
Buscar texto completoCai, Ye Tan. "Assessment of central arterial hemodynamics, arterial stiffness, and vascular structure in children and adolescents". Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/22921.
Texto completoTafuna'i, Nicole Denney. "Arterial Blood Flow at Rest and During Exercise with Blood Flow Restriction". BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/9003.
Texto completoZienkiewicz, A. (Aleksandra). "Blood pressure estimation using pulse transit time models". Master's thesis, University of Oulu, 2017. http://jultika.oulu.fi/Record/nbnfioulu-201712063289.
Texto completoSvensson, Per. "Blood pressure, blood pressure variability and myocardial ischemia : studies in patients with peripheral arterial disease and matched control subjects /". Stockholm, 2004. http://diss.kib.ki.se/2004/91-7349-826-2.
Texto completoWinn, M. J. "Factors influencing the control of arterial blood pressure in conscious rats". Thesis, University of Nottingham, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372016.
Texto completoArvela, Sofia Coelho. "Medição da pressão arterial em canídeos e felinos". Master's thesis, Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária, 2013. http://hdl.handle.net/10400.5/5978.
Texto completoNeste trabalho realizou-se um estudo sobre as metodologias disponíveis para avaliação da pressão arterial em canídeos e em felinos, focando aquelas metodologias exequíveis na prática clínica de forma a obter a pressão arterial de animais conscientes de uma forma rápida e prática. Realizaram-se 87 medições de pressão arterial em canídeos e felinos, incluindo animais doentes e saudáveis utilizando um aparelho oscilométrico: “PetMAP”. Os valores de pressão arterial sistólica, média e diastólica alcançados para animais saudáveis da espécie canina foram 180,73 (+/- 28,04); 124,03 (+/- 20,13) e 95,59 (+/- 17,63) respetivamente. Para animais saudáveis da espécie felina foram 166,25 (+/- 28,38); 126,36 (+/- 22,82) e 105,45 (+/- 21,04) respetivamente. O estudo da relação da pressão arterial com fatores que a influenciam demonstrou que na espécie canina é o peso que provoca variações no valor da pressão arterial enquanto que na espécie felina é a idade. Conclui-se que apesar deste tipo de aparelhos de medição indireta sobrevalorizarem ou subestimarem o valor real da pressão arterial, constituem uma ferramenta de trabalho importante para a obtenção de dados fiáveis acerca do animal alvo de medição, quando utilizados rotineiramente recorrendo a uma metodologia constante e padronizada.
ABSTRACT - In this work we conducted a study on the available methodologies to assess blood pressure in dogs and cats, focusing on those there are feasible in clinical practice in order to be able to get the blood pressure of conscious animals in a quick and convenient way. We performed 87 measurements of blood pressure in dogs and cats either sick or healthy, using an oscillometric device: PetMAP. The values of systolic, mean and diastolic blood pressure achieved for healthy animals of the canine specie were 180,73 (+/- 28,04); 124,03 (+/- 20,13) and 95,59 (+/ - 17,63) respectively. For healthy animals of the feline specie were 166,25 (+/- 28,38); 126,36 (+/- 22,82) and 105,45 (+/- 21,04) respectively . The study of the relationship of blood pressure with factors that influence it demonstrated that in dogs is the weight that causes variations in blood pressure value while in the feline specie is age. We can therefore state that in spite the fact that this indirect method overestimate or underestimate the real value of arterial pressure, it is an important working tool to obtain reliable data about the animal being examined when used routinely performing a methodology consistent and standardized.
Furusawa, Erika Arai. "Comparação das medidas de pressão arterial no consultório, no domicílio e pela monitorização ambulatorial da pressão arterial (MAPA) em crianças com hipertensão arterial". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/5/5141/tde-18122008-122329/.
