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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.
271

A Comparison of Biofeedback and Cognitive Therapy in the Control of Blood Pressure Under Stress and No-Stress Conditions

Dafter, Roger E. (Roger Edwin) 08 1900 (has links)
This study evaluated the efficacy of cognitive therapy and biofeedback training in lowering Dlood pressures of normotensives under no-stress and stress conditions. A cognitive therapy group was compared to biofeedback and habituation control groups with 32 normotensives. Subjects were taught to use the electronic sphygmomanometer that served as the device to measure blood pressure during pretreatment and posttreatment phases of the study. These measurement phases each consisted of three 19 minute periods. Trie first period consisted of no-stress, and then a stress period followed. Return-to-no-stress was the final period. Subjects in the cognitive therapy and biofeedbacK groups received five sessions of self-control training of 66 minutes each between the pre- and posttreatment phases. The cold pressor was the analogue stressor used to induce bxood pressure elevations,
272

What Explains Variability in Blood Pressure Readings? Multilevel Analysis of Data from 8,731 Older Adults in 20 Ontario Communities

O'Rielly, Susan January 2011 (has links)
Title: What explains variability in blood pressure readings? Multilevel analysis of data from 8,731 older adults in 20 Ontario Communities Objectives: Despite universal healthcare and drug coverage for adults aged 65 and over in Ontario, hypertension, a treatable condition, remains uncontrolled among many older adults. Moreover, there are geographic disparities in blood pressure and hypertension within and across Canadian provinces and territories. Using baseline data collected on 8,731 older adults participating in the Cardiovascular Health Awareness Program (CHAP) in 20 randomly selected Ontario communities, we investigated associations between systolic blood pressure (SBP) and individual- and community-level characteristics, controlling for self-reported use of blood pressure medications. Method: Older adults were recruited via invitation by local family physicians, public advertising and word of mouth to attend community pharmacy sessions. During the sessions, trained older adult volunteers assisted participants to complete a cardiovascular disease risk factor questionnaire and blood pressure assessments using an automated blood pressure measuring device. The Postal Code Conversion File Plus was used to confirm residence within one of the 20 study communities. A multilevel linear regression analysis with participants nested within communities was used to determine which individual- and/or community-level characteristics were associated with measured systolic blood pressure level controlling for self-reported use of blood pressure medication. Results: 4,706 participants (53.9%) reported the use of blood pressure medication. Mean systolic blood pressure (SBP) levels varied among the 20 communities from 128.1 mmHg to 134.7 mmHg for participants not using blood pressure medication and from 131.9 mmHg to 139.0 mmHg for participants using blood pressure medication. The intraclass correlation coefficients were very small: less than 0.2% of the total variance was between communities. Among participants not using blood pressure medication, SBP was associated with the following individual- level characteristics: age, sex, body mass index , smoking, physical activity, stress, fruit/vegetable intake, and alcohol consumption and the following community-level characteristics: community size, community growth and the Rurality Index. Among participants using blood pressure medication, SBP was associated with the following individual-level characteristics: age, sex, body mass index, diabetes, fruit/vegetable intake, alcohol intake and one community-level characteristic: community size. The significance and magnitude of these associations were modified by the use of blood pressure medication. Conclusion: The majority of the variability in blood pressure occurs at the individual-level. There are specific individual- and community-level factors that explain variability in blood pressure readings among communities. These results can be used to inform health promotion strategies to decrease mean levels of blood pressure among older adults.
273

Blood Pressure Regulation During Simulated Orthostatism Prior to and Following Endurance Exercise Training

Stevens, Glen Harold John 05 1900 (has links)
Cardiovascular responses and tolerance to an orthostatic stress were examined in eight men before and after eight months of endurance exercise training. Following training, maximal oxygen consumption and blood volume were increased, and resting heart rate reduced. Orthostatic tolerance was reduced following training in all eight subjects. It was concluded that prolonged endurance training decreased orthostatic tolerance and this decrease in tolerance appeared associated with attenuated baroreflex sensitivity and alterations in autonomic balance secondary to an increased parasympathetic tone noted with training.
274

