This thesis work presents the analysis of Oscillometric blood pressure pulse waveform under different pressure points (Systolic, Mean Arterial, and Diastolic Pressures). Pulse waveforms' characteristics were determined from the waveforms at three different pressures and are compared for subjects at three different age groups. Estimation of blood pressure using a morphology based approach was done by using the change of pulse waveform characteristics at different pressure points. Pulse waveforms' characteristics that were obtained from pulse waveforms are utilized to estimate SBP, MAP, and DBP. The estimates obtained with pulse morphology based technique are compared with a BP measurement device and Maximum Amplitude Algorithm. Maximum slope of the pulse was also used for blood pressure estimation. The effect of movement and breathing on proposed method and MAA were compared and it was observed that breathing artifacts affect less the proposed method.

This thesis work presents the analysis of Oscillometric blood pressure pulse waveform under different pressure points (Systolic, Mean Arterial, and Diastolic Pressures). Pulse waveforms' characteristics were determined from the waveforms at three different pressures and are compared for subjects at three different age groups. Estimation of blood pressure using a morphology based approach was done by using the change of pulse waveform characteristics at different pressure points. Pulse waveforms' characteristics that were obtained from pulse waveforms are utilized to estimate SBP, MAP, and DBP. The estimates obtained with pulse morphology based technique are compared with a BP measurement device and Maximum Amplitude Algorithm. Maximum slope of the pulse was also used for blood pressure estimation. The effect of movement and breathing on proposed method and MAA were compared and it was observed that breathing artifacts affect less the proposed method.

This thesis work presents the analysis of Oscillometric blood pressure pulse waveform under different pressure points (Systolic, Mean Arterial, and Diastolic Pressures). Pulse waveforms' characteristics were determined from the waveforms at three different pressures and are compared for subjects at three different age groups. Estimation of blood pressure using a morphology based approach was done by using the change of pulse waveform characteristics at different pressure points. Pulse waveforms' characteristics that were obtained from pulse waveforms are utilized to estimate SBP, MAP, and DBP. The estimates obtained with pulse morphology based technique are compared with a BP measurement device and Maximum Amplitude Algorithm. Maximum slope of the pulse was also used for blood pressure estimation. The effect of movement and breathing on proposed method and MAA were compared and it was observed that breathing artifacts affect less the proposed method.

This thesis work presents the analysis of Oscillometric blood pressure pulse waveform under different pressure points (Systolic, Mean Arterial, and Diastolic Pressures). Pulse waveforms' characteristics were determined from the waveforms at three different pressures and are compared for subjects at three different age groups. Estimation of blood pressure using a morphology based approach was done by using the change of pulse waveform characteristics at different pressure points. Pulse waveforms' characteristics that were obtained from pulse waveforms are utilized to estimate SBP, MAP, and DBP. The estimates obtained with pulse morphology based technique are compared with a BP measurement device and Maximum Amplitude Algorithm. Maximum slope of the pulse was also used for blood pressure estimation. The effect of movement and breathing on proposed method and MAA were compared and it was observed that breathing artifacts affect less the proposed method.

The oscillometric method for blood pressure measurement has been known for over a century. It was overshadowed by the classic stethoscope and cuff method until more recently when its ease of automation became useful. It is now found in the automated blood pressure cuffs used in hospitals, doctor's offices, pharmacies, and devices sold for home use. It still challenges accurate blood pressure measurement, however, due to its difficulty in compensating for pregnancy, age, hypo-, and hypertension. Global sensitivity analysis methods were used to develop a model that focuses on the most important system parameters. The most influential biological and design parameters were identified allowing the removal or fixing of less influential parameters, and the replacement of subsystems with linear models, with minimal effect on the overall system accuracy. The developed model allows for the investigation and development of new methods for extracting parameter information from the oscillometric signals. This is illustrated by the development of a method to extract the artery's cross-sectional area from standard oscillometric output. The system design requirements for accurate measurement of blood pressure are examined and discussed with recommendations for system parameter adjustment. The model's performance and usefulness is highlighted with modelled case studies of potential real-world applications for subjects with parameters or inputs for which the oscillometric method would find it difficult to compensate. Through the use of the developed model to compensate for the system errors, the measurement error can be reduced by half. Highlighting the important system parameters allows the engineer to focus on choosing the design parameters over which she or he has control. The system model provides the ability to experiment with the cuff design choices and provides information regarding system performance under conditions that are historically difficult to measure accurately. The developed model's usefulness is illustrated by applying it to parameter extraction, and to the compensation of oscillometric blood pressure readings.