Texto completoThe diagnosis and monitoring of hypertension in pediatric patients depend on the accuracy and reproducibility of blood pressure (BP) measurement. Ambulatory blood pressure monitoring (ABPM), despite its advantages over office BP, is costly and can cause discomfort to the patient. The blood pressure measured at home (HBP), although poorly studied in children, represents a potential alternative to ABPM. The objectives of this study were to compare BP measurement in four clinical conditions: office BP , casual BP measured at Liga de Hipertensão, HBP and ABPM, evaluate the effect of environment / observer and to determine the frequency of BP values compatible with the diagnosis of hypertension. This study was cross-sectional and prospective and included patients with arterial hypertension with/without properly controlled BP in the office. The means of systolic and diastolic BP were analyzed in the 4 clinical conditions. HBP was measured for 14 days using a validated fully automatic Omron HEM 705 CP device. ABPM was measured with SpaceLabs 90207 non-invasive portable oscilometric device. We analyzed data from 40 patients (14 girls and 26 boys), mean age 12.1 ± 3.6 (SD) years. There was no difference between systolic (ANOVA p = 0.3100) and diastolic (ANOVA p= 0.7700) BP in the office and daytime HBP nor with nightime systolic HBP ( ANOVA p = 0.8240) and diastolic HBP(ANOVA p = 0.1530). The average systolic and diastolic BP at the Liga de Hipertensão and ABPM were higher than office and HB P (p <0001), but there was no difference in the average systolic (p= 0.077) and diastolic (p = 0.962) BP between Liga and ABPM. The diastolic HBP was lower than office diastolic BP (p = 0001). The frequency of BP values compatible with hipertension was higher at the Liga de Hipertensão (Mc Nemar p <0005), while comparisons between officedaytime HBP, office- daytime ABPM and daytime HBP-ABPM were not significant (Mc Nemar p> 0.05). The BP measurements during nightime ABPM showed a higher frequency of values compatible with hypertension than the night HBP one. Ten patients were diagnosed hypertension in the office, ABPM confirmed the diagnosis in 7 / 10 (17.5%) patients, while 5 / 10 (12.5%) were confirmed by HBP. In this group, white-coat hypertension occurred in 3 / 10 (7.5%) patients as diagnosed by the ABPM and 5 / 10 (12.5%) as diagnosed by HBP.Thirty patients presented BP values within normal limits in the office, 24 / 30 (60%) patients confirmed this diagnosis by ABPM and 26/30 (65%) by HBP. Masked hypertension was diagnosed in 6 / 30 (15%) patients diagnosed by the ABPM and in 4 / 30 (10%) by HBP. This study confirmed a correlation between ABPM and HBP measurements (Mc Nemar test p <0.01) with good reproducibility as evaluated by the Kappa index (0.557).
Plett, Melani Irene. "Ultrasonic arterial vibrometry with wavelet based detection and estimation /". Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/5938.
Texto completoRoy, Matthew S. "Acute effects of facial cooling on arterial stiffness and wave reflection". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 56 p, 2007. http://proquest.umi.com/pqdweb?did=1397914231&sid=1&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Texto completoLiu, Yi. "A study of mathematical modelling and signal processing of cerebral autoregulation". Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273880.
Texto completoSmirl, Jonathan David. "The relationship between arterial blood pressure and cerebral blood flow : insights into aging, altitude and exercise". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54000.
Texto completoGraduate Studies, College of (Okanagan)
Graduate
Jacobs, Samier. "The comparison of non-invasive blood pressure monitoring with brachial intra-arterial blood pressure monitoring in patients with severe pre-eclampsia". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95901.