Establishing the minimal sufficient number of measurements to validate a 24h blood pressure recording

Agarwal, Rajiv 17 May 2018 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Background: Ambulatory blood pressure (BP) monitoring (ABPM) remains a reference standard but the number of readings required to make the measurement valid has not been empirically validated. Methods: Among 360 patients with chronic kidney disease and 38 healthy controls, BP was recorded 2 per hour during the night and 3 per hour during the day over 24h using a validated ABPM device; all had at least 90% of the expected readings. From this full set of ABPM recording, a variable number of BP measurements were selected and we compared the performance of the selected readings against that of the full sample using random or sequential selection schemes. To address the question whether random or sequential selection schemes affect the diagnostic performance in diagnosing hypertension control we compared the diagnostic decisions reached with the subsample and the full sample using area under the receiver operating-characteristic curves (AUC ROC). To answer the question regarding the number of readings needed to achieve over 90% coverage of the mean BP of the full ABPM sample we ascertained the point and confidence interval (CI) estimates based on the selected data. Results: To diagnose hypertension control, the number of readings randomly drawn to establish lower bound with 2.5% error of area under the receiver operating-characteristic curve (AUC ROC) of 0.9 was 3, 0.95 was 7, and 0.975 was 13 . In contrast, the corresponding number of readings with serial selections was 18, 30 and 39 respectively. With a random selection scheme, 18 readings provided 80% coverage of the 90th percentile of CI of the true systolic BP mean, for 90% coverage, 26 readings were needed, for 95% coverage 33. With serial selections, the number of readings increased to 42, 47, and 50 respectively. Similar results emerged for diastolic BP. Conclusions: For diagnosing hypertension control 3 random measurements or 18 serial measurements is sufficient. For quantitative analysis, the minimal sufficient number of 24h ambulatory BP is 26 random recordings or 42 serial recordings.
275

Health Care Provider Perceptions of High Blood Pressure Screening for Asymptomatic African American Teens

Braxton, Juanita 01 January 2016 (has links)
Health care provider perceptions of typical practices play a significant role in evaluating the efficacy of screening and diagnosis of teen high blood pressure in African Americans. African American adults are more likely to develop high blood pressure than are any other ethnic group; however, there is a gap in the literature concerning high blood pressure in teens. Approximately 1 to 5 of every 100 children has high blood pressure. This purpose of this phenomenological study was to explore the perspectives of health care providers on high blood pressure screening and diagnosis of African American asymptomatic teens. The health belief model (HBM) was the conceptual framework used to describe how beliefs and attitudes influence provider high blood pressure screening. Purposive sampling resulted in 9 health care providers (8 pediatricians and 1family medicine physician), who completed a hypertension survey and individual interview. Data were coded and analyzed using thematic analysis. Atlas.ti was used for data management. Theoretical saturation was reached after 9 interviews. Emergent themes included observations from the participants that the absence of initial standardized high blood pressure screening for teens is a significant problem and that age-appropriate high blood pressure resources are not used consistently. Study results contribute to social change by providing an opportunity for heightened awareness and education among health care providers in teen high blood pressure screening and diagnosis processing. Ongoing education and research may engender proactive steps to develop universal guidelines, tools and practices to consistently and accurately detect high blood pressure in teens.
276

Biofeedback Treatment of Systolic and Diastolic Blood Pressure Under Stress and No-Stress Conditions

Dafter, Roger E. (Roger Edwin) 05 1900 (has links)
This study compares the relative efficacy of systolic and diastolic biofeedback in lowering the systolic and diastolic blood pressures of normotensives. The importance of testing these biofeedback procedures lies in assessment of their potential as blood pressure self-control techniques for the treatment of essential hypertension.
277