The trustworthiness of the blood pressure (BP) readings acquired by oscillometric home-based monitoring systems is a challenging issue that requires patients to see the doctor for trusted measurements, especially those who are obese or have cardiovascular diseases such as hypertension or atrial fibrillation. Even with the most accurate monitors one may get different readings if BP is repeatedly measured. Trusted BP readings are those measured with accurate devices at proper measurement conditions. The accurate monitors need an indicator to assure the trustworthiness of the measured BP. In this work, a novel algorithm called the Dynamic Threshold Algorithm (DTA) is proposed that calculates trusted boundaries of the measured systolic and diastolic pressures from the recorded oscillometric waveforms. The DTA determines a threshold from the heart rate of subjects to locate the oscillometric pulse at the mean arterial pressure (PULSEMAP) and uses the peak, trough, and pressure of the located pulse to calculate the trusted boundaries. In terms of accuracy, a modeling approach is employed to estimate BP from the arterial lumen area oscillations model in the diastolic region (ALA-based). The model requires compliance parameter ‘c’ to estimate BP. To this end, a pre-developed linear regression model between ‘c’ and the corresponding amplitude ratio of the PULSEMAP is employed to evaluate ‘c’. The proposed method uses ‘c’ and estimates BP by minimizing differences between peak and trough amplitudes of the actual and corresponding simulated waveforms. The proposed DTA and ALA-based methods were tested on two datasets of healthy subjects and one dataset of sick subjects with cardiovascular diseases, and results were validated against corresponding references and compared with two popular maximum amplitude and maximum/minimum slope algorithms. Mean absolute error (MAE) and standard deviation of errors (STDE) are used to evaluate and compare the results. For healthy subjects, the MAE of the estimated systolic (SBP) and diastolic (DBP) blood pressures was improved up to 57% and 57% with an STDE of 55% and 62%, respectively. For sick subjects, the MAE was improved up to 40% and 29% with an STDE of 36% and 20% for SBP and DBP, respectively.

Blodtrycksmätning är en viktig hälsokontroll hos vuxna. Tidigare har auskultatoriska blodtrycksmätningen varit den vanligaste metoden men på senare tid har den oscillometriska metoden ofta ersatt den auskultatoriska metoden. Blodtrycksmätning är viktigt för att upptäcka hypertoni. Blodtrycksmätningen sker i olika positioner i olika verksamheter. Syftet med denna studie är att undersöka hur liggande, sittande och stående kroppsposition påverkar blodtrycket samt jämföra auskultatorisk och oscillometrisk mätmetod. En kvantitativ studie utfördes där 50 försökspersoner mellan 18–45 års ålder undersöktes. Vid jämförelse av kroppspositionerna med oscillometrisk metod visades en statistiskt signifikant skillnad mellan alla positioner med avseende på de diastoliska värdena. Däremot förekom det endast en signifikant skillnad vid jämförelse av liggande och stående position, med avseende på de systoliska värdena. Vid den auskultatoriska mätningen visades en statistisk signifikant skillnad mellan alla positioner förutom systoliskt tryck i sittande och stående positionen med ett p-värde= 0,808. En statistisk signifikant skillnad visades mellan den oscillometriska och auskultatoriska mätmetoden i de diastoliska värdena, p-värde= <0.001. Det förekommer en statistisk signifikant skillnad mellan mätvärdena vid jämförelse av kroppspositionerna, blodtrycket ökades från liggande, sittande till stående position. Den oscillometriska mätmetoden visade ett högre medelvärde på blodtrycksmätvärdena än med den auskultatoriska metoden, förutom det diastoliska trycket i liggande position.

Les auto-tensiomètres (AT) sont parmi les dispositifs les plus utilisés en clinique et à domicile pour la mesure de la pression artérielle (PA). Ces appareils utilisent deux algorithmes heuristiques (Height-Based/HB et Slope-Based/SB) pour déterminer les pressions artérielles systoliques (PAS) et diastoliques (PAD) à partir de l'enregistrement de la pression oscillométrique dans le brassard. La mise sur le marché de ces appareils est actuellement assujettie à la directive 93/42/CE, qui nécessite une étude clinique basée sur une comparaison avec des mesures de la PA par auscultation. Cette méthode, qui consiste à détecter des sons de Korotkoff dans l'artère auscultée, présente l'inconvénient d'être praticien dépendante et engendre une incertitude sur la mesure de la PAS et de la PAD. Il est donc nécessaire de s'assurer de la fiabilité de ces instruments en proposant un dispositif expérimental de référence permettant en outre de pallier l'étude clinique qui s'avère longue et coûteuse. Cette thèse est dédiée à la mise en place de ce dispositif ou chaîne de référence, qui associe un banc d'essai permettant la validation des auto-tensiomètres et une base de données de mesure de PA. Afin de réaliser notre objectif, une étude clinique a été réalisée à l'hôpital Nord de Marseille à l'issue d'un examen de coronarographie. L'étude, réalisée sur 115 patients, compare des mesures de pression invasives (mesures de référence) à des mesures de pression non-invasives : des mesures auscultatoires, des mesures via un auto-tensiomètre commercial et des mesures oscillométriques. Ces dernières ont été réalisées concomitamment avec la PA invasive. / Automated blood pressure (ABP) devices are among the most commonly used devices for diagnosis arterial blood pressure (BP) for clinical and home use. These devices use two heuristic algorithms (Height-Based/HB and Slope-Based/SB) to determine the systolic blood pressure (SBP) and the diastolic blood pressure (DBP) from the recording of an oscillometric pressure signal collected using an inflatable cuff. Currently ABP are in the scope of Directive 93/42/CE, which requires a clinical study based on a comparison of BP measurements using auscultatory method. Unfortunately auscultatory measurements have the disadvantage of the uncertainties related to perception of Korotkoff sounds, leading to an uncertainty of measuring SBP and DBP. Therefore it is necessary to ensure the reliability of these instruments and to propose an experimental reference chain to validate ABP devices without returning to expensive and long clinical campaign. The purpose of this thesis is to create and develop a calibration chain for measuring arterial BP, which is composed of database of arterial BP measurements and a patient simulator for regenerating oscillometric measurements. To achieve our target, a clinical study was conducted at the northern hospital of Marseille (l'hôpital Nord) after a coronary exam. The clinical study of 115 patients compares invasive blood pressure measurements (reference measurements) and non-invasive blood pressure measurements: auscultatory measurements, measurements using a commercial automated blood pressure device and oscillometric measurements. The latter were carried out simultaneously with the invasive BP measurements.