Texto completoENGLISH ABSTRACT: OBJECTIVE: The aim of this study was to compare the accuracy of non-invasive brachial blood pressure measurements, using automated and manual devices, to invasive brachial intra-arterial blood pressure measurements in patients with preeclampsia, during acute severe hypertension. STUDY DESIGN: A prospective descriptive cross sectional study was conducted in the Obstetrics Critical Care Unit (OCCU) of Tygerberg Hospital. Pre-eclamptic patients with acute severe hypertension, who required the placement of brachial intra-arterial lines due to failed radial intra-arterial line placement, were included in the study. Both automated oscillometric and blinded manual aneroid sphygmomanometric blood pressures were recorded during hypertensive peaks and after stabilization of BP using intravenous Labetalol or Nepresol. These two noninvasive methods of blood pressure measurements were compared to brachial intraarterial blood pressure measurements. RESULTS: There was weak correlation between manual and intra-arterial SBP (r = 0.27, p = 0.048) for SBP≥160mmHg. The calculated mean difference between manual SBP compared to the intra-arterial SBP in this group was -23.19mmHg (+/- 19.40). There was moderate correlation between automated and intra-arterial SBP (r = 0.69, p < 0.05). The calculated mean difference between automated SBP compared to the intra-arterial SBP in this group was -16.85mmHg (+/- 11.58). CONCLUSION: This study of pre-eclamptic women demonstrated that both non-invasive methods of BP measurement were inaccurate measures of the true systolic intra-arterial BP and significantly underestimated SBP≥160mmHg when compared to brachial intra-arterial measurements. The SBP was also underestimated, to a lesser degree, for mild moderate hypertension. This study also demonstrated that direct invasive BP monitoring using the brachial artery is a safe method for accurate haemodynamic monitoring. We recommend the use of intra-arterial BP monitoring in pre-eclamptic women with acute severe hypertension. Radial arterial cannulation should be used as the first option and the brachial artery should be used if the first option fails.
AFRIKAANSE OPSOMMING: DOELWIT: Die doel van hierdie studie was om die akuraatheid van nie indringende bragiale bloeddruk metings, wat met outomatiese en manuele aparate geneem is, te vergelyk met bragiale intra-arteriele bloeddruk metings gedurend akute erge hipertensie in pasiente met pre-eklampsie, STUDIE ONTWERP: ʼn Prospektiewe beskrywende dwarssnit studie was in die Obstetriese Kritiese Sorg Eenheid (OCCU) van Tygerberg Hospitaal uit gevoer. Preeklamptiese pasiente met akute erge hipertensie, wat bragiale intra-arteriele lyne nodig gehad het, as gevolg van gefaalde radiale intra-arteriele lyn plasing, was in hierdie studie ingesluit. Beide outomatiese ossilometriese en geblinde aneroide sfigmomanometriese bloeddrukke, tydens hipertensiewe pieke en na stabilisering van bloeddrukke met binneaarse Labetalol of Nepresol, was aangeteken, Die twee nie indringende metodes van bloeddruk meting was met bragiale intra-arteriele bloeddruk metings vergelyk. RESULTATE: Daar was ʼn swak korrelasie tussen manuele en intra-arteriele sistoliese bloedrukke SBP (r = 0.27, p = 0.048) vir SBP≥160mmHg. Die berekende gemiddelde verskil tussen manuele SBP en intra-arteriele SBP was -23.19mmHg (+/- 19.40) in hierdie groep. Daar was ʼn matige korrelasie tussen outomatiese en intra-arteriele SBP (r = 0.69, p < 0.05). Die berekende gemiddelde verskil tussen outomaties SBP vergelyk met intra-arteriele SBP was -16.85mmHg (+/- 11.58) in hierdie groep. GEVOLGTREKKING: Hierdie studie van pre-eklamptiese vrouens, het getoon dat beide nie indringende metodes van bloeddruk meting, nie akurate metings van ware sistoliese intraarteriele bloeddruk is nie, en SBP≥160mmHg word aansienlik onderskat wanneer dit met bragiale intra-arteriele metings vergelyk word. Die SBP was ook tot ʼn minder mate onderskat vir matige hipertensie. Die studie het ook getoon dat die direkte bragiale intra-arteriele metode van bloeddruk monitering, ʼn veilige metode van hemodinamiese monitering is. Ons beveel die gebruik van intra-arteriele bloeddruk monitering aan, in preeklamptiese vrouens met akute erge hipertensie. Radiale arteriele kanulasie moet gebruik word as die eerste opsie en die bragiale arterie moet gebruik word as die eerste opsie faal.