The Effect of a 18-Week Supervised Exercise Program on Changes in Weight and Health Status in Overweight Individuals: The Healthy Weight Beginner and Intermediate Program

Pholi, Kuda Nozibelo Grace 14 April 2023 (has links) (PDF)
Background: According to the South African National Health and Nutrition Examination Survey, approximately 69% of South African women and 29% of men are considered overweight/obese. In South Africa, overweight and obesity rates are on the rise and have reached epidemic proportions. Several conventional weight loss strategies have been employed and have been unsuccessful in addressing this issue. It is for this reason that this study strives to uncover if any improvement in weight and fitness status are associated with an improvement in health status. Methods: One of our main aims were to determine the success in weight loss and reduction in health risk factors in members who have completed 18-weeks of the Healthy weight programme. Therefore, this study is a retrospective, observational study of adults with a mean body mass index (BMI) of 32.63 ± 7.39 who completed an 18-week supervised exercise program. An online health questionnaire was completed followed by pre- intervention assessments which included: Anthropometric measures (height, weight, waist circumference, body fat percentage) followed by blood pressure, finger-prick random glucose and cholesterol measurements. A 12-min motion test to assess functional capacity were completed. All anthropometric, resting health measures and fitness tests were repeated at 12-weeks (post-beginner programme) and 18 weeks (post-intervention) after the start of the intervention. The intervention included 2 weekly classes with an optional gym class. The type of exercise intervention that was included in this study largely focused resistance training and cardiorespiratory fitness which targeted multiple large muscle groups. Each exercise session included 80 to 90 % exercise intensity as well as lumbopelvic core exercises. The data set was analysed as an intention to treat (ITT) protocol as some of the testing time points were missing. Results: Out of a possible 50 participants, 34 met the inclusion criteria of at least all 3 health measures taken on the 3 different occasions (baseline, post-beginner, postintervention). The 34 participants had a mean age of 47.26 ± 10.44 ranging between 24 years and 76 years old. 65 % of the participants were female. Anthropometric results showed significant changes in weight and waist circumference at 12- and at 18-weeks compared to baseline measures (p < 0.005). Additionally, body fat % significantly reduced at 12-weeks but increased slightly at 18 weeks diminishing the significant reduction compared to the baseline measure. In terms of fitness, participants succeeded in improving their average distance to complete a 12-min motion test by 14.5% (p < 0.001) at 12-weeks and 20% (p < 0.001) at 18-weeks compared to starting measures, respectively. After adjusting for multiple comparisons during post-hoc analysis, none of the health status outcomes (blood pressure, random glucose, random cholesterol) showed a significant improvement at any of the time points. In terms of associations, a change in body fat % could significantly explain some of the variance in the change (from baseline to 18-weeks) in cholesterol; and a change in weight could significantly explain some of the variance in the change in glucose over the same intervention time. Conclusion: The results of this study revealed the 18-week supervised exercise intervention led to a modest reduction (approximately 5%) in weight and a substantial improvement in fitness. However, no changes in health status were observed, suggesting that greater improvements in weight and fitness may be required to have a profound influence on health status.
278