La mesure de l’index de pression systolique de cheville (IPSC) constitue un outil simple et non invasif pour détecter les atteintes artérielles des membres inférieurs. Si la méthodologie et l’interprétation de cet index ont été standardisées, il demeure des divergences quant à certains aspects de sa mesure. Ainsi, les travaux de recherche menés ont investigué trois de ces aspects. Dans un premier temps, l’objectif était d’étudier l’évolution physiologique de l’IPSC avec l’avancée en âge au sein d’une population saine et physiquement active. Cette analyse a rapporté une relation positive entre l’IPSC et l’âge, tendance « logique » au regard des modifications structurales de l’artère avec la sénescence. Dans un deuxième temps, les investigations se sont orientées vers l’utilisation d’outils de mesures automatiques de la pression artérielle pour le calcul de l’IPSC en récupération d’un exercice physique. Nous avons mis en évidence que l’outil oscillométrique permettait d’obtenir une valeur d’IPSC post-effort plus rapide mais aussi de diminuer l’erreur standard de mesure. Dans un troisième temps, nous avons abordé les stratégies d’apprentissage de cette mesure vasculaire. La mesure de pression systolique de cheville (PASC) apparaît largement sous-enseignée comparativement à la mesure brachiale. L’objectif était d’étudier objectivement, via simulateur, l’effet d’une intervention pédagogique pratique supplémentaire sur la compétence d’étudiants novices à mesurer cette PASC. Un apprentissage pratique d’une heure permettait de diminuer l’erreur de mesure mais n’était pas suffisante pour harmoniser l’ensemble des paramètres de la mesure selon les standards de mesure existants. / The measurement of ankle to brachial pressure index (ABPI) is a simple and non-invasive diagnostic tool for detecting arterial involvement of the lower limbs. If the methodology and interpretation of this index have been standardized, there remain some discrepancies about some aspects of its measurement. Thus, the present thesis reports the investigations of three of these aspects. First, the objective was to study the physiological relationship between ABPI and age among healthy and physically active subjects. The results show a positive relationship. This trend is consistent with structural modifications of arterial wall with ageing. Second, our aim was to investigate the use of automatic blood pressure measurement tools for the calculation of ABPI during the recovery of a maximal physical exercise. We found that the use of anoscillometric blood pressure device allowed to obtain a faster postexercise ABPI faster than a manual recording and also to reduce the standard error of the measurement. Finally, we discussed the learning strategies of this peripheral vascular measurement. Indeed, it appears that the measurement of arterial systolic blood pressure at the ankle (ASBPa) is largely under-taught compared to the humeral measurement. The purpose was to objectively assess, by a simulator, the effect of an additional practical and pedagogical intervention on the ability of novice students to perform ASBP a measurement. The results suggest that a one-hour practical learning allows to significantly reduce the measurement error but is not sufficient to harmonize all of the measurement parameters according to the measurement standards.

In my master's tehsis I'm dealin with the methods used for non-invasive blood pressure measurement. For realization of a virtual blood pressure meter in LabVEW I have chosen the oscillometric method. Algorithm determining systolic and diastolic blood pressure is based on the relatively easy detection of maximum amplitude oscillations (corresponds with a mean arterial pressure), when thelimiting valuesof blood pressure are in a specific ratio with a maximum amplitude of oscillation. In LabVIEW was solved loading of signal from the measure card and processing pressure curve into a form suitable for the detection of the peak oscillations. The program calculates the limits of arterial pressure and mean heart rate too. Linking the virtual device with the blood pressure sensor Vernier BPS-BTA then makes up komplex for capturing the blood pressure via oscillatory method.