Loudon, Mary. "Arterial wall renin-like activity and blood pressure regulation in the rat". Thesis, University of Leicester, 1985. http://hdl.handle.net/2381/34141.
Texto completoBechtold, Andrea Galvan Scheuer Deborah A. "Effects of systemic and dorsal hindbrain glucocorticoids on arterial baroreceptor reflex control of heart rate". Diss., UMK access, 2005.
Buscar texto completo"A dissertation in pharmacology and pharmaceutical sciences." Typescript. Advisor: Deborah A. Scheuer. Vita. Title from "catalog record" of the print edition Description based on contents viewed May 31, 2006. Includes bibliographical references (leaves 238-274). Online version of the print edition.
Jonnada, Srikanth. "Cuff-less Blood Pressure Measurement Using a Smart Phone". Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115102/.
Texto completoZanoli, Luca Maria. "Inflammation and arterial stiffness". Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/1088.
Texto completoLenz, Maria do Carmo Sfreddo. "Efeito dos acordares na monitorização ambulatorial da pressão arterial". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2006. http://hdl.handle.net/10183/10329.
Texto completoObjective: Investigate the effect of distinguishing nighttime and sleep on nocturnal blood pressure results in ambulatory blood pressure monitoring (ABPM). Methods: We recruited 36 patients, 28 male, with suspected OSAHS attending a sleep clinic for diagnostic polysomnography (PSG) and who agreed to wear a Spacelabs 90207 ABP monitor during PSG. Their mean age was 45±11 years; body mass index (BMI), 30.8±5.4 kg/m2; apnea-hypopnea index (AHI), 35±29 AH/h; 13 had history of hypertension. A microphone attached to the ABP monitor recorded its sounds in the polygraph and allowed to classify each ABPM measurement as being made in electrographically-determined wake (e-wake) or sleep state (e-sleep). Results: Patients were asleep during (mean±SD) 61±24% (range 0 to 100%) of the 14±1 nighttime BP measurements. Systolic and diastolic ABPM readings were significantly higher during e-wake (121±12 / 73±9 mm Hg) than during total nighttime (119±11/70±8 m Hg) and e-sleep (116±13 / 68±9 mm Hg). Based on nighttime measurements 22 patients (61%) had nocturnal hypertension. Based on measurements made during e-sleep, nocturnal hypertension was diagnosed in 12 patients (33%; chisquare= 5.54; p= 0.018). A multiple linear regression model showed that the percentage of measurements made in e-sleep was the only variable that significantly explained the difference between nighttime and e-sleep BP figures, when controlling for gender, age, BMI, AHI, and lowest SaO2. Conclusion: During ABPM, nighttime BP readings are higher than during e-sleep and this changes dipping and nocturnal hypertension classification.
Forouzanfar, Mohamad. "A Modeling Approach for Coefficient-Free Oscillometric Blood Pressure Estimation". Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31213.
Texto completoMcGregor, Brian. "The left ventricle, aortic valve, and arterial tree - a fresh engineering perspective". Thesis, University of Ulster, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339346.
Texto completoChin, Kong Yien. "A new approach for non-invasive continuous arterial blood pressure measurement in human". Thesis, University of Leicester, 2011. http://hdl.handle.net/2381/10253.
Texto completoHendy, Emma Bernice. "Sites and mechanisms within the brainstem for chronic regulation of arterial blood pressure". Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.528103.
Texto completoDarekar, Angela Anagha. "The BOLD MRI response of the brain to alterations in arterial blood pressure". Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/196567/.
Texto completoNevala, Riikka. "Effects of genistein and daidzein on arterial tone and blood pressure in rats". Helsinki : University of Helsinki, 2001. http://ethesis.helsinki.fi/julkaisut/laa/biola/vk/nevala/.
Texto completoCunha, Marcos Guimarães de Souza [UNESP]. "Análise do fluxo sanguíneo da artéria braquial em diferentes pressões no manguito do esfigmomanômetro". Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/97138.