Cuffless Blood Pressure Estimation Using Cardiovascular Dynamics

Samimi, Hamed 06 July 2023 (has links)
Blood pressure (BP) monitoring is an important tool for management of hypertension, which is a significant risk for cardiovascular disease and premature death. Since cuff-based BP measurement can be uncomfortable and does not provide continuous readings, several cuffless methods that are typically based on within-beat information or on the pulse transit time (PTT) have recently been investigated. This work proposes a novel cuffless BP estimation approach that mainly uses the information from cardiovascular dynamics of photoplethysmogram (PPG) waveforms. This work is divided into three parts. The first part proposes a calibration-free approach that uses dynamic changes in the pulse waveform. Results from 200 patients showed that the method achieved grade B, in terms of accuracy, for diastolic blood pressure (DBP) based on the British Hypertension Society (BHS) standard and complied with the accuracy requirements of the Association for Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) standard. The second part presents a method based on calibrated cardiovascular dynamics, achieved through a mathematical model that relates reflective PTT (R-PTT) to BP. Results from 30 patients showed a mean error (ME) of 0.58 mmHg, standard deviation of the error (SDE) of 8.13 mmHg, and a mean absolute error (MAE) of 4.93 mmHg for DBP and an ME of 2.52 mmHg, SDE of 12.28 mmHg, and an MAE of 8.82 mmHg for systolic blood pressure (SBP). The third part proposes a calibration-free method that combines morphology features and dynamic changes of the pulse waveform over short intervals. In this method a neural network was trained on 200 patients and tested on never-seen data from 25 other patients and provided an ME of -0.31 mmHg, SDE of 4.89 mmHg, and MAE of 3.32 mmHg for DBP and an ME of -4.02 mmHg, SDE of 10.40 mmHg, and MAE of 7.41 mmHg for SBP. Overall, the results show that cardiovascular dynamics may contribute useful information for cuffless estimation of BP.
279

Avaliação do comportamento da pressão arterial em pacientes transplantados renais através de três métodos de mensuração / Evaluation of the blood pressure im kidney transplantation using three methods of measurement

Fabiana Agena 17 January 2011 (has links)
A hipertensão arterial apresenta alta prevalência entre os receptores de transplante renal sendo considerada um fator de risco cardiovascular importante influenciando na sobrevida do paciente e do enxerto. O objetivo principal deste estudo foi comparar se o controle da pressão arterial nos pacientes transplantados renais por meio da utilização de monitorização residencial da pressão arterial é mais comparável ao resultado da monitorização ambulatorial da pressão arterial quando comparada à medida da pressão arterial de consultório. No período de março de 2008 a abril de 2009, foram avaliados prospectivamente 183 pacientes transplantados renais, com tempo de transplante de 1 a 10 anos. Os pacientes foram submetidos a três métodos de medida de pressão arterial (PA): medida de pressão arterial em consultório, monitorização residencial da pressão arterial (MRPA), e monitorização ambulatorial da pressão arterial (MAPA). Foram avaliados 183 pacientes, dentre eles 94 eram homens (54 %) e 89 mulheres (46 %). A idade média foi de 50 ± 11 anos. O tempo de transplante médio foi de 57 ± 32 meses. Noventa e nove pacientes receberam enxertos de doadores falecidos (54 %) e 84 foram receptores de doadores vivos (46 %). Quando avaliados usando a medida de PA obtida em consultório, 56,3% apresentavam-se PA elevada e 43,7% com PA normal com média de 138,9/82,3 ± 17,8/12,1mmHg. Entretanto, quando avaliados pela MRPA, 55,2% dos