Texto completoO presente trabalho consiste no estudo do comportamento do fluxo sangüíneo na artéria braquial, através de sinais captados por um microfone acoplado no estetoscópio e utilizado para transformar o sinal acústico (sonoro) em elétrico, e enviá-lo para o computador. O estudo foi realizado oferecendo-se diferentes pressões no esfigmomanômetro, o qual foi adaptado com dois manômetros. Um dos manômetros, graduado em mmHg, não foi modificado, possui o selo do INMETRO e atuou como referência, ao outro foi inserido um extensômetro, que transformou o sinal de pressão em sinal elétrico, utilizando uma ponte amplificada, enviando-o para uma placa de aquisição de dados no computador. Foi traçada uma curva de calibração do sinal elétrico (em mV) com relação ao manômetro graduado em mmHg. Foi proposto um protocolo para aquisição destes sinais a serem analisados, baseado em protocolos de aferição de pressão arterial. O comportamento do fluxo sangüíneo foi comparado às diferentes pressões exercidas pelo esfigmomanômetro. Ao analisar estes dados, foram propostos limites de normalidades da intensidade do sinal do fluxo sangüíneo em diferentes freqüências nas cinco fases da escala de Koroktov. O trabalho mostrou também os limites de normalidade da pressão arterial, utilizando-se o sinal adquirido pela extensometria. Finalmente, foi oferecido mais um auxílio no diagnóstico de patologias do sistema cardiovascular.
The present work consists to study the features of blood flow in to the brachial artery through signals detected by a microphone coupled together a stethoscope. This apparatus changes the acoustics in eletric signal and, then, sends to the computer. This study was implemented exhibiting different pressures in the sphygnomanometer, where two manometers, graded in mmHg, were coulpled. One that has the INMETRO certificate of gauging instruments was not modificate and, then, it was used as the standard. In the other, an extensometer was coupled together, which through an amplifier bridge, pressure signals are transformed in electric signals and sent to a data adapter unit connected to the computer. A gauging curve for the eletric signals versus pressure signals was ploted. It was proposed a protocol to adquire these data signals, based on the protocol of brachial pressure measurement. The features of blood flow were compared at different sphygnomanometer pressures. In the analysis process of the data, normality boundaries of intensity were proposed to the blood flow signal at different frequencies in the five phases of the Koroktov scale. The work also showed the normality boundaries of brachial pressure using the data signals adquired by the extensometry process. Finally, it was provided an one more aid in to diagnose pathologies in the cardiovascular system.
Jeddy, T. A. "Changes following balloon angioplasty of the superficial femoral artery and the effect of low molecular weight heparin : assessment using colourflow doppler ultrasound". Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246086.
Texto completoSilva, Giovanio Vieira da. "Monitorização residencial da pressão arterial (MRPA) no controle da pressão arterial de pacientes em hemodiálise". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/5/5148/tde-31102008-174347/.
Texto completoINTRODUCTION: It is not known whether the adjustment of the antihypertensive therapy based on Home Blood Pressure Monitoring (HBPM) can improve blood pressure (BP) control in hemodialysis patients. OBJECTIVES: To compare the reduction in BP and in the left ventricular mass index (LVMI) obtained with the use of HBPM in relation to that achieved with predialysis BP measurements in hemodialysis patients. METHODS: Hypertensive patients on hemodialysis were randomized to have the antihypertensive therapy adjusted according two groups: control, based on the predialysis BP measurements, and intervention, based on HBPM. Before and after 06 months of follow-up, patients were submitted to Ambulatory Blood Pressure Monitoring (ABPM) for 24 hours, HBPM during one week and transthoracic echocardiogram. RESULTS: 34 and 31 patients completed the study in the intervention and control groups, respectively. The systolic (SBP) and diastolic (DBP) blood pressure in the interdialytic period by ABPM were significantly lower in the intervention group compared with the control group at the end of the study (mean 24-hours BP: 135 ± 13 mm Hg / 76 ± 7 mmHg versus 147 ± 15 mm Hg / 79 ± 8 mmHg, respectively - p <0.05). When the interdialytic BP was analysed by HBPM, the intervention group showed significant reduction only for the PAS in comparison with control group (mean weekly BP: 144 ± 21 mm Hg versus 154 ± 22 mm Hg, respectively - p <0.05). There were no differences between intervention and control groups in relation to LVMI at the end of the study (108 ± 36 g/m2 versus 110 ± 33 g/m2, respectively - p> 0.05). CONCLUSIONS: The systematic use of HBPM in the adjustment of antihypertensive therapy in patients on hemodialysis has led to better control of BP during interdialytic period compared to that achieved with the predialysis BP measurements. The HBPM can be used as a useful adjunct instrument to control blood pressure in hemodialysis patients
Crossley, Kent Westerberg. "Effect of Cuff Pressure on Blood Flow DuringBlood Flow-Restricted Rest and Exercise". BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8259.
Texto completoMiller, Mark E. "Estimation of limb occlusion pressure by adaptation of oscillometry for surgical tourniquet control". Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/29688.
Texto completoApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Chen, Silu. "Improving Algorithms for Oscillometric Blood Pressure Estimation by Suppressing Breathing Effects". Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28784.
Texto completoZakrzewski, Aaron Michael. "Multi-scale quantitative elastography and its application to blood pressure estimation". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/87919.
Texto completoCataloged from PDF version of thesis.
Includes bibliographical references (pages 113-119).
Elastography is a method that can be used to measure the elasticity of soft biological tissue and, ultimately, to detect cancerous tumors. In this thesis, quantitative compression based ultrasound elastography is developed using a fast multi-scale approach. The inverse problem optimization methods of elastography are applied to estimate noninvasively the arterial wall stiffness of a vessel as well as blood pressure. Simulation and experimental results are presented that predict the accuracy of the methods. A method is also introduced to eliminate the need for a reference pressure during the optimization over blood pressure. Using ultrasound, these techniques could provide noninvasive continuous measurement of blood pressure in major arteries and could give doctors another way to gather information about a patients cardiovascular health.
by Aaron Michael Zakrzewski.
S.M.
Carvalho, Vera Lúcia Almeida Brazão de. "Hipertensão arterial felina". Bachelor's thesis, Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária, 2009. http://hdl.handle.net/10400.5/1005.
Texto completoNos animais saudáveis a pressão arterial (PA) mantém-se dentro de um determinado intervalo de valores. Uma elevação anormal e persistente acima do limite máximo desse intervalo define-se como hipertensão sistémica, podendo determinar patologia com ou sem expressão clínica. A hipertensão sistémica é dividida em primária (ou essencial) e secundária. Apesar da hipertensão primária (sem causa subjacente) representar mais de 90% de todos os casos de hipertensão sistémica em humanos, a hipertensão secundária, com origem em determinadas doenças, representa praticamente todos os casos de elevação da PA nos animais de companhia. A insuficiência renal crónica (IRC) e o hipertiroidismo são as causas mais comuns de hipertensão felina, o que implica que os principais sintomas em gatos hipertensos sejam a poliúria/polidipsia (PU/PD), perda de peso e alterações no apetite. O aumento da PA pode ser observado nos estadios iniciais do processo de doença, contribuindo para o seu diagnóstico precoce. A medição da PA pode ser efectuada através de métodos directos (invasivos) ou indirectos (não invasivos), com recurso a aparelhos que incorporam um cuff compressivo (método Doppler