indivíduos apresentavam-se PA normal e 44,8 % apresentavam-se PA elevada com média de 131,1/78,5 ± 17,4/8,9. Utilizando a MAPA observamos que 63,9 % dos indivíduos apresentavam-se PA normal e 36,1 % dos indivíduos apresentavam-se PA elevada com média de 128,8/80,5 ± 12,5/8,1. Verifica-se que os dois métodos (Consultório e MRPA) tem concordância significativa com a MAPA, mas a MRPA tem uma concordância maior que a medida de Consultório, comprovado pelo teste Exato de Fisher, com valor descritivo de 0,026. Pelo teste de McNemar, verificamos que não há simetria nos dados nos dois métodos (MRPA e Consultório). Os índices de correlação linear de Pearson dos métodos, comparadas a MAPA, foram de 0,494 para medida de consultório e de 0,768 para MRPA, com a MRPA com melhor correlação com a MAPA. Comparando os erros dos dois métodos pelo teste t pareado, obteve-se o nível descritivo de 0,837, pelo qual concluí-se que o erro médio da PA de Consultório é igual ao do MRPA. Analisando a curva ROC para as medidas de PA em cada método, observa-se que a PA em consultório apresenta-se áreas sob a curva mais baixas que as obtidas pela MRPA em relação a MAPA. Concluí-se que os resultados pressóricos obtidos com a MRPA são mais comparáveis aos resultados obtidos pela MAPA em relação àqueles obtidos pela medida de consultório, sendo factível sua realização em um hospital publico / Hypertension is highly prevalent among kidney transplantation recipients and considered an important cardiovascular risk factor influencing patient survival and kidney graft survival. The aim of this study were to compare the blood pressure (BP) control in kidney transplant patients through the use of home blood pressure monitoring is more comparable with the results of ambulatory blood pressure monitoring compared to the measurement of office blood pressure. From March 2008 to April 2009 prospectively we were evaluated 183 kidney transplant recipients with time after transplantation 1 - 10 years. Patients underwent three methods for measuring blood pressure: office blood pressure measurement (OM), home blood pressure monitoring (HBPM) and ambulatory blood pressure monitoring (ABPM). We evaluated 183 patients, among them 94 men (54%) and 89 women (46%). The average age was 50 ± 11 years. The average time of transplant was 57 ± 32 months. Ninety-nine patients received grafts from deceased donors (54%) and 84 were recipients of living donors (46%). When assessed using OM, 56.3% presented with uncontrolled and 43.7% with adequate control of BP with an average of 138.9 / 82.3 ± 17.8 / 12.1 mmHg. However, when measured by HBPM, 55.2% of subjects were controlled and 44.8% presented with uncontrolled BP with an average of 131.1 / 78.5 ± 17.4 / 8.9 mmHg. Using the ABPM we observed that 63.9% of subjects had was controlled and 36.1% of patients presented uncontrolled BP with an average 128.8 / 80.5 ± 12.5 / 8.1.mmHg We found that the two methods (OM and HBPM) has a significant agreement, but the HBPM has a higher agreement than OM, confirmed by Fisher exact test, with descriptive value of 0.026.We found that there is no symmetry in the data for both methods with McNemar test. Person´s correlation for the ABPM with the other two methods were 0.494 for office measurement and 0.768 for HBPM, best value of HBPM with ABPM. Comparing the errors of the two methods by paired t-test, we obtained the descriptive level of 0.837, we conclude that the average error is equal to OM of HBPM. Looking at the ROC curve for BP measurements in each method, we observed that BP in practice presents lower than those obtained by HBPM in relation to ABPM. We conclude that the results obtained with HBPM were closer to the ABPM results than those obtained with blood pressure obtained at OM
280