e método oscilométrico), associados a diferentes níveis de confiança. Apesar do método intra-arterial ser o mais preciso na avaliação da PA, este é tecnicamente difícil e nem sempre se torna prático nos diferentes casos clínicos. A hipertensão tem efeitos adversos para o organismo, afectando sobretudo os órgãos mais vascularizados, nos quais se incluem os olhos (descolamento de retina, cegueira súbita), rins (insuficiência renal), coração (hipertrofia ventricular esquerda, sopros cardíacos, arritmias) e sistema nervoso central (depressão, letargia, convulsões). A normalização da PA e a reversibilidade das lesões orgânicas, quando possível, são os objectivos do tratamento. Este passa pelo controlo da doença primária, mas muitas vezes é necessário efectuar um tratamento adicional com medicação antihipertensiva. A amlodipina, um bloqueador dos canais de cálcio, tem sido bastante eficaz no tratamento da hipertensão felina, e a sua crescente popularidade expandiu o seu uso na área veterinária. A relutância na comunidade veterinária em adoptar a prática da medição da PA é atribuída à incerteza que envolve a definição de hipertensão, bem como a dúvidas acerca de quais os métodos indirectos fiáveis para medição da PA. Actualmente, os veterinários têm a capacidade técnica para medir a pressão sistólica (PS) e a pressão diastólica (PD) de forma não invasiva e com resultados fiáveis. Similarmente, os diversos estudos realizados permitem chegar a um consenso quanto aos valores de PA que determinam a necessidade de tratamento antihipertensivo e quais os melhores protocolos terapêuticos que visam atingir esse objectivo. Estes mais recentes desenvolvimentos justificam que o processo de medição da PA se torne parte integrante dos cuidados veterinários actuais.
ABSTRACT - In healthy animals blood pressure is maintained within a determined range of values. An abnormal and persistent increase above the upper limit of that range is defined as systemic hypertension, which can result in pathology with or without clinical significance. Systemic hypertension is divided into primary (or essential) and secondary hypertension. Although primary hypertension (without an underlying factor) accounts for more than 90% of all cases of hypertension in humans, secondary hypertension, with origin in certain diseases, accounts for almost all identified cases of elevated blood pressure in companion animals. Chronic renal failure and hyperthyroidism are the most common causes of feline hypertension, which implies that frequent symptoms in hypertensive cats may be polyuria/polydipsia, weight loss and alterations in appetite. An increase in the blood pressure can be seen in the early stages of disease process, allowing its early diagnosis. Measurement of the patient’s blood pressure can be done by direct means (invasively) or indirectly (non-invasively) by devices that incorporate a compressive cuff (Doppler and oscillometric techniques), with different confidence levels. Although measurement by an intra-arterial mean provides the most accurate measure of arterial blood pressure, this is technically difficult and is not always practical in clinical cases. Hypertension has adverse effects on the organism, mainly affecting irrigated organs, such as eyes (retinal detachment, acute onset of blindness), kidneys (renal failure), heart (left ventricular hypertrophy, systolic murmur, arrhythmias) and central nervous system (depression, lethargy, seizures). Normalization of blood pressure and reversal of existing end-organ damage, if possible, are the goals to strive for with institution of treatment. It should tempt correction of the underlying cause for the hypertension, but additional treatment with antihypertensive drugs may be necessary. Amlodipine, a calcium channel blocker, does appear to be very effective in decreasing arterial blood pressure in cats, and has gained widespread popularity that expanded its use in the veterinary clinical practice. The reluctance of veterinary community to embrace the practice of blood pressure measurement has been attributable to the uncertainty involving the definition of hypertension, as well as confusion about which indirect blood pressure measurement techniques are accurate. Actually, veterinarians have the technical capabilities to measure systolic and diastolic blood pressure non-invasively and reliably in small animal practice. Similarly, recent studies suggest a consensus about values that determine necessity of antihypertensive treatment and what are the best therapeutical protocols to achieve this goal. These recent events justify that blood pressure measurement should become an integral part of modern veterinary medical care.
Wijkman, Magnus. "Acute, ambulatory and central blood pressure measurements in diabetes". Doctoral thesis, Linköpings universitet, Internmedicin, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-75352.
Texto completoHe, Shan. "Time-interval based Blood Pressure Measurement Technique and System". Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38600.
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