Avaliação do comportamento da pressão arterial em pacientes transplantados renais através de três métodos de mensuração / Evaluation of the blood pressure im kidney transplantation using three methods of measurement

Agena, Fabiana 17 January 2011 (has links)
A hipertensão arterial apresenta alta prevalência entre os receptores de transplante renal sendo considerada um fator de risco cardiovascular importante influenciando na sobrevida do paciente e do enxerto. O objetivo principal deste estudo foi comparar se o controle da pressão arterial nos pacientes transplantados renais por meio da utilização de monitorização residencial da pressão arterial é mais comparável ao resultado da monitorização ambulatorial da pressão arterial quando comparada à medida da pressão arterial de consultório. No período de março de 2008 a abril de 2009, foram avaliados prospectivamente 183 pacientes transplantados renais, com tempo de transplante de 1 a 10 anos. Os pacientes foram submetidos a três métodos de medida de pressão arterial (PA): medida de pressão arterial em consultório, monitorização residencial da pressão arterial (MRPA), e monitorização ambulatorial da pressão arterial (MAPA). Foram avaliados 183 pacientes, dentre eles 94 eram homens (54 %) e 89 mulheres (46 %). A idade média foi de 50 ± 11 anos. O tempo de transplante médio foi de 57 ± 32 meses. Noventa e nove pacientes receberam enxertos de doadores falecidos (54 %) e 84 foram receptores de doadores vivos (46 %). Quando avaliados usando a medida de PA obtida em consultório, 56,3% apresentavam-se PA elevada e 43,7% com PA normal com média de 138,9/82,3 ± 17,8/12,1mmHg. Entretanto, quando avaliados pela MRPA, 55,2% dos indivíduos apresentavam-se PA normal e 44,8 % apresentavam-se PA elevada com média de 131,1/78,5 ± 17,4/8,9. Utilizando a MAPA observamos que 63,9 % dos indivíduos apresentavam-se PA normal e 36,1 % dos indivíduos apresentavam-se PA elevada com média de 128,8/80,5 ± 12,5/8,1. Verifica-se que os dois métodos (Consultório e MRPA) tem concordância significativa com a MAPA, mas a MRPA tem uma concordância maior que a medida de Consultório, comprovado pelo teste Exato de Fisher, com valor descritivo de 0,026. Pelo teste de McNemar, verificamos que não há simetria nos dados nos dois métodos (MRPA e Consultório). Os índices de correlação linear de Pearson dos métodos, comparadas a MAPA, foram de 0,494 para medida de consultório e de 0,768 para MRPA, com a MRPA com melhor correlação com a MAPA. Comparando os erros dos dois métodos pelo teste t pareado, obteve-se o nível descritivo de 0,837, pelo qual concluí-se que o erro médio da PA de Consultório é igual ao do MRPA. Analisando a curva ROC para as medidas de PA em cada método, observa-se que a PA em consultório apresenta-se áreas sob a curva mais baixas que as obtidas pela MRPA em relação a MAPA. Concluí-se que os resultados pressóricos obtidos com a MRPA são mais comparáveis aos resultados obtidos pela MAPA em relação àqueles obtidos pela medida de consultório, sendo factível sua realização em um hospital publico / Hypertension is highly prevalent among kidney transplantation recipients and considered an important cardiovascular risk factor influencing patient survival and kidney graft survival. The aim of this study were to compare the blood pressure (BP) control in kidney transplant patients through the use of home blood pressure monitoring is more comparable with the results of ambulatory blood pressure monitoring compared to the measurement of office blood pressure. From March 2008 to April 2009 prospectively we were evaluated 183 kidney transplant recipients with time after transplantation 1 - 10 years. Patients underwent three methods for measuring blood pressure: office blood pressure measurement (OM), home blood pressure monitoring (HBPM) and ambulatory blood pressure monitoring (ABPM). We evaluated 183 patients, among them 94 men (54%) and 89 women (46%). The average age was 50 ± 11 years. The average time of transplant was 57 ± 32 months. Ninety-nine patients received grafts from deceased donors (54%) and 84 were recipients of living donors (46%). When assessed using OM, 56.3% presented with uncontrolled and 43.7% with adequate control of BP with an average of 138.9 / 82.3 ± 17.8 / 12.1 mmHg. However, when measured by HBPM, 55.2% of subjects were controlled and 44.8% presented with uncontrolled BP with an average of 131.1 / 78.5 ± 17.4 / 8.9 mmHg. Using the ABPM we observed that 63.9% of subjects had was controlled and 36.1% of patients presented uncontrolled BP with an average 128.8 / 80.5 ± 12.5 / 8.1.mmHg We found that the two methods (OM and HBPM) has a significant agreement, but the HBPM has a higher agreement than OM, confirmed by Fisher exact test, with descriptive value of 0.026.We found that there is no symmetry in the data for both methods with McNemar test. Person´s correlation for the ABPM with the other two methods were 0.494 for office measurement and 0.768 for HBPM, best value of HBPM with ABPM. Comparing the errors of the two methods by paired t-test, we obtained the descriptive level of 0.837, we conclude that the average error is equal to OM of HBPM. Looking at the ROC curve for BP measurements in each method, we observed that BP in practice presents lower than those obtained by HBPM in relation to ABPM. We conclude that the results obtained with HBPM were closer to the ABPM results than those obtained with blood pressure obtained at OM

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